DCDC internal Oscillator output Frequency accuracy

[rock_zhu]

oscillator output frequency

Hello.
I am trying to design a buck dcdc convertor.
And a ring osc is needed. I wonder is it necessary aim to get a high accuracy osc output frequency. If the frequency varies with PVT seriously. what will happen?
Thanks in advance.

Is there any book analysis PWM PSM and current mode well?
could you introduce me quick reference book for dcdc convertor?

 

[dick_freebird]

If you want a really accurate frequency, you probably
want a SYNC pin and a synchronizable oscillator.

If you have a low-TC resistor then a switched-RC
oscillator can be very temperature and voltage stable.
Process, however, would need trimming to take out the
"make" tolerance.

 

[rock_zhu]

thanks. dick.
I don;t know whether a high accuracy osc is needed.
will the frequency affect the output ripple or others?