1

HV852

Initial Release

Features

No external components required when using an

external EL clock frequency

EL frequency can be set by an external resistor

Low Noise

DC to AC converter

Output voltage regulation

Enable function

Applications

Cellular phone keypad

Watches

Small handheld wireless devices

MP3 Players

►

►

►

►

►

►

►

►

►

►

►

General Description

The Supertex HV852 is a high voltage, low noise, inductorless

EL (electroluminescent) lamp driver. It is designed to drive EL

an input voltage range of 2.4V to 5.0V. The HV852 converts

a low voltage DC input to a high voltage AC output across an

EL lamp. It uses a charge pump scheme to boost the input

voltage eliminating the need for an external inductor, diode,

and high voltage capacitor commonly found in conventional

topologies.

The charge pump circuit discharges its energy into an EL lamp

through a high voltage H-bridge. Once the voltage reaches

its regulated limit, it is turned off to conserve power. The EL

lamp is then discharged to ground and the H-bridge changes

state to allow the charge pump to charge the EL lamp in the

opposite direction.

Typical Application Circuit

High Voltage, Low Noise,

Inductorless EL Lamp Driver

EL Lamp frequency set by R

EL

+

-

EL

LAMP

V

DD

C

DD

R

EL

V

GND = OFF

HV852

GND

EN