-
Contents
Introduction VIII 1 Battery Chargers and Zappers 1 2 Power
Supplies-Fixed 23 3 Power Supplies- High Voltage 84 4 Power
Supplies- Variable 101 5 Power Supply Monitors 112 6 Power Supply
Protection Circuits 119
Sources 125 Index 129
-
1
Battery Chargers and Zappers
The sources of the following circuits are contained in the
Sources section, which begins on page 125. The figure number in the
box of each circuit correlates to the source entry in the Sources
section.
Lead-Acid Battery Charger 12-V Battery Charger 200-mA-hour 12-V
NiCad Battery Charger NiCad Charger with Current and Voltage
Limiting 14-V 4-A Battery Charger/Power Supply Fast Charger for
NiCad Batteries Current-Limited 6-V Charger NiCad Charger Simple
NiCad Battery Zapper Battery Charger Automatic Shutoff Battery
Charger Battery-Charging Regulator 12-V Battery-Charger Control (20
rms Max.) Battery Charger Universal Battery Charger Lead-Acid
Low-Battery Detector
Universal Battery Charger UJT Battery Charger Automotive Charger
for NiCad Battery Packs Constant-Voltage Current-Limited Charger
Versatile Battery Charger Gel-Cell Charger NiCad Battery Zapper PUT
Battery Charger Thennally Controlled NiCad Charger NiCad Battery
Zapper ll Portable NiCad Battery Charger Lithium Battery Charger
Rapid Battery Charger for Icom IC-2A Battery Charger Operates on
Single Solar Cell Wmd-Powered Battery Charger
1
-
v,..
100 ,.F :
.....
-
EDN
+ ::
t... tN400t ~
REGULATOR V'" VOUT
ADJ
-dmA AI 2k
: 2.7k
L Sk 12V R,
...
LM R 33.
33 -
Rs
LEAD-ACID BATTERY CHARGER
eA
A~ 1e} v A, 3.3 0 .1
220
A, 1k
1k LED 1 ~~CHAAG
6V ~ 4.7k 7 1.8k loo' ~ 2 4.7k -1..,..1\ 6 LM301A
1.5k R, .... V ir--. 3 ".. / 2N3906 1.8k Ill 'Jir.. +
tOO R4 100pF 4 8PIN DIP
LED ' ~ ::;:FLOAT
VOUT
+
LEAD-ACID --BATTERY --r
3 or 6 CELLS
(6 or t 2V)
Fig. 11
This circuit furnishes an initial voltage of 2.5 V per cell at
25C to rapidly charge a battery. The charg-ing current decreases as
the battery charges, and when the current drops to 180 mA, the
charging circuit reduces the output voltage to 2.35 V per cell,
leaving the battery in a fully charged state. This lower volt-age
prevents the battery from overcharging, which would shorten its
life.
The LM301A compares the voltage drop across Rl with an 18 m V
reference set by R2 . The compara-tor's output controls the voltage
regulator, forcing it to produce the lower .float voltage when the
battery-charging current, passing through RI. drops below 180 mA.
The 150 m V difference between the charge and float voltages is set
by the ratio of R3 to R4. The LEOs show the state of the
circuit.
Temperature compensation helps prevent overcharging,
particularly when a battery undergoes wide temperature changes
while bemg charged. The LM334 temperature sensor should be placed
near or on the battery to decrease the charging voltage by 4 mV/C
for each cell . Because batteries need more tem-perature
compensation at lower temperatures, change R5 to 30 n for a tc of -
5 m V /C per cell if applica-tion will see temperatures below -
20C.
The charger's input voltage must be filtered de that is at least
3 V higher than the maximum required output voltage: approximately
2.5 V per cell. Choose a regulator for the maximum current needed:
LM371 for 2 A, LM350 for 4 A, or LM338 for 8 A. At 25C and with no
output load, adjust R7 for a V ouT of 7.05 V, and adjust R8 for a
Vour of 14.1 V.
2
-
12-V BATTERY CHARGER
500 ............
'.,.,.
_ .... LMJ50
LED ry" : > R2 )>15 :J ~
: : 11> R5 1J> Rl .. 111 11> ZlO ~
~ > R4 4 >m Q1"a
ZNZHfi ~ 1 N41il
1
~ ~ ~ R1 .. ~311 ~ +
0.111F l 11F ,
"'
START4
T --
NATIONAL SEMICONDUCTOR
R& 02
......... .,..,..,
V+ 3 l LMJ01A
~ ~ 2 -
1000 ,F
-
""' +
-
TO 12V BATTERY
Fig. 1-2
This circuit is a high-performance charger for geUed-electrolyte
lead-acid batteries. This charger quickly recharges the battery and
shuts off at full charge. Initially, charging current is limited to
2 A. As the battery voltage rises, current to the battery
decreases, and when the current has decreased to 150 mA, the
charger switches to a lower float voltage, which prevents
overcharge. When the start switch is pushed, the output of the
charger goes to 14.5 V. As the battery approaches fuiJ charge, the
charging current decreases and the output voltage is reduced from
14.5 V to about 12.5 V, terminating the charging. Tran-sistor Q1
then lights the LED as a visual indication of full charge .
3
-
200-mA/HOUR, 12-V NICAD BATTERY CHARGER
,.
HAM RADIO
2 H221t .. I H 4 00t ~_...,,..,._____,. __ ---+ SAT T/IY
I H 752
2 N2 212
TO 11 r -CHAIIG0 2 t
Fig. 1-3
This circuit charges the battery at 75 rnA until the battery is
charged, then it reduces the current to a trickle rate. It will
completely recharge a dead battery in four hours and the battery
can be left in the charger indefinitely. To set the shut-off point,
connect a 270-0 , 2-W resistor across the charge tenninals and
adjust the pot for 15.5 V across the resistor.
NICAD CHARGER WITH CURRENT AND VOLTAGE LIMITING
CI470~F OR GRE ATER
...----, CIG LGHR PLUG
73 AMATEUR RADIO
+
+
+
Ll 6 OR 12V LAMP
12-15VOC
01 +
Fig. 1-4
Lamp Ll will glow brightly and the LED will be out when the
battery is low and being charged, but the LED will be bright and
the light dim when the battery is almost ready. Ll should be a bulb
that is rated for the current you want (usually the battery
capacity divided by 10). Diode Dl should be at least 1 A, and Zl is
a 1-W zener diode with a voltage detennined by the full-charge
battery voltage minus 1.5 V. After the battery is fully charged,
the circuit will float it at about battery capacity divided by 100
mA.
4
-
SILICONIX
14-V 4-A BATTERY CHARGER/POWER SUPPLY
110 VAC-HVCT
o, 1N~2
c , so ,.F I
SOV
--
1N241
--
1N241
c2 IOOO~F I --
VNMGA
SI 0
7SOpF
150kll
CA3140 OR LM324
.150, 2w
2NUOO
110 0
--
1011.0
10110
--
1N4100
--
Ffg. 1-5
Operational amplifier Al directly drives the VN64GA with the
error signal to control the output volt-age. Peak rectifier 01 , Cl
supplies error amplifier Al and the reference zener. This extra
drive voltage must exceed its source voltage by several volts for
the VN64GA to pass full load current. The output volt-age is
pulsating de, which is quite satisfactory for battery charging. To
convert the system to a regulated de supply, capacitor C2 is
increased and another electrolytic capacitor is added across the
load. The response time is very fast, determined by the op amp. The
2N4400 current-limiter circuit prevents the output cur-rent from
exceeding 4.5 A. However, maintaining a shorted condition for more
than one second will cause the VN64GA to exceed its temperature
ratings. A generous heatsink, on the order of 1 CIW, must be
used.
5
-
6
FAST CHARGER FOR NICAD BATTERIES
+V--------4~----------e-------~--------~--------------~~----~
1&V
101t 10k Sk
10k 2 INPUT
\ 6 AOJ 20k 02
LM335 3
\ \
10k \
THERMAllY COUPLE '-- - -
Adjust 01 to 50 mV greater Vz than 02. Charge terminates on 5 C
temperature rise . Couple 02 to battery . NATIONAL
SEMICONDUCTOR
CURRENT-LIMITED 6-V CHARGER LM317L
V1N V V 9V TO JOV ~ ~ IN OUTI----4~-----. AOJ
+ I 000 ,u F *
~-.......... 100
.. ~240
~ 1 lk ~
-
--
2N2222 1-'V .... \1""1\r .. ------~ /lt" .... ~ ~RI :>w
----4 ---~t-----' * Sets peak c urren l. I PEAK = 0 6Vi R 1
1000 ,,F IS recommended to filt er out an y 1nput t
rans1ents
NATIONAL SEMICONDUCTOR Fig. 1-7
LMJ11
OUT
10k 1.2
--
--
200
Fig. 1-6
-
I I I I I I I I I I 1 SW1b
~o-----....1 OV ELECTRONICS TODAY INTERNATIONAL
NICAD CHARGER
SW2
LED2
SW3
SERIES CELL
SINGLE '"""':!T~ CELL I
-Ye
I I I
PARALLEl CELLS
Fig. 1-8
This circuit uses constant current LEDs to adjust charging
current. It uses LEDs that pass a constant current of about 15 rnA
for an applied voltage range of 2 to 18 V. They can be paralleled
to give any multiple of 15 mA and they light up when current is
flowing. The circuit will charge a single cell at 15, 30, or 45 mA,
or cells in series up to the rated supply voltage limit (about 14
V).
