Direct-current power supply under-voltage alarm circuit

The utility model discloses a direct current power supply voltage under-voltage alarm circuit, which comprises a comparison unit, a judgment unit, a first control unit and an alarm unit, and is characterized in that the comparison unit is used for comparing the voltage of a direct current power supply with an upper limit set value and a lower limit set value respectively to obtain and output a corresponding first comparison result and a corresponding second comparison result; the judgment unit is used for judging the voltage state of the direct-current power supply according to the first comparison result and the second comparison result and outputting a first control signal according to the judgment result; and the first control unit is used for receiving the first control signal output by the judgment unit so as to control the opening or closing of the alarm unit. The under-voltage alarm circuit is connected to the output end of the direct-current power supply and is used for carrying out under-voltage dete