US Patent No. 9,520,868

POWER TRANSISTOR DRIVING CIRCUITS AND METHODS FOR SWITCHING MODE POWER SUPPLIES


Patent No. 9,520,868
Issue Date December 13, 2016
Title Power Transistor Driving Circuits And Methods For Switching Mode Power Supplies
Inventorship Jinhua Duan, Shanghai (CN)
Qiang Zong, Shanghai (CN)
Yajiang Zhu, Shanghai (CN)
Assignee BCD Semiconductor Manufacturing Limited, Shanghai (CN)

Claim of US Patent No. 9,520,868

1. A driver circuit, the driver circuit comprising:
a current mirror having first and second PMOS transistors;
a bipolar transistor coupled to the second PMOS transistor of the current mirror to receive a first current; and
a plurality of serially connected diode devices coupled between a collector and a base of the bipolar transistor;
wherein the collector of the bipolar transistor is configured to provide a driving voltage according to the number of the
plurality of serially-connected diode devices and the size ratio between the first and the second PMOS transistors.