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High Voltage EL Lamp Driver
Ordering Information
Package Options
Device Input Voltage 8-Lead SO Die
HV823 2.0V to 9.5V HV823LG HV823X
HV823
HV823
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
Applications
❏ Handheld personal computers
❏ Electronic personal organizers
❏ GPS units
❏ Pagers
❏ Cellular phones
❏ Portable instrumentation
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
to VDD and disabled when connected to GND.
EL-osc
The HV823 has two internal oscillators, a switching MOSFET,
and a high-voltage EL lamp driver. The frequency for the switching converter MOSFET is set by an external resistor connected
between the R
pin and the supply pin VDD. The EL lamp
SW-osc
driver frequency is set by an external resistor connected between R
connected between the L
capacitor is connected between C
connected between V
pin and the VDD pin. An external inductor is
EL-osc
and VDD pins. A 0.01µF to 0.1µF
x
and VB.
A
and GND. The EL lamp is
S
The switching MOSFET charges the external inductor and
discharges it into the Cs capacitor. The voltage at Cs will start to
increase. Once the voltage at C
reaches a nominal value of 90V,
s
the switching MOSFET is turned OFF to conserve power. The
outputs VA and VB are configured as an H-bridge and are
switched in opposite states to achieve 180V peak-to-peak across
the EL lamp.
Pin Configuration
Absolute Maximum Ratings*
Supply Voltage, V
Output Voltage, V
DD
Cs
Operating Temperature Range -25°C to +85°C
Storage Temperature Range -65°C to +150°C
-0.5V to +10V
-0.5V to +120V
ςΑ V
R
DD
SW-osc
C
s
L
x
1
2
3
4
SO-8
8
R
EL-osc
7
V
A
6
V
B
5
GND
Power Dissipation 400mW
Note:
*All voltages are referenced to GND.
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.
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Electrical Characteristics
DC Characteristics (V
Symbol Parameter Min Typ Max Units Conditions
R
DS(on)
V
CS
- V
V
A
I
DDQ
I
DD
I
IN
V
CS
f
EL
f
SW
D Switching transistor duty cycle 88 %
On-resistance of switching transistor 2 6 Ω I = 100mA
Output voltage VCS Regulation 80 90 100 V VIN = 2.0 to 9.5V
Output peak to peak voltage 160 180 200 V VIN = 2.0V to 9.5V
B
Quiescent VDD supply current, disabled 30 100 nA R
Input current going into the VDD pin 150 200 µAVIN = 3.0V. See Figure 1.
Input current including inductor current 25 33 mA VIN = 3.0V. See Figure 1.
Output voltage on V
V
output drive frequency 330 380 450 Hz VIN = 3.0V. See Figure 1.
A-B
Switching transistor frequency 50 60 70 KHz VIN = 3.0V. See Figure 1.
= 3.0V, RSW = 750KΩ, REL = 2.0MΩ, TA = 25°C unless otherwise specified)
IN
= Low
SW-osc
= 5.0V. See Figure 2.
IN
= 9.0V. See Figure 3.
IN
CS
300 µAV
500 µAV
60 70 85 V VIN = 3.0V. See Figure 1.
HV823
Recommended Operating Conditions
Symbol Parameter Min Typ Max Units Conditions
V
DD
T
A
Supply voltage 2.0 9.5 V
Operating temperature -25 +85 °C
Enable/Disable Table (See Figure 4)
RSW resistor HV823
V
DD
0V Disable
Enable
2
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Block Diagram
V
DD
R
SW-osc
Enable *
GND
R
EL-osc
Switch
Osc
Disable
HV823
L
x
C
s
Q
V
A
+
C
_
Vref
Q
Output
Osc
Q
V
B
Q
* Enable is available in die form only.
Figure 1: Test Circuit, VIN = 3.0V (Low input current with moderate output brightness).
ON=V
VDD=VIN= 3.0V
DD
OFF=0V
560µH
0.1µF
1
1N4148
2
0.1µF
100V
750K
2M
Ω
DD
SW-osc
s
x
R
EL-osc
GND
8
2.0K
V
A
7
V
B
6
5
Ω
10nF
Equivalent to 3 square inch lamp.
V
1
Ω
R
2
C
3
L
4
HV823
Typical Performance
Lamp Size V
2
3.0 in
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
IN
3.0v 25mA 65v 385Hz 6.5ft-lm
I
V
IN
CS
f
EL
For additional information, see Application Notes AN-H33 and AN-H34.
Brightness
3
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Typical Performance Curves for Figure 1 using 3in2 EL Lamp.
HV823
V
CS vs. VIN
90
80
70
(V)
60
cs
V
50
40
123456789
VIN (V)
Brightness vs. V
12
10
8
6
4
2
Brightness (ft-Im)
0
123456789
VIN (V)
IN
I
IN vs. VIN
30
25
20
15
(mA)
10
IN
I
5
0
123456789
VIN (V)
30
25
20
15
(mA)
10
IN
I
I
IN vs. VCS
5
0
(V)
40 50 60 70 80 90
VCS (V)
IIN, VCS, Brightness vs. Inductor Value
90
80
70
60
(V)
50
CS
40
(mA), V
IN
I
Brightness (ft-lm)
30
20
IIN(mA)
10
0
100 250 400 550 700 850
Inductor Value (µH)
VCS(V)
1000
9.0
8.0
7.0
Brightness (ft-Im)
6.0
5.0
4.0
3.0
2.0
1.0
0
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Figure 2: Typical 5.0V Application
ON=V
DD
OFF=0V
2M
HV823
Ω
1
560µH
VDD=VIN= 5.0V
1N4148
750K
2
0.1µF
0.01µF
100V
Typical Performance
Lamp Size V
2
6.0 in
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
IN
5.0v 25mA 75v 380Hz 6.5ft-lm
I
V
IN
CS
f
EL
For additional information, see Application Notes AN-H33 and AN-H34.
