Analog Devices, Inc.
PEAK CURRENT MODE CONTROL FOR BUCK-BOOST REGULATORS

Abstract:

Controller circuitry can employ a method to provide control signals to bridge switches operating an inductor for switched-mode inductive buck-boost voltage regulation. The buck mode can operate the bridge switches in a buck current control mode when the input voltage exceeds the output voltage. The boost mode can operate the bridge switches in a boost current control mode when the output voltage exceeds the input voltage. The buck-boost transition mode can operate the bridge switches in a peak buck-boost current control mode that minimizes a minimum duty cycle (having a minimum "on" duty time and a minimum "off" duty time) when the output voltage is approximately equal to the input voltage during a transition from at least one of the current control buck mode to the current control boost mode or from the current control boost mode to the current control buck mode.