Dynamic dropout control of a power supply
AssigneeRichtek Technology Corporation
InventorsTsung-Wei HUANG, Shui-Mu Lin
Life of this patent
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Abstract
A power supply uses a power converter to generate a regulated voltage by referencing to a first DC voltage, a low dropout (LDO) regulator to generate an output voltage from the regulated voltage by referencing to a second DC voltage, and a reference voltage generator to dynamically adjust the first DC voltage according to the input voltage and the control voltage of the output transistor of the LDO regulator. The dropout voltage of the LDO regulator can be minimized to maintain the high efficiency of the power supply at different loading or selected output voltages.
Claims17
A power supply comprising:
- a power converter operative to convert an input voltage into a regulated voltage by referencing to a first DC voltage;
- a low dropout (LDO) regulator including an output transistor having an input terminal receiving the regulated voltage, a control terminal receiving a control voltage, and an output terminal sourcing an output voltage, and an LDO controller generating the control voltage by referencing to a second DC voltage, and modulating the control voltage responsive to an AC tone signal;
- and
- a reference voltage generator connected to the power converter and the LDO regulator, configured to adjust the first DC voltage according to the regulated voltage and the control voltage.
A method for dynamic dropout control of a power supply, comprising:
- A.) converting an input voltage into a regulated voltage by referencing to a first DC voltage;
- B.) generating a control voltage by referencing to a second DC voltage;
- C.) generating an output voltage from the regulated voltage by a transistor which has an input terminal receiving the regulated voltage, a control terminal receiving the control voltage, and an output terminal sourcing the output voltage;
- D.) modulating the control voltage responsive to an AC tone signal, for modulating the output voltage;
- and
- E.) adjusting the first DC voltage according to the regulated voltage and the control voltage.
Dependencies are inferred from the claim text.