Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Level shift your voltage reference output with a bipolar transistor. Then you get
V2=Vref-Vbe, which is a PTAT voltage. Apply this voltage across a resistor. You can have a PTAT current.
BTW: Pay attention to the temperature coefficient of the resistor.