Texas Instruments describe the TLC5940 with the following paragraph:
The TLC5940 is a 16-channel, constant-current sink LED driver. Each channel has an individually adjustable 4096-step grayscale PWM brightness control and a 64-step, constant-current sink (dot correction). The dot correction adjusts the brightness variations between LED channels and other LED drivers. The dot correction data is stored in an integrated EEPROM. Both grayscale control and dot correction are accessible via a serial interface. A single external resistor sets the maximum current value of all 16 channels.
My use for the chip will be to allow one LED driver the ability to drive multiple led bars independently. The uController (MCU) I am using, the ATMEGA328p has only 6 PWM enabled ports. 3 of these are automatically reserved for use by the SPI interface required for the wireless module. Expanding these PWM ports will mean control over more than one LED light bar per driver. The TLC5940 offers 16 ports, we consume 3 ports per bar, one for each colour of Red, Green and Blue. This means with one TLC5940 we can address 5 bars.
- 16 Channels · Monocolor, Multicolor, Fullcolor LED Displays
- 12 bit (4096 Steps) Grayscale PWM Control
- 6 bit (64 Steps)
- Storable in Integrated EEPROM
- Drive Capability (Constant Current Sink)
- 60 mA (VCC < 3.6 V) LED driver. Each channel has an individually adjust-
- 120 mA (VCC > 3.6 V) able 4096-step grayscale PWM brightness control
- LED Power Supply Voltage up to 17 V and a 64-step constant-current sink (dot correction).
- Serial Data Interface, SPI comp. dot correction data is stored in an integrated
- Controlled In-Rush Current EEPROM. Both grayscale control and dot correction
- 30-MHz Data Transfer Rate are accessible via a serial interface.
- A single external resistor sets the maximum current value of all 16
- Error Information The TLC5940 features two error information circuits.
- LOD: LED Open Detection
- TEF: Thermal Error Flag.