1
HV832
Dual High Voltage, Low Noise EL Lamp Driver
HV832
12/13/01
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.
General Description
The Supertex HV832 is a high voltage driver designed for driving
two EL lamps with a combined area of 3.5 square inches. The
input supply voltage range is from 2.0V to 5.0V. The device is
designed to reduce the amount of audible noise emitted by the
lamp. 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 HV832 has an internal oscillator, a switching MOSFET, and
two high voltage EL lamp drivers. The frequency for the switching
MOSFET is set at 51KHz nominal. The EL lamp driver frequency
is set by dividing the MOSFET switching frequency by 128. An
external inductor is connected between the L
X
and V
DD
pins or
V
IN
for split supply applications. A 0.001 to 0.01
F, 100V
capacitor is connected between C
S
and Ground. The EL lamps
are connected between EL
1
to Com and EL
2
to Com.
An input control pin is available to select various modes of the
device. Each logic pulse applied to the control pin will cause the
device to change to the next mode. The sequence for the modes
is: (1) EL
1
on only, (2) EL
2
on only, (3) both EL
1
and EL
2
on, and
(4) device shuts down. During power up of the device, the mode
will default to shut down.
The switching MOSFET charges the external inductor and
discharges it into the capacitor at Cs. The voltage at C
S
will start
to increase. Once the voltage at Cs reaches a nominal value of
90V, the switching MOSFET is turned off to conserve power. The
outputs EL
1
to Com and EL
2
to Com are configured as H bridges
EL1/EL2 and Com are switching in opposite states to achieve
180V across the EL lamp.
Features
8-pin dual EL driver IC
Input control for lamp selection
Split supply capability
Patented output timing
One minature inductor to power both lamps
150nA shutdown current
Wide input voltage range (2.0V to 5.0V)
Output voltage regulation
No SCR output
Applications
Dual display cell phones
Keypad and LCD backlighting
Dual segment lamps
Handheld wireless communication devices
Typical Application
EL Lamp 1
+
_
C
S
1
2
3
4
8
6
5
HV832MG
7
V
IN
EL
1
V
DD
Control
GND
L
X
C
S
Com
EL
2
V
DD
Logic Input Pulse
EL Lamp 2
L
X
C
IN
2
HV832
Recommended Operating Conditions
Symbol
Parameter
Min
Typ
Max
Units
Conditions
V
DD
Supply voltage
2.0
5.0
V
T
A
Operating temperature
-40
85
C
Electrical Characteristics
DC Characteristics
(Over recommended operating conditions unless otherwise specified, T
A
= 25
C)
Symbol
Parameter
Min
Typ
Max
Units
Conditions
R
DS(ON)
On-resistance of switching transistor
7.0
I = 100mA
V
CS
Output regulation voltage
80
90
100
V
V
DD
= 2.0V to 5.0V
V
diff
differential output voltage across each lamp
(EL
1
to Com, EL
2
to Com)
160
180
200
V
V
DD
= 2.0V to 5.0V
I
DDQ
Quiescent V
DD
supply current
150
nA
I
DD
Input current into V
DD
pin
150
A
V
DD
= 2.0V to 5.0V
I
IN
Input current including inductor current
27
32
mA
V
IN
= 3.0V.
Driving EL1 or EL2.
See Figure 1.
38
43
V
IN
= 3.0V.
Driving both EL1 and EL2.
See Figure 1.
V
CS
Output voltage on V
CS
68
78
87
V
V
IN
= 3.0V. Driving EL1 or
EL2. See Figure 1.
62
70
78
V
IN
= 3.0V. Driving both EL1
and EL2, See Figure 1.
f
EL
V
diff
output drive frequency
350
400
450
Hz
V
IN
= 3.0V. See Figure 1.
f
SW
Switching transistor frequency
44.8
51.2
57.6
KHz
V
IN
= 3.0V. See Figure 1.
f
SW Drift
Switching transistor frequency Drift
+/- 5.0
KHz
T
A
= -40
C to +85
C
D
Switching transistor duty cycle
85
%
See Figure 1.
I
IL
Input logic low current going
into the control pin.
0.6
A
V
DD
= 2.0V to 5.0V.
See Figure 1.
I
IH
Input logic high current going
into the control pin.
0.6
V
IL
Logic input low voltage
0
0.25
V
V
IH
Logic input high voltage
1.75
V
DD
V
* The inductor used is a 330uH Murata inductor, max DC resistance of 10 Ohms, part # LQH32CN331.
