HP (Hewlett-Packard) 6205B User Manual
TM 11-6625-2965-14&P
TECHNICAL MANUAL
OPERATOR’S ORGANIZATIONAL
DIRECT SUPPORT AND GENERAL SUPPORT
MAINTENANCE MANUAL
[INCLUDING REPAIR PARTS
AND SPECIAL TOOLS LISTS]
POWER SUPPLY PP-7548/U
(HEWLETT-PACKARD MODEL 6205B]
[NSN 6625-00-437-4861]
HEADQUARTERS, DEPARTMENT OF THE ARMY
25 FEBRUARY 1980
WARNING
HIGH VOLTAGE is used during the performance of maintenance as
instructed in this manual. DEATH ON CONTACT may result if personnel
fail to observe safety precautions.
DO NOT ATTEMPT to make internal connections or perform adjustments
unless another person, capable of performing first aid, is present.
For electric shock protection, use only extension cord and power receptacles
with a safety-ground connector, or otherwise connect the chassis to a safety
ground.
CERTIFICATION
The Hewlett-Packard Company certifies that this instrument was thoroughly
tested and inspected and found to meet its published specifications when it
shipped from the factory. The Hewlett-Packard Company further certifies that
its calibration measurements are traceable to the U.S. National Bureau of
Standards to the extent allowed by the Bureau’s calibration facility.
Was
WARRANTY AND ASSISTANCE
All Hewlett-Packard products are warranted against defects in materials and
workmanship. This warranty applies for one year from the date of delivery, or,
in the case of certain major components listed in the operating manual, for the
specified period. We will repair or replace products which prove to be
defective during the warranty period. No other warranty is expressed or
implied. We are not liable for consequential damages.
TM 11-6625-2965-14&P
This manual contains copyright material reproduced by permission of Hewlett-Packard Company
TECHNICAL MANUAL
HEADQUARTERS
DEPARTMENT OF THE ARMY
W
No. 11-6625-2965-14&P
OPERATOR’S, ORGANIZATIONAL, DIRECT SUPPORT AND
GENERAL SUPPORT MAINTENANCE MANUAL
(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LISTS)
ASHINGTON, DC, 25 February 1980
POWER SUPPLY PP-7548/U (HEWLETT-PACKARD MODEL)
(NSN 6625-00-437-4861)
REPORTING OF ERRORS
Y
OU can improve this manual by recommending improvements using DA Form 2028-2
located in the back of the manual. Simply tear out the self-addressed form, fill it out as shown on
the sample, fold it where shown, and drop it in the mail.
If there are no blank DA Forms 2028-2 in the back of your manual, use the standard DA
Form 2028 (Recommended Changes to Publications and Blank Forms) and forward to the
Commander, US Army Communications and Electronics Materiel Readiness Command, ATTN:
DRSEL-ME-MQ, Fort Monmouth, NJ 07703.
In either case a reply will be furnished direct to you.
This manual is an authentication of the manufacturer’s commercial literature which, through usage, has been
found to cover the data required to operate and maintain this equipment. Since the manual was not prepared
in accordance with military specifications, the format has not been structured to consider levels of
maintenance.
TABLE OF CONTENTS
TM 11-6625-2965-14&P
Section Page No.
O INSTRUCTIONS . . . . . . . . . . . . . . . . 0-1
0-l Scope
0-1
0-2 Indexes of Publications 0-1
0-3 Maintenance Forms,
Records and Reports
0-1
0-4 Reporting Equipment
Section
3-38
Special Operating Con-
siderations
Pulse Loading
3-39
3-41
Output Capacitance
3-43
Reverse Voltage Loading
3-45
Reverse Current Loading
Improvement Recommen-
dations (EIR)
0-5 Administrative Storage 0-1
0-6 Destruction of Army
Electronics Materiel 0-1
I
GENERAL INFORMATION . . . . . . . . . . . 1-1
1-1 Description
1-6 Specifications
1-8 Options
1-10 Accessories
1-12 Instrument and Service Man-
ual Identification
1-15 Ordering Additional Manuals 1-2
II INSTALLATION
2-1
Initia1 Inspection
Mechanical Check
2-3
Electrical Check
2-5
Installation Data
2-7
Location
2-9
Outline Diagram
2-11
Rack Mounting
2-13
2-17
Input Power Requirements
2-19
Connections for 230 Volt
Operation
Power Cable
2-21
2-24
Repackaging for Shipment
I I I OPERATING INSTRUCTIONS . . . . . . . . 3-1
3-1
Turn-on Checkout Procedure
3-3
Operating Modes
3-5
Norma1 Operating Mode
3-7
Constant Voltage
3-9
Changing Current Limit
3-11
Connecting Load
3-14
Operation Beyond Norma 1
Rated Output
3-16
Optional Operating Modes
3-17
Remote Programming, Con-
stant Voltage
3-25
Remote Sensing
3-30
Series Operation
3-35
Auto-Tracking Operation
. . . . . . . . . . . . . . . . . . .
0-1
1-1
1-1
1-1
1-2
1-2
2-1
2-1
2-1
2-1
2-1
2-1
2-1
2-1
2-3
2-3
2-3
2-3
3-1
3-1
3-1
3-1
3-2
3-2
3-2
3-2
3-2
3-3
3-4
3-5
IV PRINCIPLES OF OPERATION . . . . . . . . 4-1
4-1
Overall Description
4-8 Detailed Circuit Analysis
4-9 Feedback Loop
4-13 Series Regulator
4-15 Constant Voltage Comparator 4-2
4-19 Error Amplifier and Driver
4-22 Current Limit Circuit
4-26 Reference Circuit
4-29 Meter Circuit
V MAINTENANCE
5-1
Introduction
5-3
General Measurement
Techniques
5-8
Test Equipment Required
Performance Test
5-10
5-12
Constant Voltage Tests
5-38
Output Impedance
Troubleshooting
5-48
5-53
Overa11 Troubleshooting
Procedure
5-58
Repair and Replacement
5-60
Adjustment and Calibration
Meter Zero
5-62
5-64
Ammeter Tracking
5-66
Constant Voltage Programming
Current
5-69
Reference Circuit Adjustments
5-71
Constant Voltage Transient
Recovery Time
5-73
Current Limit Adjustment
VI REPLACEABLE PARTS . . . . . . . . . . .
