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Infineon Shield Q/A

clem57

I would like to suggest this place for the exchange of information on this shield. I noticed a Google shows very little practical information, other than recent news announcing the shield. Since I am first, here is my question:

 

How are people going to power these and what input voltages/output voltages are expected?

 

Thanks and hoping the information share can benefit all imageimageimage

  • Part of the issues is that full intensity green and red are not necessarily matched, as already stated the Infineon shield is a current device, the LED strings are voltage devices. They have series resistors to limit the current at a matched amount when all strings are getting 12V, not when all are getting the same current

     

    I will be trying to adjust the colour pallet I included into my library to try to get better colours and will post the results in the next few days

  • in reply to Robert Peter Oakes

    Most of the LED strings on the market should be voltage devices.. right? So when Infineon designed the shield they would have taken that in to account?

     

    Or is it that Infineon took a design that was primarily targeted at industrial use ( light control for events, shows,  billboards, residential and commercial lighting etc)  and turned that in to an arduino shield where they get invariably used with LED strips that are voltage devices which don't play with the PDM output..Just thinking out aloud..

  • in reply to pmohan

    No not really

     

    Professional LEDs or larger LEDs are designed for Current operation (NO Resistors in series), this is why there 48V or more (Loads of LEDs in Series but not parallel)

     

    most 12V strings are a set of LEDS in series (3 mostly) and a resistor (Keeps them cheap and easy to drive) , then loads of those in parallel to make up the string but if you want to dim them you use PWM

     

    in the case of the Shield it drives a constant current no matter the input voltage (Up to a limit of about 60V ) then some fancy algorithms to both DIM (PWM but exponentially across all channels) and to vary the ratio of the colours (Linearly) on each channel

     

    What my sample sketch did was to crank up the current to the MAX as a full string will actually consume more than the shield can deliver and provide some initial colour table settings to simplify the selection of colours.

     

    the colour lookup table needs adjusting