PRELIMINARY
CM9156A
Charge Pump White LED Driver
Features
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3.0V to 6.5V input voltage range
Dual mode operation: 1x and 1.5x
Fixed 4.5V output with initial accuracy of ± 2%
Supports up to 180mA (@4V) output
High efficiency at both high and low input voltages
Low external parts count, requires no inductor
PWM brightness control via the ENA pin
Selectable 8kHz, 32kHz, 262kHz, and 650kHz
switching frequency
Low shutdown current of <1µA
Soft start prevents excessive inrush current
Over-temperature and over-current protection
Low output ripple (<1%), low EMI
Input protection provides superior ESD rating
requiring only standard handling precautions
TDFN-10 or MSOP-10 package
Optional RoHS compliant lead free packaging
Product Description
The CM9156A is an efficient, 1.5x switched capacitor
(charge pump) regulator ideal for white LED applica-
tions. It has a regulated 4.5V, 120mA output, capable
of driving up to six parallel white LEDs. With a typical
operating input voltage range from 3.0V to 6.0V, the
CM9156A can be operated from a single-cell Li-Ion
battery.
It features an efficient, 1.5x charge pump circuit that
uses only two 1.0µF ceramic bucket capacitors and two
small capacitors for VIN and VOUT. The CM9156A
offers a selectable switching frequency of 8kHz, 32kHz,
262kHz, or 650kHz. The LED brightness can be
adjusted by applying a PWM signal on the ENA pin.
The CM9156A output voltage is regulated to 4.5V, ±
5% over the line and load ranges. Up 180mA of output
current is available. The proprietary design architecture
maintains high efficiency (> 80%), and at low V
IN
pro-
vides longer battery life. With a high V
IN,
or when the
adapter is powered, it provides cool reliable operation.
It offers low output voltage ripple, typically less than
50mV. Internal over-temperature and over-current
management provide short circuit protection.
The CM9156A is packaged in either a space saving
10-Lead TDFN or 10-Lead MSOP package. It can
operate over the industrial temperature range of -25
°
C
to 85
°
C.
Applications
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Drives white LEDs to backlight color LCDs
Drives white or RGB LEDs for camera flash
Cellular phones
MP3 players
PDAs, GPS
Typical Application
4.5V
1.0uF
V OUT
C 1P
3.0V to 6.0V
V IN
1.0uF
C L K1
C L K2
C 2P
C 1N
1.0uF
30
30
30
GND
C 2N
E NA
1.0uF
PhotonIC
CM9156A
TM
©
2006 California Micro Devices Corp. All rights reserved.
04/26/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
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Tel: 408.263.3214
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Fax: 408.263.7846
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www.cmd.com
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CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
