MIC4833 Datasheet, PDF (1/12 Pages) Micrel Semiconductor – Low Noise Dual 220 VPP EL Driver With Output Voltage Slew Rate Control

MIC4833
Low Noise Dual 220 V_PP EL Driver
With Output Voltage Slew Rate Control
General Description
Features
The MIC4833 is a low noise dual Electroluminescent (EL) • Drives two EL panels, up to 4 in² each at full
Panel driver used in backlighting applications. The
brightness
MIC4833 converts a low DC voltage to a high DC voltage _{• Independent input control for each of the two panels}
using a boost converter and then alternates the high DC
and allows PWM dimming.
voltage across the EL panels using an H-bridge. The
MIC4833 incorporates internal wave-shaping circuitry
specifically designed to reduce audible noise emitted by
EL panels. The two EL panels may be dimmed by applying
a PWM signal to the device. The MIC4833 drives two
outputs from a single inductor and requires a minimum
number of passive components. It features an operating
input voltage range of 2.3V to 5.8V, making it suitable for
1-cell Li-ion and 2- or 3-cell alkaline/NiCad/NiMH battery
applications.
An external resistor may be used to adjust the output
voltage slew rate to reduce audible noise. The MIC4833
• 220Vpp regulated AC output waveform
• 2.3V to 5.8V DC input voltage
• Wave-shaping circuit to reduce audible noise
• Adjustable slew rate for audible noise reduction
• Independently adjustable boost converter and EL
panel frequency
• Single inductor to power both panels
• 0.1uA typical shutdown current
• 12 pin 3mmx3mm MLF^® package
• –40^oC to +125^oC junction temperature range
Applications
features separate oscillators for the boost and H-bridge
stages to allow independent control. External resistors set
the operating frequencies of each stage allowing the EL
circuit to optimize efficiency and brightness.
The MIC4833 is available in a 12 pin 3mmx3mm MLF^®
package, and has an operating junction temperature range
of –40°C to +125°C.
• Mobile Phones
• MP3s/Portable Media Players (PMP)
• Clocks/ Watches
• Remote Controls
• Cordless Phones
• GPS Devices
• PDAs
_________________________________________________________________________________________________
Typical Application
VIN
Li Ion
3V to 4.2V
0.01µF
High
Low
ENA
SLEW
332k
1.78M
VDD
ELA
RSW
REL
MIC4833
ELB
COM
50k
EL Lamp A
EL Lamp B
High
High
Low
Low
ENB
CS
GND
SW
VIN
Li Ion
3V to 4.2V
10µF
220µH
Low Noise Dual EL Driver
2.2nF
250V
MLF and MicroLead Frame are registered trademark of Amkor Technologies
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
October 2008
M9999-100308
[phone]