MBRS130 Ver la hoja de datos (PDF) - Monolithic Power Systems

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componentes Descripción

Fabricante

MBRS130

3A, 23V, 340KHz Synchronous Rectified Step-Down Converter

Monolithic Power Systems 

TM

MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER

2. Choose the compensation capacitor (C3) to

achieve the desired phase margin. For

applications with typical inductor values, setting

the compensation zero, fZ1, below one forth of

the crossover frequency provides sufficient

phase margin. Determine the C3 value by the

following equation:

C3 >

4

2π × R3 × fC

3. Determine if the second compensation

capacitor (C6) is required. It is required if the

ESR zero of the output capacitor is located at

less than half of the 340KHz switching

frequency, or the following relationship is valid:

1

< fS

2π × C2 × RESR 2

is the case, then add the second compensation

capacitor (C6) to set the pole fP3 at the location

of the ESR zero. Determine the C6 value by the

equation:

C6 = C2 × RESR

R3

External Bootstrap Diode

It is recommended that an external bootstrap

diode be added when the system has a 5V

fixed input or the power supply generates a 5V

output. This helps improve the efficiency of the

regulator. The bootstrap diode can be a low

cost one such as IN4148 or BAT54.

5V

BS

MP1570

SW

10nF

MP1570_F02

Figure 2—External Bootstrap Diode

This diode is also recommended for high duty

cycle operation (when VOUT >65%) and high

VIN

output voltage (VOUT>12V) applications.

TYPICAL APPLICATION CIRCUITS

INPUT

4.75V to 23V

C5

10nF

2

7 IN

EN

1

BS

SW

3

MP1570

8 SS

GND

FB 5

COMP

4

6

C6

(optional)

C3

3.3nF

D1

B130

(optional)

OUTPUT

2.5V

3A

MP1570_F03

Figure 3—MP1570 with AVX 47µF, 6.3V Ceramic Output Capacitor

MP1570 Rev. 1.5

www.MonolithicPower.com

9

1/31/2006

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© 2006 MPS. All Rights Reserved.

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