APW7158 datasheet(16/24 Pages) ANPEC

Part #	APW7158

Description	Dual Synchronous Buck PWM Controllers

Download	24 Pages

Scroll/Zoom	100%

Manufacturer	ANPEC [Anpec Electronics Coropration]

Direct Link	http://www.anpec.com.tw

Logo

16 / 24 page

Copyright

Rev. A.2 - Aug., 2009

APW7158

www.anpec.com.tw

16

Application Information

PWM Compensation

The output LC filter of a step down converter introduces a

double pole, which contributes with –40dB/decade gain

slope and 180 degrees phase shift in the control loop. A

compensation network between V

COMP, VFB and VOUT should

be added.

The compensation network is shown in Fig. 8. The out-

put LC filter consists of the output inductor and output

capacitors. The transfer function of the LC filter is given

by:

1

C

ESR

s

C

L

s

C

ESR

s

1

GAIN

OUT

2

OUT

LC

+

×

+

×

+

=

The poles and zero of this transfer function are:

OUT

LC

C

L

2

1

F

×

π

×

=

OUT

ESR

C

ESR

2

1

F

×

π

×

=

The FLC is the double poles of the LC filter, and FESR is

the zero introduced by the ESR of the output capacitor.

V

PHASE

VOUT

L

COUT

ESR

Figure 5. The Output LC Filter

Gain

FESR

FLC

Frequency

-40dB/dec

-20dB/dec

Figure 6. The LC Filter Gain & Frequency

The PWM modulator is shown in Figure. 7. The input is

the output of the error amplifier and the output is the

PHASE node. The transfer function of the PWM modula-

tor is given by:

OSC

IN

PWM

V

GAIN

∆

=

VOSC

PWM

Comparator

Driver

Output

of Error

Amplifier

VIN

V

PHASE

Figure 7. The PWM Modulator

The compensation circuit is shown in Figure 8. It pro-

vides a close loop transfer function with the highest zero

crossover frequency and sufficient phase margin.

The transfer function of error amplifier is given by:









+









+

=

3

sC

1

3

R

//

1

R

2

sC

1

2

R

//

1

sC

1

V

GAIN

OUT

COMP

AMP









×

+

×









×

+









×

+

×









×

+

×

+

=

3

C

3

R

1

s

2

C

1

C

2

R

2

C

1

C

s

3

C

)

3

R

1

R

(

1

s

2

C

2

R

1

s

1

C

3

R

1

R

3

R

1

R

The poles and zeros of the transfer function are:

2

C

2

R

2

1

F

1

Z

×

π

×

=

3

C

)

3

R

1

R

(

2

1

F

2

Z

×

+

×

π

×

=









+

×

π

×

=

2

C

1

C

2

C

1

C

2

R

2

1

F

1

P

3

C

3

R

2

1

F

2

P

×

π

×

=

Similar Part No. - APW7158

Manufacturer	Part #	Datasheet	Description
Anpec Electronics Corop...	APW7153	407Kb / 20P	3A 5V 2MHz Synchronous Buck Converter
	APW7153A	407Kb / 20P	3A 5V 2MHz Synchronous Buck Converter
	APW7153AKAI-TRG	407Kb / 20P	3A 5V 2MHz Synchronous Buck Converter
	APW7153AQBI-TRG	407Kb / 20P	3A 5V 2MHz Synchronous Buck Converter
	APW7153B	407Kb / 20P	3A 5V 2MHz Synchronous Buck Converter

More results

Similar Description - APW7158

Manufacturer	Part #	Datasheet	Description
Anpec Electronics Corop...	APW7058	174Kb / 13P	Synchronous Buck PWM and Linear Controllers
	APW7066	974Kb / 34P	Dual Synchronous Buck PWM Controllers and One Linear Controller
	APW7066	586Kb / 35P	Dual Synchronous Buck PWM Controllers and One Linear Controller
Analog Devices	ADP3171	310Kb / 12P	Synchronous Buck Controller with Dual Linear Regulator Controllers REV. 0
Richtek Technology Corp...	RT9206	338Kb / 21P	High Efficiency, Synchronous Buck with Dual Linear Controllers
Linear Technology	LTC3723-1	344Kb / 20P	Synchronous Push-Pull PWM Controllers
	LTC3723-1	339Kb / 20P	Synchronous Push-Pull PWM Controllers
	LTC3723-2	344Kb / 20P	Synchronous Push-Pull PWM Controllers
ON Semiconductor	NCP1582	155Kb / 16P	Low Voltage Synchronous Buck Controllers July, 2006 ??Rev. 2
Anpec Electronics Corop...	APW7062A	179Kb / 16P	Synchronous Buck PWM Controller

More results

APW7158 Datasheet(PDF) 16 Page - Anpec Electronics Coropration

APW7158 Datasheet(HTML) 16 Page - Anpec Electronics Coropration

Similar Part No. - APW7158

Similar Description - APW7158

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Datasheet Download

Link URL