HV825_13 Datasheet, PDF (1/5 Pages) Supertex, Inc – High Voltage EL Lamp Driver IC

Supertex inc.
HV825
High Voltage
EL Lamp Driver IC
Features
►► Processed with HVCMOS^® technology
►► 1.0 to 1.6V operating supply voltage
►► DC to AC conversion
►► Output load of typically up to 6.0nF
►► Adjustable output lamp frequency
►► Adjustable converter frequency
►► Enable function
Applications
►► Pagers
►► Portable transceivers
►► Cellular phones
►► Remote control units
►► Calculators
General Description
The Supertex HV825 is a high voltage driver designed for driv-
ing EL lamps typically up to 6.0nF. The input supply voltage range
is from 1.0V to 1.6V. The device uses a single inductor and a
minimum number of passive components. The typical output
voltage that can be applied to the EL lamp is ±56V.
The HV825 can be enabled/disabled by connecting the R_SW-Osc resistor
to VDD/GND.
The HV825 has two internal oscillators, a switching bipolar junction transistor
(BJT), and a high voltage EL lamp driver. The frequency for the switching
BJT 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 REL-Osc pin and the VDD pin. An external
inductor is connected between the LX and VDD pins. A 0.01 to 0.1µF,
100V capacitor is connected between the CS pin and the GND pin. The
EL lamp is connected between the VA pin and the VB pin.
The switching BJT charges the external inductor and discharges it into the
0.01 to 0.1µF, 100V capacitor at the CS pin. The voltage at the CS pin will
start to increase. The outputs VA and VB are configured as an H-bridge
and are switching in opposite states to achieve a peak-to-peak voltage of
two times the V_CS voltage across the EL lamp.
For additional information, see Application Notes AN-H33 and AN-
H34.
Block Diagram
VDD
RSW-Osc
Switch
Osc
LX
CS
Q
GND
VA
Q
Output
Osc
Q
REL-Osc
VB
Q
Doc.# DSFP-HV825
C072913
Supertex inc.
www.supertex.com