Prius Gen 2 Fault Signals

[stofanel]

What would be the minimum number of fault signals required to run the inverter safely? For example, the converter outputs analog versions of temperature (CT), input voltage (VL), output voltage (VH), and digital signals for converter failure (FCV) and boost voltage issues (OVL). That seems redundant to me. The same setup exists for the inverter where one can read the temperature (MIVT), phase currents, bus voltage (VH), and digital signals showing inverter failure (MFIV) as well as an overvoltage failure (OVH).

In the interest of saving a few pins on the microcontroller, would it be advisable to OR-gate all digital flags (MFIV, OVH, OVL, FCV) and have one master fail flag signal, or is there some utility in reading the individual flags? It seems to me that if the converter or the inverter fails, there is very little one can to to fix the problem with software.

[johu]

In the most recent implementation only 3 of those signals are used: VH, MIVT, MFIV. Reason being that I only have a 12-pin connector going to the inverter. I don't expect much difference between the temperatures and handling the fault signals is just useful for diagnosis - shut down is handled by the power stage itself.