Maker Pro
Maker Pro

Help with circuit design

blazini36

Oct 22, 2018
2
Joined
Oct 22, 2018
Messages
2
I'm designing a small circuit board that basically contains 2 constant current LED drivers to power the LED flash for 2 cameras. The camera's GPIO has an open drain output which is connected to the "remote" pin, the remote pin is connected to the "PWM" pin of the Meanwell driver. The PWM pin acts as a remote on/off pin, when connected to ground it turns the driver output off. The VOUT connector pins go to the LED string, not the camera itself.

The problem with this circuit is that the Meanwell driver normally outputs on until the PWM pin is grounded, then it turns off. So as it is in the drawing the Strobe LEDs will be on and the camera will turn them off. I need the Strobe to normally be off and the camera to tun them on. So I suppose I'm looking at an NPN transistor or something on the PWM pin but I'm not quite sure how to implement it. D1 D2 and D3 are indicator LEDs which I'm not 100% are implemented quite right.

Any help is appreciated
 

Attachments

  • PCB.pdf
    24.2 KB · Views: 18

ratstar

Aug 20, 2018
485
Joined
Aug 20, 2018
Messages
485
Is this just an aesthetic flaw? - as in its only visual the error - if so just invert it - theres plenty of ways to do that, im not sure of the method that ppl feel comfortable around here.
 

blazini36

Oct 22, 2018
2
Joined
Oct 22, 2018
Messages
2
No it's not just an aesthetic flaw and yes it does need to be inverted. NPN transistors confuse me but I believe it's what is necessary. I'm asking for help with inverting the signal
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
An inverter is the logic device that produces an output state opposite to the input.
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,700
Joined
Nov 17, 2011
Messages
13,700
A simple way of inverting a logic signal is shown in our resource. Using an NPN transistor and a pull-up resistor may be all you need. If you can drive the load directly from tne NPN transistor, not even a pull-up resistor is required.
 
Top