HV857LDB1 User Guide

Supertex inc.
HV857LDB1
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).
Specifications
Parameter
Value
Input voltage:
1.8 to 5.0V
Typical supply current:
27mA
Lamp size:
3.0in2
Lamp frequency:
204Hz
Converter frequency:
70kHz
Board Layout and Connection Diagram
VDD
CDD
RSW
HV857L
REL
EN
VB
VA
CIN
CS
GND
VIN
LX
D
Actual Dimensions: 12mm x 12mm
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 = VDD
OFF = 0V
Enable Signal
1
+
RSW = 560kΩ
VDD
CDD
0.1µF
-
3
REL = 2.0MΩ
+
2
4
-
VA
RSW-Osc
VB
REL-Osc
CS
GND
LX
8
EL
Lamp
7
6
BAS21
5
CS
3.3nF
100V
LX
220µH*
HV857L
CIN
4.7µF
VIN
VDD
* Murata Inductor LQH32CN221K21
The above circuit may be optimized further based on specification of the lamp used.
Typical Performance
Lamp Size
(in2)
VDD = VIN
IIN
(V)
(mA)
3.0
1.8
3.0
VCS
Brightness
fEL
(V)
(Hz)
ft-lm
cd/m2
27.06
70
202
2.49
8.51
2.0
26.95
73
202
3.04
10.40
3.0
3.0
27.01
90
204
5.49
18.78
3.0
4.0
21.94
96
204
5.97
20.42
3.0
5.0
17.55
98
204
6.24
21.33
Bill of Materials
Component
Description
Package
Manufacturer
Part #
LX
220µH Inductor
-
Murata
LQH32CN221K21
CS
3.3nF, 100V, NPO chip capacitor
0805
Novacap
0805N332K101NT
RSW
5%, 560kΩ resistor
0805
Any
---
REL
5%, 2MΩ resistor
0805
Any
---
CIN
4.7µF, 10V ceramic chip capacitor
0805
Any
---
CDD
0.1µF, 16V ceramic chip capacitor
0603
Any
---
Diode
250V fast recovery diode
SOT-23
Diodes Inc
BAS21
U1
EL driver IC
MSOP-8
Supertex Inc
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)
Supertex inc.
©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