Patent ID: 9071140
Filing Date: 2015-06-30
Classification: H02M

Abstract:
1. A method of operating a DC-DC controller which includes a plurality of switches including a first switch coupled between an input and a first node, a second switch coupled between the first node and a ground connection, a third switch coupled between the output and a second node, and a fourth switch coupled between the second node and the ground connection, and an inductor coupled between the first and second nodes, comprising: sensing voltage at an output to determine whether an output voltage is within a buck region, a buck-boost region and a boost region; sensing current in the inductor; determining a difference between a feedback voltage derived from the sensed voltage at the output and a reference voltage to generate a first control signal; comparing the sensed current to the first control signal to generate a first reset signal; shifting the first control signal to generate a second control signal; comparing the sensed current to the second control signal to generate a second reset signal; and controlling the plurality of switches to selectively operate the DC-DC controller, based on the sensed voltage, in: a first mode while the sensed output voltage is in the boost region as a boost converter by setting a first subset of the plurality of switches and repeatedly switching a second subset of the plurality of switches, a second mode while the sensed output voltage is in the buck region as a buck converter by setting the second subset of the switches and repeatedly switching the first subset of switches, and a third mode while the sensed output voltage is in the buck-boost region as a converter by alternating between operation as the boost converter by setting the first subset of switches and repeatedly switching the second subset of switches for a first period of time until reset by the second reset signal and operation as the buck converter by setting the second subset of switches and repeatedly switching the first subset of switches for a second period of time until reset by the first reset signal.