SIMPLE NICAD BATTERY ZAPPER
COMPONENTS NOT CRITICAL
73 AMATEUR RADIO
10A
DOORBELL OR + FIL XFMR 614V
0-10A
1000 eF 16V
PB
+
Fig. 1-9
This circuit is used to clear internal shorts in nickel-cadmium
batteries. To operate, connect a NiCad battery to the output and
press the pushbutton for three seconds.
7
-
16 Vac AT;;..20~
T1 TRANSFORMER 120 Vac
120 Vac 60Hz R1
330 n 'lz W
CR1
BATTERY CHARGER
M1 de AMMETER
...- 0-15A
FW BRIDGE RECTIFIER 25A 100 PIV POLY PAKS 92CU1234
R2 ~--.10 K 0 1
POT 61 -DIRECTIONAL DIODE ._---J R.S. 276-1050
R3 \ 220 n
Cl ._~~~-.--~~-4-----/ 0.1JLF 200 V
73 AMATEUR RADIO
TRI TRIAC SA 200 PRV R.S. 276-101
R4 10 n 112 w
C3 0.1 ILF 200 V
Fig. 1-10
A diac is used in the gate circuit to provide a threshold level
for firing the triac. C3 and R4 provide a transient suppression
network. Rl, R2, R3, Cl, and C2 provide a phase-shift network for
the signal being applied to the gate_ RI is selected to limit the
maximum charging current at full rotation of R2.
AUTOMATIC SHUTOFF BATTERY CHARGER 14 V
-
3on 30Il PT
~ ~ M
.,...._/G -
,..I, --..-r K
TRIAC ; TRIAC OR OR SCR IJ' SCR 47Il -L ~ ~ ww P1 /f' !OO,..F K
e 2
25V ZEIIIER soon IK 1 ~ ww ,.. CHARGE
+
STOP
73 AMATEUR RADIO Fig. 1-11
Adjust this circuit by setting the 500-0 resistor while it is
attached to a fully charged battery.
8
-
BATTERY-CHARGING REGULATOR
~ CR 3 CR4 GE A40F GE A40f/
"\ SCRI RI
117 HOHMS OLTS ( GE C220F CRI (Z WI
" i\ OR GE CI22F GE AI4A AC
r: ~7001-iMS ~ 5W Tl
~ I A/. 47 OHMS R2 ~ CR~ R4 ,A 47 OHMS UTC ... FTIO GE A40f
2~0HMS 12Wl (117112.6) '- (5W) CR2 SCR2 /
' lW GE CI06Y
+ II V / '\ v F-/ 12 VOLT -, :- - ,- -BAT TERY -=- R3 '\,r~
- VR 7!>0 116 OHMS -, L 50p I : 11< + (lW) /f- 25V
"
..L ALL RESISTORS 112 WATT EXCEPT AS NOTED
GE Fig. 1-12
The circuit is capable of charging a 12-V battery at up to a six
ampere rate. Other voltages and cur-rents, from 6 to 600 V and up
to 300 A, can be accommodated by suitable component selection. When
the battery voltage reaches its fully charged level, the charging
SCR shuts off, and a trickle charge, as deter-mined by the value of
R4, continues to flow.
12-V BATTERY-CHARGER CONTROL (20 Arms MAX.)
MA 1121 /4)
50 11 RMS MAX
(60Hz)
Zt 1 N4735
T I PRIMARY = 30 TURNS 1122 SECONDARY = 45 TURNS 1122
c. 0.1 11. F
CORE = FEAROXCUBE 203 F 181 3CJ
RI 51 K
2N6167
Rs SERIES RESISTANCE TO LIMIT CURRENT THROUGH SCR 2N6167 IS
RATED AT 20 AMPS RMS
MOTOROLA
BATTERY_J.. 12 V
Flg. 1-13
9
-
Tl
~ 120 V
~
As
F 1
-
) V S1 -- - - ON/OFF
) SWITCH
1\ 120 V, 60 Hr NOTE :
TEXAS INSTRUMENTS
2:V I
..
~ 20V I
.......
BATTERY CHARGER
01 1N1183
~ '1
..: 02
1N1183
+
Z1
Rg zoon
* Z2 TL431
~ Rl "l r- ). 11.9 kn ..
R2
TL431 2.5 kn
*
iic _.,.
~ 0 1 v TIP642 ,....
RcL 0 .227 30W
o ~O-B A A,...
V + ---V BATT -=--
Tl is TRIAD F-275 U 115 V Primary : 10 A /40 V Canter-Tap
Secondary.
+ vo
0- 15 V
Fig. 1-14
The charger is based on a charging voltage of 2.4 V per cell, in
accordance with most manufacturers' recommendations. The circuit
pulses the battery under charge with 14.4 V ( 6 cells x 2 .4 V per
cell) at a rate of 120Hz. The design provides current limiting to
protect the charger's internal components while limiting the
charging rate to prevent damaging severely
-
UNIVERSAL BATTERY CHARGER
T1 18\1 HA .-----~~~~~ ---~-----~ l~.l} ~~l05S
F 1 7-GA
Pl1 -f'\-117VAC-u-
,----, ,.-----, HA
J 100P1V ~r:.> r---:--, ~ I I ~ I I
b
; I - +1 t ,......._ , ~ I "':...a R 1
)o-'l----1,___,._....__112_c.l.;. .l)l.l::...._-+------' ~ ~ I .J:.
~ 1 ZNJD55 .._ ./
I - - I b L _ _ _ _ _I Cl _ ~ C2 R1
1000 "I" ., 10 n '-1 "
R2 100
U1 0 lM311 -=---~ AOJ REG. R3
27011 AOJ.
R9 r---< sK UJ
2113904
.= -
c A4 't\b 2.2K &
U2
RS 1K
7101 R- VOLT
REGULATOR
0
POPULAR ELECTRONICS
R7 4.7K
C4 .47
;> our
R8 . I fl
2 y.~s__.__*::::-- U3 4 ~~....,
1/4 1.Ml3t R$ 15K
C3 r 4.7 ..,.
RIO ,~ 1K ;
Fig. 1-15
The charger's output voltage is adjustable and regulated, and
has an adjustable constant-current charging circuit that makes it
easy to use with most NiCad batteries. The charger can charge a
single cell or a number of series-connected cells up to a maximum
of 18 V.
Power transistors Q1 and Q2 are connected as series regulators
to control the battery charger's out-put voltage and charge-current
rate. An LM317 adjustable voltage regulator supplies the drive
signal to the bases of power transistors Q1 and Q2. Potentiometer
R9 sets the output-voltage level. A current-sampling resistor, R8
(a 0.1-0 , 5-W unit), is connected between the negative output lead
and circuit ground. For each amp of charging current that flows
through R8, a 100 m V output is developed across it. The voltage
developed across R8 is fed to one input of comparator U3. The other
input of the comparator is connected to variable resistor R10.
As the charging voltage across the battery begins to drop, the
current through R8 decreases. Then the voltage feeding pin 5 of U3
decreases, and the comparator output follows, turning Q3 back off,
which completes the signal's circular path to regulate the
battery's charging current.
The charging current can be set by adjusting R10 for the desired
current. The circuit 's output voltage is set by R9.
11
-
LEAD-ACID LOW-BATTERY DETECTOR r---~----.------- BATTERY ()Jl
Pul
LINEAR TECHNOLOGY
T R, 1~ 1M
LT 1004 1 2
3
2
UNIVERSAL BATTERY CHARGER
DC INPUT
,:..
;..
0 v,"~ I Cl Vou SI LM3t7
POWER VAOJ 'R6
VOLTAGE r+': ~ ' illil
CHARGE SCR1 ( CICDI :)
I'
01 INtOCM
RI: ......
Ri 220fl ..
