1
HV823
HV823
High Voltage EL Lamp Driver
Features
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
Package Options
Device
Input Voltage
8-Lead SO
Die
HV823
2.0V to 9.5V
HV823LG
HV823X
Ordering Information
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 0.01
F to 0.1F
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.
Pin Configuration
V
DD
R
EL-osc
R
SW-osc
V
A
C
s
V
B
L
x
GND
Applications
Handheld personal computers
Electronic personal organizers
GPS units
Pagers
Cellular phones
Portable instrumentation
Absolute Maximum Ratings*
Supply Voltage, V
DD
-0.5V to +10V
Output Voltage, V
Cs
-0.5V to +120V
Operating Temperature Range
-25
C to +85C
Storage Temperature Range
-65
C to +150C
Power Dissipation
400mW
Note:
*All voltages are referenced to GND.
1
2
3
4
8
7
6
5
SO-8
11/12/01
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
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.
2
HV823
Symbol
Parameter
Min
Typ
Max
Units
Conditions
R
DS(on)
On-resistance of switching transistor
2
6
I = 100mA
V
CS
Output voltage V
CS
Regulation
80
90
100
V
V
IN
= 2.0 to 9.5V
V
A
- V
B
Output peak to peak voltage
160
180
200
V
V
IN
= 2.0V to 9.5V
I
DDQ
Quiescent V
DD
supply current, disabled
30
100
nA
R
SW-osc
= Low
I
DD
Input current going into the V
DD
pin
150
200
A
V
IN
= 3.0V. See Figure 1.
300
A
V
IN
= 5.0V. See Figure 2.
500
A
V
IN
= 9.0V. See Figure 3.
I
IN
Input current including inductor current
25
33
mA
V
IN
= 3.0V. See Figure 1.
V
CS
Output voltage on V
CS
60
70
85
V
V
IN
= 3.0V. See Figure 1.
f
EL
V
A-B
output drive frequency
330
380
450
Hz
V
IN
= 3.0V. See Figure 1.
f
SW
Switching transistor frequency
50
60
70
KHz
V
IN
= 3.0V. See Figure 1.
D
Switching transistor duty cycle
88
%
Electrical Characteristics
DC Characteristics
(V
IN
= 3.0V, R
SW
= 750K
, R
EL
= 2.0M
, T
A
= 25
C unless otherwise specified)
Symbol
Parameter
Min
Typ
Max
Units
Conditions
V
DD
Supply voltage
2.0
9.5
V
T
A
Operating temperature
-25
+85
C
Recommended Operating Conditions
R
SW
resistor
HV823
V
DD
Enable
0V
Disable
Enable/Disable Table
(See Figure 4)
3
HV823
Figure 1: Test Circuit, V
IN
= 3.0V
(Low input current with moderate output brightness).
Block Diagram
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5
)
2. Larger values may be required depending upon supply impedance.
Lamp Size
V
IN
I
IN
V
CS
f
EL
Brightness
3.0 in
2
3.0v
25mA
65v
385Hz
6.5ft-lm
Typical Performance
For additional information, see Application Notes AN-H33 and AN-H34.
Switch
Osc
C
+
_
Vref
Disable
Output
Osc
GND
V
DD
R
EL-osc
Q
Q
Q
V
A
C
s
L
x
V
B
Q
R
SW-osc
Enable *
* Enable is available in die form only.
1
7
2
3
4
8
6
5
V
DD
= V
IN
= 3.0V
ON = V
DD
OFF = 0V
0.1F
100V
0.1F
2
560H
1
1N4148
750K
2M
2.0K
10nF
Equivalent to 3 square inch lamp.
HV823
L
x
GND
V
B
V
A
R
EL-osc
V
DD
R
SW-osc
C
s
4
HV823
Typical Performance Curves for Figure 1 using 3in
2
EL Lamp.
I
IN
(mA)
Brightness (ft-Im)
I
IN
(mA)
V
IN
(V)
Brightness vs. V
IN
V
IN
(V)
I
IN
vs.
V
IN
V
CS
(V)
I
IN vs.
