Question about the accuracy of non-quartz clock

[wptfks]

i want to design a internal time reference, with no qurzt.
now i am considering to have a temperature independent current source, and then
charge the capacitor. how accurate can this time reference be??

 

[renwl]

accurate clock

it's inaccurate too.
the accuracy of the capacitor is about 10%.

 

[wptfks]

Re: accurate clock

well, i will use on chip OTP to trim, what I care about is the voltage and temperature influence

 

[fala]

Re: accurate clock

What you want already has been built within a 555 timer. All you need is to put a stable voltage On it, it has all other circuits including comparator and flip-flop. But again all it depends what accuracy we are talking about, surely a crystal oscillator will be much more accurate.