Ω
V
1
DD
R
2
SW-osc
C
3
s
L
x
4
HV823
1nF
16v
Brightness
R
EL-osc
V
V
GND
8
3.1K
A
7
B
6
5
Ω
20nF
Equivalent to 6 square inch lamp
Typical Performance Curves for Figure 2
V
CS vs. VIN
90
85
80
(V)
75
CS
V
70
65
54786
VIN (V)
8
7.5
7
6.5
6
Brightness (ft-Im)
5.5
Brightness vs. V
54786
(V)
V
IN
IN
40
38
36
34
(mA)
IN
I
32
30
40
38
36
(mA)
34
IN
I
32
30
70 80 85 9075
IIN
vs. VIN
54786
V
IN
I
IN vs. VCS
V
CS
(V)
(V)
(V)
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Figure 3: Typical 9.0V Application*
3
5
0V
0.01
µ
00V
560
µ
8
330K
3
D
osc
SW-osc
s
0.1
µ
V
= V
DD
IN
= 9.
Typical Performance
Lamp Size V
2
12.0 in
Notes:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
IN
9.0v 30mA 75v 380Hz 8.5ft-lm
1N414
1
I
V
IN
CS
f
EL
2MΩ
v
Brightness
HV823
-
4.9KΩ
42nF
N
Equivalent to 12 square inch lamp
2
For additional information, see Application Notes AN-H33 and AN-H34.
Typical Performance Curves for Figure 3
V
CS vs. VIN
85
80
75
(V)
CS
70
V
65
54786
VIN (V)
8
7.5
7
6.5
6
Brightness (ft-Im)
5.5
Brightness vs. V
54786
V
(V)
IN
IN
40
38
36
34
(mA)
IN
I
32
30
40
38
36
(mA)
34
IN
I
32
30
70 80 85 9075
IIN
vs. VIN
54786
V
IN
I
IN vs. VCS
V
CS
(V)
(V)
(V)
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HV823
3
5
S
00V
5V
8
G
D
osc
SW-osc
s
able
External Component Description
External Component Selection Guide Line
Diode Fast reverse recovery diode, 1N4148 or equivalent.
Cs Capacitor 0.01µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor.
R
EL-osc
R
SW-osc
CSW Capacitor A 1nF capacitor is recommended on R
Lx Inductor The inductor Lx is used to boost the low input voltage by inductive flyback. When the internal switch is on,
Lamp As the EL lamp size increases, more current will be drawn from the battery to maintain high voltage across
The EL lamp frequency is controlled via an external REL resistor connected between R
device. The lamp frequency increases as R
of current drawn from the battery will increase and the output voltage V
decreases. As the EL lamp frequency increases, the amount
EL
will decrease. The color of the EL
CS
and VDD of the
EL-osc
lamp is dependent upon its frequency.
A 2MΩ resistor would provide lamp frequency of 330 to 450Hz. Decreasing the R
by a factor of 2 will
EL-osc
increase the lamp frequency by a factor of 2.
The switching frequency of the converter is controlled via an external resistor, RSW between R
SW-osc
and V
of the device. The switching frequency increases as RSW 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
will also decrease.
to GND when a 0.01µF CS capacitor is used. This capacitor
is used to shunt any switching noise that may couple into the R
SW-osc
pin. The CSW capacitor may also be
SW-osc
needed when driving large EL lamp due to increase in switching noise.
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
. The energy stored in the capacitor is connected to the internal
S
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
) should be increased to avoid saturation.
SW
560µH Murata inductors with 14.5Ω series DC resistance is typically recommended. For inductors with the
same inductance value but with lower series DC resistance, lower RSW value is needed to prevent high current
draw and inductor saturation.
the EL lamp. The input power, (V
x IIN), will also increase. If the input power is greater than the power
IN
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.
CS
DD
,
Enable/Disable Configuration
The HV823 can be easily enabled and disabled via a logic control
signal on the R
The control signal can be from a microprocessor. R
and REL resistors as shown in Figure 4 below.
SW
SW
and R
are typically very high values. Therefore, only 10’s of microam-
EL
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.
Figure 4: Enable/Disable Configuration
ON =V
DD
OFF = 0V
VIN = V
-
Remote
n
1N414
µF
1
1
R
-
EL Lamp
N
HV823L
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HV823
3
5
S
00V
0.1
µ
8
SW
G
D
osc
SW-osc
s
able
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 100µA at a V
of 3.0V. Therefore, the regulated
DD
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.
Figure 5: Split Supply Configuration
ON =V
OFF = 0
V
DD
DD
= Regulated
Voltage
Remote
n
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
its specifications of 2.0V to 9.5V.
R
-
, to the HV823 device is within
DD
VIN = Battery
+
Voltage
-
1N414
1
*Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
EL Lamp
N
HV823L
©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
11/12/01
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 744-0100 • FAX: (408) 222-4895
8
www.supertex.com
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