Pulse Width Modulator Control Circuits

The SG3525A, SG3527A pulse width modulator control circuits offer improved performance and lower external parts count when implemented for controlling all types of switching power supplies. The on–chip +5.1 V reference is trimmed to ±1% and the error amplifier has an input common–mode voltage range that includes the reference voltage, thus eliminating the need for external divider resistors. A sync input to the oscillator enables multiple units to be slaved or a single unit to be synchronized to an external system clock. A wide range of deadtime can be programmed by a single resistor connected between the CT and Discharge pins. These devices also feature built–in soft–start circuitry, requiring only an external timing capacitor.

• 8.0 V to 35 V Operation
• 5.1 V ± 1.0% Trimmed Reference
• 100 Hz to 400 kHz Oscillator Range
• Separate Oscillator Sync Pin
• Adjustable Deadtime Control
• Input Undervoltage Lockout
• Latching PWM to Prevent Multiple Pulses
• Pulse–by–Pulse Shutdown
• Dual Source/Sink Outputs: ±400 mA Peak