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US 9,178,417 B2Granted
DC-DC converter and voltage conversion method thereof
AssigneeuPI Semiconductor Corp.
InventorHua-Chiang Huang
Life of this patent
Estimating the term…
Abstract
A DC-DC converter is provided. When a load of the DC-DC converter is too light, the DC-DC converter can raise a frequency of its PWM signal, and reduce a pulse width of the PWM signal, so as to avoid the frequency of the PWM signal falling into a frequency range that can heard by human's ear and maintain high conversion efficiency of the DC-DC converter.
Claims12
A direct current (DC)-DC converter, comprising:
- an adjustment circuit, outputting a pulse width modulation (PWM) signal according to a first control signal and a second control signal;
- and
- a control circuit, coupled to the adjustment circuit, for detecting a frequency of the first control signal or the PWM signal, wherein the control circuit comprises a frequency detecting unit and a reduction control unit, the reduction control unit is coupled to the frequency detecting unit and provides the second control signal to the adjustment circuit according to a frequency detecting result generated by the frequency detecting unit, wherein the reduction control unit comprises an adjustable current source, coupled to a timing generator of the adjustment circuit, and providing the second control signal to the timing generator to reduce a pulse width of the PWM signal,
- wherein when the frequency of the first control signal or the PWM signal is lower than a predetermined frequency, the control circuit outputs the second control signal to the adjustment circuit to reduce the pulse width of the PWM signal.
1 more element
A voltage conversion method, adapted to a direct current (DC)-DC converter, the voltage conversion method comprising:
- outputting a PWM signal according to a first control signal and a second control signal;
- detecting whether a frequency of the first control signal or the PWM signal is lower than a predetermined frequency;
- provides the second control signal according to a frequency detecting result;
- and
- providing the second control signal to reduce a pulse width of the PWM signal,
- wherein when the frequency of the first control signal or the PWM signal is lower than the predetermined frequency, the second control signal is provided to reduce the pulse width of the PWM signal.
3 more elements
A direct current (DC)-DC converter, comprising:
- an adjustment circuit, outputting a pulse width modulation (PWM) signal according to a first control signal and a second control signal;
- and
- a control circuit, coupled to the adjustment circuit, for detecting a frequency of the first control signal or the PWM signal, wherein the control circuit comprises a frequency detecting unit and a reduction control unit, the reduction control unit is coupled to the frequency detecting unit and provides the second control signal to the adjustment circuit according to a frequency detecting result generated by the frequency detecting unit, wherein the reduction control unit comprises:
- an operation unit, coupled to a timing generator of the adjustment circuit;
- and
- an adjustable voltage source, coupled to the operation unit, the adjustable voltage source providing a control voltage to the operation unit according to the frequency detecting result to reduce a pulse width of the PWM signal,
- wherein when the frequency of the first control signal or the PWM signal is lower than a predetermined frequency, the control circuit outputs the second control signal to the adjustment circuit to reduce the pulse width of the PWM signal.
4 more elements
A voltage conversion method, adapted to a direct current (DC)-DC converter, the voltage conversion method comprising:
- outputting a PWM signal according to a first control signal and a second control signal;
- and
- detecting whether a frequency of the first control signal or the PWM signal is lower than a predetermined frequency;
- provides the second control signal according to a frequency detecting result;
- and
- providing an adjustable voltage source to provide a control voltage according to the frequency detecting result to reduce a pulse width of the PWM signal,
- wherein when the frequency of the first control signal or the PWM signal is lower than the predetermined frequency, the second control signal is provided to reduce the pulse width of the PWM signal.
4 more elements
Dependencies are inferred from the claim text.