US 12,081,129 B2
Power control device, DC-DC converter, and AC-DC converter
Yoshinori Sato, Kyoto (JP); and Satoru Nate, Kyoto (JP)
Assigned to Rohm Co., Ltd., Kyoto (JP)
Appl. No. 17/799,449
Filed by Rohm Co., Ltd., Kyoto (JP)
PCT Filed Oct. 29, 2020, PCT No. PCT/JP2020/040618
§ 371(c)(1), (2) Date Aug. 12, 2022,
PCT Pub. No. WO2021/171700, PCT Pub. Date Sep. 2, 2021.
Claims priority of application No. 2020-031188 (JP), filed on Feb. 27, 2020.
Prior Publication US 2023/0062534 A1, Mar. 2, 2023
Int. Cl. H02M 3/335 (2006.01); H02M 1/08 (2006.01)
CPC H02M 3/33507 (2013.01) [H02M 1/08 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A power control device for use in an insulation-type DC-DC converter,
wherein
the DC-DC converter includes:
a transformer having a primary winding and a secondary winding; and
a switching transistor connected to the primary winding,
the power control device includes:
a control pulse generator configured to generate a control pulse signal with a duty in accordance with a feedback signal generated based on an output voltage of the DC-DC converter to drive and control the switching transistor based on the control pulse signal; and
a burst comparator configured to compare the feedback signal with a threshold value to generate a burst enable signal as a comparison result,
the control pulse generator is configured to alternate between driving and not driving the switching transistor in accordance with a level of the burst enable signal to perform a burst operation in which switching is performed intermittently in the switching transistor, and
the power control device further includes:
a mode setter configured to, upon detecting a light load in the burst operation, change a mode from a normal mode to a low-power mode; and
a minimum on-period setter configured to, when the mode is changed to the low-power mode, change a minimum on-period of the switching transistor from a first minimum on-period to a second minimum on-period longer than the first minimum on-period.