1

2

3

4

10

9

8

7

PGOOD

VOS

FB

COMP_EN

BOOT

SW

HDRV

LDRV_OC

TPS51113

5

6

VDD

GND

11

R6

47 k

W

C4

1

mF

R4

10 k

W

R1

2 k

W

R3

130

W

C3

8.2 nF

D1

MBR0530Tx

C5

0.1

mF

V

OUT

C2

3.9 nF

R2

2.7 k

W

C1

22 nF

Enable

R5

10 k

W

R

BIAS

2 k

W

R

OC

7 k

W

L1

1.5

mH

V

IN

Q2

BSC079N03S

C6

470

mF

C7

47

mF

–

+

UDG-08107

Q1

BSC079N03S

V

OUT

Choosing the Inductor

(

)

f

IN

O

O

IN

RIPPLE

SW

V

V

V

L

1.534 H

V

I

-

´

=

=

m

´

´

Calculating Output Capacitance

( ) ( )

(

)

( ) ( )

2

2

OH

OL

OUT

2

2

f

i

L

I

I

C

279 F

V

V

´

-

=

=

m

-

(29)

TPS51113, TPS51163

Figure 9. Design Example, 12 V to 1.6 V/10 A DC-DC Converter

Typically the peak-to-peak inductor current

ΔI is selected to be approximately between 20% and 40% of the rated

Therefore, an inductor value of 1.5

µH is selected in practical, and the inductor ripple current is 3.08 A.

Minimum capacitance value can be calculated according to the demand of the load transient response.

Considering 0-A to 10-A step load and 10% overshoot and undershoot, the output capacitance value can be

estimated by using Equation 6,

A 470-

µF POS-CAP with 18-mΩ ESR and a 47-µF ceramic capacitor are paralleled for the output capacitor.

Copyright © 2009, Texas Instruments Incorporated

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