how to design a triangular wave generator for a frequency of 20Khz?

[rakesh]

Hello everyone am trying to design a pulse width modulation circuit . To generate the PWM pulses i'll feed the triangular wave at one input and a control voltage at the other input of an comparator to get the pulses at the required duty cycle. I need to have a triangular wave which varies from 0 to 5Volt (not a 5volt peak to peak)at a frequency of about 20 Khz. i searched in the internet and found many of the circuits consists of a comparator and integrator to generate the triangular wave which varies peak to peak and those circuits uses a negative voltage supply. My guess is i don't need a negative supply for my kind of circuit design.
I found the formula used to design the integrator which is based on the negative and positive saturation voltages of the op amps.
Am really confused to design this circuit and also for choosing the right op amp with the enough slew rate for a proper triangular wave at the output.

Am just a beginner with the electronics please correct me if i am wrong.