Power converter
AssigneeDelta Electronics, Inc.
InventorKuo-Jung Wang
Life of this patent
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Abstract
A power converter, and more particularly a switched AC/DC converter provided with input current shaping (ICS) function is disclosed. The ICS function is carried out by adjusting the conducting angle of the input current for the rectifier in virtue of the central tap of the main transformer, and a higher power factor can be obtained. Owing to the action of the ICS, the ripples on the feedback signal are usually larger. The present invention uses the ripples to modulate the switching frequency to effectively disperse and planarize the electromagnetic energy distribution of the power supply, and obviate the electromagnetic interference deficiency of the power supply.
Claims5
A power converter for converting an alternating-current power into a direct-current power for user by a load, comprising:
- a rectifier having an input terminal for receiving said alternating-current power;
- a single-stage single-switch input current shaping circuit coupled between an output terminal of said rectifier and said load, which outputs a direct-current voltage signal in response to the magnitude of said load;
- a feedback circuit coupled to an output terminal of said single-stage single-switch input current shaping circuit for converting said direct-current voltage signal into a feedback signal for output;
- a pulse width modulation control circuit coupled with said single-stage single-switch input current shaping circuit and said feedback circuit, which outputs a pulse width modulation signal to said single-stage single-switch input current shaping circuit in response to a signaling level of said feedback signal;
- and
- a frequency modulation circuit coupled between said pulse width modulation control circuit and said feedback circuit, which performs a frequency modulation process to said pulse width modulation signal according to said feedback signal to abate an energy concentration effect of the electromagnetic harmonics of said power converter.
Dependencies are inferred from the claim text.