Switching converters with adaptive constant on-time control and control methods thereof
AssigneeChengdu Monolithic Power Systems Co., Ltd.
InventorsJian Zhang, Xingwei Wang
Life of this patent
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Abstract
A switching converter with adaptive constant on-time control has a power switch and a control circuit. The switching converter converts an input voltage into an output voltage. When the switching converter is in a light-load state, the on-time of the power switch is controlled to be smaller than the on-time of the power switch in a normal-load state, wherein the normal-load state includes a continuous current mode (CCM) or a discontinuous current mode (DCM).
Claims22
A control circuit used in a switching converter, wherein the switching converter has a power switch and converts an input voltage into an output voltage, the control circuit comprising:
- a light-load regulating current generator configured to receive a state indication signal indicative of a light-load state and generate a light-load regulating current signal based on the state indication signal;
- an on-time control circuit configured to receive the light-load regulating current signal and generate an on-time control signal based on the light-load regulating current signal, wherein based on the on-time control signal, the on-time of the power switch in the light-load state is controlled to be smaller than the on-time of the power switch in a normal-load state;
- a comparing circuit configured to receive a feedback voltage signal indicative of the output voltage and a reference voltage signal, and generate a comparing signal based on the feedback voltage signal and the reference voltage signal;
- and
- a logic circuit configured to receive the comparing signal and the on-time control signal, and generate a switch control signal to control the power switch based on the comparing signal and the on-time control signal.
A switching converter, comprising:
- a switching circuit having a power switch and configured to convert an input voltage into an output voltage;
- a feedback circuit coupled to the switching circuit and configured to provide a feedback voltage signal indicative of the output voltage;
- a light-load regulating current generator configured to receive a state indication signal indicative of a light-load state and generate a light-load regulating current signal based on the state indication signal;
- an on-time control circuit configured to receive the light-load regulating current signal and generate an on-time control signal based on the light-load regulating current signal, wherein based on the on-time control signal, the on-time of the power switch in the light-load state is controlled to be smaller than the on-time of the power switch in a normal-load state;
- and
- a comparing circuit configured to receive the feedback voltage signal and a reference voltage signal, and generate a comparing signal based on the feedback voltage signal and the reference voltage signal;
- a logic circuit configured to receive the comparing signal and the on-time control signal, and generate a switch control signal to control the power switch based on the comparing signal and the on-time control signal;
- wherein the normal-load state comprises a continuous current mode (CCM) or a discontinuous current mode (DCM).
A control method used in a switching converter, wherein the switching converter has a power switch and converts an input voltage into an output voltage, the control method comprising:
- judging whether the switching converter is in a light-load state;
- generating a light-load regulating current signal when the switching converter is in the light-load state;
- and
- generating an on-time control signal based on the light-load regulating current signal, wherein based on the on-time control signal, the on-time of the power switch in the light-load state is controlled to be smaller than the on-time of the power switch in a normal-load state, wherein the normal-load state comprises a continuous current mode (CCM) or a discontinuous current mode (DCM).
Dependencies are inferred from the claim text.