Cross-interference reduction of a buck power converter
AssigneeRichtek Technology Corporation
InventorJing-Meng Liu
Life of this patent
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Abstract
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.
Claims18
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.
A buck power converter comprising:
- a first conversion stage converting an input voltage to a first output voltage;
- a second conversion stage converting the first output voltage to a second output voltage;
- an error amplifier generating a first error signal according to a reference voltage and a first feedback signal, wherein the first feedback signal is a first function of the second output voltage;
- and
- an analog summing circuit receiving a feed forward signal to reduce 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, wherein the feed forward signal is a second function of the error signal;
- wherein both the first output voltage and the second output voltage can supply different output loads with stable voltages simultaneously.
Dependencies are inferred from the claim text.