Ri'" + :
I B' I
I -
'R5 TRIP
POINT
RADtO-ElECTRONICS Fig. 1-17
When power is applied to the circuit, SCRI is off, so there is
no bias-current path to ground; thus, LM317 acts as a current
regulator. The LM317 is connected to the battery through steer-ing
diode D 1, limiting resistor Rl, and bias resistor R2. The steering
diode prevents the battery from discharging through the LED and the
SCR when power is removed from the circuit. As the battery charges,
the voltage across trip-point potentiome-ter RS rises, and at some
point, turns on the SCR. Then, current from the regulator can flow
to ground, so the regulator now functions in the volt-age mode.
When the SCR turns on, it also provides LEDl with a path to ground
through R3. So, when LEDl is on, the circuit is in the
voltage-regulating mode; when LEDI is off, the circuit is in the
cur-rent-regulating mode.
12
..:.. 12V
.I --
6 .>--LO BATTERY LOW 8
10 MEG t R, SETS TRIP POINT. 60.4k PER CELL FOR 1.8VICEU
Fig. 116
UJT BATTERY CHARGER Rs' MCR3818
MRI1 11
)(\ V Ill'S MIIX \60 1111
6.8k Re
ce 5 1 t 111/4735 O.i ,.F
T 1 - PRIMARY = 30 TURNS 11 22 SECONDARY : 45 TURNS l!t22 CORE
FERROXCUBE 203 F 181 3C3
' RS- SERIES RESISTANCE fO liMIT CURRENT THROUGH SCR MCR 28183
IS RATED AI 20 AMPS ms
MOTOROLA Fig. 118
This circuit will not work unless the battery to be charged is
connected with proper polarity. The battery voltage controls the
charger and when the battery is fully charged, the charger will not
supply current to the battery. The battery charging current is
obtained through the SCR when it is triggered into the conducting
state by the U]T relaxation oscillator. The oscillator is only
activated when the battery voltage is low. V82a1 of the UJT is
derived from the voltage of the battery to be charged, and since
Vp= Vo= Va2o1; the higher V&.~s11 the higher Vp. When Vp
exceeds the breakdown voltage of the zener diode Zl, the UJT will
cease to fire and the SCR will not conduct. This indicates that the
bat-tery has attained its desired charge as set by R2.
-
AUTOMOTIVE CHARGER FOR NICAD BATTERY PACKS REGULAR CHARGE
.,. __ ___.,/ TO AUTO CIGAREnE LIGHTER F'LUG
TAB BOOKS
RAPID CHARGE LEO
720HM I WAn
~70HM I WAn
1200HM I WAn
~ SILICONOIOOES ~ 50P.I.V.AT200mA
~ _. SUFFICIENT. LARGER JVI>I'v-.olltt-- VALUES
ACCEPTABLE.
~SEETEXT
Fig. 1-19
The number of silicon diodes across the output is determined by
the voltage of the battery pack. Fig-ure each diode at 0 .. 7 V.
For example, a 10.9-V pack would require 10.9/0.7 = 15.57, or 16
diodes.
CONSTANT-VOLTAGE CURRENT-LIMITED CHARGER
IC LM723C VOLTAGE REGULATOR (FOR 12V de OUTPUT 0.42A MAX.)
TRI RI 02
AS --
IC LM723C For 12-V sealed lead-acid batteries.
YUASA BATTERY
Tl 01,02 Cl TAl IC Rl R2 R3 R4 RS VR C2
Transformer, Ck: 13V (rms), 13A (rms) IOOV lA Oioda SOV. 470pF
Eleclmlytlc Condenser MJ2840 lOA 60V 150W (Molorola) LM723C
(National Semiconduelor) 4. 7 Ohm 1/2W 3F' 5.1K0hm 114W 3.9K Ohm
114W 7.5K Ohm 114W 8.2K Ohm 114W 2KOhm 50V 1000pF
Fig. 120
13
-
VERSATILE BATTERY CHARGER
I
Tl 01 DJ !SI< - ~ .:l'IV g INI/111 IN'#OOJ. f'~W L. SI ~ 11
;'7 I Cl R I 'Jt-- . foC.2. l/ D'l- -r:.too 15K. \/PC IH'ftHl. ...
JJF 05 ::~!~F D.t. / 4/oV tf2. 11 IN'f'l'll. T NT.
INI/otU. ---
5 \'7 a / J ll.ll 01/T ICI IN
LM317 6 :l. 4 n.. ZC 2 1/:LW RDJ 7 CO IfS# !
06 07 08 D'f 0/0 .!Q. INI/1~3 IN'I1~3 INI/7~:J 1/VII7.S.J INI/
7.J:J
)_ ) ' 1. _"l '\ LEO C" LEO;_,. ~- LED ...;. LEO ..... ~ LeO-'/
LEO/,.,. I ,_....t,.,. ,2~ 3~ ~~~ s,C\ 6 r.:'";-\ ( .. ,. \.!;Y \
') \...../ .S ~ 'D ~ S061 '-' S05 O'/ 503 SO..l 501 A Rs R6 R7 ~8
~" 1?10 lOOn. IOO il. /0011. 100!2 / 00!2 1oo.n
1/.ZW I/2W
RADIOELEC:rRONICS
R3 1'1 2 .8/IIIEG I
:l.
.3
\1
'''-
RCj .U.,.uF TIINr. .
~ 7 ME.Cr 8 91
V N671fF D/
'\ "?"
s 1 1/ G
-
..
-
-
Fig. 1-21
An LM317 voltage regulator is configured as a constant-current
source. It is used to supply the 50-mA charging current to S01-S06,
an array of AA-ceU battery holders. Each of the battery holders is
wired in series with an LED and its associated shunt resistor. When
the battery holder contains a battery, the LED glows during
charging. Each battery holder/ LED combination is paralleled by a
5.1-V zener diode . If the battery holder is empty, the zener
conducts the current around the holder.
A timing circuit prevents overcharging. When power is applied to
the circuit, timing is initiated by IC2. a CD4541
oscillator/programmable timer. The output of IC2 is fed to Ql. When
that output is high, the transistor is on, and the charging circuit
is completed. When the output is low, the transistor is off, and
the path to ground is interrupted.
14
-
ck IOv REOI.I.)O'E[)
RI 2211 5%
112 27011
~ 4
(\ l ') T~~ll ~
1
R4 71511 1 '4
GEL-CELL CHARGER
6V 1.2
..JG1. C
c,.', IN4()()o
R6 I 40 , ...
This circuit detects a full-charge state and auto-matically
switches to a float condition-from 240 to 12 mA.
6 '" f:oo,..F NE555V 35H
Ul .... '~
4 2 I
L.
ELECTRONIC DESIGN
Between 20 V to 60 V de
WILLJAM SHEETS
) +
C) -
-
lf7 t 47\ 10 , ...
--
Fig. 1-22
NICAD BATTERY ZAPPER Charge 220 0 (20 W) - - ./V\, - -
Zap !(_ C106B 1 kO AA vvv
+ C ) Ni-Cads to be
- c ) zapped
+
12,000 ,.,.F 80 V (min.)
Fig. 1-23
The short in a NiCad battery can be ''burned off'' with this
zapper. Use of the SCR keeps heavy discharge current from damaging
switch contacts.
15
-
THERMALLY CONTROLLED NICAD CHARGER
r---------,
I I
0.60 YN
1600 1500 1400 1300 1200 11 00
-~ 1000 - 900 IEaoo
! : 500 400 300 200 100
!\.
1\
'
\
stHGL POIHT GROUND THERMOCOUPLES ARE t4Q~VtC CHROMEL-AlUMEL
(TYPE K)
0 0 30 60 90 120 150 lall - -
YlfCUTES
LINEAR TECHNOLOGY CORP. Fig. 1-24
One way to charge NiCad batteries rapidly wiU10ut abuse is to
measure cell temperature and taper the charge accordingly. The
circuit uses a thermocouple for this function. A second
thermocouple nulls out the effects of ambient temperature. T he te
mperature difference betwee11 the two thermocouples determines the
voltage, which appears at the amplifier 's positive input. As
battery temperature rises, this small nega-tive voltage (1 C
difference between the thermocouples equals 40 p. V) becomes
larger. The amplifier, operating at a gain of 4300, gradually
reduces ilie current through the battery to maintain its inputs at
balance. The battery charges at a high rate until heating occurs
and the circuit then tapers the charge. The values given in the
circuit limit the battery-surface temperature rise over ambient to
about 5C.
