HT7937

Built-in OVP White LED Step-up Converter

Block Diagram

Rev 1.10

1

January 18, 2010

Features

Applications

General Description

The HT7937 is high efficiency boost converter with a

constant current output to provide back light functions in

handheld devices. Applications with series connected

LEDs ensure constant and identical LED currents re-

sulting in uniform brightness. A continuous LED output

current is setup using the FB pin regulated voltage

tween the FB pin and ground. The integrated open load

protection circuitry prevents damage resulting from an

open circuit condition. The low 95mV feedback voltage

minimises power losses in the current setting resistor

which improves efficiency. The HT7937 has a high

switching frequency of up to 1.2MHz which permits the

use of lower value extremely small outline inductor and

filter capacitor.

The HT7937 is supplied in a space-saving, 6-lead

SOT23-6 package type.

å

O V P

F B

1 . 2 M H z

O s c i l l a t o r

C o n t r o l

L o g i c

G N D

S W

S H D N

2 8 V

9 5 m V

V I N