I have a vintage car that has a shunt ammeter. The needle sits in the middle and fully deflects in either direction for about 2A of current.
I want to convert it to a voltmeter with an 8 to 16V range. A 12V reference power supply came to mind using a SEPIC DC-DC converter. The SEPIC supply is connected to one side of the ammeter and a current limiting resistor and the battery is connected to the other side.
When the battery voltage is +/-4V different that the 12V reference and with 2 ohms of circuit resistance, 2A would be flowing and the ammeter would be fully deflected in one direction or the other. Current and subsequent ammeter deflection would be linear for < +/-4V.
Problem here is that a SEPIC converter can't sink current. I could add a current sink transistor switch and resistor possibly that turns on only when 12V < battery voltage.
4 switch Synchronous DC-DC converters can sink current, but this solution is expensive and i'm trying to find the lowest cost solution.
What do you guys recommend? I thought of using a Power Op Amp, but I think it would require a V+ and V- power input. I'm a bit rusty on Op Amps so I can use some help though.
I want to convert it to a voltmeter with an 8 to 16V range. A 12V reference power supply came to mind using a SEPIC DC-DC converter. The SEPIC supply is connected to one side of the ammeter and a current limiting resistor and the battery is connected to the other side.
When the battery voltage is +/-4V different that the 12V reference and with 2 ohms of circuit resistance, 2A would be flowing and the ammeter would be fully deflected in one direction or the other. Current and subsequent ammeter deflection would be linear for < +/-4V.
Problem here is that a SEPIC converter can't sink current. I could add a current sink transistor switch and resistor possibly that turns on only when 12V < battery voltage.
4 switch Synchronous DC-DC converters can sink current, but this solution is expensive and i'm trying to find the lowest cost solution.
What do you guys recommend? I thought of using a Power Op Amp, but I think it would require a V+ and V- power input. I'm a bit rusty on Op Amps so I can use some help though.