Hi all,
I need to drive a LED at 1kHz with a square wave signal and feed that signal as a reference into another circuit. At present I've been using a microcontroller (Arduino) to switch a digital pin on and off, but I've noticed significant gitter in the square wave pulse, and I want a more accurate and precise solution. The LED was switched on and off via a simple transistor switch using this signal, and it was designed for a LED current of 75mA.
A 555 timer comes to mind to provide the square wave pulse, and I've read that this can also sink or source up to 200mA. Has anyone had experience with this circuit, and can tell me another about how constant a current it can provide? Would it instead be better to drive the transistor switch circuit to drive my LED with the output instead? (as is shown in the attached circuit schematic).
Does anyone know if there are dedicated high precision chips that can encompass both square wave generation (at an arbitrary frequency), a LED driver capable of driving 75mA of _constant_ current, and an enable pin to turn it all on or off. Or am I asking too much?
I've attached the most obvious solution (at least to me). Can I still run the reference signal into the other circuit as pictured? (which will go into the input of an op-amp).
Any suggestions much appreciated! Thanks in advance!
I need to drive a LED at 1kHz with a square wave signal and feed that signal as a reference into another circuit. At present I've been using a microcontroller (Arduino) to switch a digital pin on and off, but I've noticed significant gitter in the square wave pulse, and I want a more accurate and precise solution. The LED was switched on and off via a simple transistor switch using this signal, and it was designed for a LED current of 75mA.
A 555 timer comes to mind to provide the square wave pulse, and I've read that this can also sink or source up to 200mA. Has anyone had experience with this circuit, and can tell me another about how constant a current it can provide? Would it instead be better to drive the transistor switch circuit to drive my LED with the output instead? (as is shown in the attached circuit schematic).
Does anyone know if there are dedicated high precision chips that can encompass both square wave generation (at an arbitrary frequency), a LED driver capable of driving 75mA of _constant_ current, and an enable pin to turn it all on or off. Or am I asking too much?
I've attached the most obvious solution (at least to me). Can I still run the reference signal into the other circuit as pictured? (which will go into the input of an op-amp).
Any suggestions much appreciated! Thanks in advance!
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