6-1 Introduction 6-1
6-4 Ordering Information
APPENDIX A
B
C
D
VII CIRCUIT
Page No.
. . . . . . . . . . . . . . . . . . .
References
Components of End
Item
Maintenance
Allocation
Manual
Changes
DIAGRAMS
backdating
........... 7-1
3-6
3-6
3-6
3-6
3-6
4-1
4-2
4-2
4-2
4-2
4-3
4-3
4-3
5-1
5-1
5-1
5-2
5-3
5-3
5-7
5-9
5-9
5-12
5-13
5-13
5-13
5-13
5-15
5-15
5-15
. . . . 6-1
6-1
A-1
B-1
C-1
ii
TM 11-6625-2965-14&P
LIST OF ILLUSTRATIONS
Figure
2-1
2-2
2-3
2-4
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
4-1
Page No.
Outline Diagram 2-1
Rack Mounting, Two Units 2-2
Rack Mounting, One Unit 2-2
Primary Connections 2-3
Front Panel Controls and Indicators 3-1
Normal Strapping Pattern
Current Limit Alteration
Remote Resistance Programming 3-3
Remote Voltage Programming
Remote Sensing 3-3
Norma I Series Connections 3-4
Auto-Series, Two and Three Units 3-4
Auto-Parallel, Two and Three
Units
Auto-Tracking, Two and Three
Units 3-5
Overa11 Block Diagram 4-1
3-1
3-2
3-3
3-5
LIST OF TABLES
Figure
4-2
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
Page No.
Multiple Range Meter Circuit,
Simplified Schematic
Front Panel Terminal Connections 5-1
Output Current Measurement
Technique
Differential Voltmeter Substitute,
Test Setup
Output Current, Test Setup 5-4
Load Regulation, Test Setup
CV Ripple and Noise, Test Setup 5-5
CV Noise Spike, Test Setup
Transient Recovery Time,
Test Setup
Transient Recovery Time,
Waveforms
Output Impedance, Test Setup
Servicing Printed Wiring Boards
4-4
5-1
5-2
5-4
5-6
5-7
5-7
5-8
5-14
Table
1-1 Specifications
5-1 Test Equipment Required
5-2 Reference Circuit Troubleshooting
5-3 Overall Trouble shooting 5-9
5-4 High Output Voltage Troubleshooting
5-5 Low Output Voltage Troubleshooting
5-6 Selected Semiconductor Characteristics
5-7 Checks and Adjustments After Replacement of Semiconductor Devices 5-12
6-1 Reference Designators
6-2 Description Abbreviations
6-3 Code List of Manufacturers
6-4 Replaceable Parts
Page No.
1-3
5-2
5-9
5-11
5-11
5-12
6-1
6-1
6-2
6-5
iii
SECTION O
INSTRUCTIONS
TM 11-6625-2965-14&P
0-1.
Model 6205) having serial prefix number 7L2301 and up. For serial prefixes
below 7L2301 refer to Appendix E.
inclusion of change page.
0-2.
whether there are new editions , changes, or additional publications pertain-
ing to the equipment.
modification work orders (MWO
0-3.
the Army forms and procedures used for equipment maintenance will be those
described by TM 38-750, The Army Maintenance Management System,
DD Form 6 (Packaging Improvement Report) as prescribed in AR 700-58/
NAVSUPINST 4030.29/AFR 71-12/MCO P4030.29A, and DLAR 4145.8.
SCOPE
This manual applies directly to Power Supply PP-7548/U (Hewlett-Packard
For serials above 7L4450 check for
INDEXES OF PUBLICATIONS
DA Pam 310-4.
a.
b.
DA Pam 310-7.
MAINTENANCE FORMS, RECORDS AND REPORTS
a.
Reports of Maintenance and Unsatisfactory Equipment.
b.
Report of Packaging and Handling Deficiencies.
Refer to the latest issue of DA Pam 310-4 to determine
Refer to DA Pam 310-7 to determine whether there are
S
) pertaining to the equipment.
Department of
Fill out and forward
c.
Discrepancy in Shipment Report (DISREP) (SF 361). Fill out and
forward Discrepancy in Shipment Report (DISREP) (SF 361) as prescribed in
AR 55-38/NAVSUPINST 4610.33B/AFR 75-18/MCO P461O.19C and DLAR 4500.15.
0-4.
Send us an EIR.
don’t like about your equipment.
Tell us why a procedure is hard to perform.
Deficiency Report).
Electronics Materiel Readiness Command and Fort Monmouth, ATTN: DRSEL-ME-
MQ, Fort Monmouth, New Jersey 07703. We'll send yOu a reply.
0-5.
shall be in accordance with paragraph 2-5.
0-6.
accordance with TM 750-244-2.
REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS(EIR)
If your Power Supply PP-7548/U (HP-6205) needs improvement, let us know.
You, the user,
Mail it to Commander, US Army Communications and
ADMINISTRATIVE STORAGE
Administrative storage of equipment issued to and used by Army activities
DESTRUCTION OF ARMY ELECTRONICS MATERIEL
Destruction of Army electronics materiel to prevent enemy use shall be in
are the only one who can tell us what you
Let us know why you don’t like the design.
Put it on an SF 368 (Quality
0-1
TM 11-6625-2965-14&P
1-1 DESCRIPTION
1-2
This power supply, Figure 1-1, is completely
transistorized and suitable for either bench or relay rack operations, The dual supply consists of
two independently controlled dual range sections;
both identical to the other. Each section can fur-
nish either a 0-40 Volt output at 300mA or a 0-20
Volt output at 600mA. Each section has its own
front panel meter and operating controls, The oper-
ating modes (40V or 20V) are selected by means of
the front panel RANGE switches, The VOLTAGE controls permit each output voltage to be continuously
adjusted throughout either output range.
may be programmed from a remote location by
means of an external voltage source or resistance.
b. Remote Sensing. The degradation in
regulation which would occur at the load because
of the voltage drop which takes place in the load
leads can be reduced by using the power supply in
the remote sensing mode of operation.
c. Series and Auto-Series Operation, Power
supplies may be used in series when a higher output voltage is required in the voltage mode of operation or when greater voltage compliance is required in the constant current mode of operation,
Auto-Series operation permits one knob control of
the total output voltage from a “master” supply.
d. Parallel and Auto-Parallel Operation, The
power supply may be operated in parallel with a
similar unit when greater output current capability
is required.
knob control of the total output current from a
“master” supply.
e. Auto-Tracking.
used as a “master” supply, having control over one
(or more) “slave”
ages for a system.
