MCP41010 regulate the resistance in 9V circuit

Hello everyone, I am trying to using chips MCP41010 regulate the resistance in the circuit, in which there is a + 9V (replacement potentiometer circuit guitar pedals), but the controller itself for some reason get these 9B, he immediately disconnected from usb, and the circuit itself is working but not as they should, and if you disable usb wire, then it will still burn diodes, and wherein the controller is strongly heated. And when replacing other potentiometers guitar pedals of this scheme are all excellent. As can be fixed a given problem? Thanks in advance.

Maybe I should put a diode on the chip inputs?

Never used one of these MCP41xxx yet, but they look cool:

So MCP41010 is the 10K ohm version, and the resistance between PW0 and PA0 can be programmed down to about 39 Ohm (10k/256). Is something going to limit the current from 9V? The way I read the datasheet the wiper current (PW0) must be between +1mA and -1mA.

ron_sutherland:
Never used one of these MCP41xxx yet, but they look cool:
http://ww1.microchip.com/downloads/en/DeviceDoc/11195c.pdf

So MCP41010 is the 10K ohm version, and the resistance between PW0 and PA0 can be programmed down to about 39 Ohm (10k/256). Is something going to limit the current from 9V? The way I read the datasheet the wiper current (PW0) must be between +1mA and -1mA.

ron_sutherland many thanks for you answer. Here this scheme, the resistor R1 Under load current is 150mA.

So R1 has 150mA under load? If so then the digital potentiometer will need help, for example it could control a transistor or opamp that is able to deliver that load. Unfortunately, all I can think of is how to setup a circuit able to control the current or voltage (individually) as a function of the programming resistor, but it needs to control both the voltage and current linearly as a function of the programming resistor or it may mess up the sound.

Another issue is battery voltage, which is above Vdd and that is not allowed. There is a way to do what you want. For example devices like electronic loads:
http://www.bkprecision.com/products/dc-electronic-loads/8540-150-w-dc-electronic-load.html

They can control Constant current (CC), constant voltage (CV), and constant resistance (CR). CC and CV circuits are easy to do, but CR is what I am forgetting.

Many thanks, i will try it.

Guess this was bugging me, so I found a constant resistance (CR) type circuit on EDN, and have twisted it to work with potentiometer in simulation anyway (the simulation needs chrome browser).

also found MightyWatt which is missing resistor mode (it has CC and CV, but not CR):

and the EDN article that gave the ideas:

I may need something like MightyWatt (but with CR) for my solar charge controller project, so...

ron_sutherland wow! great work! thx! jrc4558 and bs170 field-effect transistor suitable for this circuit? By the way I put 1n4001 5 volts from the Arduino Arduino on to power did not come with a guitar pedal, and it works without any additional conversion circuit, it's weird.

Both op-amps need their input to work on the negative supply rail, so something like LMC6082 would be better. If the MOSFET has 150mA at 9V it will dissipate 1.35W of heat, thus needs a big package like TO220 (may still need a small heat sink if it gets hot) and have a fairly low gate threshold, so IRLZ34NPBF may be good.

ron_sutherland thank you very much for your help, I'll try!