Permits the use of high-resistance elastomeric lamp
connectors
❏
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
❏
Very low standby current – 30nA typical
General Description
The Supertex HV830 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 2.0V 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
±100V.
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 HV830 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
100V, 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 200V peak-to-peak across
the EL lamp.
Applications
❏
Handheld personal computers
❏
Electronic personal organizers
❏
GPS units
❏
Pagers
❏
Cellular phones
❏
Portable instrumentation
Pin Configuration
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.
-0.5V to +10V
-0.5V to +120V
-25°C to +85°C
-65°C to +150°C
400mW
V
DD
R
SW-osc
C
s
L
x
1
2
3
4
8
7
6
5
R
EL-osc
V
A
V
B
GND
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
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.
HV830
Electrical Characteristics
DC Characteristics
(V
DD
= 3.0V, R
SW
= 1MΩ, R
EL
= 3.3MΩ, T
A
= 25°C unless otherwise specified)
Symbol
R
DS(on)
V
CS
V
A
- V
B
I
DDQ
I
DD
I
IN
V
CS
f
EL
f
SW
D
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
Input current including inductor current
Output voltage on V
CS
V
A-B
output drive frequency
Switching transistor frequency
Switching transistor duty cycle
220
55
90
180
Min
Typ
2
100
200
30
100
35
95
250
65
88
280
75
150
40
Max
6
110
220
Units
Ω
V
V
nA
µA
mA
V
Hz
KHz
%
I = 100mA
V
DD
= 2.0V to 9.5V
V
DD
= 2.0V to 9.5V
R
SW-osc
= Low
V
DD
= 3.0V. See Figure 1.
V
DD
= 3.0V. See Figure 1.
V
DD
= 3.0V. See Figure 1.
V
DD
= 3.0V. See Figure 1.
V
DD
= 3.0V. See Figure 1.
Conditions
Recommended Operating Conditions
Symbol
V
DD
f
EL
T
A
Supply voltage
V
A-B
Output drive frequency
Operating temperature
-25
Parameter
Min
2.0
Typ
Max
9.5
1.5
+85
Units
V
KHz
°C
Conditions
Enable/Disable Table
R
SW
resistor
V
DD
0V
(See Figure 2)
HV830
Enable
Disable
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
* Alternate Enable is available in die form only.
2
HV830
Figure 1: Test Circuit, V
IN
= 3.0V
ON = V
DD
OFF = 0V
5.1MΩ
1
1MΩ
220µH
1
V
DD
= V
IN
= 3.0V
0.1µF
2
0.01µF
200V
V
DD
R
SW-osc
C
s
L
x
R
EL-osc
V
A
V
B
GND
8
7
6
5
10 square inch lamp.
2
3
BAS21LT1
4
HV830
1nF
Notes:
1. Murata part # LQH4N221K04 (DC resistance < 5.4Ω)
2. Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
Enable/Disable Configuration
The HV830 can be easily enabled and disabled via a logic control
signal on the R
SW
and R
EL
resistors as shown in Figure 2 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-
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 2: Enable/Disable Configuration
ON =V
DD
OFF = 0V
Remote
Enable
R
EL
1
R
SW
L
x
+
V
IN
= V
DD
-
4.7µF
15V
BAS21LT1
V
DD
R
SW-osc
C
s
L
x
R
EL-osc
V
A
V
B
GND
8
7
EL Lamp
2
3
4
C
S
200V
6
5
HV830LG
1nF
Split Supply Configuration Using a Single
Cell (1.5V) Battery
The HV830 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 3. The regulated voltage can
be used to run the internal logic of the HV830. The amount of
current necessary to run the internal logic is typically 100µA
at a V
DD
of 3.0V. Therefore, the regulated voltage could easily
provide the current without being loaded down. The HV830
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 2.
3
Split Supply Configuration for Battery
Voltages of Higher than 9.5V
Figure 3 can also be used with high battery voltages such as 12V
as long as the input voltage, V
DD
, to the HV830 device is within
its specifications of 2.0V to 9.5V.
HV830
External Component Description
External Component
Diode
Cs Capacitor
R
EL-osc
Selection Guide Line
Fast reverse recovery diode, BAS21LT1 or equivalent.
0.01µF to 0.1µF, 200V capacitor to GND is used to store the energy transferred from the inductor.
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 3.3MΩ resistor would provide lamp frequency of 220 to 280Hz. 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.
A 1nF capacitor is recommended on R
SW-osc
to GND when a 0.01µF 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 an increase in switching noise.
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.
220µH Murata inductors with 5.4Ω 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.
C
SW
Capacitor
Lx Inductor
Figure 3: Split Supply Configuration
ON = V
DD
OFF = 0V
V
DD
= Regulated
Voltage
R
SW
L
x
+
V
IN
= Battery
Voltage
BAS21LT1
Remote
Enable
R
EL
1
2
3
–
0.1µF*
C
S
200V
V
DD
R
SW-osc
C
s
L
x
R
EL-osc
V
A
V
B
GND
8
7
EL Lamp
6
5
4
HV830LG
1nF
*Larger values may be required depending upon supply impedance.
For additional information, see Application Notes AN-H33 and AN-H34.
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