CM9140
Four Output Driver for White LEDs
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2.9V to 5.5V input voltage range
Powered display backlight and/or flash WLED
Low external parts count, requires no inductor and
ballast resistors
Low EMI and reflected ripple
Adaptive charge pump ratio (1x or 1.5x) maximizes
efficiency at both high and low input voltage
Precision regulation for each output with 2% cur-
rent matching at 20mA
Programmable LED current via ISET pin
Typical 500kHz fixed switching frequency
Supports up to 300mA, drives four LEDs regulated
to 50mA each
Analog and PWM intensity control
Less than 10µA shutdown current
Over-current and over-temperature protection
Undervoltage lockout
Soft-start limits start-up inrush current
16-lead TQFN, RoHS compliant lead-free package
Product Description
The CM9140 is an adaptive fractional switched capaci-
tor (charge pump) regulator optimized for driving four
white LEDs. Each LED's driver current is matched to
within 2% for uniform intensity. The CM9140 supports
an input voltage range of 2.9V to 5.5V with undervolt-
age lockout. A failure detection circuit prevents the loss
of power when one or more LEDs fail (short or open).
Internal over-temperature and over-current manage-
ment provide short circuit protection.
The CM9140 regulates up to 300mA of output current
to drive WLEDs, allowing up to 50mA per LED chan-
nel. The maximum LED current is programmed with an
external resistor. The EN input allows for Analog and
PWM brightness control. The CM9140 can also be
used for a camera flash. In full shutdown mode, the
CM9140 draws only 10µA.
The CM9140 automatically selects the most efficient
charge pump ratio based on the operating voltage
requirement of the white LEDs. The proprietary design
architecture maintains high efficiency (> 80%), and at
low VIN provides longer battery life. With a high VIN, or
when the adapter is powered, it provides cool reliable
operation.
The CM9140 is available in a compact, 16-lead TQFN-
package. It can operate over the industrial temperature
range of –40°C to 85°C.
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Applications
•
•
•
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Drives white LEDs for STN/TFT color LCD back-
lighting
Cell phones, PDAs
Digital still cameras
Flash for DSC
Typical Application
1.0μF
1.0μF
C1P C1N
C2P
C2N
2.9V to 6.0V
VIN
VOUT
1μF
Enable
PhotonIC
CM9140
EN
ISET
GND
R
1μF
LED1
LED2
LED3
LED4
off
on
R
SET
©
2006 California Micro Devices Corp. All rights reserved.
11/06/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
1
CM9140
Package Pinout
PACKAGE / PINOUT DIAGRAM
Bottom View
8 C2N
5 NC
6 NC
7 NC
ISET
VIN
4
3
2
1
9 EN
10 GND
11 C1N
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DAP
C1P
LED1
12 LED4
16
15
14
LED3
LED2
16-Lead TQFN Package
(4mm x 4mm)
Note: This drawing is not to scale.
PIN DESCRIPTIONS
LEAD(s)
NAME
DESCRIPTION
1
2
LED1
C1P
VIN
Cathode of LED1 pin.
This pin is the plus side of charge pump bucket capacitor C1. Connect a 1.0μF ceramic
capacitor with a voltage rating of 10V or greater between C1N and C1P.
Positive supply voltage input pin. This voltage should be between 2.9V and 5.5V. This
pin requires a 1.0μF or larger ceramic capacitor to ground.
3
Enable pin and Current set pin for drivers, active low.
To set the LED current, a resistor, R
SET
, is connected between this pin and ground. The
regulated LED current is 1000x the current flowing in R
SET
, and is approximately:
0.66V -
I
LED
(
A
)
= -------------------------
×
1000
R
SET
(
kΩ
)
4
ISET
If this resistor is tied directly to ground (and the enable function is not used), then Logic
Low = 0. Otherwise subtract the voltage drop of the device that drives this pin low.
5
6
7
8
9
10
NC
NC
NC
C2N
EN
GND
This pin is the minus side of charge pump bucket capacitor C2. Connect a 1.0μF
ceramic capacitor between C2N and C2P.
Enable pin, active high. Should be tied high when not used.
Ground terminal pin.
©
2006 California Micro Devices Corp. All rights reserved.
2
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
VOUT
C2P
13
l
Fax: 408.263.7846
l
www.cmd.com
11/06/06
CM9140
Specifications (cont’d)
PIN DESCRIPTIONS
11
12
13
14
C1N
LED4
C2P
LED3
This pin is the minus side of charge pump bucket capacitor C1. Connect a 1.0μF
ceramic capacitor between C1N and C1P.
