Supertex inc.
Low Noise, Dimmable
EL Lamp Driver Demoboard
General Description
The Supertex HV860DB1 demoboard contains all necessary
circuitry to demonstrate the features of the HV860 EL lamp
driver.
Simply connect it to a power supply and a lamp as shown in
Figure1. For EL lamp dimming, either a potentiometer or an n-
channel open drain PWM signal can be used, but not both.
The potentiometer is used as a variable voltage divider to
change the voltage at the VREG pin. The V
REF
is voltage divided
to change the V
REG
voltage thereby changing the V
CS
voltage.
The V
CS
voltage amplitude, and thereby the lamp brightness,
increases when the potentiometer is rotated counter-clockwise,
and the lamp brightness decreases when it is rotated clockwise.
HV860DB1
Specifications
Parameter
Input voltage:
VIN inductor supply voltage:
Value
2.4 to 4.5V
5.5V
10mA
3.5in
2
200Hz
150kHz
Typical supply current:
Lamp size:
Lamp frequency:
Converter frequency:
Board Layout and Connection Diagram
EN
VDD
PWM
Potentiometer
R
SW
R
EL
C
DD
HV860DB1
R
DIM
R
PWM
C
IN
C
DIM
C
S
VA
VB
L
X
D
VIN
GND
Actual Dimensions: 20mm x 25mm
Connections:
EN - (Enable Input)
A CMOS logic input which enables/disables the lamp driver. A logic
high (1.5V) enables the driver and a logic low (connect to GND)
disables the driver.
VDD - (IC Supply)
Supplies the HV860 EL driver IC. The supplied demo board is op-
timized for 3.0V operation, with an operating range from 2.4V to
4.5V. It connects to the positive terminal of a power supply.
PWM - (PWM Input)
Supplies the PWM signal for dimming the EL lamp. The frequency
of this signal can vary between 20kHz and 100kHz. For EL lamp
dimming using the PWM input, either the potentiometer has to be
removed or its value set to for maximum lamp brightness.
The n-channel open drain PWM signal pulls the 10kΩ resistor to
ground. When the duty cycle of this PWM signal is changed, the
effective voltage on the V
REG
pin is changed. This changes the V
CS
voltage, and hence the lamp brightness. The higher the duty cycle,
the higher the lamp brightness, and vice versa.
VA and VB - (Lamp Connections)
They connect to the EL lamp terminals. Polarity is irrelevant.
VIN - (Inductor Supply)
Supplies the high voltage power converter. The demo board is op-
timized for 5.5V operation. It connects to the positive terminal of a
power supply.
GND - (Circuit Ground)
Connect to VDD and VIN negative terminals. Supply bypass ca-
pacitor for both VDD and VIN are provided on the demo board.
External supply bypass capacitors are not required.
Note:
All of the above connections must be made before powering up the supply voltages.
The V
REG
pin should not be touched after power-up.
Doc.# DSDB-HV860DB1
A032813
Supertex inc.
www.supertex.com
HV860DB1
Figure 1: Circuit Schematic
V
IN
+
-
C
IN
4.7 F
2M
Potentiometer
n-channel Open Drain PWM signal
+
V
DD
-
C
DD
0.1 F
590k
10
12
2.0M
ON = 1.5V
OFF = 0V
1
11
1
2
3
10k
3.3M
2
VREG
VDD
Cooper Inductor
SD3114-221, 220 H
3
VREF
5
LX
CS
BAS20HT1
7
RSW-Osc
REL-Osc
EN
HV860K7
3.3nF,
200V
1206 Package
VA
GND
VB
9
8
EL Lamp
4
Typical Performance
Lamp Size
(in
2
)
3.5
3.5
3.5
V
DD
(V)
3.0
3.0
3.0
The specific external components used in the circuit schematic are: L
X
= 220μH Cooper (SD3114-221), C
S
= 3.3nF 200V NPO and the 2MΩ potentiometer.
V
IN
(V)
5.2
5.5
5.8
I
IN
(mA)
9.0
8.4
7.9
V
CS
(V)
110
110
110
f
EL
(Hz)
190
190
190
Brightness
ft-lm
6.20
6.22
6.24
cd/m2
21.21
21.27
21.33
Bill of Materials
Component
L
X
C
S
R
SW
R
EL
R
DIM
R
PWM
C
DIM
C
IN
C
DD
Diode
POT
U1
220μH inductor
Description
Package
---
1206
0603
0603
0603
0603
---
0603
0603
SOD-323
---
12-Lead QFN
Manufacturer
Cooper
Tecate
Any
Any
Any
Any
---
Any
Any
Diodes Inc.
Bourns Inc.
Supertex
Part Number
SD3114-221
CMC-200/332JN1206T
---
---
---
---
---
---
---
BAS20HT1
3352T-205
HV860K7
3.3nF, 200V, NPO chip capacitor
1%, 590kΩ chip resistor
1%, 2MΩ chip resistor
5%, 3.3MΩ chip resistor
1%, 10kΩ chip resistor
Optional capacitor for dimming control
4.7μF, 10V ceramic chip capacitor
0.1μF, 16V ceramic chip capacitor
200V fast recovery diode
2MΩ Potentiometer
EL driver IC
Note:
The above circuit may be optimized further based on specification of the lamp used.
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-HV860DB1
A032813
100110
2
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
Supertex inc.
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