mic4833 Micrel Semiconductor, mic4833 Datasheet

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mic4833

Manufacturer Part Number
mic4833
Description
Low Noise Dual 220 Vpp El Driver With Output Voltage Slew Rate Control
Manufacturer
Micrel Semiconductor
Datasheet
General Description
The MIC4833 is a low noise dual Electroluminescent (EL)
Panel driver used in backlighting applications. The
MIC4833 converts a low DC voltage to a high DC voltage
using a boost converter and then alternates the high DC
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
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.
_________________________________________________________________________________________________
Typical Application
MLF and MicroLead Frame are registered trademark of Amkor Technologies
October 2008
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
3V to 4.2V
Low
Li Ion
High
VIN
0.01µF
Low
Low
Low Noise Dual EL Driver
High
1.78M
High
332k
3V to 4.2V
Li Ion
VIN
10µF
ENA
VDD
RSW
REL
ENB
GND
®
MIC4833
Features
Applications
408
220µH
With Output Voltage Slew Rate Control
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
Drives two EL panels, up to 4 in
brightness
Independent input control for each of the two panels
and allows PWM dimming.
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
–40
Mobile Phones
MP3s/Portable Media Players (PMP)
Clocks/ Watches
Remote Controls
Cordless Phones
GPS Devices
PDAs
SLEW
COM
Low Noise Dual 220 V
ELA
ELB
SW
CS
o
C to +125
EL Lamp A
EL Lamp B
50k
o
C junction temperature range
2.2nF
250V
MIC4833
®
package
PP
2
each at full
EL Driver
(408) 955-1690
M9999-100308

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mic4833 Summary of contents

Page 1

... General Description The MIC4833 is a low noise dual Electroluminescent (EL) Panel driver used in backlighting applications. The MIC4833 converts a low DC voltage to a high DC voltage using a boost converter and then alternates the high DC 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 ...

Page 2

... Optional resistor to set output current drive to control slew rate of load. If left open, the default slew current limit is 5mA. Heat Sink Pad. Connect to ground externally. 2 Lead Finish Pb-free / RoHS Compliant 12 SLEW 11 ELA 10 ELB 9 COM (ML) – Top View ) to VDD. Connecting the GND disables EL MIC4833 SW M9999-100308 (408) 955-1690 ...

Page 3

... J ® θ MLF -12L …………………….................... 60°C/W JA ≤ 85°C. J Min Typ Max Units 2 250 175 445 80 2.5 7 0.4 20 MIC4833 DD 5.8 V 152 220 µA 0.1 1 µA 6.0 12.0 Ω 120 109 kHz 100 125 kHz 350 ...

Page 4

... INPUT VOLTAGE (V) Brightness vs. Input Voltage Distance = 135kHz 225Hz 220µ 2.5 3 3.5 4 4.5 5 5.5 6 INPUT VOLTAGE (V) 4 MIC4833 Input Current vs. EL Frequency (Single EL Lamp 3. 75kHz ...

Page 5

... SLEW October 2008 220µH VDD VDD SW SW Oscillator Driver VREF REL EL Oscillator ENA EL-A Enable ENB EL-B Enable Output Wave-Shaping Figure 1. MIC4833 Block Diagram Output Driver PGND VSENSE Output Driver Driver Logic & PWM Dimming Output Driver PGND GND GND MIC4833 VCS 2 ...

Page 6

... Micrel Functional Description Overview The MIC4833 is a high-voltage dual output EL driver with a peak-to-peak AC output voltage of 220V 2 capable of driving two panels. The MIC4833 drives EL panels by converting a low DC input voltage high output voltage using the boost regulator circuit and then alternating the high DC voltage across the EL panel using an H-Bridge ...

Page 7

... Figure 2. 150Hz Output Waveform Figure 3. 250Hz Output Waveform Figure 4. 350Hz Output Waveform October 2008 PWM Dimming The MIC4833 may be dimmed by adding a shunt capacitor ( the REL pin, shown in Figure 5. PWM The duty cycle of the PWM signal changes the frequency of the EL panel, thereby changing its brightness ...

Page 8

... ESR capacitor improves the efficiency of the MIC4833 circuit. Selection of the capacitor value depends upon the peak inductor current, inductor size, and the load. The MIC4833 is designed for use Lowering the with an output capacitance as low as 2.2nF. For minimum audible noise, the use of a C0G/NPO dielectric output capacitor is recommended ...

Page 9

... VIN VDD RSW 332k C1 RSW 0.01µF REL MIC4833 1.78M REL High ENB Low GND VIN 220µH Li Ion 3V to 4.2V C2 10µF Figure 6: Typical Li-Ion Powered MIC4833 Circuit 150 200 250 2.80 2.10 1.69 ) 324 340 357 ) 138 132 126 357 365 392 ) 125 122 ...

Page 10

... I . (4mmx4mmx1.2mm) SAT (2) Vishay 200V/200mA Hi-Voltage Switching Diode (2) Vishay 332kΩ, 1%, 1/16W, Size 0603 (2) Vishay 1.78MΩ, 1%, 1/16W, Size 0603 (3) Micrel Low Noise Dual 220Vp-p EL Driver with Output Slew Control 10 Description M9999-100308 (408) 955-1690 MIC4833 Qty Optional 1 ...

Page 11

... Micrel Layout Recommendation October 2008 Top Layer Bottom Layer 11 MIC4833 M9999-100308 (408) 955-1690 ...

Page 12

... Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully October 2008 12-Pin 3mm x 3mm MLF indemnify Micrel for any damages resulting from such use or sale. © 2008 Micrel, Incorporated. 12 ® (ML) MIC4833 nt M9999-100308 (408) 955-1690 ...

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