NATIONAL RADIO ASTRONOMY OBSERVATORYGreen Bank, West Virginia

Electronics Division Internal Report No. 138

UNIVERSAL VOLTAGE REGULATOR

Don Q. Morris

FEBRUARY 1974

NUMBER OF COPIES: 150

•• O OOO • •

• •

OOOOO •• • •

UNIVERSAL VOLTAGE REGULATOR

Don Q. Morris

TABLE OF CONTENTS

Page

Introduction • ••• • • • • • • • • •••••••••••••••••••••••••••••• O OOOO ••••••••• 1General Description ... ... ..... . • • ..... • • • • • • • • • • • • • • • • • • • • OOOOOOOOO •

Applications • OOOOOOOOO • • . • • • • • . • • • • • • • . • • • • • • • • • • • • • OOOOOOOOOOOOOOOOOO •

789

101112131415

• • •

• • • • • • • •

• •

2555556677

91010111213141516171819202122

Options 1. Remote voltage control, VL _ 30 V • • • • • • • • • • • • • • • • OOOOO • • OOOOO • • • •

2. Remote sensing • • • OOO • O • • • • •3. Remote metering .. . . . . . . . • • •

4. Remote shutdown • • • • • • • • • •

5. Thermal shutdown ..... ••••••••••••••6.

• • • OOO • O • • • •

• • • • • • •

• • • • • •

• It • • • • • • • • • • • • • • • • • • •

• • • • • • • • • • •

• • • • • • • • • • •

• • • OOOOO • • • • • • • •

Short circuit shutdown, manual reset .......7. Fault indication OOOOOOO OOOOO OOOOO

8. Overvoltage protection ...........••••••••••••••••••••••

• • • • • • • • OOOO • • •

LIST OF FIGURES

1 Packaging of regulator and 0/V protection cards . .. • • • • • • •

2 Regulator card and panel ...... OOOOOOO . . . . • • • • • • • • . • • .

3 Overvoltage protection card and panel • • • • ... ... • • •4 Low current regulator card OOOOO ...... • • • • • • • • . • • • • • • • • • • • • • •5 Regulator card with 13 W heatsink . OOOOOOO • .... ..... • •6 Regulator card assembly .• OOOOO ..•••. O OOOO ••••••••• • • • • 0 •

Overvoltage protection card assembly . . . . • • • • • • • • • • • • • • • • • • • • • • • • • •Application and option chart .......... . • . • • • • • • • • • • • • • • •

Regulator circuit diagram OOOOOOOO ... . . . • • • • • • • • • • • • • • •Overvoltage protection circuit diagram . . • • • • • • • • • • • • • • • • • •••• • •Regulator card layout .... OOOOO .... • • • • • • • • • • • • • • • • • • •Overvoltage protection card layout .. OOOOOOOO ... . . . ...

Heatsink/panel for regulator card ............. • . . ... •13 W heatsink for regulator card OOOOO ......... . . . ... ..

Heatsink/panel for overvoltage protection card . • • • • • • • • • • • • ••

. • • •

(i)

UNIVERSAL VOLTAGE REGULATOR

Don Q. Morris

Introduction

The power supply components to be described in this report were originally

designed to power and protect Gunn diode oscillators having critical operating

parameters. However, they should be suitable for a wide variety of applications

due to the many electrical and mechanical options incorporated.

General Description

1. The voltage regulator card is 2.75 inches wide by 3.43 inches long, to

be used with 15 pin edge connector, Cinch 50-30A-30. The associated panel and/or

heatsink is designed to allow side by side placement of cards on one inch centers.

The regulator circuit is designed around the Motorola integrated circuit voltage

regulator MC 1469R, with the necessary flexibility of connections to satisfy most

voltage regulator needs. It is especially useful when multiple output voltages

are desired without the expense and space required for separate regulated supplies.

2. The overvoltage protection card is the same size and uses the same type

connector as the regulator card. The heatsink and panel (Figure 15) is designed

for side by side mounting with the regulator card using heatsink/panel, Figure 13.

The handles used are H. H. Smith #1641.

The basic circuit is a crowbar with adjustable trip point. When the voltage

across the load exceeds a predetermined level set by R2, Ql triggers driving the

SCR Q2 into full conduction within 0.5 psec. When Q2 is conducting the output is

shorted, blowing fuse Fl.

