Hi,
1st post on the forum and very new to power electronics design, and to electronics in general. I designed the attached circuit to attempt to power on and off a solenoid coil. I have no prior experience of using mosfets, other than using off the shelf H-Bridge modules such as the IBT-2 and IBT-4. In this application I don't need to switch direction of current flow, so opted for a single low-side mosfet per coil instead of H bridge.
The problem is that when I supply the gate of the mosfet with what should be zero volts, zero duty from the MCU (pin21) then it is switching on. If I leave it open circuit then it is off.
High voltage/current supply is 12V (limited to 2A by PSU), MCU is 3V3.
I've checked the code by using an off the shelf h-bridge (IBT-2). I don't have a scope unfortunately, but I've measured the voltage at pin21 to be 90mV max, and on the Hz/Duty setting it's reading 0Hz and 0% duty. As you can see from the picture, I've only populated 1 channel for debugging, and bypassed the current sense part.
I'd be grateful if somebody could take a look at the Schematic and let me know what stupid thing(s) I've done please with the design.
1st post on the forum and very new to power electronics design, and to electronics in general. I designed the attached circuit to attempt to power on and off a solenoid coil. I have no prior experience of using mosfets, other than using off the shelf H-Bridge modules such as the IBT-2 and IBT-4. In this application I don't need to switch direction of current flow, so opted for a single low-side mosfet per coil instead of H bridge.
The problem is that when I supply the gate of the mosfet with what should be zero volts, zero duty from the MCU (pin21) then it is switching on. If I leave it open circuit then it is off.
High voltage/current supply is 12V (limited to 2A by PSU), MCU is 3V3.
I've checked the code by using an off the shelf h-bridge (IBT-2). I don't have a scope unfortunately, but I've measured the voltage at pin21 to be 90mV max, and on the Hz/Duty setting it's reading 0Hz and 0% duty. As you can see from the picture, I've only populated 1 channel for debugging, and bypassed the current sense part.
I'd be grateful if somebody could take a look at the Schematic and let me know what stupid thing(s) I've done please with the design.
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