1-6 SPECIFICATIONS
Auto-Parallel operation permits one
The power supply may be
supplies that furnish various volt-
Figure 1-1. DC Power Supply, Model 6205B
1-3 Both sections of the supply are of the regulated, Constant Voltage/Current Limiting, type.
Each section is fully protected from overloads by
the fixed current limit which is set by means of an
internal adjustment.
1-4 Both front and rear terminals are available
for each section. Either the positive or negative
terminals may be grounded or the supply can be
operated at up to a maximum of 300 Volts off ground.
Each meter can be used to measure either output
voltage or output current in one of two ranges. The
voltage or current ranges are selected by the ap-
plicable METER switch on the front panel.
1-5 Two sets of programming terminals, located
at the rear of the unit, allow ease in adapting to
the many operational capabilities of the supply. A
brief description of these capabilities is given
below:
a, Remote Programming,
The power supply
1-7 Detailed specifications for the power supply
are given in Table 1-1.
1-8 OPTIONS
1-9 Options are factory modifications of a standard instrument that are requested by the customer.
The following options are available for the instru-
ment covered by this manual, Where necessary, de-
tailed coverage of the options is included through-
out the manual.
Option No.
07
11
Voltage 10-Turn Pot: A single control
that replaces both coarse and fine
voltage controls and improves output
nettability.
Overvoltage_Protection_“Crowbar”:
A completely separate circuit for protecting delicate loads against power
supply failure or operator error. This
independent device monitors the output voltage and within 10µsec imposes
a virtual short-circuit (crowbar) across
the power supply output if the preset
Description
11
TM 11-6625-2965-14P
trip voltage is exceeded. When Option 11 is requested by the customer
the device is connected at the factory.
Trip Voltage Range: 2.5 to 44 Volts,
screwdriver adjustable.
Detailed coverage of Option 11 is included in Appendix A at the rear of
manuals that support power supplies
containing Option 11.
13
28
1-10 ACCESSORIES
1-11 The accessories listed in the following chart
may be ordered with the power supply or separately
from your local Hewlett-Packard field sales office
(refer to list at rear of manual for addresses).
Three Digit Graduated Decadial
Voltage Control: Control that replaces
coarse and fine voltage controls permitting accurate resettability.
230Vac Input:
shipped is wired for l15Vac input.
Option 28 consists of reconnecting
the input transformer for 230Vac operation.
Supply as normally
14523A
1-12 INSTRUMENT AND SERVICE MANUAL
IDENTIFICATION
1-13 Hewlett-Packard power supplies are identified by a three-part serial number tag. The first
part is the power supply model number. The second part is the serial number prefix, which consists of a number-letter combination that denotes
the date of a significant design change. The number designates the year, and the letter A through
L designates the month, January through December
respectively, with “I” omitted. The third part is
the power supply serial number.
1-14 If the serial number prefix on your power
supply does not agree with the prefix on the title
page of this manual, change sheets are included
to update the manual. Where applicable, backdating information is given in an appendix at the
rear of the manual.
ORDERING ADDITIONAL MANUALS
1-15
Rack Kit for mounting two 3½” high
supplies. (Refer to Section II for de-
tails.)
C05
14513A
Description
8” Black Handle that can be attach-
ed to side of supply.
Rack Kit for mounting one 3½” high
supply. (Refer to Section II for details.)
1-16
One manual is shipped with each power supply, Additional manuals may be purchased from
your local Hewlett-Packard field office (see list
at rear of this manual for addresses). Specify the
model number, serial number prefix, and Part
number provided on the title page.
1-2
Table 1-1.
Specifications
TM 11-6625-2965-14&P
INPUT:
l15Vac ±10%, single phase, 48-440 Hz.
OUTPUT:
Two independent outputs, each of which can
be set at either 0-40 Volts @ 0.3 Amp or 0-20
Volts @ 0.6 Amp.
LOAD REGULATION:
Less than 0,01% plus 4mV for a full load to no
load change in output current.
LINE REGULATION:
Less than 0.01% plus 4mV for any line voltage
change within the input rating.
RIPPLE AND NOISE:
Less than 200µVrms 1mV p-p,
TEMPERATURE RANGES:
operating: 0 to 50°C. Storage: -40 to + 750C.
TEMPERATURE COEFFICIENT:
Less than 0.02% plus lmV per degree Centi-
grade.
STABILITY.
Less than 0.10% plus 5mV total drift for 8
hours after an initial warm-up time of 30 minutes at constant ambient, constant line voltage,
and constant load.
INTERNAL IMPEDANCE AS A CONSTANT VOLT-
AGE SOURCE:
Less than 0.02 ohms from dc to lkHz.
Less than 0.5 ohms from lkHz to 1OOkHz.
Less than 3.0 ohms from 1OOkHz to lMHz.
TRANSIENT RECOVERY TIME:
Less than 50µsec for output recovery to with-
in 10mV following a full load current change in
the output.
OVERLOAD PROTECTION:
A fixed current limiting circuit protects the
power supply for all overloads including a
direct short placed across the terminals in con-
stant voltage operation.
METERS:
Each front panel meter can be used as either a
0-50 or 0-5 Volt voltmeter or as a 0-0.75 or
0.075 Amp ammeter.
OUTPUT CONTROLS:
RANGE switches select desired operating mode
for each section and coarse and fine VOLTAGE
controls set desired output voltages.
OUTPUT TERMINALS:
Six “five-way” output posts (three for each
section of supply) are provided on the front
panel and two output terminal strips (one per
section) are located on the rear of the chassis.
