PRELIMINARY
CM9156B
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 voltage
Low external parts count, requires no inductor
PWM brightness control via the ENA pin
Selectable 262kHz or 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 package
Product Description
CM9156B 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
CM9156B 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 CM9156B
offers a selectable switching frequency of 262kHz or
650kHz. The LED brightness can be adjusted by apply-
ing a PWM signal on the ENA pin.
The CM9156B output voltage is regulated to 4.5V, ±
5% over the line and load ranges. Up 180mA of output
current is available. The proprietary design architec-
ture maintains high efficiency (> 80%), and at low V
IN
provides longer battery life. With a high V
IN,
or when
the adapter is powered, it provides cool reliable opera-
tion. It offers low output voltage ripple, typically less
than 50mV. Internal over-temperature and over-current
management provide short circuit protection.
The CM9156B 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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Drive white LEDs to backlight color LCDs
Drive 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
CLK
C 2P
C 1N
1.0uF
PhotonIC
TM
CM9156B
1.0uF
GND
C 2N
E NA
©
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 ]
