Patent ID: 8242763
Filing Date: 2012-08-14
Classification: H02M,Y02B

Abstract:
1. A DC to DC converter, comprising: a first transistor coupled between a first power supply terminal and a first node; a second transistor coupled between the first node and a second power supply terminal; a first diode coupled in parallel with the first transistor between the first node and the first power supply terminal; a second diode coupled in parallel with the second transistor between the first node and the second power supply terminal; an inductor having a first terminal coupled to the first node and a second terminal coupled to an output terminal for receiving a variable load; transistor drive circuitry coupled to the first transistor and second transistor, the transistor drive circuitry controlling conduction of the first and second transistor in a non-overlapping conduction operation; a duty cycle controller coupled to the transistor drive circuitry for controlling a duty cycle for each of the first transistor and the second transistor to be conductive; and control circuitry coupled to the duty cycle controller for determining a mode of operation of the DC to DC converter by monitoring cycles of operation and detecting a predetermined pattern of cycles in which inductor current becomes negative, wherein a first mode of operation permits both the first transistor and the second transistor to alternately conduct and a second mode of operation does not permit the second transistor to conduct during each cycle when the inductor current is reduced to substantially zero.