A1l power supply output terminals are isolated
from the chassis and either the positive or negative terminals may be connected to the chassis
through separate ground terminals located on
the output termina1 strips.
ERROR SENSING:
Error sensing is normally accomplished at the
front terminals if the load is attached to the
front or at the rear terminals if the load is at-
tached to the rear terminals. Also, provisions
are included on the rear termina1 strips for remote sensing.
REMOTE RESISTANCE PROGRAMMING:
200 ohms per Volt.
REMOTE VOLTAGE PROGRAM MING:
1 Volt per Volt.
COOLING:
Convection cooling is employed. The supply
has no moving parts.
SIZE:
3~½" H x 12-5/8" D x 8½" W. Two of the units
can be mounted side by side in a standard 19”
relay rack.
WEIGHT:
10 lbs, net, 13 lbs. shipping.
FINISH:
Light gray front panel with dark gray case.
POWER CORD:
A three-wire, five-foot power cord is provided
with each unit.
1-3
TM 11-6625-2965-14&P
SECTION II
INSTALLATION
2-1 INITIAL INSPECTION
2-2 Before shipment, this instrument was in-
spected and found to be free of mechanical and
electrical defects. As soon as the instrument is
unpacked,
occurred in transit. Save all packing materials
until the inspection is completed. If damage is
found, a claim should be filed with the carrier.
Hewlett-Packard Sales and Service office should
be notified.
2-3 MECHANICAL CHECK
2-4 This check should confirm that there are no
broken knobs or connectors, that the cabinet and
panel surfaces are free of dents and scratches,
and that the meter is not scratched or cracked.
2-5
inspect for any damage that may have
ELECTRICAL CHECK
2-6 The instrument should be checked against its
electrical specifications. Section V includes an
“ in-cabinet” performance check to verify proper
instrument operation,
2-7 INSTALLATION DATA
2-8 The instrument is shipped ready for bench
operation. It is necessary only to connect the instrument to a source of power and it is ready for
operation.
2-9 LOCATION
2-10 This instrument is air cooled. Sufficient
space should be allotted so that a free flow of
cooling air can reach the sides and rear of the in-
strument when it is in operation. It should be used
in an area where the ambient temperature does not
exceed 50°C.
2-11 OUTLINE DIAGRAM
2-12 Figure 2-1 is an outline diagram showing the
dimensions of the instrument.
2-13 RACK MOUNTING
2-14 This instrument may be rack mounted in a
standard 19 inch rack panel either alongside a
similar unit or by itself. Figures 2-2 and 2-3 show
Figure 2-1. Outline Diagram
how both types of installations are accomplished.
2-15 To mount two units side-by-side, proceed
as follows:
a. Remove the four screws from the front
panels of both units.
b. Slide rack mounting ears between the
front panel and case of each unit.
c. Slide combining strip between the front
panels and cases of the two units.
d. After fastening rear portions of units together using the bolt, nut, and spacer, replace
panel screws.
2-16 To mount a single unit in the rack panel,
proceed as follows:
a. Bolt rack mounting ears, combining
straps, and angle brackets to each side of center
2-1
TM 11-6625-2965-14&P
Figure 2-2. Rack Mounting, Two Units
Figure 2-3.
Rack Mounting, One Unit
TM 11-6625-2965-14&P
spacing panels. Angle brackets are placed behind
combining straps as shown in Figure 2-3.
b. Remove four screws from front panel of
unit.
Slide combining strips between front
c.
panel and case of unit.
d. Bolt angle brackets to front sides of case
and replace front panel screws.
2-17 INPUT POWER REQUIREMENTS
2-18 This power supply may be operated from
either a nominal 115 Volt or 230 Volt 48-440 Hertz
power source. The unit, as shipped from the factory, is wired for 115 Volt operation. The input
power required when operated from a 115 Volt 60
Hertz power source at full load is 31 Watts and
0.35 Amperes.
2-19 CONNECTIONS FOR 230 VOLT OPERATION
2-20 Normally, the two primary windings of the
input transformer are connected in parallel for operation from 115 Volt source. To convert the power
supply to operation from a 230 Volt source, the
power transformer windings are connected in series
as follows:
a.
Unplug the line cord and remove the unit
from case.
b. Break the copper between 54 and 55 and
also between 50 and 51 on the printed circuit
board. The se are shown in Figure 2-4, and are
labeled on copper side of printed circuit board.
Add strap between 50 and 55.
c.
d. Replace existing fuse with 1 Ampere,
230 Volt fuse.
normally.
Return unit to case and operate
2-21 POWER CABLE
2-22 To protect operating personnel, the National
Electrical Manufacturers Association (NEMA) recommends that the instrument panel and cabinet be
grounded. This instrument is equipped with a
three conductor power cable. The third conductor
is the ground conductor and when the cable is
plugged into an appropriate receptacle, the instrument is grounded. The offset pin on the power
cable three-prong connector is the ground connection.
2-23 To preserve the protection feature when operating the instrument from a two-contact outlet,
use a three-prong to two-prong adapter and connect the green lead on the adapter to ground.
2-24 REPACKAGING FOR SHIPMENT
2-25 To insure safe shipment of the instrument, it
is recommended that the package designed for the
Figure 2-4.
instrument be used. The original packaging material is reusable. If it is not available, contact
your local Hewlett-Packard field office to obtain
the materials. This office will also furnish the
address of the nearest service office to which the
instrument can be shipped. Be sure to attach a
tag to the instrument which specifies the owner,
model number, full serial number, and service re-
quired, or a brief description of the trouble,
2-3
Primary Connections
SECTION Ill
OPERATING INSTRUCTIONS
TM 11-6625-2965-14&P
3-1 TURN-ON CHECKOUT PROCEDURE
Figure 3-1.
3-2 The front panel controls and indicators are
shown in Figure 3-1.
is described below:
A. Push ON/OFF button
that button lights,
B. Set range switch
mode and meter switch to desired voltage range.
C. Adjust coarse and fine voltage controls
Front Panel Controls and Indicators
The normal turn-on sequence,
① and observe
② to desired operating
③ until desired output voltage is indicated on
meter.
