Undervoltage protection circuit and overvoltage protection circuit

An undervoltage protection circuit comprising:

• a first comparator having a first input terminal, a second input terminal and a first output terminal, the first input terminal being coupled with a voltage level shifter, and the voltage level shifter being coupled with a delay circuit;
• and
• a second comparator having a third input terminal, a fourth input terminal and a second output terminal, the third input terminal receiving a reference voltage, and the fourth input terminal receiving a first feedback voltage;
• wherein the first output terminal and the second output terminal are coupled with a logic device, the first feedback voltage is converted to a second feedback voltage by the delay circuit and the voltage level shifter, the first input terminal receives the second feedback voltage, and the second input terminal receives the first feedback voltage;
• wherein the first comparator outputs a detection enabling voltage to the logic device when the first feedback voltage is lower than the second feedback voltage, and the logic device outputs an undervoltage protection voltage level when the first feedback voltage is lower than the reference voltage.