US 11,990,843 B2
Methods and circuits for sensing isolated power converter output voltage across the isolation barrier
Yan-Fei Liu, Kingston (CA); Yang Chen, Hefei (CN); Binghui He, Kingston (CA); Wenbo Liu, Meihekou (CN); and Bo Sheng, Kingston (CA)
Assigned to Queen's University at Kingston, Kingston (CA)
Filed by Queen's University at Kingston, Kingston (CA)
Filed on Jul. 24, 2023, as Appl. No. 18/225,325.
Application 18/225,325 is a continuation of application No. 17/742,846, filed on May 12, 2022, granted, now 11,711,023.
Claims priority of provisional application 63/188,752, filed on May 14, 2021.
Prior Publication US 2024/0097573 A1, Mar. 21, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01); H02M 3/00 (2006.01)
CPC H02M 3/33576 (2013.01) [H02M 1/0003 (2021.05); H02M 3/01 (2021.05); H02M 3/33515 (2013.01); H02M 3/3353 (2013.01); H02M 3/33573 (2021.05); H02M 3/33553 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A control circuit for an isolated power converter, comprising:
a first secondary side circuit that senses a secondary side output voltage of the isolated power converter and produces a pulse width modulation (PWM) signal having a logic high time (T_high) interval that is proportional to a value of the secondary side output voltage;
a first isolator that transfers the PWM signal across an isolation barrier to a primary side of the isolated power converter; and
a first primary side circuit including a processor that receives the PWM signal from the first isolator;
wherein the first primary side circuit comprises a sampling circuit including a capacitor that is charged and discharged according to the T_high interval of the PWM signal and a switch that shapes the PWM signal received from the first isolator by reducing a falling time and rising time of the PWM signal;
wherein the first primary side circuit samples a voltage across the capacitor at a sampling time set by a period of the PWM signal; and
wherein the sampled voltage across the capacitor is used by the processor to determine a gain of the sampling circuit and to control primary side power switching devices of the isolated power converter to regulate the secondary side output voltage at a selected value.