Power-on detection circuit

A power-on detection circuit receiving a first supply voltage in a first power domain and a second supply voltage in a second power domain, the power-on detection circuit comprising:

• a pull-up circuit connected between the second supply voltage and a first node;
• a pull-down circuit receiving the first supply voltage, wherein the pull-down circuit is connected between the first node and a ground voltage;
• a Schmitt trigger connected to the first node, configured to provide hysteresis between a high threshold voltage and a low threshold voltage, wherein the Schmitt trigger generates a Schmitt output signal according to a voltage at the first node;
• a level shifting circuit, wherein an enable terminal of the level shifting circuit receives the Schmitt output signal, a first input terminal of the level shifting circuit receives a first input signal, and an output terminal of the level shifting circuit generates a first level-shifted signal at the second supply voltage when the first input signal is at the first supply voltage;
• and
• a combinational logic circuit receiving the first level-shifted signal and the Schmitt output signal, and configured to generate a first power detecting signal in a predetermined logic level state when the Schmitt output signal and the first level-shifted signal are at the second supply voltage;
• wherein the first input signal is a signal belonging to the first power domain,
• wherein the voltage at the first node, the first level-shifted signal, the Schmitt output signal, the first power detecting signal are signals belonging to the second power domain.