IRU3034 & (PbF)

7

www.irf.com

Figure 5 - The circuit in figure 5 is designed to provide loss-less output short detection by detecting the DC voltage

across the inductor and shutting down the MOSFET and entering HICCUP mode. Note that the current limit point

is a function of the inductor resistance and in this application with approximately 8mΩ resistance the peak CL is

set at 10A. See application note on how to set the current limiting threshold.

TYPICAL APPLICATION

5V to 3.3V with loss-less short circuit protection (Output UVLO detection)

Ref Desig

Description

Qty

Part #

Manuf

U1

Switcher IC

1

IRU3034CS (8-Pin SOIC)

IR

Q2

MOSFET

1

IRL3303 (TO-263)

IR

D1

Schottky Diode

1

PBYR735 (Axial Thru Hole pkg)

PBYR1035B (SMT, T-263 pkg)

Motorola

L2

Inductor

1

Core: T50-18, L=4µH

Micro Metal

Turns: 7T, 18 AWG

(core)

L1

Inductor

1

L=µH

R1,2

Resistor

2

10Ω, 5%, SMT

R3

Resistor

1

182KΩ, 1%, SMT

R4

Resistor

1

1KΩ, 1%, SMT

R5

Resistor

1

576Ω, 1%, SMT

R7

Resistor

1

3.83KΩ, 1%, SMT

R6

Resistor

1

1KΩ, 1%, SMT

C1

Capacitor

1

470µF, Elect

C2

Capacitor

1

6MV1000GX, 1000µF, 6.3V, Elect

Sanyo

C3

Capacitor

1

1µF, Ceramic, SMT

C5

Capacitor

1

10pF, Ceramic, SMT

Sanyo

C6

Capacitor

1

0.1µF

C7

Capacitor

2

6MV1000GX, 1000µF, 6.3V, Elect

Sanyo

C8

Capacitor

1

0.047µF

5V

C1

L1

C3

Q2

C2

L2

R4

C7

D1

R2

C4

R5

R1

12V

R3

C5

C8

U1

R6

C6

R7

Drv

Gnd

CS- CS+

SS