Voltage-switch drivers, constant-current
drivers, and Flash LED drivers
LED controllers
LEDs are used in a wide range of applications, from low-end status indicators to high-end video displays. System designers often
need the ability to control these LEDs, but can’t afford to tie up the system processor to do so. NXP’s LED controllers solve this
problem, performing a variety of control tasks while ofoading the system processor. Having sent instructions to the LED controller,
the processor is free to engage in other tasks or go into a low-power state.
NXP’s LED controllers offer a variety of features needed in LED-driving applications. Some of these features include:
} Blinking and dimming capability
} Pulse-width modulation (PWM) for LED control
} Color mixing capabilities
} Fast-mode Plus (Fm+) communication channel with data transfer rate of up to 1 Mbps over the I2C-bus.
} Different output drive types (push-pull, open-drain voltage switch or constant-current driver)
} Independent control of LEDs
} LED status and fault reading
} Short-circuit protection
} Over-temperature protection
Voltage-Switch Drivers
Voltage-switch output driver devices control the LED
connected to the output pin by switching the connection
to ground or supply on or off. A series resistor connected
between the LED and the device limits the current that ows
through the LED into the device.
Voltage-switch devices have the advantage of dissipating the
heat outside the device, in the series resistor. Therefore the
device is insensitive to heat dissipation and is good for driving
multiple LEDs in series, with different forward-bias voltages
(Vf), from the same supply.
Constant-Current Drivers
A current-regulated LED driver results in the LED light
remaining constant with the supply-voltage uctuations.
NXP constant-current LED drivers are used for low-current
luminary lighting applications requiring accurate lighting
control independent of supply voltage, temperature, and LED
forward-bias voltage.
Flash LED Drivers
NXP Flash LED Drivers are high-efciency, maximum-output,
small footprint devices with touch capability and an indicator
LED output feature. These devices are highly integrated with
hardware and I2C interface modes.
The devices are classied in three groups: voltage-switch drivers, constant-current drivers, and Flash LED drivers.
These groups are discussed below.
The LED controllers are supported by application boards and daughter cards, an established manufacturing infrastructure that
supports high volumes, and several technical documents. NXP helps system designers make lighting affordable, in everything
from indoor consumer electronics and appliances to outdoor decorative lighting.
(a) Example Voltage-Switch Output Structure (b) Example Constant-Current Output Structure
LED Controllers Selection Guide
Device
Function
Number of LED Outputs
Operating Voltage Range
Standby Current [1]
Type of LED Drive
Max LED Drive Current
Max LED Drive Voltage
Output Type
Default POR LED Output State
LED Pin can be used as Input
Number of PWMs
Individual PWM Resolution (Steps)
Group PWM Resolution (Steps)
Individual Brightness Control
Group Brightness Control
Output Enable / PWM Control
Programmable Output Delay
Dimming Capability
Blinking Capability
Pattern Sequencer
LED Error Detection
Thermal Shutdown
Interface
Number of Device Addresses
Hardware Reset
Internal Oscillator Frequency
Oscillator Calibration
External Oscillator Input
Individual PWM Frequency
Group PWM Frequency
Status
PCA9550 Blinker 2 2.3 V -
5.5 V 1.9 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - Y N N N N Y N N N I2C, Fm 2 Y 330 KHz - - 0.172 Hz -
44 Hz - In Production
