November 2011

Doc ID 018526 Rev 3

1/26

AN3352

Application note

Dual LNB power supply based on the LNBH24L

supply and control IC with step-up and I²C interface

Introduction

This application note is intended to provide additional information and suggestions for the

correct use of the LNBH24L device. All waveforms shown are based on the demonstration

board order code STEVAL-CBL008V1 described in Section 3.

The LNBH24L is an integrated solution for supplying/interfacing two independent LNB

down-converters in antenna dishes and/or multi-switch box. It gives good performance in a

simple and cheap way, with minimum external components necessary. It includes all

functions needed for LNB supplying and interfacing, in accordance with international

standards. Moreover, it includes an I²C bus interface and, thanks to a fully integrated step-up

DC-DC converter, it functions with a single input voltage supply ranging from 8 V to 15 V.

Figure 1.

LNBH24L internal block diagram

SDA SCL

LNBH24L

A-GND

I²C Diagnostics

PDC

22 kHz

Oscillator

Rsense

EN-A

VSEL-A

Linear Post-reg

+Protections

+Diagnostics

TTX-A

EN-A

VSEL-A

VOUT-A Control

PDC

Rsense

EN-B

VSEL-B

Linear Post-reg

+Protections

+Diagnostics

TTX-B

EN-B

VSEL-B

VOUT-B Control

Byp

Vcc

Preregulator

+U.V.lockout

+P.ON reset

ISEL-A

ISEL-B

TEN-A

TEN-B

TEN-B

TTX-A

TTX-B

TEN-A

FB

FB

Pull Down

Controller

Pull Down

Controller

22 kHz

Oscillator

-

-

²

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Rsense

-

-

-

-

-

-

-

-

-

-

-

-

-

-

B

TEN-B

FB

FB

FB

FB

AM09362v1

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