Temperature Compensation for Ring

[GP14]

Hi! Can someone help me how can I have a < 2% frequency deviation in terms of temperature change for a Current Starved Ring Oscillator.

What Compensation Circuits can I used? and how it works to compensate with the temperature change .. Thanks!

 

[d123]

Hi,

Without knowing anything about your circuit, or the components involved, a simple possibility - if it uses resistors - is to play around with positive and negative tempco values to find a suitable combination that reduces the deviation. This works a bit with BJT circuits to offset the -2mV/ºC aspect.

Other solutions I've seen involve more complex, and larger, compensation circuits which switch the (key) resistor(s) over temperature, and look hard to implement without bringing other, new problems to solve, if you see what I mean - every solution can be another problem.

I think you can use an ADC and other parts to compensate for temperature drift, but haven't looked into the details.

Another option is to use a PIC, etc., and set it to adjust the output to correct for the deviation based on a temperature chart.