Multi-junction semiconductor circuit and method

A method comprising:

• passing respective currents through first and second current paths, each current path having respective first and second common voltage nodes that provide an output that is proportional to absolute temperature,
• exhibiting, via a first p-n junction in the first current path, a first current density;
• exhibiting, via a second p-n junction in the second current path, a second current density that is proportionally different than the first current density;
• and
• wherein passing the current through the second current path includes
• passing current through a resistor connected between the second p-n junction and the common voltage node in the second current path, and
• diverting a portion of current that flows through the resistor away from the second p-n junction, at a node connected between the resistor and the second p-n junction.

An apparatus for use with a multi-junction semiconductor circuit including first and second current paths each having a current source and a p-n junction via which current generated by the current source passes, the p-n junctions exhibiting current densities that are different, comprising:

• an impedance circuit in the second current path and having a first terminal connected to the current source in the second current path and a second terminal connected to the p-n junction in the second current path;
• a feedback circuit configured and arranged to set a voltage at the p-n junction in the first current path and a voltage at the first terminal to a value that is about equal;
• and
• a current-tap path connected to the second terminal and being configured and arranged to divert a portion of current that flows from the current source in the second path away from the p-n junction in the second current path, the current-tap path being configured and arranged with the impedance circuit and the feedback circuit to provide current flowing through the impedance circuit that is proportional to absolute temperature, based on a difference between forward-biased junction voltages of the p-n junctions.