PCA9553 Blinker 4 2.3 V -
5.5 V 1.9 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - N N N N N Y N N N I2C, Fm 1 N 330 KHz - - 0.172 Hz -
44 Hz - In Production
PCA9551 Blinker 8 2.3 V -
5.5 V 1.9 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - N N N N N Y N N N I2C, Fm 8 Y 330 KHz - - 0.172 Hz -
44 Hz - In Production
PCA9552 Blinker 16 2.3 V -
5.5 V 2,1 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - N N N N N Y N N N I2C, Fm 8 Y 330 KHz - - 0.172 Hz -
44 Hz - In Production
PCA9530 Dimmer &
Blinker 22.3 V -
5.5 V 1.9 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - Y N N N Y Y N N N I2C, Fm 2 Y 330 KHz - - 0.591 Hz -
152 Hz - In Production
PCA9533 Dimmer &
Blinker 42.3 V -
5.5 V 1.9 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - N N N N Y Y N N N I2C, Fm 2 N 330 KHz - - 0.591 Hz -
152 Hz - In Production
PCA9531 Dimmer &
Blinker 82.3 V -
5.5 V 1.9 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - N N N N Y Y N N N I2C, Fm 8 Y 330 KHz - - 0.591 Hz -
152 Hz - In Production
PCA9532 Dimmer &
Blinker 16 2.3 V -
5.5 V 2,1 mA Voltage
switch 25 mA 5 V Open Drain Hi-Z Input Y 2 256 - N N N N Y Y N N N I2C, Fm 8 Y 330 KHz - - 0.591 Hz -
152 Hz - In Production
PCA9632 Dimmer &
Blinker 42.3 V -
5.5 V
0,005
mA
Voltage
switch
-10 mA
25 mA 5 V Push Pull
(Congurable) Hi-Z N 4 + 1 256
(64)
64
(16) Y Y N N Y Y N N N I2C, Fm+ 1, 4 N 400 KHz N N 1.56 KHz 190 Hz
(6.25 KHz) In Production
PCA9633 Dimmer &
Blinker 42.3 V -
5.5 V 3,8 mA Voltage
switch
-10 mA
25 mA 5 V Push Pull
(Congurable)
Push Pull
Logic H N 4 + 1 256 256 Y Y Y N Y Y N N N I2C, Fm+ 1, 4,
126 N 25 MHz N N 97 KHz 190 Hz
(97 KHz) In Production
PCA9634 Dimmer &
Blinker 82.3 V -
5.5 V 3,8 mA Voltage
switch
-10 mA
25 mA 5 V Push Pull
(Congurable)
Push Pull
Logic H N 8 + 1 256 256 Y Y Y N Y Y N N N I2C, Fm+ 1, 4,
126 N 25 MHz N N 97 KHz 190 Hz
(97 KHz) In Production
PCA9635 Dimmer &
Blinker 16 2.3 V -
5.5 V 3,8 mA Voltage
switch
-10 mA
25 mA 5 V Push Pull
(Congurable)
Push Pull
Logic H N 16 + 1 256 256 Y Y Y N Y Y N N N I2C, Fm+ 126 N 25 MHz N N 97 KHz 190 Hz
(97 KHz) In Production
PCA9685 Dimmer 16 2.3 V -
5.5 V 2,2 mA Voltage
switch
-10 mA
25 mA 5 V Push Pull
(Congurable)
Push Pull
Logic L N 16 4096 - Y N Y Y Y Y N N N I2C, Fm+ 126 N 25 MHz N Y 40 Hz -
1000 Hz - In Production
PCA9624 Dimmer &
Blinker 82.3 V -
5.5 V 2,1 mA Voltage
switch 100 mA 40 V Open Drain Hi-Z N 8 + 1 256 256 Y Y Y N Y Y N N N I2C, Fm+ 126 N 25 MHz N N 97 KHz 190 Hz
(97 KHz) In Production
PCA9622 Dimmer &
Blinker 16 2.3 V -
5.5 V 1.05 mA Voltage
switch 100 mA 40 V Open Drain Hi-Z N 16 + 1 256 256 Y Y Y N Y Y N N N I2C, Fm+ 126 N 25 MHz N N 97 KHz 190 Hz
(97 KHz) In Production
PCA9626 Dimmer &
Blinker 24 2.3 V -
5.5 V 6.0 mA Voltage
switch 100 mA 40 V Open Drain Hi-Z N 24 + 1 256 256 Y Y Y N Y Y N N N I2C, Fm+ 126 N 25 MHz N N 97 KHz 190 Hz
(97 KHz) In Production
PCA9901 Blinker 1 2.1 V -
5.5 V 0,3 mA
Constant
Current
(Source)
1 to 20
mA 5 V Open Drain
(Source) Hi-Z N 0 4096 - N N N N N Y Y Y Y 1-Wire 1 N 18 KHz N N N N In Production
PCA9922 Signage 8 3.3 V -
5.5 V 3.2 mA Constant
Current
15 to 60
mA 5 V Open Drain
(Sink) Hi-Z N 0 - - N N Y N N N N Y Y SPI, 25
MHz - N - - - N N In Production
PCA9952 Dimmer &
Blinker 16 3.0 V -
5.5 V 500 mA Constant
Current 50 mA 34 V Open Drain
(Sink) Hi-Z N 16 + 1 256 256 Y Y Y Y Y Y N Y Y I2C, Fm+ 8, 4 Y 8 MHz Y N 31.5 KHz 122 Hz In Development
PCA9955 Dimmer &
Blinker 16 3.0 V -
5.5 V 500 mA Constant
Current 50 mA 34 V Open Drain
(Sink) Hi-Z N 16 + 1 256 256 Y Y N Y Y Y N Y Y I2C, Fm+ 16, 4 Y 8 MHz Y N 31.5 KHz 122 Hz In Development
[1] Typical value, measured with VDD = 5.5 V, no load, VI = VDD or VSS, and FSCL = 0 KHz.
