Power supply circuit and related methods for generating a power supply voltage in a semicondutor package

A method of generating a power supply voltage, the method comprising:

• determining whether at least one of a first input voltage and/or a second input voltage are received, wherein a voltage level of the second input voltage is different from a voltage level of the first input voltage;
• when the first input voltage is received, outputting a first voltage as the power supply voltage to an output terminal by enabling a first path and a first voltage regulator and by generating the first voltage based on the first input voltage, wherein the first path is configured to directly provide the first input voltage to the first voltage regulator, and wherein a voltage level of the first voltage is substantially same as the voltage level of the second input voltage;
• and
• when the second input voltage is received, outputting the second input voltage as the power supply voltage to the output terminal by disabling the first voltage regulator and by enabling a second path, wherein the second path is configured to directly provide the second input voltage to the output terminal, and wherein the second input voltage bypasses the first voltage regulator.

A power supply circuit comprising:

• a first input terminal configured to receive a first input voltage;
• a second input terminal configured to receive a second input voltage, wherein a voltage level of the second input voltage is different from a voltage level of the first input voltage;
• a reference voltage generator configured to generate a first reference voltage that is used to check whether the first input voltage and the second input voltage are received;
• a first comparator configured to compare the first input voltage with the first reference voltage to generate a first control signal representing whether the first input voltage is received;
• a second comparator configured to compare the second input voltage with the first reference voltage to generate a second control signal representing whether the second input voltage is received;
• a first voltage regulator configured to be selectively enabled based on the first control signal and the second control signal, and configured to generate a first voltage based on the first input voltage, wherein a voltage level of the first voltage is substantially same as the voltage level of the second input voltage;
• an output terminal configured to output one of the second input voltage or the first voltage from the first voltage regulator as a power supply voltage;
• a first path configured to directly connect the first input terminal receiving the first input voltage with the first voltage regulator, and configured to directly provide the first input voltage to the first voltage regulator;
• and
• a second path configured to directly connect the second input terminal receiving the second input voltage with the output terminal, and configured to directly provide the second input voltage to the output terminal, the second input voltage bypassing the first voltage regulator.