Granted Patent B2

US 7,489,116 · App. 11/904,148 · Granted Feb 10, 2009

Abstract

Claims (65)

1. A circuit for power factor correction, comprising:

a waveform generator to receive an AC input voltage and generate a haversign waveform;

a pulse width modulator to generate a pulsed signal based on an intermediate DC voltage, the intermediate DC voltage being based on a rectified AC input voltage;

a multiplier to multiply the haversign waveform and the pulsed signal and to create a haversign signal; and

a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal for a first switch to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage.

2. The circuit of claim 1 , further including an integrator to strip off high frequency characteristics of the haversign signal before the first control circuit compares the magnitude of the haversign signal to the magnitude of the first inductor current.

3. The circuit of claim 1 , further including a second control circuit to compare the magnitude of the haversign signal to a magnitude of a second inductor current to generate a second drive signal for a second switch to control an inductor current waveform to assist in forming the substantially sinusoidal waveform that is in phase with the AC input voltage.

4. The circuit of claim 1 , wherein the pulse width modulator compares a periodic ramp signal to an error signal to generate the pulsed signal.

5. The circuit of claim 4 , further including an error amplifier to compare a reference voltage with the intermediate DC output in order to generate an error signal.

6. A circuit for power factor correction, comprising:

a waveform generator to receive an AC input voltage and generate a haversign waveform;

a pulse width modulator to generate a pulsed signal based on an intermediate DC voltage, the intermediate DC voltage being based on a rectified AC input voltage;

a multiplier to multiply the haversign waveform and the pulsed signal and to create a haversign signal; and

a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal for a first switch to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage, wherein the waveform generator includes a first waveform generator and a second waveform generator, the first waveform generator receiving the AC input and creating a sinusoidal shaped waveform for a positive cycle of the AC input and no waveform for the negative cycle of the AC input and the second waveform generator generating a sinusoidal waveform during the negative cycle of the AC input and generating no waveform during the positive cycle of the AC input.

7. A circuit for power factor correction, comprising:

a waveform generator to receive an AC input voltage and generate a haversign waveform;

a pulse width modulator to generate a pulsed signal based on an intermediate DC voltage, the intermediate DC voltage being based on a rectified AC input voltage;

a multiplier to multiply the haversign waveform and the pulsed signal and to create a haversign signal; and

a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal for a first switch to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage wherein the pulse width modulator compares a periodic ramp signal to an error signal to generate the pulsed signal and

the periodic ramp signal is operating at a similar frequency to an operating frequency of the first control circuit.

8. A power adapter including a circuit for power factor correction, comprising:

an electromagnetic interference filter to remove high frequency noise from an AC input to the power adapter;

the circuit for power factor correction, the circuit including:

a waveform generator to receive an AC input voltage and generate a haversign waveform;

a pulse width modulator to generate a pulsed signal based on an intermediate DC voltage, the intermediate DC voltage being based on a rectified AC input voltage;

a multiplier to multiply the haversign waveform and the pulsed signal and to create a haversign signal; and

a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal for a first switch to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage; and

a transformer to generate a second intermediate voltage based on the intermediate voltage.

9. The power adapter of claim 8 , further including an integrator to strip off high frequency characteristics of the haversign signal before the first control circuit compares the magnitude of the haversign signal to the magnitude of the first inductor current.

10. The power adapter of claim 8 , further including a second control circuit to compare a magnitude of the haversign signal to a magnitude of a second inductor current to generate a second drive signal for a second switch to control an inductor current waveform to assist in forming the substantially sinusoidal waveform that is in phase with the AC input voltage.

11. The power adapter of claim 8 , wherein the pulse width modulator compares a periodic ramp signal to an error signal to generate the pulsed signal.

12. The power adapter of claim 8 , further including an error amplifier to compare a reference voltage with the intermediate DC output in order to generate an error signal.

13. A power adapter including a circuit for power factor correction, comprising:

an electromagnetic interference filter to remove high frequency noise from an AC input to the power adapter;

circuit for power factor correction, the circuit including:

a waveform generator to receive an AC input voltage and generate a haversign waveform;

a pulse width modulator to generate a pulsed signal based on an intermediate DC voltage, the intermediate DC voltage being based on a rectified AC input voltage;

a multiplier to multiply the haversign waveform and the pulsed signal and to create a haversign signal; and

a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal for a first switch to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage; and

a transformer to generate a second intermediate voltage based on the intermediate voltage,

wherein the waveform generator includes a first waveform generator and a second waveform generator, the first waveform generator receiving the AC input and generating a sinusoidal shaped waveform for a positive cycle of the AC input and no waveform for the negative cycle of the AC input and the second waveform generator generating a sinusoidal waveform during the negative cycle of the AC input and no waveform during the positive cycle of the AC input.

14. A power adapter including a circuit for power factor correction, comprising:

an electromagnetic interference filter to remove high frequency noise from an AC input to the power adapter;

the circuit for power factor correction, the circuit including:

a waveform generator to receive an AC input voltage and generate a haversign waveform;

a pulse width modulator to generate a pulsed signal based on an intermediate DC voltage, the intermediate DC voltage being based on a rectified AC input voltage;

a multiplier to multiply the haversign waveform and the pulsed signal and to create a haversign signal; and

a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal for a first switch to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage; and

a transformer to generate a second intermediate voltage based on the intermediate voltage, further including a regulator that receives the second intermediate voltage and generates a power output including a regulated voltage and a current.

15. The power adapter of claim 14 , further including an error correction system that receives a programming signal and inputs an error correction signal to the regulator to regulate a magnitude of the power output by the regulator.

16. A method of power factor correction, comprising:

receiving an AC input voltage;

generating an intermediate DC voltage;

generating, at a waveform generator, a haversign waveform;

generating a pulsed signal based on the intermediate DC voltage;

multiplying the haversign waveform and the pulsed signal to create a multiplied haversign signal;

receiving a first inductor current;

comparing a magnitude of the multiplied haversign signal with a value of the first inductor current; and

generating a first driving signal to control a switching device if the value of the first inductor current is larger than the magnitude of the haversign signal to control an inductor current waveform to assist in forming a substantially sinusoidal waveform that is in phase with the AC input voltage.

17. The method of claim 16 , further including:

receiving the AC input voltage at a first inductor and a second inductor; and

rectifying the AC input voltage using the first switch, the second switch, a first diode, and a second diode to produce the intermediate DC voltage.

18. The method of claim 16 , further including

receiving a second inductor current; and

generating a second driving signal to control a second switching device if the value of the second inductor current is larger than the magnitude of the haversign signal to control an inductor current waveform of the second inductor current to assist in forming the substantially sinusoidal waveform that is in phase with the AC input voltage.

Assignments (6)