HV857DB1
HV857DB1
EL Lamp Driver
Introduction
The Supertex HV857DB1 demo board contains all necessary
circuitry to demonstrate the features of the HV857 EL lamp
driver.
Simply connect it to a power supply and a lamp. For additional
assistance in designing EL driver circuits, please refer to appli-
cation notes AN-H33 (effect of external components on perfor-
mance of Supertex EL drivers) and AN-H43 (EL lamp driver
circuits to reduce audible lamp noise).
Specifications
Input Voltage
Supply Current
Lamp Size Range
Lamp Frequency
Converter Frequency
1.8V to 5.0V
25mA
up to 2.6in
2
250Hz
80KHz
Board Layout and Connections
V
DD
Rsw
Rel
EN
GND
V
IN
+
Cdd
V
B
V
A
HV857
Cin
Cs
L
X
D
Demo Board Connections:
EN
Enable Input
Enables/Disables the lamp driver. A logic high (connect to V
DD
)
enables the driver and a logic low (connect to GND) disables the
driver. This input can be connected to a mechanical switch, or
to a logic circuit output with a source impedance of less than
20K鈩?
V
IN
Inductor Supply
Supplies the high voltage power converter. Connect to positive
terminal of a power supply.
GND
Circuit Ground
Connect to V
DD
and V
IN
negative terminals. Supply bypass
capacitors for both V
DD
and V
IN
are provided on the demo board.
External supply bypass capacitors are not required.
V
DD
IC Supply
Supplies the HV857 EL driver IC. The supplied circuit is opti-
mized for 3.0V operation. The operating range can be from 1.8V
to 5.0V. Connect to positive terminal of a power supply.
V
A
and V
B
Lamp Connections
Connect to an EL lamp. Polarity is irrelevant.
* Note: Make sure all the above connections are made before powering up the supply voltages.
11/27/01
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.
1
1
2
