HV824
Advanced Information
High Voltage EL Lamp Driver
Ordering Information
Package Options
Device
HV824
Input Voltage
1.0V to 1.6V
8-Lead SO
HV824LG
Die
HV824X
Features
Processed with HVCMOS
®
technology
1.0V to 1.6V supply voltage
DC to AC conversion
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
General Description
The Supertex HV824 is a high voltage driver designed to drive EL
lamps with capacitive loads of 2nF to 15nF. The input supply voltage
range is 1.0V to1.6V. The device uses a single inductor and a
minimum number of passive components. Typical output voltage
applied to the EL lamp is 120V to 150V peak-to-peak. The HV824
can be enabled/disabled by connecting the R
SW
resistor to
V
DD
/ground. In die form, the device has an enable bar pad which
enables the IC when it is at logic low.
The HV824 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 V
DD
pin. The EL lamp driver frequency is set by
an external resistor connected between the 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
pins. The EL lamp is connected between V
A
and V
B
.
The switching MOSFET charges the external inductor and dis-
charges it into the 0.01µF to 0.1µF capacitor at C
s
. The voltage at
C
S
will start to increase. Once the voltage at C
s
reaches a nominal
value of 75V, 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 a maximum voltage of
180V peak-to-peak across the EL lamp.
Applications
Pagers
Portable Transceiver
Portable Instrumentation
Cellular Phones
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.
Pin Configuration
ςΑ
V
DD
R
SW-osc
R
EL-osc
GND
1
2
3
4
8
7
6
5
-0.5V to +2.0V
-0.5V to +120V
-25°C to +85°C
-65°C to +150°C
400mW
V
A
V
B
C
S
L
X
SO-8
top view
15-25
SUPERTEX [ Supertex, Inc ]
