SUPERTEX HV832MG

HV832
HV832
Dual High Voltage, Low Noise EL Lamp Driver
Features
General Description
❏ 8-pin dual EL driver IC
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.
❏ Input control for lamp selection
❏ Split supply capability
❏ Patented output timing
❏ One minature inductor to power both lamps
❏ 150nA shutdown current
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 LX and VDD pins or
VIN for split supply applications. A 0.001 to 0.01µF, 100V
capacitor is connected between CS and Ground. The EL lamps
are connected between EL1 to Com and EL2 to Com.
❏ Wide input voltage range (2.0V to 5.0V)
❏ Output voltage regulation
❏ No SCR output
Applications
❏ Dual display cell phones
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) EL1 on only, (2) EL2 on only, (3) both EL1 and EL2 on, and
(4) device shuts down. During power up of the device, the mode
will default to shut down.
❏ Keypad and LCD backlighting
❏ Dual segment lamps
❏ Handheld wireless communication devices
The switching MOSFET charges the external inductor and
discharges it into the capacitor at Cs. The voltage at CS 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 EL1 to Com and EL2 to Com are configured as H bridges
EL1/EL2 and Com are switching in opposite states to achieve
180V across the EL lamp.
Typical Application
VDD
Logic Input Pulse
EL Lamp 1
+
VIN
_
CIN
1 EL1
EL2
8
2 VDD
Com
7
3 Control
CS
6
4 GND
LX
5
EL Lamp 2
HV832MG
LX
CS
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
1
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.
HV832
Electrical Characteristics
DC Characteristics (Over recommended operating conditions unless otherwise specified, TA = 25°C)
Symbol
Parameter
Min
Typ
Max
Units
Conditions
7.0
Ω
I = 100mA
RDS(ON)
On-resistance of switching transistor
VCS
Output regulation voltage
80
90
100
V
VDD = 2.0V to 5.0V
Vdiff
differential output voltage across each lamp
(EL1 to Com, EL2 to Com)
160
180
200
V
VDD = 2.0V to 5.0V
IDDQ
Quiescent VDD supply current
150
nA
IDD
Input current into VDD pin
150
µA
IIN
Input current including inductor current
27
32
mA
VCS
Output voltage on VCS
38
43
68
78
87
62
70
78
V
VDD = 2.0V to 5.0V
VIN = 3.0V.
Driving EL1 or EL2.
See Figure 1.
VIN = 3.0V.
Driving both EL1 and EL2.
See Figure 1.
VIN = 3.0V. Driving EL1 or
EL2. See Figure 1.
VIN = 3.0V. Driving both EL1
and EL2, See Figure 1.
fEL
Vdiff output drive frequency
350
400
450
Hz
VIN = 3.0V. See Figure 1.
fSW
Switching transistor frequency
44.8
51.2
57.6
KHz
VIN = 3.0V. See Figure 1.
fSW Drift
Switching transistor frequency Drift
+/- 5.0
KHz
TA = -40°C to +85°C
D
Switching transistor duty cycle
IIL
Input logic low current going
into the control pin.
0.6
IIH
Input logic high current going
into the control pin.
0.6
VIL
Logic input low voltage
0
0.25
V
VIH
Logic input high voltage
1.75
VDD
V
85
%
See Figure 1.
µA
VDD = 2.0V to 5.0V.
See Figure 1.
* The inductor used is a 330uH Murata inductor, max DC resistance of 10 Ohms, part # LQH32CN331.
Recommended Operating Conditions
Symbol
Parameter
Min
Typ
Max
Units
VDD
Supply voltage
2.0
5.0
V
TA
Operating temperature
-40
85
°C
Ordering Information
Absolute Maximum Ratings*
Supply voltage, VDD
Output voltage, VC
S
Operating Temperature Range
Conditions
Package Options
-0.5V to 7.5V
-0.5V to +120V
Device
MSOP-8
Die
HV832
HV832MG*
HV832X
-40°C to +85°C
* Product supplied on 2500 piece carrier tape reels.
Storage Temperature Range
8 Pin MSOP Power Dissipation
-65°C to +150°C
300mW
* All voltages are referenced to ground.
2
HV832
Function Table
Control Pin
EL1
EL2
Com
IC
Power up
HI Z
HI Z
HI Z
OFF
1st pulse L to H
ON
HI Z
ON
ON
2nd pulse L to H
HI Z
ON
ON
ON
3rd
pulse L to H
ON
ON
ON
ON
4th pulse L to H
HI Z
HI Z
HI Z
OFF
Pin Configuration
EL1
1
8
EL2
VDD
2
7
Com
Control
3
6
VCS
GND
4
5
LX
top view
MSOP-8
3
HV832
Functional Block Diagram
LX
VDD
CS
Control
Control Logic &
Switch Osc
GND
Disable
EL1
Vsen
+
C
_
Vref
EL Osc =
Switch Osc ÷ 128
High
Voltage
Level
Translator
EL2
Com
Figure 1: Typical Application Circuit/Test Circuit
VDD = VIN
VDD
Logic Input Pulse
EL Lamp 1=1.5in2
1 EL1
EL2
8
2 VDD
Com
7
CS
6
LX
5
3 Control
VIN
4
+
_
GND
HV832MG
4.7µF
EL Lamp 2=1.5in2
IN914*
LX
330µH
3.3nF
100V
LX = 330µH Murata (LQH32CN331)
* any (equivalent or better) >90V, fast reverse recovery diode
Device
HV832MG
Lamp
EL1 or EL2 ON
Both EL1 and EL2 ON
VDD
3.0V
IDD
VCS
27mA
78V
38mA
70V
4
fEL
400Hz
Brightness
7.5ft-lm
6.2ft-lm
HV832
Typical Performance Curves for Figure 1 with one output ON
(EL Lamp=1.5in2, VDD=3.0V)
Vcs vs Vin
100
Iin vs Vin
30
28
80
lin (mA)
70
26
24
22
60
20
50
1.5
2
2.5
3
3.5
4
4.5
5
1.5
5.5
2.5
3.5
5.5
Vin (V)
Vin (V)
Brightness vs Vin
Iin vs Vcs
10
30
9
28
lin (mA)
8
7
6
26
24
22
5
4
20
1.5
2.5
3.5
4.5
5.5
60
65
70
75
Vin (V)
80
85
90
Vcs (V)
IIN, VCS, Brightness vs. Inductor Value
Iin, Vcs, Brightness vs. Inductor Value
90
10
80
Vcs
70
Iin(mA),
Vcs(V)
IIN (mA), VCS
(V)
Brightness (ft-lm)
4.5
9
60
8
50
Brightness
40
7
30
20
6
Iin
10
0
5
200
300
400
Inductor Value (µH)
5
500
600
Brightness (ft-lm)
VCS (V)
90
95
HV832
External Component Description
External Component
Selection Guide Line
Diode
Fast reverse recovery diode, IN914 or equivalent.
Cs Capacitor
0.003µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor.
Lx Inductor
The inductor Lx 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 CS. 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, (VIN x IIN), 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 150µA Max at a VDD of 3.0V. Therefore,
the regulated voltage could easily provide the current without
being loaded down.
Figure 2: Split Supply
Regulated Voltage=VDD
Logic Input Pulse
+
Battery Voltage=VIN
_
EL Lamp 1
1 EL1
EL2
8
2 VDD
Com
7
3 Control
CS
6
4 GND
LX
5
EL Lamp 2
HV832MG
CIN
LX
CS
12/13/01rev.8
©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
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TEL: (408) 744-0100 • FAX: (408) 222-4895
www.supertex.com