Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

pwm to voltage conversion.

Status
Not open for further replies.
H

hiren_dave

Member level 1
Member level 1
Joined
Jul 3, 2012
Messages
40
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,288
Location
AHMEDABAD,INDIA
Activity points
1,535
Hi. friends...

i shown one circuit it gives variable output voltage as per the change in input pulse width.
if input pulse width (on time) will increase than output voltage also increases and vice verse.
how it can be?
how should i design this circuit???
 

There are various direct ICs available in the market like LM2907N, LM2907 Frequency to Voltage Converter.
Try with them.

Wish u all the best..
 

    V

    Points: 2
    Helpful Answer Positive Rating
Frequency to voltage is not the same as PWM to voltage conversion. For PWM to voltage, a simple resistor charging a capacitor is all that is required.

Keith
 

    V

    Points: 2
    Helpful Answer Positive Rating
See below. Choose R and C to suit the frequency of the PWM. It is quite a common way of getting an analogue voltage out of a microcontroller without a DAC.

93_1345713486.gif


Keith
 

    V

    Points: 2
    Helpful Answer Positive Rating
If you have a DC signal (signal is always higher than ground, no minus voltage), this will do:

https://upload.wikimedia.org/wikipedia/commons/3/3b/RC_Divider.svg

You'll have to remember that you shouldn't put too much load on this circuit though. Or if you do, you need to buffer it with an op amp or such. having a 10k load in Vout, would leave you only half of the actual voltage.

Edit: Keith was faster.
 

    V

    Points: 2
    Helpful Answer Positive Rating
You could do something more complicated with less ripple. For example, charge up a capacitor with a constant current when the PWM is high then a sample & hold of the capacitor voltage on the falling edge and then reset the charging capacitor. However, if you don't mind the smoothing required for a simple CR it actually works very well.

Keith
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top