Protection circuit and protection method

A protection method, comprising:

• providing a reference voltage;
• generating a first divided voltage and a second divided voltage based on a power voltage;
• respectively comparing the reference voltage with the first divided voltage and the second divided voltage to respectively generate a first comparison result and a second comparison result;
• when a first state or a second state occurs, conducting part of current of the power voltage to a reference voltage terminal;
• wherein
• the first state is:
• the first divided voltage being greater than the reference voltage;
• the second state is:
• the first divided voltage being less than or equal to the reference voltage, and the second divided voltage being greater than the reference voltage;
• and
• when a third state or a fourth state occurs, stopping conducting part of current to the reference voltage terminal, wherein
• the third state is:
• the first divided voltage being less than or equal to the reference voltage, and the second divided voltage being greater than the reference voltage and after a delay time counted by a delay and logic circuit;
• the fourth state is:
• the first divided voltage being less than or equal to the reference voltage, and the second divided voltage being less than or equal to the reference voltage.

A protection circuit, comprising:

• a voltage dividing circuit, configured to generate a divided voltage based on a power voltage;
• a comparator, coupled to the voltage dividing circuit, and configured to compare the divided voltage with a first reference voltage and a second reference voltage to generate a comparison result, wherein the first reference voltage is greater than the second reference voltage;
• a switch, coupled to the comparator;
• and
• a delay and logic circuit, coupled to the comparator, and configured to receive the comparison result;
• wherein when a first state or a second state occurs, the switch is turned on to conduct part of current of the power voltage to a reference voltage terminal, wherein
• the first state is:
• the divided voltage being greater than the first reference voltage;
• the second state is:
• the divided voltage being less than or equal to the first reference voltage, and the divided voltage being greater than the second reference voltage;
• and when a third state or a fourth state occurs, the switch changes from turn-on to turn-off, wherein
• the third state is:
• the divided voltage being less than or equal to the first reference voltage, and the divided voltage being greater than the second reference voltage, and after a delay time counted by the delay and logic circuit;
• the fourth state is:
• the divided voltage being less than or equal to the second reference voltage.