NICAD BATTERY ZAPPER 11
8 2 kO C106Y + ~ ...! 0 ~
..... v./'1,
"'
1N4006 s 220 kZ ~ 3.9 k > Ni-CAD ---
battery :::: ::
0 ) NE2 ...,. 100 ) I'F
\.0 ~ 1 kO 200 V -
-~
WILLIAM SHEETS Fig. 1-25
T his zapper clears intemal shorts in nickel-cadmium batte ries
by buming iliem away. CAUTION: The negative battery terminal is
connected to one side of the ac line. For safe operation. use a 1:
1 isolation transformer.
16
-
PORTABLE NICAD BATTERY CHARGER
RI r 1 IM.n
Wl rwz
~
Rl RJ Cl~!: m'F I lO.n. IO.n.
TRlv ZTX "650 .
4 ~~~ ~~ ~0 OIJJf 1N414 ov
ZETEX (formerly FERRANTI)
WJ
02 evv
n -s
= ~
0 3 BVV27 S
IOO.uF OUTPUT 25V
----+--o v
CJ 4700pF
Tl DETAILS Core FX3437 With Gap/ Spacer
of 0 .08mm Former DT2492
Winding order W2. W4. W3 then W 1
W2 W4 W3 W1
40T 20T 13T 12T
30awg. 30awg. 36awg. 36awg.
Fig. 1-27
This circuit was designed to charge NiCad battery packs in the
range of 4.8 to 15.6 V from a conve-nient remote power source, such
as an automobile battery. When power is first applied to the
circuit, a small bias current supplied by Rl via winding Wl ,
starts to turn on the transistor TRl. This forces a volt-age across
W2 and the positive feedback given by the coupling of Wl and W2
causes the transistor to turn hard on, applying the full supply
across W2. The base drive voltage induced across Wl makes the
junction between Rl and R2 become negative with respect to the 0-V
supply, forward-biasing diode Dl to provide the necessary base
current to hold TRl on.
With the transistor on, a magnetizing current builds up in W2 ,
which eventually saturates the ferrite core of transformer Tl .
This results in a sudden increase on the collector current flowing
through TRl , causing its collector-emitter voltage to rise, and
thus reducing the voltage across W2. The current flowing in W2
forces the collector voltage of the TRl to swing positive until
restricted by transformer output load-ing. Re network R4 and C3
1imits the turn off transient TRl . R3 and C2 maintain the loop
gain of the circuit when diode D 1 is not conducting.
18
-
D.C. CHARGING VOlTAGE
+ 3
LM317T U2
V on Voul
AOJ
UTHIUM BATTERY CHARGER
Dl R3 IN4095 2
I I 1- table below ) 1
+ POWER
TO DEVICE
R. > IK AS R1 : : > IKS IM (AC ADAPTER)
1
D2 ~ - ~ CHARGING' R2
( IM
D 02 '--
01 I G 7 ,... .......
I
r-~f._/ 2N5306 s OR EO NFEi
IRF520 OR SIMILAR
~ Re R9 8
2 - 5 ov
~ R7 :::. :2 > RIO _.., x ....
-
a.c.
T 1 24 v.
500 m A
I / "'
CQ
RAPID BATTERY CHARGER FOR ICOM IC-2A LED's 680
,.... V so A
680 150 ... vv
680 2Sy L
.A ,.... vv
,!'
tO
1N4002 ....... ----111
(4 req'd) )-~--t-----1 11 LM723
470,~~F , ; , : .1 50v. I '-6 tJ
SlA &4?0 V
518
15
500.L
't,'ltl , 1.5n
. &
500.1'
27n .A
'VV
3~---------4 1.81<
~OK ~ .,. , , ~ ~LTAGE
'---U ,-....... --------1 AOJ IJ$1 SOOpF
> 1.81< > L. -
L~,O ~
TRICKLE SCR .. ._j c
1K
"" mA Optional .J
~ 1N4001
I- pin LEGEND:
All resistors Yow. except where marked. 51 A, 8 DP3T
52 SPST pushbutton SCR 2N5062, 2N5063, 2N2328
Radio Sh~~ 275 1067 c. CB A
BOTTOM VIEW Fig. 1-29
Rectified and filtered voltage from the 24-Vac transformer is
applied to the LM723 voltage regulator and the npn pass transistor
set up for constant current supply. The 4 70-0 resistor limits
trickle current until the momentary pushbutton (S2) is depressed,
the SCR turns on, and current flows through the previ-ously
determined resistor network, which limits the charging current. The
SCR will turn off when the thermal cutout circuit inside the
battery pack opens up.
-
BATTERY CHARGER OPERATES ON SINGLE SOLAR CELL
Al 100 k ~
CdS PHOTOCELL AA
Uld Ulc
_.._ 02 ff 1.-. ff,_ ~ r- 03 ./
: >A3 A2 >2.7k 820 k r-4
FAIL-6V ;;~Cl .ff ff N. Cd ......::.... SAFE
.01 '
I - EXCITATION ;r U1a
' Ul b SUPPLY
01 02 M lo ouv /,-r-~ r-
~ MTH35N05
... 1/ -- '= ..
SOLAR CELL
+ A. .A.. .A.. .A.. A. .A.. 110Vi6.3V
T1 FILAMENT r-' T T T T T T TRANSFORMER
~ 1N4001 9V Ni-Cd
Ul = MC14093B MOTOROLA
-....
......::.... -
0 4 914 1N
--.
~
,.. ~
Fig. 1-30
The circuit charges a 9-V battery at about 30 mA per input
ampere at 0.4 V. Ul, a quad Schmitt trig-ger, operates as an
astable multivibrator to drive push-pull TMOS devices, Ql and Q2.
Power for Ul is derived from the 9-V battery via D4; power for Ql
and Q2 is supplied by the solar cell. The multivibrator frequency,
determined by R2/Cl, is set to 180Hz for maximum efficiency from a
6.3-V filament trans-former, Tl. The secondary of the transformer
is applied to a full-wave bridge rectifier, Dl, which is con-nected
to the batteries being charged. The small NiCad battery is a
fail-safe excitation supply to allow the system to recover ifthe
9-V battery becomes fully discharged.
A CdS photocell shuts off the oscillator in darkness to preserve
the fail-safe battery during shipping, storage, and prolonged
darkness.
21
-
WIND-POWERED BATTERY CHARGER
-
,..
-WIND
-
12V GENERATOR r-
-... r. 'T
J LM334 1-
680
11:;1< lOOk 4I :.~ 'T
- ::; --
.1. ;; IOk LTIOI)I I2~ ~
fl'1 n .., I 7
LINEAR TECHNOLOGY
107k
IOk -i=o F r. ~
oF WITHIN WINDOW
' ~ 114.001
!._- ,2V ..:.... LEAO ACIO
3&0 SW
13 8V TO 1~. IY I; MTP8110!> .....
'-' J]-1 IOM ,..., j} UC11)12 ; i' -.
::::! ;t O.l,f OVER VOlTABE .... 11'"' ( > 1S.IV) n .,
MTP8/IOS
- -
Fig. 1-31
The de motor is used as a generator; the voltage output is
proportional to its rpm. The LTC1042 monitors the voltage output
and provides the following control functions.
1. If generator voltage output is below 13.8 V, the control
circuit is active and the NiCad battery is charg-ing through the
LM334 current source. The lead-acid battery is not being
charged.
2. If the generator voltage output is between 13.8 and 15.1 V.
the 12-V lead-acid battery is being charged at about l-amp/hour
rate (limited by the power FET).
3. If generator voltage exceeds 15.1 V (a condition caused by
excessive wind speed or when the 12-V bat-tery is fully charged),
then a fixed load is connected, which limits the generator rpm to
prevent damage.
This charger can be used as a remote source of power where wind
energy is plentiful, such as on sailboats or at remote radio
repeater sites. Unlike solar-powered panels, this system will
function in bad weather and at night.
22
-
2
Power Supplies-Fixed
The sources of the following circuits are contained in the
Sources section, which begins on page 125. The figure number in the
box of each circuit correlates to the source entry in the Sources
section.
