Power factor correction control circuit for regulating the current waveshape in a switching power supply
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Aug 14, 2001
Grant Date -
N/A
app pub date -
Jun 27, 2000
filing date -
Jun 27, 2000
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A switching power supply comprises an AC rectifier adapted to receive an AC line voltage and provide an input voltage (V.sub.IN) therefrom having a haversine waveform. A switching power converter is connected to the AC rectifier and provides a DC output voltage (V.sub.OUT) for a load. The switching power converter comprises an inductor and a power switch adapted to control current in the inductor. A pulse width modulator provides a drive signal to the power switch having a variable duty cycle to regulate current provided to the load by the switching power converter. A power factor correction circuit is adapted to control operation of the pulse width modulator so that a waveshape of the current from the AC rectifier matches the output voltage (V.sub.OUT) with changes in the input voltage (V.sub.IN) and load. More particularly, the power factor correction circuit further comprises a voltage error circuit providing a voltage error signal corresponding to a difference between the output voltage (V.sub.OUT) and a reference voltage, a differential amplifier circuit generating a current program signal based in part on the voltage error signal, including an amplifier circuit to amplify a scaled input voltage (V.sub.IN) signal with gain determined by the voltage error signal, and a current error circuit controlling the pulse width modulator based on the current program signal and a current sense signal corresponding to the current from the AC rectifier. The amplifier circuit further comprises a field effect transistor (FET) biased in a saturation condition to thereby provide a resistance that varies in accordance with the voltage error signal. The gain of the amplifier circuit is determined by the resistance. The differential amplifier circuit further comprises a second amplifier circuit adapted to amplify a difference between the scaled input voltage (V.sub.IN) signal and the amplified scaled input voltage (V.sub.IN) signal from the first amplifier circuit.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully