illustrate

The UC3572 is a passive output flyback pulse-width modulator that regulates the positive input voltage and negative output voltage. The chip is optimized for the use of an external PMOS switch in a single flyback switching converter inductor negative. The block consists of a high accuracy reference, voltage mode operation of an error amplifier, an oscillator, a PWM comparator with latching logic, and a 0.5A peak gate driver configuration. The UC3572 includes an undervoltage lockout circuit to ensure that sufficient input supply voltage exists before any conversion activity can occur for a pulse of pulse current limiting. The output current can be sensed and is limited to determining the maximum value for the user.

characteristic

• A simple single inductor generates PWM with a reverse negative voltage
• External PMOS switch of the hard disk
• Contains UVLO circuitry
• Includes pulse pass-through pulse current limiting
• Low 50uA sleep mode current