current source for LDO's opamp

[jutek]

ldo opamp

hello

i need a current source for LDO's opamp. Vin changes from 1.3 to 3.3 so i need something voltage independent. simple use of resistor to create a reference current is very inacurrate.

what can i use with so high voltage change?

 

[smartdream]

You can available from bandgap.I think

 

[nagag]

I think you can use constant gm bias circuit.You can refer razavi or John& martin for this.