2023 Microchip Technology Inc. and its subsidiaries DS20005711A-page 1
HV859
Features
• Patented Audible Noise Reduction
• Patented Lamp Aging Compensation
• 210 VPP Output Voltage for Higher Brightness
• Patented Output Timing for High Efficiency
• Single-cell Lithium Ion Compatible
• 150 nA Shutdown Current
• Wide Input Voltage range of 1.8V to 5V
• Separately Adjustable Lamp and Converter
Frequencies
• Output Voltage Regulation
• Split Supply Capability
Applications
• LCD Backlighting
• Mobile Cellular Phone Keypads
• PDAs
• Handheld Wireless Communication Products
• Global Positioning Systems (GPS)
General Description
The HV859 is a high-voltage driver designed for driving
Electroluminescent (EL) lamps of up to 5 in
2. The input
supply voltage range is from 1.8V to 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 ±105V. The
chip can be enabled/disabled by connecting the
resistor on RSW-Osc to VDD/Ground.
The HV859 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 VDD pin. The EL lamp driver frequency is set by an
external resistor connected between RSW-Osc pin and
the VDD pin. An external inductor is connected
between the LX and VIN for split supply applications. A
capacitor with a value between 0.003 µF to 0.1 µF,
200V rated, is connected between C
S and ground. The
EL lamp is connected between VA and VB.
The switching MOSFET charges the external inductor
and discharges it into the capacitor at C
S
. Then, the
voltage at CSwill start to increase. Once the voltage at
CS reaches a nominal value of 105V, 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 ±105V across
the EL lamp.
Package Types
Pads of the 8-lead DFN are at the bottom of the package. See Table 2-1 for pin
information.
8-lead MSOP 8-lead WDFN
1
2
3
4
8
7
6
5
VA
VB
CS
LX
VDD
RSW-Osc
REL-Osc
GND
VDD
RSW-Osc
REL-Osc
GND
1
2
3
4
8
7
6
5
VA
VB
CS
LX
High-Voltage EL Lamp Driver for Low-Noise Applications
