HV823
HV823
High Voltage EL Lamp Driver
Ordering Information
Package Options
Device
HV823
Input Voltage
2.0V to 9.5V
8-Lead SO
HV823LG
Die
HV823X
Features
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Processed with HVCMOS
®
technology
2.0V to 9.5V operating supply voltage
DC to AC conversion
180V peak-to-peak typical output voltage
Large output load capability typically 50nF
Permits the use of high-resistance elastomeric lamp
components
Adjustable output lamp frequency to control lamp color,
lamp life, and power consumption
Adjustable converter frequency to eliminate harmonics and
optimize power consumption
Enable/disable function
Low current draw under no load condition
General Description
The Supertex HV823 is a high-voltage driver designed for driving
EL lamps of up to 50nF. EL lamps greater than 50nF can be
driven for applications not requiring high brightness. The input
supply voltage range is from 2.0 to 9.5V. The device uses a single
inductor and a minimum number of passive components. The
nominal regulated output voltage that is applied to the EL lamp
is
±90V.
The chip can be enabled by connecting the resistors on
R
SW-osc
and R
EL-osc
to V
DD
and disabled when connected to GND.
The HV823 has two internal oscillators, a switching MOSFET,
and a high-voltage EL lamp driver. The frequency for the switch-
ing converter MOSFET is set by an external resistor connected
between the R
SW-osc
pin and the supply pin V
DD
. The EL lamp
driver frequency is set by an external resistor connected be-
tween R
EL-osc
pin and the V
DD
pin. An external inductor is
connected between the L
x
and V
DD
pins. A 0.01µF to 0.1µF
capacitor is connected between C
S
and GND. The EL lamp is
connected between V
A
and V
B
.
The switching MOSFET charges the external inductor and
discharges it into the C
s
capacitor. The voltage at C
s
will start to
increase. Once the voltage at C
s
reaches a nominal value of 90V,
the switching MOSFET is turned OFF to conserve power. The
outputs V
A
and V
B
are configured as an H-bridge and are
switched in opposite states to achieve 180V peak-to-peak across
the EL lamp.
Applications
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Handheld personal computers
Electronic personal organizers
GPS units
Pagers
Cellular phones
Portable instrumentation
Pin Configuration
ςΑ
V
DD
R
SW-osc
C
s
L
x
1
2
3
4
8
7
6
5
Absolute Maximum Ratings*
Supply Voltage, V
DD
Output Voltage, V
Cs
Operating Temperature Range
Storage Temperature Range
Power Dissipation
Note:
*All voltages are referenced to GND.
11/12/01
R
EL-osc
V
A
V
B
GND
-0.5V to +10V
-0.5V to +120V
-25°C to +85°C
-65°C to +150°C
400mW
SO-8
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
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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.
HV823
Electrical Characteristics
DC Characteristics
(V
IN
= 3.0V, R
SW
= 750KΩ, R
EL
= 2.0MΩ, T
A
= 25°C unless otherwise specified)
Symbol
R
DS(on)
V
CS
V
A
- V
B
I
DDQ
I
DD
Parameter
On-resistance of switching transistor
Output voltage V
CS
Regulation
Output peak to peak voltage
Quiescent V
DD
supply current, disabled
Input current going into the V
DD
pin
80
160
Min
Typ
2
90
180
30
150
Max
6
100
200
100
200
300
500
I
IN
V
CS
f
EL
f
SW
D
Input current including inductor current
Output voltage on V
CS
V
A-B
output drive frequency
Switching transistor frequency
Switching transistor duty cycle
60
330
50
25
70
380
60
88
33
85
450
70
Units
Ω
V
V
nA
µA
µA
µA
mA
V
Hz
KHz
%
I = 100mA
V
IN
= 2.0 to 9.5V
V
IN
= 2.0V to 9.5V
R
SW-osc
= Low
V
IN
= 3.0V. See Figure 1.
V
IN
= 5.0V. See Figure 2.
V
IN
= 9.0V. See Figure 3.
V
IN
= 3.0V. See Figure 1.
V
IN
= 3.0V. See Figure 1.
V
IN
= 3.0V. See Figure 1.
V
IN
= 3.0V. See Figure 1.
Conditions
Recommended Operating Conditions
Symbol
V
DD
T
A
Supply voltage
Operating temperature
Parameter
Min
2.0
-25
Typ
Max
9.5
+85
Units
V
°C
Conditions
Enable/Disable Table
R
SW
resistor
V
DD
0V
(See Figure 4)
HV823
Enable
Disable
2
HV823
Block Diagram
L
x
V
DD
C
s
R
SW-osc
Enable *
Switch
Osc
Q
GND
Disable
V
A
+
C
_
Q
Vref
Output
Osc
Q
V
B
R
EL-osc
Q
* Enable is available in die form only.
Figure 1: Test Circuit, V
IN
= 3.0V
ON = V
DD
OFF = 0V
(Low input current with moderate output brightness).
2M
Ω
1
750K
Ω
560
µ
H
V
DD
= V
IN
= 3.0V
1N4148
0.1
µ
F
2
1
V
DD
R
EL-osc
V
A
V
B
GND
8
2.0K
Ω
2
3
4
R
SW-osc
C
s
L
x
7
10nF
6
5
Equivalent to 3 square inch lamp.
0.1
µ
F
100V
HV823
Typical Performance
Lamp Size
3.0 in
2
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
V
IN
3.0v
I
IN
25mA
V
CS
65v
f
EL
385Hz
Brightness
6.5ft-lm
For additional information, see Application Notes AN-H33 and AN-H34.
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