juhhi
Newbie level 3
Hello!
I am using microcontroller to collect data from car. I have input channels for digital and analog sensors and I would need to protect those channels in some way.
Digital channels should accept both, DHE and inductive sensor outputs, so the input circuit should be capable to trigger approx 100Vpp sine-wave with +2V offset and with no modifications also square-wave with 0 to +12V levels (dont mind open-collector output of the DHE, it is noticed previously).
At the moment I am using diode and zener-diode with 47k series resistor to pass through voltages between -0.5V and +5V on digital input channels and 5.6V zener-diode with 1k series resistor on analog channels. Two problems are faced on digital channels:
1. Zener-diodes cause some phase shift on signal and requirements on digital signals acquisition are pretty high.
2. Space is limited, so smaller (maybe packaged to IC) solution would be nice.
I am thinking to use TVS-diodes or similar solution on next version. I would appreciate your ideas because I am not sure at all about using TVS-diodes with inductive sensors because voltages and their length is comparatively long.
I am using microcontroller to collect data from car. I have input channels for digital and analog sensors and I would need to protect those channels in some way.
Digital channels should accept both, DHE and inductive sensor outputs, so the input circuit should be capable to trigger approx 100Vpp sine-wave with +2V offset and with no modifications also square-wave with 0 to +12V levels (dont mind open-collector output of the DHE, it is noticed previously).
At the moment I am using diode and zener-diode with 47k series resistor to pass through voltages between -0.5V and +5V on digital input channels and 5.6V zener-diode with 1k series resistor on analog channels. Two problems are faced on digital channels:
1. Zener-diodes cause some phase shift on signal and requirements on digital signals acquisition are pretty high.
2. Space is limited, so smaller (maybe packaged to IC) solution would be nice.
I am thinking to use TVS-diodes or similar solution on next version. I would appreciate your ideas because I am not sure at all about using TVS-diodes with inductive sensors because voltages and their length is comparatively long.