Input Logic Level Voltage Selection Based on a Communication Voltage

A circuit comprising:

• a detector having a first input and a second input, and an output, the first input coupled to a bus terminal and the second input coupled to a bus voltage threshold terminal;
• a logic circuit having an input, and first and second outputs, the input coupled to the output of the detector;
• and
• a bus mode selector circuit having first, second and third inputs, the first input coupled to the first output of the logic circuit, the second input coupled to the second output of the logic circuit, and the third input coupled to the bus terminal.

A system comprising:

• a power device comprising:
• a bus controller coupled to a power management (PMBus) and configured to operate in a first bus mode, wherein in the first bus mode the bus controller uses a first input voltage threshold for interpreting bus signals transmitted on the PMBus;
• a detector coupled to the PMBus and configured to:
• determine a bus voltage level on the PMBus based on a respective bus signal of the bus signals;
• and
• instruct the bus controller to either continue operating in the first bus mode or switch to operating in a second bus mode based on the determined bus voltage level, wherein in the second bus mode the bus controller uses a second input voltage threshold for interpreting the bus signals.