Power management circuit and electronic device

A power management circuit coupled between a power supply and a load, the power management circuit comprising:

• a sampling unit for sampling an input voltage from the power supply to generate a sampling voltage;
• a reference voltage unit for receiving the input voltage and generating a reference voltage when the input voltage is larger than a predetermined value;
• a comparator comprising an operational amplifier and a generator, the operational amplifier comprising an inverting input terminal coupled to the reference voltage unit, a non-inverting input terminal coupled to sampling unit, and an output terminal coupled to the power managing unit, the operational amplifier used for comparing the sampling voltage with the reference voltage, generating a first level voltage when the sampling voltage is larger than the reference voltage, and generating a second level voltage when the sampling voltage is smaller than the reference voltage, the generator generating a first signal according to the first level voltage and the input voltage, and generating a second signal according to the second level voltage and the input voltage;
• and
• a power managing unit for establishing an electrical connection between the power supply and the load according to the first signal, and cutting off the electrical connection between the power supply and the load according to the second signal.

An electronic device comprising a power supply, a power management circuit, and a load, the power management circuit coupled between the power supply and the load, the power management circuit comprising:

• a sampling unit for sampling an input voltage from the power supply to generate a sampling voltage;
• a reference voltage unit for receiving the input voltage and generating a reference voltage when the input voltage is larger than a predetermined value;
• a comparator for comparing the sampling voltage with the reference voltage, generating a first signal when the sampling voltage is smaller than the reference voltage, and generating a second signal when the sampling voltage is larger than the reference voltage;
• and
• a power managing unit for establishing an electrical connection between the power supply and the load according to the first signal, and cutting off the electrical connection between the power supply and the load according to the second signal.