General-Purpose Power Supply 12-Vdc Battery-Operated 120-Vac
Power Source Simple Power Supply Charge-Pool Power Supply Bilateral
Current Source 3- to 30-V Universal Power-Supply Module
Regulator/Current Source Low-Power Switching Regulator Variable
Voltage Regulator Switching Power Supply 100-kHz Multiple-Output
Switching Power Supply Isolated Feedback Power Supply Dual-Tracking
Regulator + 15-V 1-A Regulated Power Supply -15-V 1-A Regulated
Power Supply Hand-Held Transceiver de Adapter Low-Dropout 5-V
Regulator Triac-Controlled Voltage Doubler High-Stability 10-V
Regulator Voltage-Controlled Current Source
Low-Power Inverter Three-Rail Power Supply Programmable Power
Supply Efficient Negative Voltage Regulator 5 V-to-Isolated 5 V (at
20 rnA) Converter Positive Regulator with npn and pnp Boost
Tracking Preregulator Adjustable 10-A Regulator Low-Cost
Low-Dropout Linear Regulator Voltage Doubler Safe Constant -Current
Source Low-Cost 3-A Switching Regulator 50-W Off-Line Switching
Power Supply Positive Regulator with pnp Boost Low Forward-Drop
Rectifier Circuit Low-Ripple Power Supply 5.0-V/10-A Regulator
5.0-V /3.0-A Regulator Bench-Top Power Supply Variable Current
Source (lOO mA to 2 A)
23
-
Basic Single-Supply Voltage Regulator 8-A Regulated Power Supply
for Operating Mobile
Equipment Low-Voltage Regulators with Short-Circuit
Protection High-Stability 1-A Regulator High-Current
lnductorless Switching Regulator 200-kHz Switching Regulator 5-V
0.5-A Power Supply 3-W Switching-Regulator Circuit Regulated Split
Power Supplies from a Single
Supply Switching Step-Down Regulator Single-Ended Regulator 50-V
Push-Pull Switched-Mode Converter 5-V/0.5-A Buck Converter Slow
Turn-On 15-V Regulator ac Voltage Regulator Uninterruptible + 5-V
Supply Stand-By Power For Nonvolatile CMOS RAMs 5-V Supply With
Stabilized Momentary Backup Uninterruptible Power Supply for
Personal
Computers 90-Vrms Voltage Regulator Using a PUT Switch-Mode
Power Supply Micropower Bandgap Reference Supply 50-V Feed-Forward
Switch-Mode Converter TraveUer's Shaver Adapter 100-V/0.25-A
Switch-Mode Converter Voltage Regulator Dual-Polarity Power Supply
5.0-V/6.0-A/25-kHz Switching Regulator With
Separate Ultra-Stable Reference
24
Mobile \bltage Regulator Negative Switching Regulator Positive
Switching Regulator Positive Floating Regulator Negative Floating
Regulator Negative Voltage Regulator -15-V Negative Regulator Slow
Turn-On 15-V Regulator High-Stability 10-V Regulator 5-V /1-A
Switching Regulator 15-V/1-A Regulator with Remote Sense Increasing
the Power Rating of Zener Diodes Voltage Regulator Zener Diode
Regulator 12- to 14-V Regulated 3-A Power Supply de-to-de SMPS
Variable (18 to 30 V Out at 0.2 A) SCR Preregulator Fits Any Power
Supply Off-Line Flyback Regulator 500-kHz Switching Inverter for
12-V Systems 10-A Regulator with Current and Thermal
Protection Bipolar Power Supply For Battery Instruments Power
Supply for 25-W Arc Lamp Power-Switching Circuit 100-V /0.25-A
Switch Mode Converter Radiation-Hardened 125-A Linear Regulator
Supply \bltage Splitter 3- to 5-V Regulated Output Converter
Memory-Save On Power-Down 100-Vrms Voltage Regulator
-
GENERAL-PURPOSE POWER SUPPLY
120~11 DIODES
6A - 50PIV A
TRANSFORMER
R2 7600
FROM 10 TO 40 VOLTS AT A AND 8 DEPENDING ON OUTPUT REQUIRED.
TEXAS INSTRUMENTS
E
uA723 Rsc 3
R3 .. Note1
10000 RS 7 100pf R4
Note1
NOTE 1: FOR 14 V TO 36 V OUTPUT- R3 2k, R4 5000 FOR 1 V TO 14 V
OUTPUT - R3 2 k, P4 2 k
0.85V CURRENT LIMIT Rsc - -
IIJimid
+
10010F
Fig. 2-1
The supply can be used for supply output voltages from 1 to 35
V. The line transformer should be selected to give about 1.4 times
the desired output voltage from the positive side of filter
capacitor Cl to ground. Potentiometer R2 sets the output voltage to
the desired value by adjusting the reference input. Rsc is the
current limit set resistor. Its value is calculated as:
Rsc= 0.65 V . It
For example, if the maximum current output is to be 1 A, Rsc=
0.65/1.0 =0.65 n. The 1-kfl resistor, R5 , is a light-loaded
resistor designed to improve the no-load stability of the
supply.
25
-
12-Vdc BATTERY-OPERATED 120-Vac POWER SOURCE
a,. a,= 2N58n
EON
TRANSFORMER UTC TYPE FT. 10 ORSTANCOR TYPEP6377
LOAD 20W MAX
Fig. 2-2
A simple 120 V: 24 V, center-tapped control transformer and four
additional components can do the job. This circuit outputs a clean
200-V pk-pk square wave at 60 Hz and can supply up to 20 W. The
circuit is self-starting and free-running.
If Ql is faster and has a higher gain than Q2, it will turn on
first when you apply the input power and will hold Q2 off. Load
current and transformer magnetizing current then flows in the upper
half of the primary winding, and auto transformer action supplies
the base drive until the transformer satu-rates. When that action
occurs, Q1 loses its base drive. As it turns off, the transformer
voltages reverse, turning Q2 on and repeating the cycle. The output
frequency depends on the transformer iron and input voltage, but
not on the load. The fre-quency will generally range between 50 to
60 Hz with a 60-Hz transformer and car battery or equiva-lent
source. The output voltage depends on turns ratio and the
difference between input voltage and transistor saturation voltage.
For higher power, use larger transformers and transistors. This
type of inverter normally is used in radios, phonographs, hand
tools, shavers, and small fluorescent lamps. It will not work with
reactive loads (motors) or loads with high inrush currents, such as
coffee pots, fry-ing pans, and heaters.
SIMPLE POWER SUPPLY
117 VAC
01-04 IN4001 (4)
03
)0---.------o +9V Cl IOOI'F
16V
GROUND C2 +
._ __ IO_O.:....~'.:....F, _16_V__.. __ - .gV
HANDS-ON ELECTRONICS Fig. 2-3
26
This power supply delivers plus and minus 9 V to replace two 9-V
batteries. The rectifier circuit is actually two separate full-wave
rectifiers fed from the secondary of the transformer. One full-wave
rectifier is composed of diodes D 1 and D2, which develop + 9 V,
and the other is composed of D3 and D4, which develop - 9 V.
Each diode from every pair rectifies 6.3 Vac, half the secondary
voltage, and charges the associ-ated filter capacitor to the peak
value of the ac waveform, 6.3xl.414=8.9 V. Each diode should have a
PIV, Peak Inverse Voltage, rating that is at least twice the peak
voltage from the transformer, 2 x 8. 9 = 18 V. The 1N4001 has a PIV
of 50 V.
-
CHARGE-POOL POWER SUPPLY
OPTIONAL HARRIS
+5V OUTPUT TO LOOP
_ TIIAIIIMITTER
Fig. 2-4
It is usually desirable to have the remote trans-mitter of a 4-
to 20-mA current loop system pow-ered directly from the
transmission line. In some cases, this is not possible because of
the high-power requirements set by the remote sensor/ transmitter
system. In these cases, an alternative
to the separate power supply is still possible. If the remote
transmitter can be operated in a pulsed mode where it is active
only long enough to per-form its function, then a charge pool power
supply can still allow the transmitter to be powered directly by
the current loop. In this circuit, constant current / 1 is supplied
to the charge pool capacitor, CP, by the HA-5141 (where 11 =3 mA).
The voltage V 1 continues to rise until the output of the HA-5141
approaches + Vs or the optional voltage limiting pro-vided by Z2.
The LM2931 voltage regulator sup-plies the transmitter with a
stable + 5-V supply from the charge collected by CP. Available
power supply current is determined by the duration, allow-able
voltage drop on CP, and required repetition rate. For example, if
V1 is allowed to drop 4.4 V and the duration of operation is 1 ms,
the available power supply current is approximately:
dVt 4.4 V =CP-=68 p.Fx--=30 mA dt 1 ms
BILATERAL CURRENT SOURCE
R1 2M
r
L
R2
1M + 15V This circuit uses a CA3193 precision op amp to deliver
a current independent of variations in Re. With Rl set equal to R3,
and R2 approximately equal to R4 + R5, the output current, h. is:
V1N (R4)/(R3) (R5). 500-p.A load current is constant for load
values from 0 to 3 0.
