UC2845

电流模式 PWM 控制器

DESCRIPON

The UC1842/3/4/5 family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include under-voltage lockout featuring start up current less than 1mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched

operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N Channel MOSFETs, is low in the off state.

FEATURES

• Optimized For Off-line And DC To DC Converters

• Low Start Up Current <1mA

• Automatic Feed Forward Compensation

• Pulse-by-pulse Current Limiting

• Enhanced Load Response Characteristics

• Under-voltage Lockout With Hysteresis

• Double Pulse Suppression

• High Current Totem Pole Output

• Internally Trimmed Bandgap Reference

• 500khz Operation

• Low ROError Amp