MIC4832
Low Noise 220V
PP
EL Driver
General Description
The MIC4832 is a low noise 220V
PP
electroluminescent
lamp (EL) driver. Using advanced Bipolar, CMOS, DMOS
(BCD) technology, the MIC4832 integrates a high voltage
boost converter and an H-bridge driver for driving a large
EL lamp. The MIC4832 can drive large panel displays for
mobile phones, multimedia players or automotive
electronics where EL panels are used for backlighting.
The MIC4832 offers design flexibility with adjustable lamp
and boost converter frequencies, simply by applying
external resistors. A new H-Bridge design reduces audible
noise by creating smoother AC voltage across the EL
panel.
The MIC4832 is offered in MLF
®
3mm x 3mm and MSOP-
8 lead-free and RoHS-compliant packaging with a -40°C to
85°C junction temperature range.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
1.8V to 5.5V DC input voltage
220Vpp output voltage capable
Low audible noise EL drive waveform
Supports EL panel sizes up to 3in
2
(19cm
2
)
Low 45µA operating supply current
Small inductor size with low profile (220uH)
Tiny 8-pin 3mm x 3mm MLF
®
package
Adjustable boost converter frequency
Adjustable EL lamp frequency
10nA shutdown current
Applications
•
•
•
•
•
•
•
•
LCD panel backlight
Mobile Phones
PDAs
Pagers
Calculators
Multimedia Players
Remote controls
GPS Receivers
___________________________________________________________________________________________________________
Typical Application
Low Noise EL Driver
MLF and
MicroLeadFrame
is a registered trademark of Amkor Technologies, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
March 2009
M9999-033109-C
Micrel
MIC4832
Ordering Information
Part Number
MIC4832YML
MIC4832YMM
Note
*MLF
is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
®
Junction Temp. Range
–40° to +85°C
–40° to +85°C
Package
8-Pin 3mm × 3mm MLF
®
8-Pin MSOP
Lead Finish
RoHS Compliant / Pb-Free / Halogen Free*
RoHS Compliant / Pb-Free
Pin Configuration
8-Pin MSOP (MM)
8-Pin 3mm × 3mm MLF
®
(ML)
Pin Description
Pin Number
1
2
Pin Name
VDD
RSW
Pin Function
Supply (Input): 1.8V to 5.5V for internal circuitry.
Switch Resistor (External Component): Set switch frequency of the internal
power MOSFET by connecting an external resistor to VDD. Connecting the
external resistor to GND disables the switch oscillator and shuts down the
device.
EL Resistor (External Component): Set EL frequency of the internal H-bridge
driver by connecting an external resistor to VDD. Connecting the external
resistor to GND disables the EL oscillator.
Ground
Switch Node (Input): Internal high-voltage power MOSFET drain.
Regulated Boost Output (External Component): Connect to the output capacitor
of the boost regulator and connect to the cathode of the diode.
EL Output: Connect to one end of the EL lamp. Polarity is not important.
EL Output: Connect to one end of the EL lamp. Polarity is not important.
3
REL
4
5
6
7
8
GND
SW
CS
VB
VA
March 2009
2
M9999-033109-C
Micrel
MIC4832
Absolute Maximum Ratings
(1)
Supply Voltage (V
DD
)...................................... –0.5V to 6.0V
Output Voltage (V
CS
) ..................................... –0.5V to 120V
EL Lamp Terminals (V
A
, V
B
)................................... V
CS
+ 3V
Switch Voltage (Vsw) ..................................... -0.5V to 120V
Frequency Control Voltage
(V
RSW
,
V
REL
) ................................... –0.5V to (V
DD
+0.3V)
Storage Temperature (T
S
).........................–65°C to +150°C
ESD Rating
(4)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
DD
).................................... +1.8V to +5.5V
Lamp Drive Frequency (f
EL
) ....................... 60Hz to 1000Hz
Switching Frequency (f
SW
).........................65kHz to 250kHz
Ambient Temperature (T
A
) .......................... –40°C to +85°C
Package Thermal Resistance
(3)
MSOP
(θ
JA
) .....................................................206°C/W
MLF
®
(θ
JA
) .........................................................63°C/W
Electrical Characteristics
(5)
V
IN
= V
DD
= 3.0V, R
SW
= 338KΩ, R
EL
= 1.78MΩ. T
A
= 25°C unless otherwise specified.
Bold
values indicate
–40°C
≤
T
A
≤
+85°C
Parameter
On-resistance
CS Voltage Variation
Enable Input Low Voltage
(turn-off)
Enable Input High Voltage
(turn-on)
Shutdown current
Input supply current
V
DD
= 1.8V to 5.5V
V
DD
= 1.8V to 5.5V
R
SW
Resistor = LOW; R
EL
Resistor = LOW; V
DD
= 5.5V
R
SW
Resistor = HIGH;
R
EL
Resistor = HIGH;
V
CS
= 110V; V
A
, V
B
OPEN
Input current including
inductor
V
A
– V
B
output drive
frequency
Switching transistor
frequency
Switching transistor duty
cycle
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation of any T
A
(ambient temperature) is P
D
(max) = (T
J
(max) – T
A
) /
θ
JA
. Exceeding the maximum allowable
power dissipation will result in excessive die temperature.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
5. Specification for packaged product only.
Condition
I
SW
= 100mA
Min
91
Typ
3.8
105
Max
7
119
0.5
Units
Ohm
V
V
VDD-
0.5
0.01
45
0.5
75
μA
μA
V
IN
= V
DD
= 3.2V; R
SW
= 338KΩ, R
EL
= 1.78MΩ;
L=220µH; R
OUT
=10kΩ; Lamp = 2in
2
R
EL
= 1.78MΩ
R
SW
= 338KΩ
158
90
24
200
112
90
242
134
mA
Hz
kHz
%
March 2009
3
M9999-033109-C
Micrel
MIC4832
Typical Characteristics
March 2009
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M9999-033109-C
Micrel
MIC4832
Functional Diagram
Figure 1. MIC4832 Block Diagram
Functional Description
Overview
The MIC4832 is a high-voltage EL driver with an AC
output voltage of 220V peak-to-peak capable of
driving EL lamps up to 3 in
2
. Input supply current for
the MIC4832 is typically 45µA reducing to 10nA in
shutdown. The high voltage EL driver has two
internal oscillators to control the switching MOSFET
and the H-bridge driver. Both of the internal
oscillators’ frequencies can be individually
programmed through the external resistors to
maximize the efficiency and the brightness of the EL
lamp.
Regulation
Referring to Figure 1, initially power is applied to
V
DD
. The internal feedback voltage is less than the
reference voltage causing the internal comparator to
go high which enables the switching MOSFET’s
oscillator. When the switching MOSFET turns on,
current flows through the inductor and flows into the
switch. The switching MOSFET will typically turn on
for 90% of the switching period. During the on-time,
energy is stored in the inductor. When the switching
MOSFET turns off, current flowing into the inductor
forces the voltage across the inductor to reverse
polarity. The voltage across the inductor rises until
the external diode conducts and clamps the voltage
at V
OUT
+ V
D1
. The energy in the inductor is then
discharged into the C
OUT
capacitor. The internal
comparator continues to turn the switching MOSFET
on and off until the internal feedback voltage is
above the reference voltage. Once the internal
feedback voltage is above the reference voltage, the
internal comparator turns off the switching
MOSFET’s oscillator.
When the EL oscillator is enabled, V
A
and V
B
switch
in opposite states to achieve a 220V peak-to-peak
AC output signal. The external resistor that connects
to the REL pin determines the EL frequency.
March 2009
5
M9999-033109-C
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