ALL RESISTORS ARE 1 Ofb ALL RESISTANCE VALUES ARE IN OHMS
IF R1 = R3 AND R2 "" R4 + RS THEN
IL IS INDEPENDENT OF VARIATIONS IN RL FOR RL VALUES OF 00 to 3KO
WITH V = 1 V
V R4 V 1M V IL = R3 R5 = (2M)(1 K) = 2K = SOOj.tA
GE/RCA Fig. 2-5
27
-
3- to 30-V UNIVERSAL POWE.R-SUPPLY MODULE
Ul, an LM317 adjustable regulator provides short-circuit
protection and automatic current limiting at 1.5 A. The input
voltage to the regulator is supplied by DBl , a 4-A 100 PIV
full-wave bridge rectifier. Capacitor Cl provides initial
filtering. Ul provides additional electronic filtering as part of
the regulating function. The output level of the regulator is set
by trim-pot Rl . Bypass capacitors on the input and output of Ul
prevent high-frequency oscillation. The current rating of the
transformer must be at least 1.8 times the rated continuous-duty
output of the supply. This means that a 1.5-A supply should use a
2. 7 -A trans-former. For light or intermittent loads, a smaller
2.0-A transformer should suffice.
Wiring a second LM317, U2, in parallel with Ul is a quick and
clean way to increase the current-limiting threshold to 3 A without
sacrificing short-circuit protection. When more than 3 A is
required, the regulator module can be used to drive the base of one
or more pass-transistors (see Fig. 2-6B).
28
-
15V
EDN
REGULATOR/CURRENT SOURCE
R,
-15V
o, VNtOKM
100~
IN9658
-15V
Fig. 27
The circuit powers the load via the regulator's input instead of
its output. Because the regulator's output sees constant dummy load
Rl, it tries to consume a constant amount of current, no matter
what the voltage across the actual load really is. Hence, the
regulator's input serves as a constant-current source for the
actual load. Power the circuit with any one of the commonly
available 15- or 12-V sup-plies. The voltage dropped across the
regulator and dummy load decreased the total compliance voltage of
the circuit. You set the load's current with Rl. The current equals
1.25 A/flxR1-
LOW-POWER SWITCHING REGULATOR
+9V 01 L1 t------2~N2.907rA_ ...... _,-,1,-,0m,.,Hy"-~P-+--
.-5VotJT
IM
I 2k
L1 ~ DALE TE3103/TA
LINEAR TECHNOLOGY CORP.
1N4148
3901<
50k OUTPUT ADJUST
Fig. 2-8
29
-
LOW-POWER SWITCHING REGULATOR (cont.)
A simple battery-powered switching regulator provides 5 V out
from a 9-V source with 80% efficiency and 50-mA output capability.
When Ql is on, its collector voltage rises, forcing current through
the induc-tor. The output voltage rises, causing Al's output to
rise. Ql cuts off and the output decays through the load. The
100-pF capacitor ensures clean switching. The cycle repeats when
the output drops low enough for AI to turn on Ql. The 1-J.tF
capacitor ensures low battery impedance at high frequencies,
preventing sag during switching.
VOLTAGE IN
HAM RADIO
VARIABL.E VOLTAGE REGULATOR
CRI 1N4002
/Cl Vour Lltt 117 K 1-----41...,_;..;....-+----~
Cl l O.li'F ADJ Rl 237.fl VOLTAGE OUT
Fig. 2-9
The variable voltage regulator lets you adjust the output
voltage of a fixed de power supply between 1.2 and 37 Vdc, and will
supply the output current in excess of 1.5 A. The circuit
incorporates an LM117K three-terminal adjustable output positive
voltage regulator in a T0-3 can. Thermal overload protection and
short-circuit current-limiting constant with temperature are
included in the package. Capacitor Cl reduces sensitivity to input
line impedance, and C2 reduces excessive ringing. Diode CRI
prevents C2 from dis-charging through the IC during an output
short.
30
-
GE
SWITCHING POWER SUPPLY
All Resistors 1/2 Watt Except As Noted Otherwise +310V 101(
A15M (4PI~) ~ 10V~
o--
2'20V/'C, 50/60Hz +
*-100 I'F 35011
15K SW
R0- 0n Time Adjust RL- Load Voltage Adjust
R~Feedback Gain Adjust
02 t\ (C1060) ~
47K 3W
:- Cl "" " 10nF
.....___ +
2.2,.F ;:':::;
100 11 L A14U
(Q 100 ~CA1 4 C2 '-!..- tJ\ SUS
1 nF ~ \: po- 2N4988
VES702
Ass 0.39 3W
PC1
6900 10 BA1S9
;: r: 3 .4nF 1Kv
01- 064VP5 Selected for Vce11 ?:. 800 Volts L-2S!lH Output
Transformer SCR1 BRYS5S All Unmarked Diodes- A 1148 04,05-2N6001
V0o;r-2 Volts-VDC IL -0- 10 Amperes
Bifilar Core-8SOGER 42 x 21 x 15 (LCC) Wound 1 nl-95 Turns 1/J =
0.6 mm Nearest n2-96 Turns 1/J = 0.6 mm Core n3-3 Turns of 4
Strands !l 1 mm Parallel
n4-3 Turns !l = 0.4 mm Fig. 210
This low-voltage high-current output, switching de power supply
is running off the 220-Vac input. In this circuit, an ST2 diac
relaxation oscillator, Q3, Cl, and the diac, initiates conduction
of the output switching transistor Ql , the on-time of which is
main-tained constant by a separate timing/commutation network
consisting of Q2, C2, SUS, and SCR 1. The output voltage,
consequently, is dependent on the duty cycle. To compensate for
unwanted variations of output voltage because of input voltage or
load resistance fluctuations, an Hll C wired as a linear-model
unilateral pop transistor in a stable differential amplifier
configuration is connected into the galvanically isolated
negative-feedback loop. The loop detennines the duty cycle and
hence the output voltage. Of further interest in this circuit is
the use of several low-current, high-voltage, 400-V VoRM thyristors
(Q2, Q3), which are also used as pnp remote-base transistors.
Short-circuit protection is assured by coupling Ql
collector-current feedback into the turn-off circuitry via Rss.
-
SJLJCONJX
.. .,.
"" ...
"""
"" tOOK
R1 330 .. , w
100-kHz MULTIPLE-OUTPUT SWITCHING POWER SUPPLY
Cl
I,. :ooov
CH ..
. ,
..
o 1-"--+ ........ ..,...._< ~
AOJ\JSl
...
'' .
c
~ L-----------------------------~_.~ ______ ._ ______ ~--~
2000'
c .. >0
tfCJ"'5 CAPACI10~S IN M.CAQf.AJV.OS UNlESS NOTED RfSIS'roflS IN
OHMS 1/W, ~~ IJN~ESS NOTED
t THESE PARTS MOUNl'I!D ON HEAT SINKS. 'f t . T2. lJ, LI
L21.)l._StETEXTFOROETAII ... S
Fig. 2-11
The power supply uses two VN4000A 400-V MOSPOWER FETs in a
half-bridge power switch configuration. Outputs available are + 5 V
at 20 A and 15 V (or 12 V) at 1 A. Since linear three-terminal
regulators are used for the low-current outputs, either 12 V or 15
V can be made available with a simple change in the transformer
secondary windings. A TU94 switching regulator IC provides
pulse-width modulation control and drive signals for the power
supply. The upper MOSPOWER FET. Q7, in the power switch stage is
driven by a simple transformer drive circuit. The lower MOS, Q6,
since it is ground referenced, is directly driven from the control
IC.
-
ISOLATED FEEDBACK POWER SUPPLY
v
+11000,.1 IOV
r--------, I c I I I I Vllt.TS _, o I I I I I I I I I I I I I
L-----------~~~~----~~< I
I I I I
L--~ -----..J
TEXAS INSTRUMENTS Fig. 2-12
Figure 2-12 is a power supply circuit using the isolated
feedback capabilities of the TL3103 for both cur-rent and voltage
sensing. This supply is powered from the ac power line and has an
output of 5 V at 1.5 A. Both output voltage and current are sensed
and the error voltages are applied to the error amplifiers of the
TL594 PWM control IC. The 24-V transformer produces about 35 V at
the 1000-JLF filter capacitor. The 20-kHz switching frequency is
set by the 6-kO resistor and the 0.01-JLF capacitor on pins 6 and
5, respectively. The TL594 is set for push-pull operation by tying
pin 13 high. The 5-V reference on pin 14 is tied to pin 15, which
is the reference or the current error amplifier. The 5-V reference
is also tied to pin 2 which is the reference for the output voltage
error amplifier. The output voltage and current limit are set by
adjustment of the 10-kO pots in the TL3103 error-sensing circuits.
A pair of TIP31E npn transistors are used as switching transistors
in a push-pull circuit.
