I want to drive a number of 2.3" alphanumeric LEDs (http://www.kingbright.com/manager/upload/pdf/PSA23-11SRWA(Ver1189413285.10) which have an interesting design in that they have different current requirements for the different type of segments - the big segments are two sets of two LEDs and the small segments are one set of two LEDs.
I also want:
- to be able to have a variable input supply voltage (let's say 10 to 15v) with minimum regulation for the LEDs, due to power dissipation in the regulator (SMPS is OTT for this)
- minimum component count
- variable brightness
So I've found the TLC5940 (http://www.farnell.com/datasheets/85896.pdf) which seems to fit the bill - constant current with varying LED supply in the right range, adjustable correction per LED, PWM control for brightness etc - but it looks a bit of a beast to control to get all these features - message formats as well as the implementation across a SPI-like interface
Anyone done it with a PICAXE - or used any other driver chip with similar capabilities ??
TIA
Martin
I also want:
- to be able to have a variable input supply voltage (let's say 10 to 15v) with minimum regulation for the LEDs, due to power dissipation in the regulator (SMPS is OTT for this)
- minimum component count
- variable brightness
So I've found the TLC5940 (http://www.farnell.com/datasheets/85896.pdf) which seems to fit the bill - constant current with varying LED supply in the right range, adjustable correction per LED, PWM control for brightness etc - but it looks a bit of a beast to control to get all these features - message formats as well as the implementation across a SPI-like interface
Anyone done it with a PICAXE - or used any other driver chip with similar capabilities ??
TIA
Martin