The Supertex HV833 is a high voltage driver designed for driving
EL lamps of up to 35nF (10-12in
2
). The input supply voltage
range is from 1.8V to 6.5V. 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
鹵90V.
The chip can be enabled/disabled by connecting the resistor on
R
SW-OSC
to V
DD
/ground.
The HV833 has two internal oscillators, a switching MOSFET,
and a high voltage EL lamp driver. The frequency for the
switching 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 between
R
EL-osc
pin and the V
DD
pin. An external inductor is connected
between the L
X
and V
DD
or V
IN
pins. A 0.003-0.1碌F capacitor is
connected between C
S
and ground. The EL lamp is connected
between V
A
and V
B
.
The switching MOSFET charges the external inductor and
discharges it into the capacitor at C
S
. 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
switching in opposite states to achieve 180V peak-to-peak
across the EL lamp.
Features
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1.8V to 6.5V operating supply voltage
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DC to AC conversion
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Separately adjustable lamp and converter frequency
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Output voltage regulation
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Enable/disable function
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Patented output timing for high efficiency
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<100nA shutdown current
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Split supply capability
鉂?/div>
LCD backlighting
Applications
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Portable Transceivers
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Remote Control Units
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Calculators
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PDAs
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Global Positioning Systems (GPS)
Typical Application
ON=V
DD
OFF=0
V
DD
Enable Signal
1
V
DD
2
R
SW-osc
V
A
V
B
8
EL Lamp
7
+
V
IN
_
3
R
EL-osc
4
Gnd
C
S
6
1N914
L
X
5
L
X
HV833MG
Cs
100V
05/02/02
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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