PeakSwitch Design Guide

PeakSwitch Design Guide:The PeakSwitch family is a highly integrated, monolithic,
off-line switcher IC designed for use in power supplies that have to deliver peak loads for short durations. Example applications include inkjet printers, audio amplifiers and DVRs. When peak power is required, the effective switching frequency can approach
277 kHz, allowing a transformer with a small core size to be used. Innovative proprietary features, such as adaptive switching cycle on-time control, adaptive current limit, AC line sense and fast AC reset greatly simplify the design. This reduces engineering design time and system cost while providing complete
system-level protection and robust functionality.
Each member of the family has a high-voltage power MOSFET and its controller integrated onto the same die. Internal start-up bias current is drawn from a high-voltage current source connected to the DRAIN pin, eliminating the need for external start-up components. The internal oscillator is frequency modulated (jitter) to reduce EMI. In addition, the ICs have integrated functions that provide system-level protection. The auto-restart function limits the dissipation in the MOSFET, the transformer and the output diode during overload, output short- circuit and open-loop conditions, while the auto-recovering hysteretic thermal shutdown function disables MOSFET switching during a thermal fault. On-time extension enables more power to be delivered at low line and extends hold-up time. The smart AC line sense and undervoltage lockout (UVLO) functions enable the IC to latch off whenever a fault activates the auto-restart function, and to be reset quickly after AC power is removed.
Power Integrations’ EcoSmart® technology enables supplies designed around the PeakSwitch family members to consume
<300 mW of no-load power and to meet harmonized energy efficiency standards such as the California Energy Commission (CEC), EU and ENERGY STAR.