[volt-nuts] monitoring LTZ1000 chip temperature

[Jan Fredriksson]

The base-drain Q1 and Q2 can of course be used. The problem is that the
base-drain voltages to temperature is only approximately known. You would
need to calibrate those, using external heating. As they can be be expected
to be linear, you only need two or three temperature points for an decent
approximation.

You can also do a thermal energy balance and compare it to the electrical
heat balance if you measure the input current and the voltage / current
over external components, ie the resistors, opamps and external transistor.
Most of the energy should be dissipated from the heater anyway, and the
diode current is known....