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HV829A/B

09/05/02

Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate "products liability

indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to

workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the

Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.

HV829A/B

High Voltage EL Lamp Driver

Advance Information

Features

❑ V

❑ Adjustable DC-DC converter frequency

❑ Continious output voltage regulation control

(from 50V to 200V)

Application

❑ Electronic Organizers

❑ Handheld Portable Computers

❑ Display Signs

❑ Portable Instrumentation Equipment

General Description

The Supertex HV829A/B are high voltage EL lamp driver inte-

grated circuits designed for driving EL lamps of up to 70nF at

1000Hz. The input supply voltage range is from 2.7V to 5.5V.

These devices use a single inductor, a high voltage switching

FET and a minimum number of passive components. The

HV829A/B will supply the EL lamp with an AC square wave with

a peak-to-peak voltage of two times the set regulated DC

voltage.

The HV829A/B has one internal oscillator and a high voltage EL

lamp driver. The frequency for the external switching MOSFET

is set by an external resistor connected between the R

and GND. The EL frequency for the HV829A is equal to the

switching frequency divided by 64 where the EL frequency for the

HV829B is equal to the switching frequency divided by 128. Gate

of the external MOSFET is connected to the Gate pin. An

external inductor is connected between the Drain of external

MOSFET and V

between Cs and ground. The EL lamp is connected between V

A

and V

V

voltage regulation can be controlled continuously between 50V

and 200V depending on the voltage applied to V

to 3V).

The switching MOSFET charges the external inductor and

discharges it into the capacitor at C

to increase. Once the voltage at C

chosen by the user, the switching MOSFET is turned OFF to

conserve power. The outputs V

bridge and are switching in opposite states to achieve the AC

voltage of +/- VREG voltage across the EL lamp.

Typical Application Circuit

VN2224N3 or

TN2425N8

EL Lamp

1

2

3

4

8

7

6

5

GND

HV829ASG

Lx

BAV21

Gate

On=GND

Vreg

+

-

250V