6

HV857

1235 Bordeaux Drive, Sunnyvale, CA 94089

TEL: (408) 744-0100 • FAX: (408) 222-4895

www.supertex.com

11/14/01rev.10

©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.

Split Supply Configuration

The HV857 can also be used for handheld devices operating

from a battery where a regulated voltage is available. This is

shown in Figure 2. The regulated voltage can be used to run

the internal logic of the HV857. The amount of current neces-

Therefore, the regulated voltage could easily provide the

current without being loaded down.

Figure 2: Split Supply and Enable/Disable Configuration

Enable/Disable Configuration

The HV857 can be easily enabled and disabled via a logic control

signal on the R

The control signal can be from a microprocessor. R

are typically very high values. Therefore, only 10’s of microam-

peres will be drawn from the logic signal when it is at a logic high

(enable) state. When the microprocessor signal is high the

device is enabled and when the signal is low, it is disabled.

EL Lamp

+

_

1

2

3

4

8

6

5

HV857MG

7

Gnd

Enable Signal

OFF=0