Low voltage detecting circuit for detecting input power of a modem

A low voltage detecting circuit for detecting a drop of an input power voltage of a modem below a predetermined voltage, the low voltage detecting circuit comprising:

• a first transistor having a first electrode electrically coupled to a reference voltage, a control electrode electrically coupled to the input power voltage, and a third electrode;
• a second transistor having a first electrode, a control electrode electrically coupled to the second electrode of the first transistor, and a second electrode electrically coupled to a logic low voltage;
• and
• a resistor electrically coupled between a logic high voltage and the first electrode of the second transistor;
• wherein when the input power voltage drops below the predetermined voltage, the voltage at the control electrode of the first transistor drops below the reference voltage to turn on the first transistor and consequently the second transistor so that a logic low signal is output from the first electrode of the second transistor.