US 12,074,528 B2
Secondary side controlled QR flyback converter using a programmable valley algorithm
Pulkit Shah, Bangalore (IN); Arun Khamesra, Bangalore (IN); Hariom Rai, Bangalore (IN); Aniket Shashikant Mathad, San Jose, CA (US); and Kailas Narayana Iyer, Bangalore (IN)
Assigned to Cypress Semiconductor Corporation, San Jose, CA (US)
Filed by Cypress Semiconductor Corporation, San Jose, CA (US)
Filed on Jan. 13, 2022, as Appl. No. 17/575,001.
Prior Publication US 2023/0223858 A1, Jul. 13, 2023
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01)
CPC H02M 3/33592 (2013.01) [H02M 1/0012 (2021.05); H02M 1/0058 (2021.05); H02M 3/33515 (2013.01); H02M 3/33576 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A secondary-side-controller for a quasi-resonant (QR) flyback converter, the secondary-side-controller comprising:
a driver configured to control a power-switch (PS) on a primary side of the QR flyback converter, the driver operable to cause turn-on of the PS when a sinusoidal input voltage to the QR flyback converter is at one of a plurality of valleys;
an analog to digital converter (ADC) coupled to receive an input voltage signal, an output voltage signal, and a load current signal, the ADC operable to generate a number of digital signals based thereon; and
a valley-controller coupled to the driver, the ADC, a look-up-table and to a pulse width modulator (PWM), the valley-controller operable to receive the number of digital signals from the ADC and based on the number of digital signals received determine from values stored in the look-up-table at which valley of the plurality of valleys to couple a PWM signal from the PWM to the driver.