HV852 Datasheet, PDF (1/6 Pages) Supertex, Inc – High Voltage, Low Noise, Inductorless EL Lamp Driver

High Voltage, Low Noise,
Inductorless EL Lamp Driver
HV852
Initial Release
Features
► No external components required when using an
external EL clock frequency
► EL frequency can be set by an external resistor
► Low Noise
► DC to AC converter
► Drives up to 5.3nF (approx. 1.5in² lamp) load
► Output voltage regulation
► Enable function
Applications
► Cellular phone keypad
► Watches
► Small handheld wireless devices
► MP3 Players
General Description
The Supertex HV852 is a high voltage, low noise, inductorless
EL (electroluminescent) lamp driver. It is designed to drive EL
lamps of up to 1.5in², with capacitive values up to 5.3nF over
an input voltage range of 2.4V to 5.0V. The HV852 converts
a low voltage DC input to a high voltage AC output across an
EL lamp. It uses a charge pump scheme to boost the input
voltage eliminating the need for an external inductor, diode,
and high voltage capacitor commonly found in conventional
topologies.
The charge pump circuit discharges its energy into an EL lamp
through a high voltage H-bridge. Once the voltage reaches
its regulated limit, it is turned off to conserve power. The EL
lamp is then discharged to ground and the H-bridge changes
state to allow the charge pump to charge the EL lamp in the
opposite direction.
Typical Application Circuit
HV852
+
R_EL
V_DD
V_A
V_DD
C_DD
R_EL
V_B
-
EN
GND
V_DD = ON
GND = OFF
CLK_IN
CLK_EN
EL Lamp frequency set by R_EL
EL
LAMP
1