DESCRIPTION

The SG1844/45 family of control ICs provides all the necessary features to implement off-line fixed frequency, current-mode switching power supplies with a minimum number of external components. Current-mode architecture demonstrates improved line regulation, improved load regulation, pulse-bypulse current limiting and inherent protection of the power supply output switch.

KEY FEATURES

■ OPTIMIZED FOR OFF-LINE CONTROL

■ LOW START-UP CURRENT (<1mA)

■ AUTOMATIC FEED FORWARD COMPENSATION

■ TRIMMED OSCILLATOR DISCHARGE CURRENT

■ PULSE-BY-PULSE CURRENT LIMITING

■ ENHANCED LOAD RESPONSE CHARACTERISTICS

■ UNDER-VOLTAGE LOCKOUT WITH 6V HYSTERESIS (SG1844 only)

■ DOUBLE PULSE SUPPRESSION

■ HIGH-CURRENT TOTEM-POLE OUTPUT

■ INTERNALLY TRIMMED BANDGAP REFERENCE

■ 500kHz OPERATION

■ UNDERVOLTAGE LOCKOUT SG1844 - 16 volts SG1845 - 8.4 volts

■ LOW SHOOT-THROUGH CURRENT