33
-
IUOUl -I&V. I !Iool
MAXIM
u IIDJl
DUAL-TRACKING REGULATOR
u ltO!l
1111< !GO~ r---~r---+-~rJTn~~~~-t--~--~~~:.~
1a 11
Fig. 2-13
A MAX634 inverting regulator is combined with a MAX630 to
provide a dual tracking 15-V output from a 12-V battery. The
reference for the -15-V output is derived from the positive output
via R3 and R4 . Both regulators are set to maximize output power at
low battery voltages by reducing the oscillator frequency, via LBR,
when V8An falls to 8.5 V.
+ 15-V 1-A REGULATED POWER SUPPLY
120V~III A se 0.43 n
6 2 REF
uA723 3
5 4
c C2 100 pf
TEXAS INSTRUMENTS
Cl ,oo"F T
T
AI 12 kn
R2 10kn
15V R3 OUTPUT 1.ooon
Fig. 2-14
The supply receives + 20 V de from the rectifier/filter section.
This is applied to pins 11 and 12 of the uA 723, as well as to the
collector of the 2N3055 series-pass transistor. The output voltage
is sampled through R1 and R2, providing about 7 V with respect to
ground at pin 4. The reference terminal at pin 6 is tied directly
to pin 5, the noninverting input of the error amplifier. For fine
trimming the output voltage, a potentiometer can be installed
between R1 and R2. A 100-pF capacitor from pin 13 to pin 4
furnishes gain compensation for tl1e amplifier.
34
-
+ 15-V 1-A REGULATED POWER SUPPLY (cont.)
Base drive to the 2N3055 pass transistor is furnished by pin 10
of the uA723. Since the desired output of the supply is 1 A,
maximum current limit is set to 1.5 A by resistor Rsc whose v
-
12 V OC IN
QST
HAND-HELD TRANSCEIVER de ADAPTER
+o----...... - -t
0.1 11F + 35V
TANTAI.UM
Cl
RI 2-40 .n. 112 w
* USE H EAT SINK
C2 + IJIF
3~ V TANTAI.U III
9 V OC OU T
Fig. 2-16
This de adapter provides a regulated 9-V source for operating a
Kenwood TR-2500 hand-held trans-ceiver in the car. The LM317T's
mounting tab is electrically connected to its output pin, so take
this into account as you construct your version of the adapter. The
LM317T regulator dissipates 2 or 3 W in this application, so mount
it on a 1- x -2-inch piece of lfs-inch-thick aluminum heatsink.
36
LOW-DROPOUT 5-V REGULATOR
21112219
10011
100 Ill!
S HORT CIRCUIT FEEDBACK AMP 1 M!l PAOTECTION 8 fi
-4 EVEREADY _ Ell CElLS -I V
2,-----
LT1004 1.2 V
0 .01 0
1.2 kfl
V*-' at I rnA I ,.y V-~ M 10 rnA - 11 mV V*opout et 100 mA U
rnA
TEXAS INSTRUMENTS
IN91-4
)1--..---.vo - 6 v
30k{l
120 kO
LOAD
Fig. 2-17
-
TRIAC-CONTROLLEO VOLTAGE DOUBLER HIGH-STABILITY 10-V
REGULATOR
117V { AC
Cl + 250J.If
250WVDC
------------~----~ DC LOAD
r I L * ~.11,F
~,.
.. ;.
Ul lo LM331 J
AOJ ~ R I 2K
R2 1 5K
~ r' LM3298
R3 267ll
GNO
HANOS.ON ELECTRONICS Fig. 218 POPULAR ELECTRONICS Fig. 2-19
VOLTAGE-CONTROLLED CURRENT SOURCE + >V
lk 1. r-~- -,
OI'EIIJ.l(S fROM l Slt4QI !>Y SUPI'I.Y
LINEAR TECHNOLOGY CORP. Fig. 7-20
This is a simple, precise voltage-controlled cur-rent source.
Bipolar supplies will permit bipolar output. Configurations
featuring a grounded volt-age-control source and a grounded load
are usually more complex and depend upon several compo-nents for
stability. In this circuit, accuracy and sta-bility almost entirely
depend upon the 100-fl shunt.
37
-
LOW-POWER INVERTER
RI IKl"' I/4 W
R2 12Kl"' I/4W 2.6
+12V INPUT
4,14
Ul 556
73 AMATEUR RADIO
R3 IK!'I
S-8,12 I/ 4W
9
R4 I K!'I I/4W
Tl 120V 18VCT RADIO SHACK 273-151 58
Tl I\[ ouTPUT
Fig. 2-21
This low-power inverter uses only 9 parts and turns 10 to 16 Vdc
into 60-Hz, 115-V square-wave power to operate ac equipment up to
25 W. The first section of the 556 timer chip is wired as an
astable oscillator with R2 and Cl setting the frequency. The output
is available at pin 5. The second section is wired as a phase
inverter. That output is available at pin 9. Resistors R3 and R4
keep output transistors Q1 and Q2 from loading down the oscillator.
The two transistors drive the transformer push-pull fashion. When
one transistor is biased-on, the other is cut-off. The transformer
is a 120 V/18 VCT unit that is connected backwards. so that it
steps the voltage up rather than down. Oscillator circuit lJl, R1 ,
R2, and Cl operates from about 4 to 16 V with a very stable
output.
EDN
38
7.SV AA; 2A o,
THREE-RAIL POWER SUPPLY
IC,
t------+------o Vo,
r---~--~~---~~---~._-----~-----QCOMMOO
7.SV AC 2A
t-------- --o v.,
Fig. 2-22
-
THREE-RAIL POWER SUPPLY (cont.)
This circuit generates three supply voltages using a minimum of
components. Diodes 02 and D3 per-form full-wave rectification,
alternately charging capacitor C2 on both halves of the ac cycle.
On the other hand, diode Dl with capacitor Cl, and diode D4 with
capacitor C3 each perform half-wave rectification. The full- and
half-wave rectification arrangement is satisfactory for modest
supply currents drawn from - 5 and + 12-V regulators IC3 and IC2.
You can use this circuit as an auxiliary supply in an up-based
instru-ment, for example, and avoid the less attractive
alternatives of buying a custom-wound transformer. build-ing a more
complex supply, or using a secondary winding, say 18 Vac, and
wasting power in the 5-V regulators.
PROGRAMMABLE POWER SUPPLY
+VREF
10K
LOAD
HARRIS Fig. 2-23
Many systems require one or more relatively low-current voltage
sources which can be programmed to a few predetermined levels. The
circuit shown above produces positive output levels, but could be
modi-fied for negative or bipolar outputs. Ql is the series
regulator transistor, selected for the required current and power
capability. Rl, Q2, and Q3 form an optional short circuit
protection circuit, with Rl chosen to drop about 0. 7 V at the
maximum output current. The compensation capacitor, C, should be
chosen to keep the overshoot, when switching, to an acceptable
level.
39
-
EFFICIENT NEGATIVE VOLTAGE REGULATOR Ftedlmk 11'111 MUR410 1
...... t 5 V OU1jlll1
If ..... -:: + (typical) +VIn ~ '470 ,..F MUR410 ~ LT1D86
_.._.
v,. v , ... R, + ADJ -:o1 .., :;;~ 470 ,,J 124
L1 1 ~+c R2 ""~o ,.r .4 '- Switching T 1o.:r 1.G7k regul,1or
~ MUR410 LT1086 lllo..J V In V..,, ..... R, .1
+ ADJ 124 + ~
+12V 1.SA
I ~ 1 D 114002
.,..
~ D I ELECTRONIC DE SIGN :;;~470 ,. F ~ c, R2 ro,.F 1N 4002 Fig.
2-24
*1% film resis1ol1 l 1D,,.f 1.07k -12V
1.SA
One way to provide good negative-voltage regulation is with a
low-dropout positive-voltage regulator operating from a
well-isolated secondary winding of a switch-mode circuit
transformer. The technique works with any positive-voltage
regulator, although highest efficiency occurs with low-dropout
types.
Under all loading conditions, the minimum voltage difference
between the regulator VIN and V oUT pins must be atleast 1.5 V, the
LT1086's low-dropout voltage. If this requirement isn't met, the
output falls out of regulation. Two programming resistors, Rl and
R2, set the output voltage to 12 V, and the LT1086's servo the
voltage between the output and its adjusting (ADJ) terminals to
1.25 V. Capacitor Cl improves ripple rejection, and protection
diode 01 eliminates common-load problems.
Since a secondary winding is galvanically isolated, a
regulator's 12 V output can be referenced to ground. Therefore, in
the case of a negative-voltage output, the positive-voltage
terminal of the regulator connects to ground, and the -12 V output
comes off the anode of Dl. The V1N terminal floats at 1.5 V or more
above ground.
