UC1907, UC2907, UC3907
LOAD SHARE CONTROLLER
SLUS165C 鈥?MARCH 1999 - REVISED JANUARY 2002
FEATURES
D
Fully Differential High Impedance Voltage
D
D
D
D
D
Sensing
C/S OUT
C/S (+)
Accurate Current Amplifier for Precise
C/S (鈥?
Current Sharing
(鈥? SENSE
Opto Coupler Driving Capability
POWER RETURN
1.25% Trimmed Reference
ARTIFICIAL GND
Master Status Indication
VREF
ISET
4.5-V to 35-V Operation
C/S OUT
PLCC-20, LCC-20,
Q OR L PACKAGE
(TOP VIEW)
CURRENT SHARE BUS
STATUS INDICATE
SOIC-16 DW PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
16
15
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11
10
9
STATUS INDICATE
CURRENT SHARE BUS
ADJ OUT
ADJ INPUT
COMP
(+) SENSE
VCC
OPTO DRIVE
C/S (+)
3
2
N/C
DIL-16 J or N PACKAGE
(TOP VIEW)
C/S OUT
C/S (+)
C/S (鈥?
(鈥? SENSE
POWER RETURN
ARTIFICIAL GND
VREF
ISET
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1
20 19
18
17
16
15
14
C/S (鈥?
(鈥? SENSE
N/C
POWER RETURN
ARTIFICIAL GND
4
5
6
7
8
9 10 11 12 13
ADJ OUT
ADJ INPUT
N/C
COMP
(+) SENSE
OPTO DRIVE
VREF
ISET
N/C
DESCRIPTION
The UCx907 family of load share controller ICs provides all the necessary features to allow
multiple-independent-power modules to be paralleled such that each module supplies only its proportionate share
to total-load current.
This sharing is accomplished by controlling each module鈥檚 power stage with a command generated from a
voltage-feedback amplifier whose reference can be independently adjusted in response to a common-share-bus
voltage. By monitoring the current from each module, the current share bus circuitry determines which paralleled
module would normally have the highest output current and, with the designation of this unit as the master, adjusts
all the other modules to increase their output current to within 2.5% of that of the master.
The current share bus signal interconnecting all the paralleled modules is a low-impedance, noise-insensitive line
which will not interfere with allowing each module to act independently should the bus become open or shorted to
ground. The UC3907 controller will reside on the output side of each power module and its overall function is to supply
a voltage feedback loop. The specific architecture of the power stage is unimportant. Either switching or linear designs
may be utilized and the control signal may be either directly coupled or isolated though the use of an optocoupler or
other isolated medium.
Other features of the UC3907 include 1.25% accurate reference: a low-loss, fixed-gain current-sense amplifier, a fully
differential, high-impedance voltage sensing capability, and a status indicator to designate which module is
performing as master.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
VCC
STATUS INDICATE
CURRENT SHARE BUS
ADJ OUT
ADJ INPUT
COMP
(+) SENSE
VCC
OPTO DRIVE
Copyright
錚?/div>
2000, Texas Instruments Incorporated
www.ti.com
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