HV833_13 Datasheet, PDF (1/8 Pages) Supertex, Inc – High Voltage EL Lamp Driver

Supertex inc.
HV833
High Voltage
EL Lamp Driver
Features
►►1.8 to 6.5V operating supply voltage
►►DC to AC conversion
►►Separately adjustable lamp and converter
frequency
►►Output voltage regulation
►►Enable/disable function
►►Patented output timing for high efficiency
►►<100nA shutdown current
►►Split supply capability
►►LCD backlighting
Applications
►►Portable transceivers
►►Remote control units
►► Calculators
►► PDAs
►►Global Positioning Systems (GPS)
General Description
The Supertex HV833 is a high voltage driver designed for driving EL
lamps of up to 35nF (10-12in²). The input supply voltage range is from
1.8 to 6.5V. 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/disabled by
connecting a resistor between the RSW-Osc pin and the VDD/GND
pins.
The HV833 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 RSW-Osc pin
and the VDD supply pin. The EL lamp driver frequency is set by an
external resistor connected between the REL-Osc pin and the VDD
pin. An external inductor is connected between the LX pin and VDD
or VIN pin. A 0.003-0.1µF capacitor is connected between the CS pin
and the GND pin. The EL lamp is connected between the VA pin and
the VB pin.
The switching MOSFET charges the external inductor and discharges
it into the capacitor at CS. The voltage at CS will start to increase.
Once the voltage at CS reaches a nominal value of 90V, the switching
MOSFET is turned OFF to conserve power. The outputs VA and VB
are configured as an H bridge and are switching in opposite states to
achieve 180V peak-to-peak across the EL lamp.
Typical Application Circuit
ON = V_DD
OFF = 0
V_DD
Enable Signal
+
_ ^VIN
1 VDD
VA 8
2 RSW-Osc VB 7
3 REL-Osc CS 6
4 GND
LX 5
HV833
1N914
L_X
EL Lamp
C_S
100V
Doc.# DSFP-HV833
A061813
Supertex inc.
www.supertex.com