Cross-interference reduction of a buck power converter

摘要

A power converter includes a first conversion stage for converting an input voltage to a first output voltage and a second conversion stage for converting the first output voltage to a second output voltage. An error signal is generated according to a reference voltage and a feedback signal extracted from the second conversion stage, and a feed forward signal is generated from the error signal and injected into the first conversion stage to stabilize the first output voltage. The feedback signal is a function of the second output voltage and thus, the error signal varies with the second output voltage. As a result, the first output voltage will be stabilized when the second output voltage varies, due to the varied feed forward signal.

主权项

1. A feed forward method for cross-interference reduction of a buck power converter including a first conversion stage converting an input voltage to a first output voltage and a second conversion stage converting the first output voltage to a second output voltage, with which both the first output voltage and the second output voltage can supply different output loads with stable voltages simultaneously, comprising the steps of:
generating a first error signal according to a reference voltage and a feedback signal, wherein the feedback signal is a function of the second output voltage; generating a feed forward signal from the first error signal; and reducing cross-interference to maintain the first output voltage at a target value by injecting the feed forward signal to a control loop of the first conversion stage to cancel part or all transient interference from the second conversion stage to the first conversion stage when a load transient event is happening at the second output voltage.