Supertex inc.
Low Noise, High Voltage
EL Lamp Driver IC Demoboard
General Description
The Supertex HV857DB1 demoboard 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 application notes
AN-H33 (effect of
external components on performance of Supertex
EL drivers)
and
AN-H43 (EL lamp driver circuits to
reduce audible noise).
HV857DB1
Specifications
Parameter
Input voltage:
Typical supply current:
Lamp size:
Lamp frequency:
Converter frequency:
Value
1.8 to 5.0V
26mA
2.6in
2
206Hz
80kHz
Board Layout and Connection Diagram
V
DD
R
SW
R
EL
EN
C
IN
GND
V
IN
Actual Dimensions: 12mm x 12mm
C
DD
V
A
V
B
HV857
C
S
L
X
D
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 that has a
source impedance of less than 20kΩ.
V
DD
- IC Supply
Supplies the HV857 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 positive terminal of a power
supply.
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
capacitor for both V
DD
and V
IN
are provided on the demo
board. External supply bypass capacitors are not required.
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.
Supertex inc.
●
1235 Bordeaux Drive, Sunnyvale, CA 94089
●
Tel: 408-222-8888
●
www.supertex.com
1
HV857DB1
Schematic
ON = V
DD
OFF = 0V
Enable Signal
C
DD
0.1µF
R
SW
= 560kΩ
1
VDD
2
RSW-Osc
3
REL-Osc
4
GND
VA
8
VB
7
CS
6
LX
5
+
V
DD
EL Lamp
BAS21
-
R
EL
= 2.0MΩ
C
IN
4.7µF
+
V
IN
-
HV857MG-G
L
X
220µH*
Note:
Tie V
DD
and V
IN
together if split supplies are not used.
*
Murata Inductor LQH32CN221K21
C
S
3.3nF
100V
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
2.6
2.6
2.6
2.6
2.6
1.8
1.8
1.8
1.8
1.8
1.8
2.0
3.0
4.0
5.0
1.8
2.0
3.0
4.0
5.0
24.6
25.2
23.6
19.2
15.4
20.8
17.3
13.9
9.6
7.2
76.4
82.8
86.4
88.0
90.0
84.0
84.8
86.8
88.0
90.0
206
206
206
206
206
206
206
206
206
206
3.65
4.24
5.41
5.88
6.23
4.56
4.91
5.53
5.94
6.20
12.5
14.5
18.5
20.1
21.3
15.6
16.8
18.9
20.3
21.2
Bill of Materials
Component
L
X
C
S
R
SW
R
EL
C
IN
C
DD
Diode
Clip
Boot
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
Micro alligator clip
Flexible vinly insulation
EL driver IC
Package
-
0805
0805
0805
0805
0603
SOT-23
-
-
8-Lead MSOP
Manufacturer
Murata
Novacap
Any
Any
Any
Any
Diodes Inc
Mueller
Mueller
Supertex Inc
Part #
LQH32CN221K21
0805N332K101NT
---
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BAS21
BU-34
BU-36-0
HV857MG-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)
©2010
Supertex inc.
All rights reserved. Unauthorized use or reproduction is prohibited.
100110
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
2
Supertex inc.
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