US 12,218,591 B2
Switching power converter and conversion control circuit thereof
Po-Yen Chen, Hsinchu (TW); and Hsing-Shen Huang, Hsinchu (TW)
Assigned to Richtek Technology Corporation, Hsinchu (TW)
Filed by Richtek Technology Corporation, Hsinchu (TW)
Filed on Dec. 23, 2022, as Appl. No. 18/145,863.
Claims priority of provisional application 63/301,057, filed on Jan. 20, 2022.
Claims priority of application No. 111138645 (TW), filed on Oct. 12, 2022.
Prior Publication US 2023/0231478 A1, Jul. 20, 2023
Int. Cl. H02M 1/00 (2007.01); H02M 3/156 (2006.01); H02M 3/157 (2006.01); H02M 3/158 (2006.01)
CPC H02M 3/157 (2013.01) [H02M 1/0022 (2021.05); H02M 1/0054 (2021.05); H02M 3/158 (2013.01); H02M 3/156 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A conversion control circuit for use in a switching power converter configured to convert an input power to an output power, wherein the switching power converter includes a plurality of switches, the conversion control circuit comprising:
a trigger signal generation circuit, configured to generate a turn-on trigger signal according to a feedback signal relevant to the output power;
an on-time control circuit, configured to generate a turn-off trigger signal to determine an on-time and/or an off-time of a pulse width modulation (PWM) signal, wherein the PWM signal is configured to control the plurality of switches, such that at least one of the plurality of switches is periodically turned on according to the on-time and/or the off-time; and
a logic driver circuit, configured to generate the PWM signal according to the turn-on trigger signal and the turn-off trigger signal, wherein the turn-on trigger signal is configured to enable the PWM signal, and the turn-off trigger signal is configured to disable the PWM signal;
wherein the on-time control circuit adjusts the length of the on-time and/or the length of the off-time according to an input voltage of the input power and an output voltage of the output power, wherein when a conversion ratio between the output voltage and the input voltage is higher than a first conversion ratio threshold, a switching frequency of the PWM signal decreases as the conversion ratio increases, and/or when the conversion ratio is lower than a second conversion ratio threshold, the switching frequency decreases as the conversion ratio decreases;
wherein the value of the output voltage is lower than the value of the input voltage; the conversion ratio is a quotient of the value of the output voltage divided by the value of the input voltage; and the first conversion ratio threshold is higher than the second conversion ratio threshold;
wherein the switching frequency is inversely proportional to a total of the on-time and the off-time.