Cathode of LED4 pin.
This pin is the plus side of charge pump bucket capacitor C2. Connect a 1.0μF ceramic
capacitor between C2N and C2P.
Cathode of LED3 pin.
Charge pump output voltage pin, which connects to the anodes of all LEDs. A 1μF
capacitor to ground is recommended.
Cathode of LED2 pin.
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15
16
VOUT
LED2
NC
DAP
Ordering Information
PART NUMBERING INFORMATION
Package
TQFN
Lead-free Finish
Leads
16
Ordering Part Number
1
CM9140-04QE
Part Marking
CM9140 04QE
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
Specifications
PARAMETER
ABSOLUTE MAXIMUM RATINGS
RATING
UNITS
kV
V
V
V
V
°C
°C
°C
ESD Protection (HBM)
±2
Pin Voltages
VIN to GND
V
OUT
to GND
ISET, EN to GND
All other pins to GND
[GND - 0.3] to +6.0
[GND - 0.3] to +7.0
[GND - 0.3] to +5.0
[GND - 0.3] to +5.0
–65 to +150
–40 to +85
300
Storage Temperature Range
Operating Temperature Range (ambient)
Lead Temperature (Soldering, 10sec)
©
2006 California Micro Devices Corp. All rights reserved.
11/06/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
3
CM9140
Specifications (cont’d)
ELECTRICAL OPERATING CHARACTERISTICS
VIN = 3.6V, all outputs are on. Typical values are at T
A
= 25°C.
SYMBOL
VIN
I
Q
I
SD
PARAMETER
Supply Voltage Range
Quiescent Current
Shutdown Supply Current
CONDITIONS
VIN = 4.5V
V
EN
< 0.4V
MIN
2.9
TYP
500
2
10
5.5
MAX
5.5
UNITS
V
μA
μA
V
mA
103
5
%
%
mA
V
0.4
5
V
mA
°C
°C
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VOUT Charge Pump
Output Voltage
V
OUT
I
LED TOT
Acc
I
OUT
= 0mA to 120mA,
VIN = 3.0 to 5.5V
4.2
Total I
LED
Current
Σ
I
LED1
thru I
LED4
+photoflash
300
ILED
Accuracy of ILED
(1)
VIN = 4.0V; ISET = 33k
Ω
(0.1%)
97
Mism
I
LED
Max
Mismatch current between LED1
to LED4
(2)
Max I
LED
per driver
VIN = 4.0V, R
SET
= 33k
Ω
(0.1%)
VIN = 3.6V; R
SET
= 12k
Ω
2
50
EN, ISET
V
IH
V
IL
High Level Input Voltage
Low Level Input Voltage
1.8
Protection
I
SC
Input current under short circuit
condition on V
OUT
V
OUT
= 0; VIN = 3.6
R
SET
= 33k
Ω
OTP
OTPH
Over-temperature Limit
Over-temperature Hysteresis
∑
I
LED1 – 4
(
mA
)
-
Note 1: Accuracy =
------------------------------------------
80
135
15
-
Note 2: Mismatch =
---------------------------------------------------------------------------------
Max
(
I
LED1 – 4
)
– Min
(
I
LED1 – 4
)
Max
(
I
LED1 – 4
)
+ Min
(
I
LED1 – 4
)
©
2006 California Micro Devices Corp. All rights reserved.
4
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
11/06/06
CM9140
Functional Block Diagram
Charge Pump Efficiency
100
90
80
70
Vled=3.2V
200
Source Current
Vled=3.2V
Input Current (mA)
175
150
125
100
75
50
Iout=120mA
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Iout=120mA
Iout=30mA
Iout=60mA
Iout=30mA
Iout=60mA
Efficiency (%)
60
3.0
3.5
4.0
4.5
5.0
5.5
6.0
25
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Input Voltage (V)
Input Voltage (V)
Typical Waveforms
Typical Waveforms
Cin=C2=C3=Cout=1uF, Iout=120mA
Cin=C2=C3=Cout=1uF, Iout=120mA
100 mV/
div
20mA/
div
Vout
100 mV/
div
Vout
Iin
20mA/
div
Iin
50mV/
div
Vin
50mV/
div
Vin
1us/div
1.0x mode
1us/div
1.5x mode
Startup
LED Current vs. Vin
Cin=C2=C3=Cout=1uF, Iout=120mA
25
20
15
10
5
ENB
Iin
200mA/
div
2V/
div
.5ms/div
Vout
LED Current (mA)
2V/
div
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Input Voltage (V)
©
2006 California Micro Devices Corp. All rights reserved.
11/06/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
5
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