Supertex inc.
Low Noise, High Voltage
EL Lamp Driver IC Demoboard
General Description
The Supertex HV857LDB1 demoboard contains all
necessary circuitry to demonstrate the features of the
HV857L EL lamp driver.
Simply connect it to a power supply and a lamp. For
additional assistance in designing EL driver circuits,
please refer to application notes
AN-H33 (effect of
external components on performance of Supertex
EL drivers).
HV857LDB1
Specifications
Parameter
Input voltage:
Typical supply current:
Lamp size:
Lamp frequency:
Converter frequency:
Value
1.8 to 5.0V
27mA
3.0in
2
204Hz
70kHz
Board Layout and Connection Diagram
VDD
R
SW
R
EL
EN
GND
VIN
Actual Dimensions: 12mm x 12mm
C
DD
VA
HV857L
VB
C
IN
C
S
L
X
D
Connections:
EN - Enable Input
Enables/Disables the lamp driver. A logic high, (connect
to VDD) 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 that has a
source impedance of less than 20kΩ.
VDD - IC Supply
Supplies the HV857L EL driver IC. The supplied circuit is
optimized for 3.0V operation. The operating range can be
from 1.8 to 5.0V. Connect to the positive terminal of a power
supply.
VIN - Inductor Supply
Supplies the high voltage power converter. Connect to the
positive terminal of a power supply.
GND - Circuit Ground
Connect to VDD and VIN negative terminals. Supply bypass
capacitors for both VDD and VIN are provided on the demo
board. External supply bypass capacitors are not required.
VA and VB - 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.
Doc.# DSDB-HV857LDB1
A032813
Supertex inc.
www.supertex.com
HV857LDB1
Circuit Schematic
ON = V
DD
OFF = 0V
+
V
DD
-
+
V
IN
-
C
DD
0.1µF
R
EL
= 2.0M
C
IN
4.7µF
Enable Signal
1
R
SW
= 560k
VDD
RSW-Osc
REL-Osc
GND
VA
VB
CS
LX
8
7
6
5
2
3
4
EL
Lamp
BAS21
L
X
220µH*
C
S
3.3nF
100V
HV857L
*
Murata Inductor LQH32CN221K21
The above circuit may be optimized further based on specification of the lamp used.
Typical Performance
Lamp Size
(in
2
)
V
DD
= V
IN
(V)
(mA)
I
IN
V
CS
(V)
(Hz)
f
EL
Brightness
ft-lm
cd/
m
2
3.0
3.0
3.0
3.0
3.0
1.8
2.0
3.0
4.0
5.0
27.06
26.95
27.01
21.94
17.55
70
73
90
96
98
202
202
204
204
204
2.49
3.04
5.49
5.97
6.24
8.51
10.40
18.78
20.42
21.33
Bill of Materials
Component
L
X
C
S
R
SW
R
EL
C
IN
C
DD
Diode
U1
Description
220µH Inductor
3.3nF, 100V, NPO chip capacitor
5%, 560kΩ resistor
5%, 2MΩ resistor
4.7µF, 10V ceramic chip capacitor
0.1µF, 16V ceramic chip capacitor
250V fast recovery diode
EL driver IC
Package
-
0805
0805
0805
0805
0603
SOT-23
MSOP-8
Manufacturer
Murata
Novacap
Any
Any
Any
Any
Diodes Inc
Supertex Inc
Part #
LQH32CN221K21
0805N332K101NT
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BAS21
HV857LMG-G
Supertex inc.
does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives
an adequate “product liability indemnification insurance agreement.”
Supertex inc.
does not assume responsibility for use of devices described, and limits its liability
to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and
specifications are subject to change without notice. For the latest product specifications refer to the
Supertex inc.
(website: http//www.supertex.com)
©2013
Supertex inc.
All rights reserved. Unauthorized use or reproduction is prohibited.
Doc.# DSDB-HV857LDB1
A032813
2
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
Supertex inc.
Embedded System
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