Linear Ramo Circuit controlled by PWM

[agdemir]

I need PWM driving linear Ramp circuit, output is 1 to 5VDC . Component count is critical fpr the place.
Thank you very much

 

[crutschow]

So do you need a PWM circuit, a filter for the PWM circuit, or what? Whats a Ramo circuit?

 

[agdemir]

So do you need a PWM circuit, a filter for the PWM circuit, or what? Whats a Ramo circuit?

I have a PWM signal.
I need Linear Ramp circuit (linearized charge capacitor with constant current)

 

[crutschow]

What is the modulation on the PWM signal? Can it be whatever you need?

 

[agdemir]

Re: Linear Ramp Circuit controlled by PWM

What is the modulation on the PWM signal? Can it be whatever you need?

Thank you very much for your response. Please find the picture attached, it will be more clear.

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[crutschow]

That picture just shows a varying pulse width signal converted to a ramp, not a PWM signal. If you want to do than then feed the pulse into an op amp integrator circuit with a reset circuit to discharge the integrator capacitor at the end of the ramp. What is the frequency and pulse-width of the pulse?

 

[BradtheRad]

Going by your diagram, a capacitor can create those waveforms.



The switch can be a mechanical component, or an electronic component.

The diode is added to discharge the capacitor immediately when a pulse ends.

 

[dick_freebird]

A fixed current source, a shorting switch and a capacitor is
pretty much it. But getting the first and last, ideal, small and
cheap, is maybe the harder problem.

Do you really need a linear ramp? If so then an op amp integrator
might be cheapest, I know of no good fixed current reference
piece-parts. But in a closed loop setup ramp linearity isn't good
for much. Switched RC can be "close enough", often.