HV831

High Voltage Dual EL Lamp Driver

1

A081005

Features

Independent input control for lamp selection

Split supply capability

Patented output timing

One miniature inductor to power both lamps

Low shutdown current

Wide input voltage range 2.0V to 5.0V

Output voltage regulation

No SCR output

Available in 10 - pin MSOP package

Applications

Mobile cellular phones, dual display

Keypad and LCD backlighting

Portable instrumentation

Dual segment lamps

Hand held wireless communication devices

General Description

The Supertex HV831 is a high voltage driver designed for driving

two EL lamps with a combined area of 3.5 square inches. The input

supply voltage range is from 2.0V to 5.0V. The device is designed to

reduce the amount of audible noise emitted by the lamp. This device

uses a single inductor and minimum number of passive components

to drive two EL lamps. The nominal regulated output voltage of ±80V

is applied to the EL lamps. The two EL lamps can be turned on

and off by the two logic input control pins, C

disabled when both C

The HV831 has an internal oscillator, a switching MOSFET, and two

high voltage EL lamp drivers. An external resistor connected between

the R

switching MOSFET. The EL lamp driver frequency is set by dividing

the MOSFET switching frequency by 128. An external inductor is

connected between the L

Depending on the EL

lamp size, a 1.0 to 10.0nF, 100V capacitor is connected between C

S

and Ground. The two EL lamps are connected between EL

and EL

The switching MOSFET charges the external inductor and discharges

it into the capacitor at C

The voltage at C

Once the

voltage at C

is turned off to conserve power. The outputs EL

Com are configured as H bridges and switch in opposite states to

achieve 160V across the EL lamp.

Typical Application Circuit

D

+

-

+

-

1

2

3

4

56

7

8

9

10

0 = OFF

0 = OFF

HV831MG

V

DD

Com

C2

GND

EL

2

L

X

C

S

R

SW-OSC

~

1 The bigger sized lamp should be tied to EL1 and the smaller

sized lamp to EL2 terminals (pins 10 and 9 respectively)