Temperature independent Current reference from PTAT and CTAT currents

[thanu]

I'm using Vdd=1.9V for 0.18u technology and obtaining the PTAT and CTAT currents. Now i've to obtain the current reference output using these currents. How is it possible to do so?

 

[erikl]

You can simply add current sources in parallel.

 

[thanu]

It means we are shorting two terminals of current sources, guess that will be a major problem

 

[erikl]

Not at all - if they are really "good" current sources: high output impedance against the input impedance of the summing node, e.g. "diode" (gate-to-source) connected "master" transistor of a current mirror - the "slave" transistor mirrors the added current.

Didn't you study the circuit which you copied? Not only subtracting, also adding currents is shown there!