FEATURES
2.7-V to 20-V Operation
8-Pin Package
Requires Minimum Number of External
Components
Compatible with Existing Power Supply
Designs Incorporating Remote Output
Voltage Sensin
Differential Share Bus
Precision Current Sense Amplifier (40 Gain)
UVLO (Undervoltage Lockout) Circuitry
User Programmable Share Loop
Compensation

APPLICATIONS
Paralelled Power Supplies

DESCRIPTION
The UC3902 load share controller is an 8-pin
device that balances the current drawn from
independent, paralleled power supplies. Load
sharing is accomplished by adjusting each
supplies’ output current to a level proportional to
the voltage on a share bus.
The master power supply, which is automatically
designated as the supply that regulates to the
highest voltage, drives the share bus with a
voltage proportional to its output current. The
UC3902 trims the output voltage of the other
paralleled supplies so that they each support their
share of the load current. Typically, each supply is
designed for the same current level although that
is not necessary for use with the UC3902. By
appropriately scaling the current sense resistor,
supplies with different output current capability
can be paralleled with each supply providing the
same percentage of their output current capability
for a particular load.