CURRENT MODE PWM CONTROLLER

DESCRIPTION

The UTC UC2846 control IC offers all necessary features for

accomplishment of fixed frequency, current mode control functions,

however it contains the least external parts. The performance of this

technique is superior to the others in better line regulation, enhanced

load response characteristics while designing a simpler and easier

control loop for design. It owns topological advantages of inherent

pulse-by-pulse current limiting, automatic symmetry correction for

push-pull converters, and the ability to parallel “power modules" for

equal current sharing.

Protection loop includes soft start, built-in under-voltage lockout

and programmable current limit. The shutdown circuitry can provide

either a complete shutdown with automatic restart or the supply

off-latch.

In addition, many other features can also be available, including

fully latched operation, double pulse suppression, deadline adjust, and

a ±1% trimmed bandgap reference.

The UTC UC2846 features low outputs in the OFF state.

FEATURES

* Built-in under-voltage lockout

* Soft start

* Shutdown function

* 500kHZ operation

* Feed forward compensation

* ±1% bandgap reference

* Programmable pulse-by-pulse current limiting

* Improved load response characteristics

* Parallel operation capability for modular power systems

* Differential current sense amplifier with wide common mode range

* Double pulse suppression

* 500mA (Peak) totem-pole outputs

* Automatic symmetry correction in push-pull configuration