Set meter switch to highest current range
D.
and short
meter.
terminals
be used for both sections of supply.
circuit output terminals.
E.
Observe short circuit output current on
Remove short and connect load to output
F.
(front or rear),
For Model 6205B, this procedure should
G.
erational capabilities of the supply. A more theoretical description concerning these operational
features is contained in Application Note 90 and
in various Tech Letters. Copies of these can be
obtained from your local Hewlett-Packard field
office,
3-5 NORMAL OPERATING MODE
3-6 The power supply is normally shipped with
its rear terminal strapping connections arranged
for Constant Voltage/Current Limiting, local sensing, local programming, single unit mode of operation. This strapping pattern is illustrated in Figure 3-2. The operator selects a constant voltage
output using the front panel controls (local programming, no strapping changes are necessary).
Figure 3-2.
Norma 1 Strapping Pattern
3-3 OPERATING MODES
3-4 The power supply is designed so that its
mode of operation can be selected by making
strapping connections between particular terminals
on the terminal strip at the rear of the power supply.
The terminal designations are stenciled in
white on the power supply above their respective
terminals. Although the strapping patterns illustrated in this section show the positive terminal
grounded, the operator can ground either termina1
or operate the power supply up to 300Vdc off
ground (floating). The following paragraphs describe the procedures for utilizing the various op-
3-7 CONSTANT VOLTAGE
3-8 To select a constant voltage output turn on
the supply and, with no load connected, adjust
the VOLTAGE controls for the desired output volt-
age. To check the current limit, connect an ex-
ternal ammeter across the output of the
turn the VOLTAGE controls fully clockwise, and
observe the reading.
adjusted to approximately 100mA above the current
rating of the supply.
is not compatible with the anticipated load requirements, the limit can be changed as outlined
in the following paragraphs.
3-1
The current limit is factory
If the existing current limit
supply,
TM 11-6625-2965-14&P
3-9 CHANGING CURRENT LIMIT
3-10 The current limit can be varied by adjusting
resistor R81, located on the printed wiring board.
This adjustment procedure is described in Paragraph 5-74. In Models 6204B and 6206B, the current limit may be reduced to a value lower than
that attainable by adjusting R81, by adding an external resistor as shown in Figure 3-3. The approximate value of the external resistance (Rx) can
be determined by using the following equation
=1.75
R
X
I
E
where: I = the output current
E
R = the internal current sampling resist-
I
ance for the particular operating mode
to be used.
1.75 . the approximate voltage drop across
the internal sampling resistance at
the current limit crossover point.
NOTE
The power supply’s performance will
be somewhat degraded if it is operated
too close to (within 10OmA) the current
limit crossover point.
3-13 If load considerations require that the output
power distribution terminals be remotely located
from the power supply, then the power supply output terminals should be connected to the remote
distribution terminals via a pair of twisted or
shielded wires and each load separately connected
to the remote distribution termina1s. For this case,
remote sensing should be used (Paragraph 3-25).
3-14 OPERATION BEYOND NORMAL RATED OUTPUT
3-15 Although the supply can deliver greater than
the rated output on both the lower and higher voltage ranges without being damaged, it can not be
guaranteed to meet all of its performance specifications.
Generally when operating the supply in
this manner, the output is unstable when connected to a load.
When greater than the lower rated
voltage is required, the higher voltage range
should be used.
This range will deliver half as
much output current and all specifications will
apply as listed in Table 1-1. However, if the line
voltage is maintained above its nomina1 value, the
supply will probably operate within specifications
above its rated output.
3-16 OPTIONAL OPERATING MODES
3-17 REMOTE PROGRAMMING, CONSTANT VOLTAGE
A1 A2 A6 A7 A8 A9 -S – GND + +S A10
Rx
Figure 3-3.
Current Limit Alteration
R
L
3-11 CONNECTING LOAD
3-12 Each load should be connected to the power
supply output terminals using separate pairs of
connecting wires.
This will minimize mutual cou-
pling effects between loads and will retain full
advantage of the low output impedance of the power
supply.
Each pair of connecting wires should be
as short as possible and twisted or shielded to reduce noise pickup. (If shield is used, connect one
end to power supply ground terminal and leave the
other end unconnected. )
3-18 The constant voltage output of the power
supply can be programmed (controlled) from a remote location if required. Either a resistance or
voltage source can be used for the programming
device.
The wires connecting the programming
terminals of the supply to the remote programming
device should be twisted or shielded to reduce
noise pickup. The VOLTAGE controls on the front
panel are disabled according to the following pro-
cedures.
3-19 Resistance Programming (Figure 3-4). In
this mode, the output voltage will vary at a rate
determined by the programming coefficient (200
ohms per Volt for Model 6204B and 6205B or 300
ohms per Volt for Model 6206 B). The output voltage will increase by 1 Volt for each 200 ohms (or
300 ohms) added in series with the programming
terminals. The programming accuracy is 1% of the
programmed voltage. If greater programming ac-
curacy is required, it may be achieved by chang-
ing resistor R13 as outlined in Section V.
3-20 The output voltage of the power supply
should be zero Volts ± 20 millivolts when zero
ohms is connected across the programming terminals. If a zero ohm voltage closer than this is required, it may be achieved by changing resistor
R6 or R8 as described in Section V.
3-2
A7 A6 A8 A10+S + GND - –S
Figure 3-4.
PROGRAMMING
RESISTOR
Remote Resistance Programming
R
L
3-21 To maintain the stability and temperature
coefficient of the power supply, u se programming
resistors that have stable, low noise, and low
temperature (less than 30ppm per degree Centigrade) characteristics. A switch can be used in
conjunction with various resistance values in
order to obtain discrete output voltages.
The
switch should have make-before-break contacts
to avoid momentarily opening the programming
terminals during the switching interval.
TM 11-6625-2965-14&P
programming voltage source should be approximately 1000 ohms if the temperature and stability
specifications of the power supply are to be maintained. The programming accuracy is 1% of the
programmed voltage.
3-24 Methods of voltage programming with gain
are discussed in Application Note 90, Power Supply
Handbook; available at no charge from your local
Sales Office.
