US 12,003,180 B2
Power supply for driving synchronous rectification elements of SEPIC converter
Masaru Nakamura, Niiza (JP); Shinji Aso, Niiza (JP); and Jianao Yao, Niiza (JP)
Assigned to SANKEN ELECTRIC CO., LTD., Niiza (JP)
Filed by SANKEN ELECTRIC CO., LTD., Niiza (JP)
Filed on Sep. 28, 2021, as Appl. No. 17/486,974.
Application 17/486,974 is a continuation of application No. PCT/JP2020/047724, filed on Dec. 21, 2020.
Prior Publication US 2022/0200458 A1, Jun. 23, 2022
Int. Cl. H02M 3/158 (2006.01); H02M 3/155 (2006.01)
CPC H02M 3/1588 (2013.01) [H02M 3/1557 (2021.05)] 7 Claims
OG exemplary drawing
 
1. A DC-DC converter comprising:
a first inductor connected between an input power supply and a first terminal of a coupling capacitor;
a first switching element connected between the first terminal of the coupling capacitor and a ground;
a second inductor connected between a second terminal of the coupling capacitor and the ground;
a second switching element connected between the second terminal of the coupling capacitor and an output terminal;
a drive circuit that drives the second switching element;
a drive voltage supply circuit that supplies power to the drive circuit;
a drive voltage switching circuit that switches a drive voltage of the drive circuit, wherein
the drive voltage switching circuit switches a connection so that the drive circuit supplies power with an output voltage or a voltage higher than the output voltage in response to the output voltage being higher than the drive voltage, and
the drive voltage switching circuit switches a connection so as to supply power to the drive circuit from the drive voltage in response to the output voltage being lower than the drive voltage;
an AD converter that detects the output voltage, and converts the output voltage into a digital value;
a subtractor that outputs a difference between the digital value and an output target value;
a filter calculation circuit that calculates an operation value based on the difference; and
a PWM signal generation circuit that generates a PWM signal corresponding to the operation value, wherein
the drive circuit outputs a voltage from the drive voltage switching circuit to the second switching element to drive the second switching element based on the PWM signal.