HV853_08 Datasheet, PDF (1/7 Pages) Supertex, Inc – High Voltage, Low Noise,Inductorless EL Lamp Driver

HV853
High Voltage, Low Noise,
Inductorless EL Lamp Driver
Features
► No external components required when using an
external EL clock frequency
► Audible noise reduction with improved EMI
► EL frequency can be set by an external resistor
► DC to AC converter
► Drives up to 5.3nF (approx. 1.5in² lamp) load
► Output voltage regulation
► Enable function
► EL Lamp dimming
► Available in 10-Lead DFN and 8-Lead MSOP
packages
Applications
► Cellular phone keypad
► Watches
► Small handheld wireless devices
► MP3 Players
General Description
The Supertex HV853 is a high voltage, low noise EL
(electroluminescent) lamp driver. It is the low noise version of
the HV852 with improved EMI performance, operating over an
input voltage range of 3.2V to 5.0V. It is designed to drive EL
lamps of up to 1.5in², with capacitive values up to 5.3nF. The
HV853 converts a low voltage DC input to a high voltage AC
output across an EL lamp. A nominal regulated output voltage
of ±80V is applied to the 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.
The EL lamp frequency can be set either by an external
resistor R_EL or by applying an external clock where the clock
frequency is divided by 128 to set the EL lamp frequency.
Typical Application Circuits
V_DD = ON
GND = OFF
+
V_DD
-
C_DD
1
VDD
R_{EL 2}
REL
3 _EN
4
CLKIN
VA ⁸
VB ⁷
GND ⁶
5
CLKEN
HV853MG
EL Lamp Frequency set by R_EL
V_DD = ON
GND = OFF
EL
+
LAMP ^VDD
C_DD
-
V_DD
GND
1
VDD
2
REL
3
EN
4
CLKIN
8
VA
7
VB
GND ⁶
5
CLKEN
HV853MG
EL
LAMP
V_DD
EL Lamp Frequency set by External Clock
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: [phone] ● www.supertex.com