3-25 REMOTE SENSING (See Figure 3-6)
3-26 Remote sensing is used to maintain good
regulation at the load and reduce the degradation
of regulation which would occur due to the voltage
drop in the leads between the power supply and
the load. Remote sensing is accomplished by uti-
lizing the strapping pattern shown in Figure 3-6.
The power supply should be turned off before
changing strapping patterns. The leads from the
+S terminals to the load will carry less than 10
milliamperes of current, and it is not required that
these leads be as heavy as the load leads. However, they must be twisted or shielded to minimize
noise pick-up.
CAUTION
3-22 Voltage Programming (Figure 3-5). Employ
the strapping pattern shown on Figure 3-5 for
voltage programming.
In this mode, the output
voltage will vary in a 1 to 1 ratio with the pro-
gramming voltage (reference voltage) and the load
on the programming voltage source will not exceed
25 microampere.
A7 A6 A8 A10 +S + GND - -S
REFERENCE
VOLTAGE
Figure 3-5. Remote Voltage Programming
3-23 The impedance (Rx) looking into the external
Observe polarity when connecting the
sensing leads to the load.
A7 A6 A8 A10+S + AND– –S
R
L
Figure 3-6. Remote Sensing
3-27 For reasonable load lead lengths, remote
sensing greatly improves the performance of the
supply. However, if the load is located a consid-
erable distance from the supply, added precautions
must be observed to obtain satisfactory operation.
Notice that the voltage drop in the load leads sub-
3-3
TM 11-6625-2965-14&P
tracts directly from the available output voltage
and also reduces the amplitude of the feedback error signals that are developed within the unit. Because of these factors it is recommended that the
drop in each load lead not exceed 1 Volt. If a
larger drop must be tolerated, please consuIt a
sales
engineer.
NOTE
Due to the voltage drop in the load
leads, it may be necessary to readjust
the current limit in the remote sensing
mode.
3-28
Another factor that must be considered is
the inductance of long load leads which could affect the stability of the feedback loop and cause
oscillation. In these cases, it is recommended
that the output capacitor (C20) be physically removed from the power supply and placed across
the output terminals.
3-29 Although the strapping patterns shown in
Figures 3-4 and 3-5 employ local sensing, notice
that it is possible to operate a power supply simultaneously in the remote sensing and the remote
programming modes.
ages of the individual supplies. Each of the individual supplies must be adjusted in order to obtain
the total output voltage. The power supply contains a protective diode connected internally
across the output which protects the supply if one
power supply is turned off while its series partner(s) is on.
3-32 Auto-Series Connections (Figure 3-8). The
Auto-Series configuration is used when it is desirable to have the output voltage of each of the
series connected supplies vary in accordance with
the setting of a control unit. The control unit is
called the master; the controlled units are called
slaves. At maximum output voltage, the voltage
of the slaves is determined by the setting of the
front panel VOLTAGE control on the master. The
master supply must be the most positive supply of
the series.
The current limit settings of all series
3-30 SERIES OPERATION
3-31 Normal Series Connections (Figure 3-7).
Two or more power supplies can be operated in
series to obtain a higher voltage than that available from a single supply. When this configuration
is used, the output voltage is the sum of the volt-
A7 A6 A8 A10-S + GND – –S
A7 A6 A8 A10 - S + GND – –S
Figure 3-7. Normal Series Connections
Figure 3-8, Auto-Series, Two and Three Units
3-4
units are effective and the current limit for the
entire configuration is equal to the lowest current
limit setting. If any of the settings are too low,
automatic crossover to current limiting operation
will occur and the output voltage will drop. Re-
mote sensing and programming can be used; however, the strapping arrangements shown in the applicable figures show local sensing and programming.
3-33 In order to maintain the temperature coeffi-
cient and stability specifications of the power
supply, the external resistors (Rx) shown in Figure
3-8 should be stable, low noise, low temperature
coefficient (less than 30ppm per degree Centigrade)
resistors. The value of each resistor is dependant
on the maximum voltage rating of the master sup-
ply,
The value of Rx is this voltage divided by the
voltage programming current of the slave supply
(l/Kp where Kp is the voltage programming coeffi-
cient). The voltage contribution of the slave is
determined by its voltage control setting.
TM 11-6625-2965-14&P
3-34 Auto-Parallel. The strapping patterns for
Auto-Parallel operation of two and three
plies are shown in Figure 3-9. Auto-Parallel operation permits equal current sharing under all load
conditions, and allows complete control of the output current from one master power supply. The output current of each slave will be approximately
equal to the master’s regardless of the load conditions. Because the output current controls of each
slave are operative, they should be set to maximum
to avoid having the slave revert to constant current
operation; this would occur if the master output
current setting exceeded the slave’s. In Model
6205B, it is necessary to make internal connections
in order to operate the supply in this mode. The
internal connections, specified in Figure 3-9,
made to the sampling terminals of the current sam-
pling terminals of the current sampling resistor,
R54 (see Figure 5-2).
power sup-
are
3-5
TM 11-6625-2965-14&P
3-35 AUTO-TRACKING OPERATION (See Figure 3-10)
3-36 The Auto-Tracking configuration is used
when it is necessary that several different voltages
referred to a common bus, vary in proportion to the
setting of a particular instrument (the control or
master).
A fraction of the master’s output voltage
is fed to the comparison amplifier of the slave supply, thus controlling the slave’s output. The master must have the largest output voltage of any
power supply in the group (must be the most posi-
tive supply in the example shown on Figure 3-10).
3-37 The output voltage of the slave is a percentage of the master’s output voltage, and is determined by the voltage divider consisting of R
Rx and R
supply, R
Y) and the voltage control of the slave
, where:
p
E
M RP
E = Rx+Rp
S
Turn-on and turn-off of the power supplies is controlled by the master.
Remote sensing and programming can be used; although the strapping patterns for these modes show only local sensing and
programming.
In order to maintain the temperature
coefficient and stability specifications of the pow-
er supply, the external resistors should be stable,
low noise, low temperature (less than 30ppm per
O
C) resistors.
3-38
SPECIAL OPERATING CONSIDERATIONS
X (or
not desired, set the preset limit for the peak requirement and not the average.
