Switching power supply device
First Claim
1. A switching power supply device, comprising:
- a chopper circuit that turns on/off the passage of a current to an inductor by means of a switching element; and
a switching control circuit that switches the switching element so that an input voltage waveform and an input current waveform with respect to a phase of an input voltage become substantially similar in shape,wherein the switching control circuit is configured to switch the switching element at a switching frequency that is proportional to an input voltage dependent term of a formula that expresses a third harmonic component of ripples of the current flowing to the inductor, andwherein the formula is stated as
Vfs=Vfs max*sin(3*π
*(1−
Vi/Vo)),Vfs min)where Vfs is a switching frequency control voltage, Vfs max is a voltage at a maximum oscillation frequency, Vfs min is a voltage at a minimum oscillation frequency, Vi is the input voltage, and Vo is an output voltage of the control circuit.
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Accused Products
Abstract
An object of the present invention is to achieve the reduction of EMI, the improvement of conversion efficiency, and simplification of the input filter. Provided is a switching power supply device that comprises: a chopper circuit that turns on/off the passage of a current to an inductor by means of a switching element; and a switching control circuit that switches the switching element so that an input voltage and an input current have the same phase and a similar shape. The switching control circuit is configured to switch the switching element at a switching frequency that is proportional to an input voltage dependent term of a formula that expresses a third harmonic component of ripples of the current flowing to the inductor.
6 Citations
3 Claims
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1. A switching power supply device, comprising:
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a chopper circuit that turns on/off the passage of a current to an inductor by means of a switching element; and a switching control circuit that switches the switching element so that an input voltage waveform and an input current waveform with respect to a phase of an input voltage become substantially similar in shape, wherein the switching control circuit is configured to switch the switching element at a switching frequency that is proportional to an input voltage dependent term of a formula that expresses a third harmonic component of ripples of the current flowing to the inductor, and wherein the formula is stated as
Vfs=Vfs max*sin(3*π
*(1−
Vi/Vo)),Vfs min)where Vfs is a switching frequency control voltage, Vfs max is a voltage at a maximum oscillation frequency, Vfs min is a voltage at a minimum oscillation frequency, Vi is the input voltage, and Vo is an output voltage of the control circuit. - View Dependent Claims (2, 3)
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Specification