UCC29002

UCC29002/1

UCC39002

SLUS495H − SEPTEMBER 2001 − REVISED AUGUST 2007

8

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FUNCTIONAL DESCRIPTION

error amplifier (EAO)

compensation.

The purpose of the error amplifier is to compare the average, per module current level to the output current of

represented by the load share bus is higher than the module’s own output current, an error signal will be

developed across the compensation components connected between the EAO pin and ground. The error signal

is than used by the adjust amplifier to make the necessary output voltage adjustments to ensure equal output

currents among the parallel operated power supplies.

In case the UCC39002 assumes the role of the master load share controller in the system or it is used in

typically 25 mV offset to ensure that the inverting input of the error amplifier is biased higher than the

non−inverting input. Consequently, when the two signals are equal, there will be no adjustment made and the

initial output voltage set point is maintained.

adjust amplifier output (ADJ)

of the current is set by the 500-

Ω internal resistor between ground and the emitter of the amplifier’s open

collector output transistor according to Figure 1. The adjust current value is given as:

I

V

EAO

500

W

voltage of the master module remains at its initial output voltage set point at all times.

Furthermore, at insufficient bias level, during a fault or when the UCC39002 is disabled, the non-inverting input

of the adjust amplifier is pulled to ground to prevent erroneous adjustment of the module’s output voltage by

the load share controller.

(2)