I'm trying to design a circuit that "multiplies" two signals.
I have an electrical unit with two separate circuits. One circuit drives the other one with a square signal. The width of the square signal is on the order of milliseconds. The amplitude can be set anywhere between 0 V and 10 V. The input resistance of the second circuit is 10 kΩ.
I would like to "multiply"/chop this signal with an LVTTL control signal. The width of the LVTTL can be as low as 50 ns. The amplitude is ~2 V. I want to pass the original signal if the control signal is high (2 V) and set it to zero if the control signal is low (0 V).
So far, I have tried to use a two-stage n-type MOSFET but the output dips to -0.5 V for a short time at the rising edge of the LVTTL signal. I tried different loads and stuff but did not get any good output.
- Do you know any circuit that does what I need?
- I have a buffer circuit, do I need it?
- How to avoid the negative potentials on the rising edge of the LVTTL signal?
I can upload my LTSplice circuit if you want, or you can direct me to the right discussion group.
Here are images from LTSpice: The 1st graph outlines my circuit, the 2nd, and the 3rd graphs show my input signal and my LVTTL control signal. The 4th and 5th graphs show output signals vs different input amplitudes. The 6th graph shows the signal at the output of the first MOSFET. The last two images show the outputs vs the stage 1 signal (output of the first MOSFET)