problem about bandgap

[LAS.xs]

Vref curve of simulation is concave.
Is it right?
If it is wrong, how to adjust?
Topology is the mos current mirror by using gain-boosting.

thanks

 

[tomato]

refer to

u can find that.
maybe i think that's right.

 

[analog_prodigy]

Adjust the resistor values(may be reverse). Then you will get correct convex curve.

According to principle, it should come like convex. i think there is some mistake with your resistor values

 

[LAS.xs]

The curve could turn to be convex by reducing the value of resister.
But when the curve turns to be convex, the value is very small and the current turns to high. The op doesn't work well.

Adjust the resistor values(may be reverse). Then you will get correct convex curve.

According to principle, it should come like convex. i think there is some mistake with your resistor values

 

[john cooper]

i agree
Adjust the resistor values(may be reverse). Then you will get correct convex curve.

According to principle, it should come like convex. i think there is some mistake with your resistor values

 

[LAS.xs]

The temperature coefficient of the resister is positive in the bandgap. But it is negative in the op, which is an ideal resister. Is it the reason that the curve is concave?

 

[scutlan]

I think it is caused by the offset voltage temperature coefficient, which affect the whole temperature coefficient of the bandgap.
Am I right?
I am learning bandgap now, and have this question too.

 

[smilelangjun]

If gou let the parameter ATX of bjt to more than 3, the curve will be curved.

 

[LAS.xs]

what is the parameter ATX of bjt?

If gou let the parameter ATX of bjt to more than 3, the curve will be curved.

 

[babbage]

yes, it's really related to the resistor value; Maybe u can try to use the different-value and different-temp-coefficient resistor;

 

[LAS.xs]

Why is Vt curve of simulation concave?
Does it have something to do with the unmatched current mirror?