3-41 OUTPUT CAPACITANCE
3-42 An internal capacitor, acress the output terminals of the power supply, helps to supply highcurrent pulses of short duration during constant
voltage operation.
Any capacitance added exter-
nally will improve the pulse current capability, but
will decrease the safety provided by the current
limiting circuit.
A high-current pulse may damage
load components before the average output current
is large enough to cause the current limiting circuit to operate.
3-43 REVERSE VOLTAGE LOADING
3-44 A diode is connected across the output terminals.
Under normal operating conditions, the
diode is reverse biased (anode connected to negative terminal).
If a reverse voltage is applied to
the output terminals (positive voltage applied to
negative terminal), the diode will conduct, shunting current across the output terminals and limiting the voltage to the forward voltage drop of the
diode.
This diode protects the series transistors
and the output electrolytic capacitors.
3-45 REVERSE CURRENT LOADING
3-39 PULSE LOADING
3-40 The power supply will automatically cross
over from constant voltage to constant current operation in response to an increase (over the preset
limit) in the output current, Although the
preset
limit may be set higher than the average output
current high peak currents (as occur in pulse loading) may exceed the preset current limit and cause
crossover to occur.
If this crossover limiting is
3-46 Active loads connected to the power supply
may actually deliver a reverse current to the power
supply during a portion of its operating cycle. An
external source cannot be allowed to pump current
into the supply without loss of regulation and possible damage to the output capacitor.
To avoid
these effects, it is necessary to preload the supply with a dummy load resistor so that the power
supply delivers current through the entire operating cycle of the load device.
3-6
SECTION IV
PRINCIPLES OF OPERATION
REFERENCE
REGULATOR
CIRCUIT
TM 1 I-6625-2965-14&P
t
AC
INPuT TRANSFORMER
POWER
NOTE
— DENOTES VOLTAGE
— DENOTES CURRENT
FEEOBACK PATH VOLTAGE
LIMIT PATH
I
~o
Pm
RANGE
SWITCH
(s2)
BIAS
SUPPLY
RECTIFIER
AND
FILTER
Figure 4-1.
IAS
B
v
VOLTAGES
SERIES
REGULATOR
A
DRIVER
AMPL
Overall Block Diagram
CURRENT
LIMITING
CIRCUIT
+
4
*
CURRENT
sAMPLING
RESISTORS
CONSTANT
INPUT
CIRCUIT
CIRCUIT
P/o
2
4
4
4
4
4
1,
Q
4-1 OVERALL DESCRIPTION
4-2
Figure 4-1 shows one section of the Model
6205B
dual power supply. The supply
consistsof
two dual range sections; each identical to the
other. Each section consists ofa rectifier and fil-
ter, a series regulator, an error amplifier and driver,
a constant voltage input circuit, a
cument limiting
circuit, a reference regulator circuit, a bias supply,
and a metering circuit.
Since both sections of the
supply are identical, only one section is described
below.
4-3 The ac line voltage is first applied to the
power transformer, The tap for the appropriate
voltage range is selected by S2. The input is then
rectified and filtered. This raw dc is then fed to
the series regulator which alters its conduction to
obtain the proper regulated dc output voltage.
4-4 Any changes in output voltage are felt by
constant voltage comparator which compares a
portion of the output with a fixed reference volts ge.
If a difference exists, the comparator circuit sends
a n error signal to the series regulator via the error
amplifier and driver stages. This error signal
changes the conduction of the series regulator so
that a constant output voltage is maintained.
4-5 Changes
in output current are reflected in the
voltage drop across the current sampling resistor
network. If this voltage drop exceeds a preset
limit, the current limit transistor conducts, sending
a turn-down signal to the series regulator via the
driver. This signal changes the conduction of the
4-1
the
TM 11-6625-2965-14&P
series regulator so that the output current is limited
to the proper value.
4-6 The reference circuit provides stable reference voltages used in the constant voltage comparator and current limit circuits. The bias circuit
provides the less critical bias voltages used in the
supply.
4-7 The meter circuit provides a continuous indi-
cation of output voltage or current in both ranges.
4-8 DETAILED CIRCUIT ANALYSIS
4-9 FEEDBACK LOOP
4-10 The feedback loop functions continuously to
keep the output voltage constant during normal op-
eration of the supply. For purposes of this discussion, assume that the output voltage instantane-
ously rises (goes positive) due to a variation in the
external load circuit. Note that the change may be
in the form of a slow rise in the output voltage or a
positive going ac signal. An ac signal is coupled
to summing point A6 through capacitor Cl and a dc
voltage is coupled to A6 through R 10.
4-11 The rise in output voltage causes the voltage
at A6 and thus the base of Q1A to decrease (go negative). Q1A now decreases its conduction and its
collector voltage rises. The positive going error
voltage is amplified and inverted by Q3 and fed to
the base of the series transistor(s) via emitter fol-
lower Q4. The negative going input causes the
series transistor(s) to decrease its conduction so
that it drops more of the line voltage, reducing the
output voltage to its original level.
4-12 If the external load resistance decreases to
a certain crossover point, the supply will operate
in the current limiting mode. In the current limit
mode, Q1O conducts sending a negative going,
turn-down signal to the series regulator via driver
Q4 .
4-13 SERIES REGULATOR
4-14 The series regulator consists of transistor
stage Q7 (and Q6 on Model 6206 B). The regulator
serves as a series control element by altering its
conduction so that the output voltage is kept constant and the current limit is never exceeded, The
conduction of the transistor(s) is controlled by the
feedback voltage obtained from driver Q4. Diode
CR11, connected across the regulator circuit, protects the series transistor(s) against reverse voltages that could develop across it during parallel or
auto-parallel operation if one supply is turned on
before the other.
4-15 CONSTANT VOLTAGE COMPARATOR
4-16 The circuit consists of the coarse and fine
programming resistors (Rl0A and R 10 B), and a differential amplifier stage (Ql and associated com-
ponents). Transistor Q1 consists of two transistors
housed in a single package. The transistors have
matched characteristics minimizing differential
voltages due to mismatched stages. Moreover,
drift due to thermal differentials is minimized,
since both transistors operate at essentially the
same temperature.
