HV823 Datasheet, PDF (1/8 Pages) Supertex, Inc – High Voltage EL Lamp Driver

HV823
HV823
High Voltage EL Lamp Driver
Ordering Information
Device
HV823
Input Voltage
2.0V to 9.5V
Package Options
8-Lead SO
Die
HV823LG
HV823X
Features
❏ Processed with HVCMOS^® technology
❏ 2.0V 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 2.0 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
R_SW-osc and R_EL-osc to V_DD and disabled when connected to GND.
The HV823 has two internal oscillators, a switching MOSFET,
and a high-voltage EL lamp driver. The frequency for the switch-
ing converter 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 be-
tween 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. The EL lamp is
connected between V_A and V_B.
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
outputs V_A and V_B are configured as an H-bridge and are
switched in opposite states to achieve 180V peak-to-peak across
the EL lamp.
Pin Configuration
ςΑ
Absolute Maximum Ratings*
Supply Voltage, V_DD
-0.5V to +10V
Output Voltage, V_Cs
-0.5V to +120V
Operating Temperature Range
-25°C to +85°C
V_DD 1
R_SW-osc ²
C_s 3
L_x 4
8 R_EL-osc
7 _VA
6 V_B
5 GND
Storage Temperature Range
Power Dissipation
-65°C to +150°C
400mW
SO-8
Note:
*All voltages are referenced to GND.
11/12/01
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 prod1ucts, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.