HV824 Datasheet, PDF (1/3 Pages) Supertex, Inc – High Voltage EL Lamp Driver

HV824
Advanced Information
High Voltage EL Lamp Driver
Ordering Information
Package Options
Device
Input Voltage 8-Lead SO
Die
HV824
1.0V to 1.6V
HV824LG
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
Applications
Pagers
Portable Transceiver
Portable Instrumentation
Cellular Phones
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.
Absolute Maximum Ratings*
Supply Voltage, V_DD
-0.5V to +2.0V
Output Voltage, V_Cs
-0.5V to +120V
Operating Temperature Range
-25°C to +85°C
Storage Temperature Range
-65°C to +150°C
Power Dissipation
400mW
Note:
*All voltages are referenced to GND.
Pin Configuration
ςΑ
V_DD 1
R_SW-osc 2
R_EL-osc 3
GND 4
8 V_A
7 V_B
6 C_S
5 L_X
SO-8
top view
15-25