PWM to Pulsed DC

[KPres]

Does anyone know of a simulated circuit that creates a PWM signal and uses it to modify a created pulsed DC signal to end up with a pulsed DC with the effective voltage of the PWM?

The PWM is +5V at 490Hz with an adjustable duty cycle that will represent +0 to +1.2V and the input pulsed DC is +5V, 18us PW and 3.6ms between pulses.

I am not an expert on this, so please excuse any errors in the description.

Thanks in advance!

[Dave@RPS]

This sounds like a chopper circuit.  At 490Hz the period should be 2.041mS so I don't understand your 3.6ms between pulse.

If you are working on a buck chopper and want a 1.2V output from a 5V supply then you would want a duty cycle of 1.2/5.0 = 24% which would be an on time of 190 uS.  

Below are some NI white papers talking about Co-Simulation and H-bridges.  I'd start looking through those.  The last 3 circuits are H-bridges which are more complicated than your chopper circuit but making simpler circuits once you under stand these should be straight forward.  Maybe someone has a better link to a simple half bridge or buck chopper.

Introductory Tutorial Video: Power Electronics Co-Simulation with NI Multisim and LabVIEW

http://www.ni.com/white-paper/14316/en/

THEN DO THIS

Introduction to Digital and Analog Co-simulation Between NI LabVIEW and NI Multisim

http://www.ni.com/white-paper/13663/en/

THEN DO THIS

How to Design and Simulate a Brushed DC Motor H-Bridge Circuit Using NI Multisim

http://www.ni.com/white-paper/13721/en/

Simple H Bridge drive for brushed motor with Utiliboard sample

http://www.ni.com/white-paper/13840/en/

H-Bridge DC Motor Controller Implementation with NI Circuit Design Suite and NI Single-Board RIO

http://www.ni.com/white-paper/14228/en/

[KPres]

Thank you very much for taking the time to respond.

I

am sorry, but I am afraid that my understanding of circuits is not sufficient enough to have described my situation adequately or to interpret your detailed response.

What I am trying to figure out is a circuit which imposes the effective voltage level of a PWM onto a pulsed DC.

There are 2 inputs:

1. Output of +5VDC PWM with 0V to +1.1VDC input to it.
2. +5V square waveform pulsed DC with 18us PW and 277.78 PRF.

There is 1 output:

1. Same as input B with the voltage the same level as the effective voltage of input A (actually the same voltage as the input to the PWM)

Inputs A and B represent actual inputs provided to a circuit, so the simulation would have to create them.

The 0V to +1.1VDC input to the PWM represents possible values that can change at any time, but do not vary frequently, that is it will be one value for a while and then may change.

I think that the output of the PWM would have to be smoothed to an analog signal and somehow modify the voltage of input B.

 Thanks