V
CS
(V)
V
IN
(V)
V
CS
vs.
V
IN
V
cs
(V)
1
2
3
4
5
6
7
8
9
0
5
10
15
20
25
30
40
50
60
70
80
90
0
5
10
15
20
25
30
1
2
3
4
5
6
7
8
9
0
2
4
6
8
10
12
1
2
3
4
5
6
7
8
9
40
50
60
70
80
90
100
250
400
550
700
850
1000
90
80
70
60
50
40
30
20
10
0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0
Inductor Value (
H)
IIN, VCS, Brightness vs. Inductor Value
I
IN
(mA), V
CS
(V)
Brightness (ft-Im)
V
CS
(V)
Brightness (ft-lm)
I
IN
(mA)
5
HV823
Figure 2: Typical 5.0V Application
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5
)
2. Larger values may be required depending upon supply impedance.
Lamp Size
V
IN
I
IN
V
CS
f
EL
Brightness
6.0 in
2
5.0v
25mA
75v
380Hz
6.5ft-lm
Typical Performance
For additional information, see Application Notes AN-H33 and AN-H34.
Typical Performance Curves for Figure 2
90
85
80
75
70
65
5
4
7
8
6
8
7.5
7
6.5
6
5.5
5
4
7
8
6
40
38
36
34
32
30
5
4
7
8
6
40
38
36
34
32
30
70
80
85
90
75
V
CS
(V)
I
IN
(mA)
Brightness (ft-Im)
I
IN
(mA)
V
IN
(V)
V
IN
(V)
V
IN
(V)
V
CS
(V)
V
CS vs.
V
IN
Brightness vs. V
IN
I
IN
vs.
V
IN
I
IN vs.
V
CS
(V)
1
7
2
3
4
8
6
5
V
DD
= V
IN
= 5.0V
0.01F
100V
1nF
16v
560H
1
1N4148
750K
2M
3.1K
20nF
HV823
L
x
GND
V
B
V
A
R
EL-osc
V
DD
R
SW-osc
C
s
ON = V
DD
OFF = 0V
0.1F
2
Equivalent to 6 square inch lamp
6
HV823
Figure 3: Typical 9.0V Application*
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5
)
2. Larger values may be required depending upon supply impedance.
Lamp Size
V
IN
I
IN
V
CS
f
EL
Brightness
12.0 in
2
9.0v
30mA
75v
380Hz
8.5ft-lm
Typical Performance
For additional information, see Application Notes AN-H33 and AN-H34.
85
80
75
70
65
5
4
7
8
6
8
7.5
7
6.5
6
5.5
5
4
7
8
6
40
38
36
34
32
30
5
4
7
8
6
40
38
36
34
32
30
70
80
85
90
75
V
CS
(V)
I
IN
(mA)
Brightness (ft-Im)
I
IN
(mA)
V
IN
(V)
V
IN
(V)
V
IN
(V)
V
CS
(V)
V
CS vs.
V
IN
Brightness vs. V
IN
I
IN
vs.
V
IN
I
IN vs.
V
CS
(V)
Typical Performance Curves for Figure 3
1
7
2
3
4
8
6
5
V
DD
= V
IN
= 9.0V
0.01
F
100V
1nF
16v
560
H
1
1N4148
330K
2M
4.9K
42nF
HV823
L
x
GND
V
B
V
A
R
EL-osc
V
DD
R
SW-osc
C
s
0.1
F
2
Equivalent to 12 square inch lamp
7
HV823
External Component Description
External Component
Selection Guide Line
Diode
Fast reverse recovery diode, 1N4148 or equivalent.
Cs Capacitor
0.01
F to 0.1F, 100V capacitor to GND is used to store the energy transferred from the inductor.
R
EL-osc
The EL lamp frequency is controlled via an external R
EL
resistor connected between R
EL-osc
and V
DD
of the
device. The lamp frequency increases as R
EL
decreases. As the EL lamp frequency increases, the amount
of current drawn from the battery will increase and the output voltage V
CS
will decrease. The color of the EL
lamp is dependent upon its frequency.
