do all the power on reset circuits use comparator ?

[incol]

i found in many data sheet that power on reset circuits are all using comparator, but my teacher told me it complex to use comparator, and there is more simple ciucuit that not using comparator, but i found it for many days, and didnt find it.
could anybody help me?
thanks

 

[IanP]

And what is so complex with comparators?
They are the simples circuits to compare voltages and I really doubt you can find any POR IC or circuit without a comparator(s) ..

 

[ambreesh]

Dear Incol,
Yes their are POR circuit (not IC') that use no comparator.
I had uploaded papers on POR and are in IEEE study papers section.
You would find the circuit u are looking for their.
hope it helps

 

[Btrend]

if the voltage level of ur power on reset (POR) signal is not accurate, u can use sized inverter (small PMOS+large NMOS) as a triggered device to the voltage divider form by simply diode-connected MOSs. of course, some hysteresis will be needed after the inverter.
if the voltage level of POR is accurated, u should need a reference & a comparator.
hopes this is helpful to u.

 

[bimbla]

One tip:

For your target devices, let the host processor provide the reset. This way, the host is fully in control.
I usually drive the o/p of the uC by a schmitt trigger to get a good waveshape. I do the same for clk.

bimbla.