4-17 The constant voltage comparator continuously compares a fixed reference voltage with a portion of the output voltage and, if a difference ex-
ists, produces an error voltage whose amplitude
and phase is proportional to the difference.
error output is fed back to the series regulator,
through the (mixer) error and driver amplifiers. The
error voltage changes the conduction of the series
regulator which, in turn, alters the output voltage
so that the difference between the two input voltages applied to the differential amplifier is reduced
to zero.
voltage constant.
4-18 Stage Q1B of the differential amplifier is
connected to a common (+S) potential through impedance equalizing resistor R5. Resistors R6 and
R8 are used to zero bias the input stage, offsetting minor base-to-emitter voltage differences in
Q1. The base of Q1A is connected to a summing
point at the junction of the programming resistors
and the current pullout resistors, R12 and R13.
Instantaneous changes in output voltage result in
an increase or decrease in the summing point potential. Q1A is made to conduct more or less, in
accordance with summing point voltage change.
The resultant output error voltage is fed back to
the series regulator via the remaining components
of the feedback loop.
the base Q1A, limits the current through the pro-
gramming resistors during rapid voltage turn-down.
Diodes CR1 and CR2 form a limiting network which
prevent excessive voltage excursions from over
driving stage Q1A.
programming resistors, increases the high frequency gain of the input amplifier. Resistor R1 3, shunt-
ing pullout resistor R12, is factory selected so
that all of the + 6.2 Volt reference is dropped across
R12 and R13. Linear constant voltage programming
is assured with a constant current flowing through
R1O.
removed to avoid current surges and increase the
programming speed.
4-19 ERROR AMPLIFIER AND DRIVER
4-20 The error and driver amplifiers amplify the
error signal from the constant voltage comparator
circuit to a leve1 sufficient to drive the series
regulator transistor(s).
current limiting input if Q10, the current limiting
transistor, conducts.
The above action maintains the output
Resistor Rl, in series with
Capacitor Cl, shunting the
C20 stabilizes the feedback loop and may be
Driver Q4 also receives a
The
4-2
4-21 Stage Q3 contains a feedback equalizer network, C5 and R30, which provides for high frequency roll off in the loop gain in order to stabilize
the feedback loop. Q17 establishes a stable emitter bias potential for error amplifier Q3. Emitter
follower transistor(s) Q4 (and Q5) serves as the
driver (and predriver) element for the series regula-
tor.
4-22 CURRENT LIMIT CIRCUIT
4-23 The current limit circuit limits the output
current to a preset value determined by the setting
of R81. Switch S2B selects the proper sampling
resistance to maintain an equal voltage drop acress
the current sampling network in both ranges.
TM 11-6625-2965-14&P
4-28 The reference circuit consists of series regulating transistor Q9 and error amplifier Q8. Output voltage changes are detected by Q8 whose base
is connected to the junction of a voltage divider
(R41, R42) connected directly across the supply.
Any error signals are amplified and inverted by Q8
and applied to the base of series transistor Q9.
The series element then alters its conduction in the
direction, and by the amount, necessary to maintain the voltage across VR1 and VR2 constant. Resistor R46, the emitter resistor for Q8, is connected
in a manner which minimizes changes in the refer-
ence voltage caused by variations in the input line.
Output capacitor C9 stabilizes the regulator loop.
4-29 METER CIRCUIT (Figure 4-2)
4-24 When S2 is set to the 20 Volt position, R54
and R55 are connected in parallel. When S2 is set
to the 40 Volt position, the current sampling network consists solely of R54. Note that in the
twenty Volt range, twice as much current can be
delivered as in the forty Volt range. Since the
twenty Volt range has a sampling resistance equal
to half the value of that for the forty Volt range, an
equal sampling resistor voltage drop is obtained in
both ranges. This also applies to S2 in the 6206B.
4-25 R81 sets the bias of Q10, and thus, the
threshold point at which Q10 conducts and current
limiting begins. If this threshold is exceeded, Q10
begins to conduct, forward biasing CR16 and send-
ing a turn-down signal to the series regulater via
the driver. If the current through the current sampling network decreases below the threshold point,
Q10 turns off and no longer affects the operation of
the supply.
4-26 REFERENCE CIRCUIT
4-27 The reference circuit (see schematic) is a
feedback power supply similar to the main supply.
It provides stable reference voltages which are
used throughout the unit. The reference voltages
are a 11 derived from smoothed dc obtained from the
full wave rectifier (CR22 and CR23) and filter capacitor C10. The +6.2 and -6.2 voltages, which are
used in the constant voltage input circuit for comparison purposes, are developed across temperature
compensated Zener diodes VR1 and VR2. Resistor
R43 limits the current through the Zener diodes to
establish an optimum bias level.
4-30 The meter circuit provides continuous indications of output voltage or current on a single
multiple range meter.
The meter can be used either
as a voltmeter or an ammeter depending upon the
position of the METER section of switch S2 on the
front panel of the supply. This switch also selects
one of two meter ranges on each scale. The meter
circuit consists
of METER-RANGE switch S2, vari-
ous multiplying resistors and the meter movement.
4-31 When measuring voltage, the meter is placed
directly across the output of the supply between
the +S and -S terminals. With the METER section
of S2A in the higher voltage position (terminals A2
and A10) multiplying resistors R60, R61, R72, and
the parallel combination of R73 and R87, are in
series with the meter. For low output voltages, the
METER switch S2A can be set to the first position
(terminals 1 and 9) which removes R61 from its
series position allowing a larger percentage of the
output voltage to be felt acress the meter.
4-32 When measuring current; the meter circuit is
connected across the current sampling resistor
network as shown on Figure 4-2 and indicates the
output current that flows through the network. The
RANGE section S2B connects the appropriate re-
sistance in series with the meter so that its maxi-
mum deflection range is full-scale in the high current (low voltage) operating mode and half-scale in
the low current (high voltage) operating mode. This
circuit obviates the need for a dual current scale
which would be necessary since the voltages drop-
ped across the current sampling network in both
operating modes are equal for proportional currents.
4-3
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