HV850MG-G Datasheet, PDF (1/8 Pages) Supertex, Inc – High Voltage, Low Noise, Inductorless EL Lamp Driver

Supertex inc.
HV850
High Voltage, Low Noise,
Inductorless EL Lamp Driver
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 5.0nF load (approx. 1.5in² lamp)
►► Output voltage regulation
►► Enable function
►► EL Lamp dimming
Applications
►► Cell phone keypads and displays
►► Transceivers
►► MP3 players
►► Watches
►► Pagers
►► Measuring instruments/gauges
General Description
The Supertex HV850 is a high voltage electroluminescent
(EL) Lamp Driver IC. It is designed to drive EL lamps of up to
1.5in², with capacitive values up to 5.0nF. The HV850 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 external inductors, diodes,
and high voltage capacitors, components 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 (For V_DD = 3.4V to 4.2V only)
V_DD = ON
GND = OFF
+
V_DD
C_DD
-
1 VDD
VA ⁸
HV850
2 REL
VB 7
V_DD
GND
3 EN
GND 6
4 _{CLKIN CLKEN} 5
EL lamp frequency
set by an external clock
EL Lamp
V_DD
+
V_DD
C_DD
-
V_DD = ON
GND = OFF
1 VDD
VA ⁸
R_EL
HV850
2 REL
VB 7
3 EN
GND 6
4 CLKIN CLKEN 5
EL Lamp
EL lamp frequency set by R_EL
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: [phone] ● www.supertex.com