Supertex inc.
HV860
Initial Release
Low Noise Dimmable EL Lamp Driver
The HV860 has two internal oscillators, a switching
MOSFET, and a high voltage EL lamp driver H-bridge. The
frequency for the switching MOSFET is set by an external
resistor connected between the RSW-OSC pin and the supply
pin V . The EL lamp driver frequency is set by an external
external inductor is connectedELb-OeStCween the LDXDand VDD
pins or VIN for split supply applications. A 3.0nF capacitor
is connected between CS and ground. The EL lamp is
connected between VA and VB.
Features
► Adjustable output regulation for dimming
► 220VPP output voltage for higher brightness
► Single cell lithium ion compatible
► 150nA shutdown current
► Separately adjustable lamp and converter frequencies
► 3x3 QFN-12 package
► Split supply capability
resistDoDr connected between R
pin and V pin. An
Applications
► Mobile cellular phone keypads
► PDAs
► Handheld wireless communication products
► Global Positioning Systems (GPS)
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 110V, the switching MOSFET is turned OFF to
conserve power. The outputs VA and V are configured as
an H bridge and are switching in opposiBte states to achieve
110V across the EL lamp.
General Description
EL lamp dimming can be accomplished by changing the
input voltage to the VREG pin. The VREG pin allows an external
voltage source to control the V amplitude. The VCS voltage
The Supertex HV860 is a high voltage driver designed for
driving Electroluminescent, (EL), lamps of up to 5 square
inches. The input supply voltage range is from 2.5V to 4.5V.
The device uses a single inductor and a minimum number of
passive components. Using the internal reference voltage,
the regulated output voltage is at a nominal voltage of 110V.
The EL lamp will therefore see 110V. An enable pin, (EN),
is available to turn the device on and off via a logic signal.
is approximately 87 times the CvSoltage seen on VREG
.
Typical Application Circuit
VIN
CIN
LX
D
RREG
2
3
5
CS
VREG
VDD
VREF LX
CS
10
12
7
VDD
RSW
CDD
RSW-OSC
REL-OSC
EN
9
8
VA
VB
1
EL
Lamp
REL
1.5V = On
0V = Off
11
GND
4
HV860K7
NR040306
Supertex inc. 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: (408) 222-8888 FAX: (408) 222-4895 www.supertex.com
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