operational amplifier ?

[_SquiD_]

Hi there, everyone

I kinda need to build a frequency-voltage converter using an ATMEGA128 MCU. The thing is that I've generated a PWM signal on a PB5 (OCR1A pin) and after a RC FTJ a obtain a voltage ~ AVCC/2.
Because the the ATMEGA128 has an operating voltage of ~5V - the voltage obtained after the FTJ will be around 2.5V. The thing is that I need to vary that voltage between 0-9V (by varying the PWM). How can I do such a thing ? Please give me a solution.

Thanks in advance.

- SQD -

 

[ElectroNerd]

You could probably use an op amp, or a voltage regulator. How much current does this varying voltage source need to provide?

 

[malik_123]

use low pass filter to generate DC volt and then u can used the op am to amplify it your desired level.