US 11,736,013 B2
Buck-boost switching regulator having bypass mode and control method thereof
Shei-Chie Yang, Taichung (TW); Jian-Yu Tu, New Taipei (TW); Yuan-Yen Mai, Taipei (TW); and Pao-Hsun Yu, Hsinchu (TW)
Assigned to Richtek Technology Corporation, Zhubei (TW)
Filed by Richtek Technology Corporation, Zhubei (TW)
Filed on Dec. 30, 2021, as Appl. No. 17/566,678.
Claims priority of provisional application 63/136,915, filed on Jan. 13, 2021.
Claims priority of application No. 110130737 (TW), filed on Aug. 19, 2021.
Prior Publication US 2022/0224233 A1, Jul. 14, 2022
Int. Cl. H02M 3/158 (2006.01); H02M 1/00 (2006.01)
CPC H02M 3/1582 (2013.01) [H02M 1/009 (2021.05)] 22 Claims
OG exemplary drawing
 
1. A buck-boost switching regulator for converting an input voltage into at least one output voltage, the buck-boost switching regulator comprising:
a power switch circuit including an input switch unit and an output switch unit, wherein the input switch unit is configured to operably switch a first terminal of an inductor between the input voltage and a ground level, and the output switch unit is configured to operably switch a second terminal of the inductor between at least one low dropout node and the ground level, so as to convert the input voltage at the at least one low dropout node into at least one corresponding low dropout voltage, wherein the at least one low dropout node is correspondingly coupled to at least one output high side switch of the output switch unit;
at least one low dropout regulator correspondingly coupled to the at least one output high side switch to correspondingly convert the at least one low dropout voltage into the at least one output voltage;
a bypass control circuit configured to operably generate a bypass control signal according to a conversion voltage difference between the input voltage and the corresponding low dropout voltage; and
a bypass switching circuit, wherein when the corresponding conversion voltage difference is lower than a reference voltage, the bypass control signal controls the bypass switching circuit to electrically connect the input voltage with the corresponding low dropout node, such that the buck-boost switching regulator operates in a bypass mode;
wherein the reference voltage includes a first reference voltage and a second reference voltage, wherein the corresponding bypass control signal is enabled when a difference of the corresponding low dropout voltage minus the input voltage is lower than the first reference voltage and a difference of the input voltage minus the corresponding low dropout voltage is lower than the second reference voltage, wherein the first reference voltage and the second reference voltage have one of the following relationships:
(1) the first reference voltage is equal to the second reference voltage, and both the first reference voltage and the second reference voltage are not zero;
(2) the first reference voltage is equal to zero, and the second reference voltage is not zero;
(3) the second reference voltage is equal to zero, and the first reference voltage is not zero; or
(4) the first reference voltage is not equal to the second reference voltage, and both the first reference voltage and the second reference voltage are not zero.