HV823_13 Datasheet, PDF (1/8 Pages) Supertex, Inc – High Voltage EL Lamp Driver IC

Supertex inc.
HV823
High Voltage EL Lamp Driver IC
Features
►► Processed with HVCMOS^® technology
►► 2.0 to 9.5V operating supply voltage
►► DC to AC conversion
►► 180V peak-to-peak typical output voltage
►► Large output load capability typically 50nF
►► Permits the use of high-resistance elastomeric
lamp components
►► 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
Applications
►► Handheld personal computers
►► Electronic personal organizers
►► GPS units
►► Pagers
►► Cellular phones
►► Portable instrumentation
General Description
The Supertex HV823 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 ±90V. The chip can be enabled
by connecting the resistors on the RSW-Osc pin and the REL-Osc pin
to the VDD pin, and disabled when connected to GND.
The HV823 has two internal oscillators, a switching MOSFET and a
high-voltage EL lamp driver. The frequency of the switching converter
MOSFET is set by an external resistor connected between the RSW-
Osc pin and the VDD supply pin. The EL lamp driver frequency is set
by an external resistor connected between the REL-Osc pin and the
VDD pin. An external inductor is connected between the LX pin and the
VDD pin. A 0.01µF to 0.1µF capacitor is connected between the CS pin
and the GND. The EL lamp is connected between the VA and VB pins.
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 90V, the switching MOSFET
is turned OFF to conserve power. The output pins VA and VB are con-
figured as an H-bridge and are switched in opposite states to achieve
180V peak-to-peak across the EL lamp.
For additional information, see Application Note ANH34.
Block Diagram
VDD
RSW-Osc
Enable *
GND
Switch
Osc
+
C
Disable
_
V_REF
LX
CS
Q
VA
Q
Output
Osc
Q
VB
REL-Osc
* Enable is available in die form only.
Q
Doc. # DSFP-HV823
C082213
Supertex inc.
www.supertex.com