Voltage to PWM Converter

[chinuhark]

I have wanted this for a long time now so I would just go ahead and ask.
I would like to know if there is a cheap IC that directly takes in an analog voltage (say 0-10V or 0-5V) and converts it into PWM of desired switching frequency and duty cycle should vary from 0-100% according to the analog input.
Now the traditional way of doing this is making a triangular wave generator and using a comparator to compare it to the reference input. What I do is use an Atmega 8 and use ADC and PWM out for doing the above.
Please suggest a cheap and easy to find IC that can do the above in 1 small single package.

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I would also like to add that it should be fixed frequency PWM which can be set as required

 

[BradtheRad]

"Voltage Controlled Pulse Width Oscillator"

Found in this lengthy collection of circuits for the 555 timer IC.
(Scroll halfway down.)

**broken link removed**

 

[schmitt trigger]

Unfortunately, for your requirements of 0 to 100% cannot be met with a single 555. You may want to use a 556, which is a dual.
One timer would be running as an astable, triggering the second one configured as a voltage controlled monostable.