PAM2701 Datasheet, PDF (1/14 Pages) Power Analog Micoelectronics – 4-Channel Regulated Charge Pump White LED Driver

PAM2701
4-Channel Regulated Charge Pump White LED Driver
Features
n Peak Efficiency: 90%
n Individual Current Regulation
n 3-bit Digital Output Control
n Two modes of operation:1x and 1.5x
n Current Matching with a Max Tolerance
of 3%
n Output Current up to 30mA per LED
n Total LED Current up to 4*30mA=120mA
n Fixed Frequency of 1MHz
n Open LED Protection
n Space Saving Package QFN 3mmx3mm
and QFN 4mmx4mm
n Pb-Free Package
Applications
n Cellular Phones
n LED Backlighting
n LCD Modules
n Handheld Devices
n Digital Cameras
n PDAs
n PMPs
n MP3 Players
Description
The PAM2701 is a 4-channel charge pump white
LED driver, capable of driving up to 4 LEDs in
parallel. The device operates in either 1x mode or
1.5x fractional mode, and it can switch from 1x
mode to 1.5x mode automatically when the input
voltage decreased. Its internal 4 current sink
regulators ensure both the LED current matching
and the brightness uniformity. The LED current
can be programmed by an external resistor, R , _SET
connected between the RSET pin and ground.
LED current of up to 30mA are supported by the
input supply voltage over a range of 2.7V to 5.5V,
making the device optimized for Li-Ion battery
applications.
The PAM2701 has a fixed switching frequency of
1MHz, allowing the use of very small value
ceramic capacitors. The enable input pin allows
the device to be set in shutdown mode, and the
current consumption is reduced to less than 1μA.
LED dimming can be done by several methods
including using a DC voltage to set the RSET pin
current, adding a switched resistor in parallel with
R_SET, or applying a PWM signal to CTRx pin or EN
pin.
Typical Application
1μF
1μF
8 9 11 10
C1+ C1- C2+ C2-
7
6
VIN
VOUT
EN ¹ _EN PAM2701
V_IN
C_IN
1μF ^{Control 0}
2
CTR0
LED1 ¹⁶
Control 1
3
CTR1
15
LED2
Control 2 ⁴ CTR2
14
LED3
5 _RSET
13
LED4
R_SET
24kΩ
GND
12
Co
1μF
20mA
Power Analog Microelectronics,Inc
www.poweranalog.com
1
09/2008 Rev 1.3