Hi guys,
i'm building a current drive for an electromagnet. It is supposed to provide constant current amplitude up to 1kHz. The driver should also be able to provide a phase shift with respect to the input voltage. So I implemented a two stage phase shifter as described here https://pdfserv.maximintegrated.com/en/an/AN184.pdf (attacchement phase shifter).
I soldered it on the PCB I made and started testing it at 100 Hz using the amperometer as load. The main problem is that after the first stage I see random oscillations everywhere on the other stages. I thought that the issues were either on the inverting stage (U1B) left floating or with the digital potentiometer or the op amp. So I modified the circuit as in the attachments (phase shifter 2) and used instead of the LM324 an LM6144 but still no luck.
I'm a little bit lost here, so any help would be very appreciated
i'm building a current drive for an electromagnet. It is supposed to provide constant current amplitude up to 1kHz. The driver should also be able to provide a phase shift with respect to the input voltage. So I implemented a two stage phase shifter as described here https://pdfserv.maximintegrated.com/en/an/AN184.pdf (attacchement phase shifter).
I soldered it on the PCB I made and started testing it at 100 Hz using the amperometer as load. The main problem is that after the first stage I see random oscillations everywhere on the other stages. I thought that the issues were either on the inverting stage (U1B) left floating or with the digital potentiometer or the op amp. So I modified the circuit as in the attachments (phase shifter 2) and used instead of the LM324 an LM6144 but still no luck.
I'm a little bit lost here, so any help would be very appreciated
Attachments
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