Current limit peak regulation circuit for power converter with low standby power dissipation
AssigneeChengdu Monolithic Power Systems Co., Ltd.
InventorLi Lian
Life of this patent
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Abstract
A current limit peak regulation circuit, a current limit circuit and a power converter including the current limit peak regulation circuit. The current limit peak regulation circuit provides a current limit threshold to limit a maximum allowable peak current value of a current flowing through a main switch of the power converter and adjusts the current limit threshold to decrease with decrease in a switching frequency of the power converter when the power converter is in a constant voltage mode so as to reduce power dissipation of the power converter in standby mode.
Claims17
A current limit peak regulation circuit for regulating a current flowing through a main switch of a power converter, comprising:
- a first input terminal configured to receive a frequency indication signal indicative of a switching frequency of the power converter;
- a second input terminal configured to receive a first reference signal indicative of a first predetermined frequency;
- a third input terminal configured to receive a second reference signal indicative of a second predetermined frequency;
- and
- an output terminal configured to provide a current limit threshold indicative of a maximum allowable peak current value of the current flowing through the main switch;
- wherein
- the current limit peak regulation circuit is configured to generate the current limit threshold based on the frequency indication signal, the first reference signal and the second reference signal;
- and wherein
- the current limit peak regulation circuit is further configured to adjust the current limit threshold to decrease with decrease in the switching frequency in a constant voltage mode of the power converter.
A current limit circuit for a power converter, comprising:
- a current limit peak regulation circuit configured to respectively receive a frequency indication signal indicative of a switching frequency of the power converter, a first reference signal indicative of a first predetermined frequency and a second reference signal indicative of a second predetermined frequency, to generate a current limit threshold indicative of a maximum allowable peak current value of a current flowing through a main switch of the power converter based on the frequency indication signal, the first reference signal and the second reference signal, and to adjust the current limit threshold to decrease with decrease in the switching frequency in a constant voltage mode of the power converter;
- and
- a current limit comparator configured to respectively receive the current limit threshold and a switch current feedback signal indicative of a current flowing through a main switch of the power converter, and to compare the switch current feedback signal with the current limit threshold to provide an off-control signal at an output terminal, wherein the off-control signal is configured to turn the main switch off when the switch current feedback signal reaches the current limit threshold.
A power converter comprising:
- an input port configured to receive an input voltage;
- an output port configured to provide an output voltage;
- a switch module at least comprising a main switch;
- and
- a control module configured to receive an output voltage feedback signal indicative of the output voltage and a switch current feedback signal indicative of a current flowing through the main switch, and to provide a driving signal to the switch module at least based on the output voltage feedback signal, the switch current feedback signal, a reference signal indicative of a desired value of the output voltage and a current limit threshold indicative of a maximum allowable peak current value of the current flowing through the main switch;
- wherein
- the control module comprises a current limit peak regulation circuit configured to generate the current limit threshold and to adjust the current limit threshold to decrease with decrease in the switching frequency in a constant voltage mode of the power converter.
Dependencies are inferred from the claim text.