Voltage Stepping Circuit

[fantasymick]

I'm trying to build a circuit that can produce voltage steps in response to a standard rising or falling trigger signal. For example, on the first trigger signal, the output will be -1.5V and hold there. On the next trigger signal, it'll be 0V and hold. Then 1.5V, 3V, and repeats. -1.5, 0, 1.5, 3, -1.5, 0, 1.5, 3 V etc..

I tried doing it in software using labview but it wasn't responding beyond triggers above 3 kHz. For my application (optics and phase modulation) I need ~ 25 kHz.

Can someone point me in the right direction on how to build such a circuit?

Thank you.

 

[ericgibbs]

I'm trying to build a circuit that can produce voltage steps in response to a standard rising or falling trigger signal. For example, on the first trigger signal, the output will be -1.5V and hold there. On the next trigger signal, it'll be 0V and hold. Then 1.5V, 3V, and repeats. -1.5, 0, 1.5, 3, -1.5, 0, 1.5, 3 V etc..

I tried doing it in software using labview but it wasn't responding beyond triggers above 3 kHz. For my application (optics and phase modulation) I need ~ 25 kHz.

Can someone point me in the right direction on how to build such a circuit?

Thank you.

hi,
You could do it usng a HEF4017, with outputs into a 'weighted' OPA summer, requires a +/-5V for the OPA power supply.

Do you follow.?

 

[Optikon]

hi,
You could do it usng a HEF4017, with outputs into a 'weighted' OPA summer, requires a +/-5V for the OPA power supply.

Do you follow.?

Right. Alternative to the weighted summer would be to drive an analog multiplexor that will switch your input levels (voltage divider / buffered)

Your scanning / switching rate would be determined by the analog mux (25kHz -feasible)

again, +/- supplies needed.

Switching rate with the OPA solution probably determined by slew rate & load of the opamp.

 

[fantasymick]

Thanks for the suggestions, it's exactly what I need. I think I know what I need to do.