MAXIM
40
5 V-TO-ISOLATED 5 V (AT 20 m A) CONVERTER 4.5V TO
-
5 V-TO-ISOLATED 5 V (AT 20 mA) CONVERTER (cont.)
In this circuit, a negative output voltage de-de converter
generates a -5-V output at pin A. In order to generate - 5 V at
point A, the primary of the transformer must fly back to a diode
drop more negative than -5 V. If the transformer has a tightly
coupled 1:1 turns ratio, there will be a 5 V plus a diode drop
across the secondary. The 1N5817 rectifies this secondary voltage
to generate an isolated 5-V output. The isolated output is not
fully regulated since only the - 5 V at point A is sensed by the
MAX635.
POSITIVE REGULATOR WITH npn AND pnp BOOST
R1
02 I A
...... ~ I ...
INPUT v 4
r 0 /P I l ICL 821 1 J .. :Rs 0 1 TH 1 v-
R3 OUTPUT
C2
5 R4
INTERSIL Fig. 2-26
In the circuit, Q1 and Q2 are connected in the classic SCR or
thyristor configuration. Where higher input voltages or minimum
component count are required, the circuit for thyristor boost can
be used. The thytistor is running in a linear mode with its cathode
as the control terminal and its gate as the output terminal. This
is known as the remote base configuration.
41
-
POPULAR ELECTRONICS
IN
POPULAR ELECTRONICS
42
TRACKING PREREGULATOR
ADJUSTABLE 1 0-A REGULATOR
C2 l,.F
R4 ' IK
OUTPUT ADJUST
R1 non
l-'0~r----o v our RJ 120ft
~----~--~-----o GND
Fig. 2-27
Fig. 2-28
-
LOW-COST LOW-DROPOUT LINEAR REGULATOR
I I MTP3055A I IN-4146 .0 1 J' ,- ..., L IOOV A A6 --- ! .025 0
I I~ 'I>W r- BIAS- l ,r---REGUI..4TOR-----,
01
J ll
I \l::YJ I MUR u Ll: I CAI Tl I RI R7 10 k IN9638 22k 02 ~.
~N4401 . 330 3301 I --~ 35 V I AEGIJ 35 V I R3 oc R2 Cl 10 k OUT I
k
I 22pl' I ~-- 1 R4 I Ul I k I TlV31ClP AS
1..4TED
PUT
I 2.2 k MOTOROLA
L __________ _j Fig. 2-29
This linear post regulator provides 12 V at 3 A. It employs
TL431 reference Ul which, without addi-tional amplification, drives
TMOS MTP3055A gate Q1 series pass regulator. Bias voltage is
applied through Rl to Q1 's gate, which is protected against
overvoltage by djode CRI. Frequency compensation for closed-loop
stability is provided by Cl .
Key performance features are:
Dropout voltage: 0.6 V Load regulation: 10 mV Line regulation: 5
m V Output ripple : 10 mV pk-pk
VOLTAGE DOUBLER IZV
73 AMATEUR RADIO
51
lO.OI 2-y-y
O 1---1 I I(>U
22V OC @ 150mA
18 V OC @)COmA
I N 4001
Fig. 2-30
This circuit drives relays of 24 and 18 V de from a 12-V power
supply. Use this circuit with almost any pnp or npn power
transistor.
Parts: U 1: NE 555 timer. C 1 and C2: 50 p.F I 25 Vdc. Ql:
TIP29, TIP120, 2N4922, TIP61, TIPllO, or 2N4921. Q2: TIP30, TIP125,
2N4919, TIP62 , TIP115, or 2N4918.
43
-
SAFE CONSTANT-CURRENT SOURCE
------------~----------------~---------------.-------------
+
1 25V ICL8069
ELECTRONIC ENGINEERING Fig. 2-31
In the circuit shown, a CMOS op amp controls the current through
a p-channel HEXFET power tran-sistor to maintain a constant voltage
across Rl. The current is given by: I= VREF/ R1 The advantages of
this configuration are: (a) in the event of a component failure ,
the load current is limited by Rl; and (b) the overhead voltage
needed by the op amp and the HEXFET is extremely low.
44
LOW-COST 3-A SWITCHING REGULATOR
C2 RJ 0.01 240f2
R4 SK OUTPUT R6
Cl ADJUST 15K so,~~F1
RS lOOn
1SOL10 TANTALUM
L1 600.11H'
01 INJIBD
l.8V TO 32V
GNO
coRE - ARNOLO A2541682 60 TURNS
POPULAR ELECTRONICS Fig. 2-32
-
50-W OFF-LINE SWITCHING POWER SUPPLY
MI
2 8
[ 11 ICL7675 I
Component Values Table Cl 0.022 JLF /400V 10 IOO!lar 25'C 1.1
25,.,.H C2 470 JLFI250V R2 10/IW I)[ INt937 C3 470 I'F/16V R:l
I00/0.2SW 02 MBRI035 C4 220 pF/IOOV R4 I 00 kfl/0.25W Tl Lp = 9mll.
n= 1:1OOV R8 22 Hl/IOW Ql 8UZ80A/IXTP41\'80 C9 11,000 p.F/6.3V R9
680/0.zr,w i220VAC)
CIO 10 JLF/16V RIO IO!l/0.5W Ql GE IRF823 Cll (1.04 7 p.F/ I OV
Rll 3 .30/0.5W (I IOVAC)
RI. 50/l OW
INTERSIL Fig. 2-33
The schematic shows a 50-W power supply with a 5-V 10-A output.
It is a flyback converter operating in the continuous mode. The
circuit features a primary side and secondary side controller with
full-protec-tion from fault conditions such as overcurrent. After
the fault condition has been removed, the power sup-ply will enter
the soft-start cycle before recommencing normal operation.
45
-
POSITIVE REGULATOR WITH pnp BOOST
.,..uT UY-
~
INTERSIL
I. y
0/P
tCL IJII
TH. J
1/'
r
A\ s ... ~ ,c:
''
r-...0 '
AI
AJ
~~ .~, 04./TI'\/1 1.tav.a .tv -
Fig. 2-34
The IC8211 provides the voltage reference and regulator
amplifier, while Ql is the series pass tran-sistor. Rl defines the
output current of the IC8211 , while Cl and C2 provide loop
stability and also act to suppress feedthrough of input transients
to the
output supply. R2 and R3 determine the output voltage as
follows:
In addition, the values of R2 and R3 are chosen to provide a
small amount of standing current in Ql, which gives additional s
tability margin to the circuit. Where accurate setting of the
output voltage is required, either R2 or R3 can be made adjustable.
If R2 is made adjustable, the output voltage will vary linearly
with the shaft angle; however, if the potentiometer wiper was to
open the circuit, the output voltage would rise. In general,
therefore, it is better to make R3 adjustable, since this gives
fail -safe operation.
LOW FORWARD-DROP RECTIFIER CIRCUIT
01 MTH40N05
"CATHODE"
~----~......, r+-+"D'------+---1 ve ---. I I I I
($)~~ I I I
\]
MOTOAOL.A
46
G A1
10 k
-I
+
I I I I I
DC ~ OUT~ I I
7 .:. 15 V
Fig. 2-35
A TMOS power FET, Ql, and an LM393 com-parator provide a
high-efficiency rectifier circuit. When VA exceeds V8 , Ul 's
output becomes high and Ql conducts. Conversely, when Va exceeds
VA, the comparator output becomes low and Ql does not conduct.
The forward drop is determined by Ql's on resistance and current
I . The MTH40N05 has an ON resistance of 0.028 0 ; for I= 10 A, the
forward drop is less than 0.3 V. Typically, the best Schottky
diodes do not even begin conducting below a few hundred mV.
-
LOW-RIPPLE POWER SUPPLY
ELECTRONICS TODAY INTERNATIONAL
RJ 10k
+Ve
GND
Fig. 2-36
This circuit can be used where a high current is required with a
low-ripple voltage (such as in a high-powered class AB amplifier
when high-quality reproduction is necessary). Ql, Q2, and R2 can be
regarded as a power-Darlington transistor. ZDl and Rl provide a
reference voltage at the base of Ql . ZDl should be chosen thus:
ZD1 = V001 -l.2. C2 can be chosen for the degree of smoothness as
its value is effectively multiplied by the combined gains of Ql!Q2
, if 100 JLF is chosen for C2, assuming minimum hfe for Ql and Q2,
C=100x15(Ql)x25(Q2)=37,000 J.LF.
5.0-V/10-A REGULATOR
MJ1955 OR EOUIV
MOTOROLA Fig. 2-37
5.0-V/3.0-A REGULATOR
Ill SW MJ010 OR EQUIV
10 V ...... ~NV----..A ')...-------.-..-.
HI aw
MOTOROLA Fig . 2-38
47