LED Flash Drivers Selection Guide
Device
Function
Operating Voltage Range
Flash LED Output Drive Type
Flash LEDs Driven in Series
Maximum LED Drive Current
Fixed Switching Frequency
Integrated Diodes and Resistors
Inductor Broken Coil Detect
Interface Type
Number of Device Addresses
Max Timed Flash Operation
Assist Light
Status
Flash (1 LED)
Flash (2 LEDs)
Touch Indicator
Output
SSL3250A Asynchronous
boost conerter 2.7 V - 5.5 V Low-side drive 1 or 2 500 mA 500 mA 200 mA 20 mA 1.2 MHz N N I2C, Fm or direct 1 820 ms N In
Production
SSL3252 Synchronous
boost converter 2.5 V - 5.5 V High-side drive 1 or 2 500 mA 400 mA 160 mA 10 mA 2.0 MHz Y Y I2C, Fm or direct 1 820 ms Y In
Development
PCA9622 Application Example
Architectural Lighting
Car Radio BacklightMobile Phone Application Example
Application Support
For added application support, NXP offers the following application reports on the LED driver family devices:
} AN10579: Driving LED light bars using NXP Solutions
http://www.nxp.com/documents/application_note/AN10579.pdf
} AN10733: Flash LED App. Note
http://www.nxp.com/documents/application_note/AN10733.pdf
} AN264: I2C Devices for LED Display Control App. Note
http://www.nxp.com/documents/application_note/AN264.pdf
} AN10315: LED Dimmer Board
http://www.nxp.com/documents/application_note/AN10315.pdf
For more information, visit http://ics.nxp.com/products/led.drivers/
NXP offers evaluation modules and demo boards that can be used to develop software and evaluate the performance
of the LED controllers and LED Flash drivers.
OM6279 – LED Dimmer Demo Board
NXP LED controllers and GPIO in simulated mobile phone
application showing RGB LED color mixing, LED blinking and
dimming, and backlight LED control applications.
OM6281 – PCA9698 Daughter Card for I2C 2005-1
PCA9698 40-bit GPIO with easy access to all 40 I/O pins
and several LEDs. Demonstrates using PCA9530 2-bit LED
dimmer to dim and/or blink all 40 outputs using the /OE input
of the PCA9698.
OM6282 – PCA9633 Daughter Card for I2C 2005-1
Demonstrates LED blinking, dimming, and RGBA color mixing
using PCA9633 with individual 256-step PWM per channel
and global 256-step PWM. Select any of the 64 I2C addresses
with the on-board DIP switch.
LED Flash Driver Demo Board
Provides access to the reset, ash, touch and brightness
controls of the SSL3250A. The board also has a USB port and
GUI software that can be used to control the SSL3250A.
OM6275 – I2C 2005-1 Evaluation Board
Easy experimentation and training module. I2C-bus connects
to LED controllers, other I2C peripherals, and daughter cards.
USB Connection. GUI interface allows direct control of device
without programming.
OM6276 – PCA9633 Demo Board
Evaluate LED dimming and blinking features of the PCA9633
4-bit (RGBA) PWM LED driver. RJ-45 jack allows series
connection to multiple boards to evaluate long-distance Fm+
bus and P82B96.
© 2010 NXP B.V.
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www.nxp.com/interface
Date of release: June 2010
Document order number: 9397 750 16950
Printed in the Netherlands