Absolute Maximum Ratings*
Supply voltage, V
DD
-0.5V to 7.5V
Output voltage, V
C
S
-0.5V to +120V
Operating Temperature Range
-40
C to +85
C
Storage Temperature Range
-65
C to +150
C
8 Pin MSOP Power Dissipation
300mW
* All voltages are referenced to ground.
Ordering Information
Package Options
Device
MSOP-8
Die
HV832
HV832MG*
HV832X
* Product supplied on 2500 piece carrier tape reels.
3
HV832
Function Table
Control Pin
EL
1
EL
2
Com
IC
Power up
HI Z
HI Z
HI Z
OFF
1
st
pulse L to H
ON
HI Z
ON
ON
2
nd
pulse L to H
HI Z
ON
ON
ON
3
rd
pulse L to H
ON
ON
ON
ON
4
th
pulse L to H
HI Z
HI Z
HI Z
OFF
Pin Configuration
top view
MSOP-8
1
2
3
4
8
7
6
5
EL
1
EL
2
V
DD
Com
Control
V
CS
GND
L
X
4
HV832
Functional Block Diagram
Figure 1: Typical Application Circuit/Test Circuit
C
+
_
Vref
Disable
High
Voltage
Level
Trans-
lator
GND
V
DD
EL
1
C
S
L
X
EL
2
Control
Vsen
Control Logic &
Switch Osc
EL Osc =
Switch Osc
128
Com
EL Lamp 1=1.5in
2
+
_
3.3nF
100V
1
2
3
4
8
6
5
HV832MG
7
V
IN
EL
1
V
DD
Control
GND
L
X
C
S
Com
EL
2
330
H
IN914*
4.7
F
V
DD
Logic Input Pulse
V
DD
= V
IN
EL Lamp 2=1.5in
2
L
X
L
X
= 330
H Murata (LQH32CN331)
* any (equivalent or better) >90V, fast reverse recovery diode
e
c
i
v
e
D
p
m
a
L
V
D
D
I
D
D
V
S
C
f
L
E
s
s
e
n
t
h
g
i
r
B
G
M
2
3
8
V
H
L
E
1
L
E
r
o
2
N
O
V
0
.
3
A
m
7
2
V
8
7
z
H
0
0
4
m
l
-
t
f
5
.
7
L
E
h
t
o
B
1
L
E
d
n
a
2
N
O
A
m
8
3
V
0
7
m
l
-
t
f
2
.
6
5
HV832
Iin vs Vcs
20
22
24
26
28
30
60
65
70
75
80
85
90
95
Vcs (V)
Brightness vs Vin
4
5
6
7
8
9
10
1.5
2.5
3.5
4.5
5.5
Vin (V)
Iin vs Vin
20
22
24
26
28
30
1.5
2.5
3.5
4.5
5.5
Vin (V)
Vcs vs Vin
50
60
70
80
90
100
1.5
2
2.5
3
3.5
4
4.5
5
5.5
Vin (V)
Typical Performance Curves for Figure 1 with one output ON
(EL Lamp=1.5in
2
, V
DD
=3.0V)
V
CS (
V)
lin
(
mA)
Brightness
(ft-lm
)
lin
(
mA)
0
10
20
30
40
50
60
70
80
90
200
300
400
500
600
Inductor Value (H)
5
6
7
8
9
10
IIN, VCS, Brightness vs. Inductor Value
IIN (mA), VCS (V)
Brightness (ft-lm)
Vcs
Brightness
Iin
Iin(mA), Vcs(V)
Iin, Vcs, Brightness vs. Inductor Value
6
HV832
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 744-0100 FAX: (408) 222-4895
www.supertex.com
12/13/01rev.8
2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
External Component Description
External Component
Selection Guide Line
Diode
Fast reverse recovery diode, IN914 or equivalent.
Cs Capacitor
0.003
F to 0.1
F, 100V capacitor to GND is used to store the energy transferred from the inductor.
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.
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 (300mW), an external resistor in series with one side of the lamp is recommended
to help reduce the package power dissipation.
Split Supply Configuration
The HV832 can also be used for handheld devices operating
from a battery where a regulated voltage is available. This is
shown in Figure 2. The regulated voltage can be used to run the
internal logic of the HV832. The amount of current necessary to
run the internal logic is 150
A Max at a V
DD
of 3.0V. Therefore,
the regulated voltage could easily provide the current without
being loaded down.
Figure 2: Split Supply
EL Lamp 1
+
_
C
S
1
2
3
4
8
6
5
HV832MG
7
Battery Voltage=V
IN
EL
1
V
DD
Control
GND
L
X
C
S
Com
EL
2
Regulated Voltage=V
DD
Logic Input Pulse
EL Lamp 2
L
X
C
IN
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