Design improvements for Primary-Side-Regulated high-power flyback converters in Continuous-Conduction-Mode

Primary-Side-Regulation (PSR) indirectly senses output voltage, to eliminate the secondary-side error amplifier and feedback opto-coupler - saving cost and standby power. PSR is commonly used in low-power Discontinuous-Conduction-Mode (DCM) flyback converters, but rarely at high power, or in Continuous-Conduction-mode (CCM). A new generation PSR flyback control scheme can achieve better than 1% load/line regulation and CCM operation at power levels to 100 W and beyond. The scheme uses a fixed-sample-point algorithm and a novel compensation scheme, to adjust for errors, dramatically improving static regulation, and extending PSR operation to much higher power.