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# A High Efficiency Power Factor Correction (PFC) Circuit For AC/DC Adapters

IP.com Disclosure Number: IPCOM000014633D
Original Publication Date: 2000-Sep-01
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 66K

IBM

## Abstract

A High Efficiency Power Factor Correction (PFC) Circuit For AC/DC Adapters Problem: The ac -dc adapters required for mobile products require very high efficiency and small size. The ac -dc adapter so far has not required any power factor correction. However, there is a trend to require power factor correction for these low power ac -dc adapters. Also. the existing methods for power factor correction are not suitable because of the size limitation. D11 R2

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A High Efficiency Power Factor Correction (PFC) Circuit For AC/DC Adapters Problem:

The ac -dc adapters required for mobile products require very high efficiency and small size. The ac -dc adapter so far has not required any power factor correction. However, there is a trend to require power factor correction for these low power ac -dc adapters. Also. the existing methods for power factor correction are not suitable because of the size limitation.

D11

R2

1 K1A

3

.

.

T9 1 5

V1 44 8

L10L9D10

D8

D9

C5

1 D14

2

- +

4

C6

1

3

1

3

Q1

Q2

22PWM 2

2PWM 1

3

11 D14

C1

+

C8

Error
Amp

Figure 1. A Boost and Chop Circuit for Power factor correction.

V1

2

4

- +

Q3

C7

D8

L10

2 D10

122 Q5 +

D

7

6

3 T10 1

Driver

Q4

D9

11

Square wave
Oscillator

Boost
Controller

R4

Figure 2. A PFC Circuit for AC/DC adapters

1