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.