LEDCOntrol4 v2 and CAT4101 driver

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14.12.2018, 21:12
marcer

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LEDCOntrol4 v2 and CAT4101 driver

I have bought Profilux 4 and LEDControl4 v2 to replace my Arduino that controls DYI LED lights. PWM control works with Arduino, but not with LEDControl4 v2

I have connected
a) inputs: L1/L2 from Profilux to LEDControl, 5.2V input to LEDControl
b) outputs: pin 2 to PWM whites, pin 2 to PWM for blues and pin 6 as ground
c) I use two Mean Well CLG-150 power supplies and power supplies ground is connected to pin6 ground

Should I use pull-up resistors 10k between power supplies +20V and PWM outputs? When I measure PWM without connecting to CAT 4101 driver I measure 5V and when L1/L2 is set to 10V, but when I connect PWM output pins 2,3 to CAT4101 drivers, PWM drops to 0V. Any advice?
17.12.2018, 01:30
vfitzek

Quote:

Originally Posted by marcer

I have bought Profilux 4 and LEDControl4 v2 to replace my Arduino that controls DYI LED lights. PWM control works with Arduino, but not with LEDControl4 v2

I have connected
a) inputs: L1/L2 from Profilux to LEDControl, 5.2V input to LEDControl
b) outputs: pin 2 to PWM whites, pin 2 to PWM for blues and pin 6 as ground
c) I use two Mean Well CLG-150 power supplies and power supplies ground is connected to pin6 ground

Should I use pull-up resistors 10k between power supplies +20V and PWM outputs? When I measure PWM without connecting to CAT 4101 driver I measure 5V and when L1/L2 is set to 10V, but when I connect PWM output pins 2,3 to CAT4101 drivers, PWM drops to 0V. Any advice?

Due to the fact, that the LEDControl can only switch between high resistance and zero, you need pull-ups at the outputs. The Arduino uses internal pull-ups. But be careful, your CAT4101 only accepts up to 6V at the PWM-Pin. So you have to connect the resistors to the 5V and not to the 20V.
Regards, Volker
17.12.2018, 22:09
marcer

Quote:

Originally Posted by vfitzek

Due to the fact, that the LEDControl can only switch between high resistance and zero, you need pull-ups at the outputs. The Arduino uses internal pull-ups. But be careful, your CAT4101 only accepts up to 6V at the PWM-Pin. So you have to connect the resistors to the 5V and not to the 20V.
Regards, Volker

I just tried 10k pull up resistor between PWM output and VCC 5.2V a I could not control pwm o. LED control at all, PWM seemed to be at 80%/4V.

CAT4101 datasheet shows that pull down resistance is 200k Ohms, what does it mean when I use 10k pull up resistor against VCC? for 5V it means 0.025mA sinks into CAT4101 PWM input.

I have found this about CAT4101 and pull up resistor on instructables: https://www.instructables.com/id/Eas...01-LED-Driver/
For PWM control, you need to know if your controller is a current source, sink, or push-pull. Only the current sink (like the TLC5940) needs special treatment: a 10K pullup resistor between VIN and PWM/EN, as well as an inverted PWM signal.
18.12.2018, 11:13
vfitzek

Quote:

Originally Posted by marcer

I just tried 10k pull up resistor between PWM output and VCC 5.2V a I could not control pwm o. LED control at all, PWM seemed to be at 80%/4V..

Meassure a PWM Output with a Multi-Meter does you tell almost nothing. You have to look at it with a scope, or try static testing. If you connect only the pull-up and no LEDControl it should be a logic high and the power led's should go on. If you short the Signal to ground now, it's a static low. So your LED's should go off.

Quote:

Originally Posted by marcer

CAT4101 datasheet shows that pull down resistance is 200k Ohms, what does it mean when I use 10k pull up resistor against VCC? for 5V it means 0.025mA sinks into CAT4101 PWM input...

You have 2 resistors in series. The pull-up and the internal resistance of the PWM-Pin. If the LEDControl goes in high resistance u have I=5V/210kR=24uA. That means 240mV on the pull-up and 4,76V at the PWM input. If the LEDControl switches on the sink, it (almost) shortens the internal resistance. So u have I=5V/10kR=500uA and the complete voltage should drop at the pull-up. It might be that the 500uA is a little less for the current sink. As mentioned in the documentation for the LEDControl you may reduce the pull-up down to 470R. Maybe you start with a 1kR as a pull-up to get a better result. That will give that sink about 5mA and something to do.

Quote:

Originally Posted by marcer

I have found this about CAT4101 and pull up resistor on instructables: https://www.instructables.com/id/Eas...01-LED-Driver/
For PWM control, you need to know if your controller is a current source, sink, or push-pull. Only the current sink (like the TLC5940) needs special treatment: a 10K pull-up resistor between VIN and PWM/EN, as well as an inverted PWM signal.

Quite interesting page. He wrote "a use of a pull-up with this sink is a mistake" but he didn't declare why. His solution wouldn't work here. Cause there is no current limiting resistor in the sink output of the LEDControl. I guess it would be destroyed.

regards and keep me informed if u found a solution,
volker
18.12.2018, 13:12
marcer

Quote:

Originally Posted by vfitzek

Meassure a PWM Output with a Multi-Meter does you tell almost nothing. You have to look at it with a scope, or try static testing. If you connect only the pull-up and no LEDControl it should be a logic high and the power led's should go on. If you short the Signal to ground now, it's a static low. So your LED's should go off.

I measured 4V when PWM was connected to CAT4101 with True RMS multimeter RC UNI-T UT71C so I think it was right value. I was driving about 8 Cat4101 in parallel so that might explain 4V because I had 8x200k internal at CAT4101 and 10k pull up to 5.2V

Quote:

Originally Posted by vfitzek

You have 2 resistors in series. The pull-up and the internal resistance of the PWM-Pin. If the LEDControl goes in high resistance u have I=5V/210kR=24uA. That means 240mV on the pull-up and 4,76V at the PWM input. If the LEDControl switches on the sink, it (almost) shortens the internal resistance. So u have I=5V/10kR=500uA and the complete voltage should drop at the pull-up. It might be that the 500uA is a little less for the current sink. As mentioned in the documentation for the LEDControl you may reduce the pull-up down to 470R. Maybe you start with a 1kR as a pull-up to get a better result. That will give that sink about 5mA and something to do.

I will try today evening with 1kR and see what happens. But I was surprised that I had 4V on PWM output even I changed PWM output to 0V and also when I completely disconnected PWM output from LEDcontrol. Seem to me like LEDcontrol has not enough mA on PWM outputs.

Thank you very much for your advice, It was quite time long ago I had theoretical electronics at Uni.
19.12.2018, 13:20
marcer

I checked yesterday to connect PWM from LEDcontrol4 v2 to CAT4101 with 1kR pull up and pwm outout was 5.1V (98% of 5.2 Vin). I could not control CAT4101 via 1-10V, pwm out was always 5.1V.

So I gave up and i'm returning LEDcontrol4 v2 back to shop. I bought Arduino Nano clone and terminal shield for 15 Euros, I connected 1-10V inputs (changed to 0-5V) to analog ports A0, A1, wrote short program running in loop twice a second to convert analog to pwm out on Arduino and it works like charm.