a couple of highside current sensors

Am I allowed to use this in my product gratis?

The model is different from the two-transistor configuration. Why?

Those are just two examples. There are more.

Sure.

This is my most recent current sensor, in one leg of a class-D h-bridge amp.

It lets us get the actual current waveform.

I got lucky on the layout; the resistors actually measure 24.9 milliohms. Or maybe it was skill.

There is a 53mV offset. Why is that?

Huh... (you're a wild man, but I'm missing something.) For the first one with the opamp. With one amp through R1 there's a 1 volt drop. Which gives 23 volts for U1 output. A 1 volt drop across R3 or 10 mA of current... that 10 mA must go through the negative rail resistor R2. ... Which then gives me 10V on your output. What did I do wrong?

George H.

Oops! 0.1V! I found it.... never mind. GH

The opamp version? That's the supply current of the opamp. Use a lower current amp, or calibrate it out.

I just used the default universalopamp2

It's an idea. It's free.

I like it. Thank you!

I designed a functional but clumsy highside current sensor into an EOM driver recently, to protect a $200 distributed amplifier chip. I should have done this!

My goal is for a current sensor between a solar panel and a battery. It looks and simulates as I wish.

Zetex IIRC used to make a high-side current-sense IC; basically a Wilson CM on a chip. It worked good and was cheaper than a quad transistor array.

EOL-ed, naturally

The differential ADC on an AVR can work about a volt over the processor's supply rail which comes in handy for low-voltage applications sometimes

If you're going to brag, at least do it in a hand stand with a friend:

Tim

-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website:

Which non-ideal op amp models are suitable, do you think?

RL

Interesting use of those 2N3904s.

We use two channels of high side current sense.... One for battery side and one for PV input which works up to about 300V and down to around 10V Bidirectional and up to a bit more than 100A max.

Basically an op amp with some bias and feeding a current source to feed the low side A/D converter. Like some previous HS current source tech. We just needed higher voltage so had to build our own.

Current sensing can be quite a painful thing to do well.