High efficiency inductive capacitive DC-DC converter

摘要

Disclosed examples include high-efficiency integrated circuits and inductive capacitive DC-DC converters with a first converter stage including first and second switches and an inductor, and a second converter stage including third and fourth switches and a flying capacitor. A dual mode control circuit regulates output voltage signal in a first mode when the output voltage signal is below a threshold by pulse width modulating the switches of the first converter stage. When the output voltage exceeds the threshold, the control circuit operates in a second mode with a first state to close the first and third switches, and a second state to close the fourth switch to connect the inductor in series with the flying capacitor. Dual mode operation of the first and second stages facilitates buck-boost operation with reduced inductor losses and converter switching losses, and the integrated circuit can be used in boost, buck or other configurations.

主权项

1. A DC-DC converter circuit to provide a DC output voltage signal, comprising:
a first converter stage, including: a first switch including a first terminal coupled with a first node, and a second terminal coupled with a switch node, an inductor including a first terminal coupled with the switch node, and a second terminal, and a second switch including a first terminal coupled with the switch node, and a second terminal coupled with a second node; a second converter stage, including: a third switch including a first terminal coupled with a third node, and a second terminal coupled with a fourth node, a capacitor including a first terminal coupled with the fourth node, and a second terminal coupled with the switch node, and a fourth switch including a first terminal coupled with the fourth node, and a second terminal coupled with the second node; and a control circuit operative in a first mode when an absolute value of the output voltage signal is less than a threshold to turn off the third and fourth switches of the second converter stage, and to provide pulse width modulated switching control signals to the first and second switches of the first converter stage in alternating fashion to regulate the output voltage signal according to a setpoint signal; the control circuit operative in a second mode when the absolute value of the output voltage signal is greater than the threshold to turn off the second switch, and to provide pulse width modulated switching control signals to the first, third and fourth switches to regulate the output voltage signal according to the setpoint signal.