The trip point bias is derived from the unregulated supply to permit a wide

range of adjustment of trip point.

2

Applications

1. Basic regulator for output voltage of 5 to 30 V and load current to 400 mA.

Use Thermalloy 6168B heatsink or Figure 13 heatsink and panel. Maximum heat

dissipation with either is about 3.5 watts in still air.

See Figure 8 chart for components and jumpers required. Refer to Figures 6

and 9 for connections and locations.

F2, 0.5A

R1 + R2 (2 V out - 7) Kg . R2 may be on remote panel.

R13, select for about 5 inA at desired V out.

R17 = 1.5 Q 1/2 W.

2. Basic regulator for output voltage of 5 to 30 V and load current to 1.2 amp.

Use Figure 13 heatsink/panel for on-board control and up to 3.5 watts dissipa-

tion. For power dissipation up to 13 watts use Figure 14 heatsink and re-

mote controls. If more than 13 watts dissipation is required the heatsink

may be fan cooled or external power transistor and heatsink may be used, as

in Basic Regulator No. 3.

See Figure 8 chart for components and jumpers required. Refer to Figure 6

and Figure 9 for connections and locations.

Fl - 2A

F2 - .5 A

R1 + R2 z (2 V out - 7) KQ

R13 - select for about 5 mA at desired V out.

R14 - 100 Q

R17 - 0.5 Q, 1 W.

FUSEe'\),

R17

+1 14 1011

REGULATOR BOARDSUPPLYVOLTAGE LOAD

15

3

Basic regulator for output voltage of 5 to 30 V and load current above 1.0

amp using external pass transistor.

Use Figure 13 heatsink/panel for on-board control or Figure 14 heatsink with

remote control.

See Figure 8 chart for components and jumpers required. Refer to Figure 9

for connections and Figure 6 for locations.

Fl, 2A

F2, .5 A

R1 + R2 (2 V out - 7) K

R13, select for about 5 mA at desired V out

R14, 100

R15, 100

R17 - use external current limiting resistor = 0.6/I and

sufficient power rating unless using short circuit

shutdown option. With this option a resistor of lower

power rating may be used on the board since it does not

have time to heat up before regulator shutdown.

Connect regulator board and external pass transistor as shown:

SUPPLYVOLTAGE BOARD

VOLTAGEADJUST LOAD

14

REGULATOR

100 iiF •100 V

15

4

4. Basic regulator for output voltage of 30 to 70 V and load current to 1.0 amp.

Use Figure 8 chart for components and jumpers required. Refer to Figure 9

for connections and Figure 6 for locations.

Fl, 2A

F2, .5A

Q3, substitute 2N 5192 (80 V rating)

D2, 1N 4001

VR2 select to provide approximately 30 V at pin 3 of MC 1469R

VR4 same as VR2

R1, 43K, R3, 6.8 K, omit R2

R10, 2K

Select R13, R18, and external pot to provide approximately 25 V at

arm of pot with 1 mA thru divider.

R16, 4.7

R17, 0.5 ohm

Connect external components as shown:

141

LOAD

1

•

SUPPLYVOLTAGE

REGULATOR

BOARD

5

Options

1. Remote voltage control, VL 30 V.

Omit potentiometer R2 and connect an equivalent remote potentiometer to

terminals 3 and 4 of regulator board.

2. Remote sensing.

Omit J10 and Jll on regulator board and add J9.

Make external connections to regulator board as shows:

3. Remote metering.

If desired to monitor regulated voltage and load current over a long cable,

the cable drop may be minimized by using very low current meters with series

multiplier resistors. R18 may be used as the voltmeter multiplier.

The load current may be monitored by metering the voltage drop across R17

with meter current limited by R19.

4. Remote shutdown.

The regulator may be put in a standby condition with zero output by applying

a positive voltage in excess of 1.2 V DC to terminal 6 on the regulator card.

R9 should be selected to limit current to less than 10 mA. One mA is sufficient

to shut down the regulator.

6

5. Thermal shutdown.

The voltage regulator 1C, and Q3 as well, may be protected from destruction

due to excessively high junction temperatures by the addition of VR1, R4, R7,

and R8, which are used to provide a fixed voltage of approximately 1 V at pin 2

of the regulator 1C. This will cause the regulator to shutdown when the tempera-

ture of the chip exceeds approximately 130°C, due to the negative temperature co-

efficient of the diode in series with pin 2 and the base-emitter junction of the

shutdown transistor, both in the regulator 1C.

