HV860

Features

Adjustable output regulation for dimming

220V

Single cell lithium ion compatible

150nA shutdown current

Separately adjustable lamp and converter frequencies

3x3mm 12-Lead QFN package

Split supply capability

Applications

Mobile cellular phone keypads

PDAs

Handheld wireless communication products

Global Positioning Systems (GPS)

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The HV860 has two internal oscillators, a switching

MOSFET, and a high voltage EL lamp driver H-bridge. The

frequency for the switching MOSFET is set by an external

resistor connected between the RSW-Osc pin and the

supply pin VDD. The EL lamp driver frequency is set by

an external resistor connected between REL-Osc pin and

VDD pin. An external inductor is connected between the LX

and VDD pins or VIN for split supply applications. A 3.0nF

capacitor is connected between CS and ground. The EL

lamp is connected between VA and VB.

The switching MOSFET charges the external inductor and

discharges it into the capacitor at CS. The voltage at CS will

start to increase. Once the voltage at CS reaches a nominal

value of 110V, the switching MOSFET is turned OFF to

conserve power. The outputs VA and VB are configured as

an H bridge and are switching in opposite states to achieve

±110V across the EL lamp.

EL lamp dimming can be accomplished by changing the

input voltage to the VREG pin. The VREG pin allows an

external voltage source to control the VCS amplitude. The

VCS voltage is approximately 87 times the voltage seen on

VREG.

Typical Application Circuit

Low Noise, Dimmable

EL Lamp Driver

General Description

The Supertex HV860 is a high voltage driver designed for

driving Electroluminescent, (EL), lamps of up to 5 square

inches. The input supply voltage range is from 2.5 to 4.5V.

The device uses a single inductor and a minimum number of

passive components. Using the internal reference voltage,

the regulated output voltage is at a nominal voltage of 110V.

The EL lamp will therefore see ±110V. An enable pin, (EN),

is available to turn the device on and off via a logic signal.

1.5V = On

0V = Off

EL

Lamp

D

9

7

5

3

2

10

12

1

11

4

8

HV860

VDD

VB

VA

CS

LX

VREF

VREG

REL-Osc

RSW-Osc

EN

GND