DESCRIPTION

The UTC UC2843B provides off-line or DC-DC fixed-frequency current-mode control design with minimum external components. Internally-implemented circuits include an under-voltage lockout (UVLO) and a precision reference with accuracy at the error amplifier input. The UTC UC2843B also contain internal circuits which include a pulse width modulation (PWM) comparator providing current-limit control, logic ensuring latched operation, and a totem-pole output stage designed to source or sink high-peak current. The output stage is low when it is in off-state condition and suitable for N-channel MOSFETs driving.

FEATURES

* Current mode operation:500 kHz

* Low start-up current value<0.5mA

* Latching PWM for cycle-by-cycle current limiting

* Trimmed oscillator discharge current

* Automatic feed-forward compensation

* Internally trimmed reference with UVLO

* High-current totem-pole output UVLO with hysteresis

* Double-pulse suppression