What is the circuit's name ?

[shaq]

Is this folded-cascode?

And, why does it use Rz and Cc ?

 

[nickoo]

hi,yes,the name is ok,but the reason of using RZ and CC is compesation pole & zero

 

[evi]

Two-stage Miller opamp with folded cascode first stage. RC is Miller compensation.

 

[shaq]

Thanks to nickoo and evi.

I have another question, that is, what is the value of "Slew Rate"?

i.e. what are the factors of "Slew Rate" ?

 

[electronrancher]

if the amp is toggled from one extreme to the other, the compensation cap will be charged or discharged at a linear rate by the current from M8 or M4. Slew rate follows the capacitor equation
I = C(dV/dt)

where dV/dt is the slew rate.

 

[suria3]

It is a folded cascode op-amplifier. It is basically a 2 stage op-amp so to ensure the stability of the op-amp when use in the feedback system, the pole-zero compensation which is Rz, Cc is done there. Slew rate is the measurement of how fast you output signal can change for a given input signal. Basically SL= I/CL, meaning that you need to increase the biasing current in order to increase the slew rate of the op-amp.

 

[shaq]

It is a folded cascode op-amplifier. It is basically a 2 stage op-amp so to ensure the stability of the op-amp when use in the feedback system, the pole-zero compensation which is Rz, Cc is done there. Slew rate is the measurement of how fast you output signal can change for a given input signal. Basically SL= I/CL, meaning that you need to increase the biasing current in order to increase the slew rate of the op-amp.

Thank you,suria3.

Do you mean "I" is the current of the M0?

 

[suria3]

I is the output current of M9, but increasing current also have the tradeoff with the power consumption. There are other way as well to increase the slew rate which is related to GBW, gain bandwidth product. You can refer to the below link for better understanding of SL. Hope this helps you.

https://users.ece.gatech.edu/~mleach/ece4435/tutorial.pdf

 

[tony_wu_ad]

Oh,Thinks for suria3, I have just download the pdf file

 

[shaq]

If I want to operate this circuit in 0°C to 100°C temperature, which bias circuit is the best choice?

 

[suria3]

If I want to operate this circuit in 0°C to 100°C temperature, which bias circuit is the best choice?

You mean type of reference point to bias this circuit? You may apply the resistive/mos bias divider but have to check first whether at 100 deg this break down the MOS.

 

[flushrat]

Yes, SR is related to GBW
In the above figure, the input slewrate SR_in=GWB*Vdsat(M1)


Btw,shaq, why you deleted the opamp design spec article?
I am interested in it.

 

[shaq]

Yes, SR is related to GBW
In the above figure, the input slewrate SR_in=GWB*Vdsat(M1)


Btw,shaq, why you deleted the opamp design spec article?
I am interested in it.

Sorry, flushrat...

Because nobody replay that question for a long time, so I delete it.

Now I hear you're interesting in it, I'm so surprise!

Here is my spec.

Maybe we can discuss how to design this circuit!

 

[shaq]

How to choose the value of Rz?

 

[daisyinfall]

i think Rz will bring several problem....

regards

 

[KMC]

You can choose Rz=1/gm(M9). In this case you eliminate a zero of trnasfer function.

 

[shaq]

Ohh~~~my god!!!!

I tune up these MOS' parameters all the week!

But I still cannot meet my specification!!!!!

Could anyone want to challenge this design?

Thanks so much!!!!

p.s. Boundary conditions

1.Process : TSMC 0.35µm

2.Supply voltage: 3.3V±10%

3. Temperature range : 0 ~ 100°C

4. Corner : SS,TT,FF

 

[ronaldm]

hello,is their any of you has a pioneer power amp.500w! schematic and pcb
layout. if you have could you pls. send me. to my e-mail 'www.ronaldgazi@yahoo.com.ph



thaks guys!

 

[shaq]

Ohh~~~my ---!!!!

I tune up these MOS' parameters all the week!

But I still cannot meet my specification!!!!!

Could anyone want to challenge this design?

Thanks so much!!!!

p.s. Boundary conditions

1.Process : TSMC 0.35µm

2.Supply voltage: 3.3V±10%

3. Temperature range : 0 ~ 100°C

4. Corner : SS,TT,FF

Nobody can help me?

 

[huangjw]

a folded amplifier, the r and c is to compensation