UC3843B DESCRIPTION:
The UC3843B familyofcontrolICsprovi又行desthenecessary features to implement 學什off-line or DC to DC fixed frequencycurrent 務線mode control schemes with a minimal external parts co國分unt. Internally implemented
circuits includea trimmed oscillator有很 for precise DUTY CYCLE CONTROL under voltage lockou林關tfeaturingstart-upcurrentless than0.5mA,a precision eference trimmed for accuracy at th但微e error amp input,logicto ins章日urelatchedoperation,a PWM comparatorwhich alsopro火玩videscurrentlimit con暗路trol, and a totem pole output stage們快 designed to source or sink high peakcurrent.Theoutputst雨朋age,suitable for driving N-Channel行請 MOSFETs, is low in the offstate.
Differences between members of this fam錢討ily are the under-voltagelockout thres物離holdsand maximum duty
cycle ranges. The UC3843B have UVLO thresholds of 16V雪風 (on) and 10V (off), ideally
The UC3843B can operateto duty cycles approaching 100%. A range o短林f the zero to <
50 % is obtainedby the UC3844Band農唱 UC3845Bby theadditionofan inter微司naltoggleflip flopwhich 線白blanks
the outputoff everyotherclo票友ck cycle.

HIGH PERFORMANCE CURR城對ENT MODE PWM CONTROLLER
. TRIMMED OSCILLATOR FOR數生 PRECISE FREQUENCY CON你路TROL
. OSCILLATOR FREQUENCY GU下舊ARANTEED AT 250kHz
. CURRENT MODE OPERATION TO 500厭多kHz
. AUTOMATIC FEED FORWARD COMPENSATIO見通N
. LATCHING PWM FOR CYCLE-B中照Y-CYCLE CURRENT LIMITING
.INTERNALLY TRIMMED REFEREN明風CE WITH UNDERVOLTAGE LOCKOU很師T
. HIGH CURRENT TOTEM POLE OUTPUT道區
. UNDERVOLTAGE LOCKOUT WITH分討 HYSTERESIS
. LOW START-UP AND OPERATING 明長CURRENT