A 2M
resistor would provide lamp frequency of 330 to 450Hz. Decreasing the R
EL-osc
by a factor of 2 will
increase the lamp frequency by a factor of 2.
R
SW-osc
The switching frequency of the converter is controlled via an external resistor, R
SW
between R
SW-osc
and V
DD
of the device. The switching frequency increases as R
SW
decreases. With a given inductor, as the switching
frequency increases, the amount of current drawn from the battery will decrease and the output voltage, V
CS
,
will also decrease.
C
SW
Capacitor
A 1nF capacitor is recommended on R
SW-osc
to GND when a 0.01
F C
S
capacitor is used. This capacitor
is used to shunt any switching noise that may couple into the R
SW-osc
pin. The C
SW
capacitor may also be
needed when driving large EL lamp due to increase in switching noise.
Lx Inductor
The inductor L
x
is used to boost the low input voltage by inductive flyback. When the internal switch is on,
the inductor is being charged. When the internal switch is off, the charge stored in the inductor will be
transferred to the high voltage capacitor C
S
. The energy stored in the capacitor is connected to the internal
H-bridge and therefore to the EL lamp. In general, smaller value inductors, which can handle more current,
are more suitable to drive larger size lamps. As the inductor value decreases, the switching frequency of the
inductor (controlled by R
SW
) should be increased to avoid saturation.
560
H Murata inductors with 14.5 series DC resistance is typically recommended. For inductors with the
same inductance value but with lower series DC resistance, lower R
SW
value is needed to prevent high current
draw and inductor saturation.
Lamp
As the EL lamp size increases, more current will be drawn from the battery to maintain high voltage across
the EL lamp. The input power, (V
IN
x I
IN
), will also increase. If the input power is greater than the power
dissipation of the package (400mW), an external resistor in series with one side of the lamp is recommended
to help reduce the package power dissipation.
Enable/Disable Configuration
The HV823 can be easily enabled and disabled via a logic control
signal on the R
SW
and R
EL
resistors as shown in Figure 4 below.
The control signal can be from a microprocessor. R
SW
and R
EL
are typically very high values. Therefore, only 10's of microam-
Figure 4: Enable/Disable Configuration
peres will be drawn from the logic signal when it is at a logic high
(enable) state. When the microprocessor signal is high the
device is enabled and when the signal is low, it is disabled.
1
7
2
3
4
8
6
5
V
IN
= V
DD
ON =V
DD
OFF = 0V
C
S
100V
4.7
F
15V
1nF
L
x
1N4148
R
SW
R
EL
EL Lamp
HV823LG
L
x
GND
V
B
V
A
R
EL-osc
V
DD
R
SW-osc
C
s
+
-
Remote
Enable
8
HV823
Split Supply Configuration Using a Single
Cell (1.5V) Battery
The HV823 can also be used for handheld devices operating
from a single cell 1.5V battery where a regulated voltage is
available. This is shown in Figure 5. The regulated voltage
can be used to run the internal logic of the HV823. The
amount of current necessary to run the internal logic is
typically 100
A at a V
DD
of 3.0V. Therefore, the regulated
voltage could easily provide the current without being loaded
down. The HV823 used in this configuration can also be
enabled/disabled via logic control signal on the R
SW
and R
EL
resistors as shown in Figure 4.
Split Supply Configuration for Battery
Voltages of Higher than 9.5V
Figure 5 can also be used with high battery voltages such as 12V
as long as the input voltage, V
DD
, to the HV823 device is within
its specifications of 2.0V to 9.5V.
Figure 5: Split Supply Configuration
*Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
1
7
2
3
4
8
6
5
V
IN
= Battery
Voltage
V
DD
= Regulated
Voltage
C
S
100V
0.1
F*
L
x
1N4148
R
SW
R
EL
EL Lamp
HV823LG
L
x
GND
V
B
V
A
R
EL-osc
V
DD
R
SW-osc
C
s
+
-
Remote
Enable
ON =V
DD
OFF = 0
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 744-0100 FAX: (408) 222-4895
www.supertex.com
11/12/01
2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
PDF 
ZIP