I have a circuit that can be broken down to this:
The M54564P has been stripped down to a single circuit from its 8 transistors to demonstrate it in a smaller scale.
The area of interest is where the Resistor-LED pairs are (which are just here to represent the load itself – values are not exact). The 5v signal comes from an Arduino and the 14v from a vehicle (car).
Lets say the 14v is always on while the 5v is switched by the Arduino.
When that happens, the M54564P will complete its circuit and output ~12v – this is where it gets complicated (for me).
I need to power on those two LEDs, preferably using the 14v signal – no relays (need to do this 6 times in total) – by using the 12v signal as activation.
While unpowered, they need to stay as demonstrated – I can't make their circuit parallel.
The Output (from the M54564P) can be used (there won't be a lot of draw from this), but I am trying to avoid this if possible – I would like to keep it as the activation signal – but the M54564P can provide the current I need with no issue (but maybe not the voltage for simultaneous output – I need at least two out of the 8 transistors active at any given time).
What do you guys/gals think?
Can I close this circuit by using the Output from the M54564P to feed the 14v to those two loads – without making them parallel while they are not powered on (they can be parallel while active of course)?
I am looking for transistors, diodes, ICs, etc – just not relays or devices that will draw too much current.
Edit:
To clarify on the outputs on the M54564P; I am already using 6 input and outputs from the M54564P (I need to control 6 independent circuits – a maximum of two circuits will be on at a time, no more) – each circuit has 2 loads that need to be switched on (that is what is represented by the Resistor-LED pair).
Edit:
While modifying my circuit on my drawing application, I might have stumbled across a way to solve my circuit.
Anyways, let me clarify a few things first:
The reason for the M54564P? It was recommended on an Arduino forum as a way to switch a positive signal on with the Arduino's 5v digital output.
As suggested by Jasen – I will look into the A2982 as a substitute. Thanks!
The load I am trying to drive is a Rostra's Dual Heated Seat control unit. It requires that a 12v signal be passed to the selected heat level and an additional (12v) signal that turns the heat unit itself on.
The part I am wiring into doesn't draw much at all and a Resistor-LED pair was the closest I could compare them to. I apologize for the confusion there.
Anyways, I spent a bit more time getting to know the control unit on the Rostra and came up with a way to power it up, send the 12v to the pin that selects the heat level while sending that same 12v signal onto the rest of the unit.
Does this look like a good solution or just a wasteful use of diodes?
I hope this does not cause further confusion – I only have my tiptoes in a bit into electrical engineering. I have a long way to go, but I have no plans to stop studying anything soon.
Best Answer
if you can use 2 (as drawn) or 6 (as written) of the outputs of the 8 provided on the M54564P, one for each LED, that would be one way to have them not paralleled.
Another would be to add diodes between a single the M54564P output and each LED.
Faced with the updated problem
It looks like you have only a single extra output, need to drive a single extra dependant load. I would thingk that driving that with a dedicated output would be preferable to using the diodes.
your drawing shouws 2 unused outputs on the driver chip and if you have a spare output on the arduino to drive the apropriate input pin just do that.
6 diodes to save one output pin seems like a lot of effort unless you haven't got a spare pin