UCC29002

UCC29002/1

UCC39002

SLUS495H − SEPTEMBER 2001 − REVISED AUGUST 2007

9

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FUNCTIONAL DESCRIPTION

enable function (CS+, CS−)

The two inputs of the current sense amplifier are also used for implementing an ENABLE function. During

normal operation CS− = CS+ and the internal offset added between the CS− voltage and the inverting input of

the enable comparator ensures that the UCC39002 is always enabled. By forcing the CS− pin approximately

0.5-V above the CS+ pin, the UCC39002 can be forced into a disable mode. While disabled, the UCC39002

disconnects itself from the load share bus and its adjust current is zero.

UDG−02087

1

CS−

2

CS+

+

ENABLE

0.5 V

Figure 1. Enable Comparator

fault protection

Accidentally, the load share bus might be shorted to ground or to the positive bias voltage of the UCC39002.

These events might result in erroneous output voltage adjustment. For that reason, the load share bus is

continuously monitored by a window comparator as shown in Figure 2.

UDG−02088

8

CSO

7

LS

+

+

FAULT

R

2R

VDD − 0.7 V

Figure 2. Fault Protection Comparators

The FAULT signal is handled by the start up and adjust logic which pulls the non-inverting input of the adjust

amplifier low when the FAULT signal is asserted.