VR1 = 1N4733A, R4 = 100 (Vs-5), R7 = 2.0 K, R8 = 560 ohm.

6. Short circuit shutdown, manual reset.

This option will latch the regulator into shutdown condition when the voltage

at junction of R12 and R13 drops more than 0.5 volt below the voltage at junction

of R5 and R7. Regulator will remain shutdown until supply voltage to R4 is tem-

porarily removed by means of Si or remotely with a normally closed switch between

Vs and terminal 2 of board. Cl delays initial voltage rise at anode of Q2,

preventing shutdown at initial turn on.

51 N-C PUSHBUTTON, Grayhill 30-2

R4 Vs - 51.015

VR1 1N4733A

Cl 100 pF, 6V

C2 .005 11F

R5 2.0K

R11 820 K

)

R12 Select to provide 5 , V at junction of R12

R13 and R13 at normal output voltage

Q2 2N6027 programmable unijunction

4- 1

SUPPLYVOLTAGE

1 1314

OVERVOLTAGE

PROTECTIONBOARD

REGULATORBOARD

+

LOAD

I -15 15

7

7. Fault indication.

A fault condition indication may be obtained whenever the regulator output

voltage drops below normal with proper supply voltage present by use of PL1, D1,

and VR3. PL1 is a 5 V Eldema lamp, which may be on the regulator board when heat-

sink/panel, Figure 13, is used, or connected to terminals 2 and 13 if remote indi-

cation is desired. D1 is a 1N4002 and serves to isolate the regulator outputs

from each other when multiple regulators are connected to a common fault indicator.

VR3 is a 1W zener diode; its zener voltage should be approximately Vs - (Vs - VL)

-3.

8. Overvoltage protection.

Overvoltage protection for the load may be provided by use of a separate over

voltage protection board PC2-490-4, together with short circuit shutdown and fault

indication options on the regulator board. With this arrangement, when an over-

voltage condition occurs and the SCR on the overvoltage protection card fires, a

short circuit appears at the output of the regulator card and the regulator is shut

down before the fuse can blow. If the regulator transistor should short, the SCR

will protect the load from overvoltage until the fuse blows. The regulator and

overvoltage protection cards should be interconnected as follows:

8. Overvoltage protection (continued):

The following parts are required for the overvoltage protection board:

(1) PC board PC2-490-4

(1) Heatsink/panel, Figure 15

(1) Handle, H. H. Smith #1641

(1) Fuse holder, Littlefuse #281002

(1) Fuse, Fl, Littlefuse Series 273.000

(3) Tip jacks, H. H. Smith #1501 or similar

(1) 5 K potentiometer, R2, Beckman 55LR5K with 55BW bushing mount

(1) Diode DI, 1N4002

(1) Zener diode VR1, Vz VL

(1) Resistor R1 = 60 (Vs - Vz)

(1) Resistor R3 = 5 K

(1) Resistor R4 = 1 megohm

(1) Resistor R5 = 100 ohm

(1) Capacitor, electrolytic, Cl = 10 pF at W.V. > Vs

(1) Capacitor, disc, C2 = .005 pF

(1) Programmable unijunction transistor Ql = 2N6027

(1) Silicon controlled rectifier Q2 = 2N4443 (UPTO 8A)

Refer to Figure 6 for component layout and Figure 9 for circuit diagram.

When setting up the trip point, adjust R2 to set voltage at VTP to 0.6 V below

desired maximum voltage at VL.

Compact arrangement of

4 regulator cards and

4 overvoltage protection

cards in package 3x4x9 in.

Figure 1

• •••;•,.

••

•

•,.••

•

Figure 2 -- Voltage regulator card

Figure 3 -- Overvoltage protection

with Fig. 13 panel and

card with Fig. 15 as

heatsink, and handle.

panel/heatsink with handle.

Figure 4 -- Regulator card for low

current applications

(up to 400 mA) not re-

quiring front panel/heat-

sink

.

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5.THERMAL SHUTDOWN

6.SHORT CIRCUIT SHUTDOWN

7.FAULT INDICATION

8.OVERVOLTAGE PROTECTION

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PC2-490-32-15-73

Figure 11 -- Voltage Regulator Card Layout

- 19 -

Figure 12 -- Overvoltage Protection Card Layout

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