Pulse width modulation signal generator and switching mode power supply including the same

PURPOSE: A PWM signal generator and an SMPS including the same are provided to reduce power consumption and control voltage by using a high voltage regulator mounted on the inside of the switching driving unit. CONSTITUTION: An SMPS comprises a power supply(100), an output unit(200), a switching driving unit(300), and a feedback circuit(400). The output unit includes a transformer connected to the power supply and outputs the power supplied from the power supply to a secondary coil of the transformer. The switching driving unit includes a first capacitor for generating a second power in accordance with a first power and generates a PWM signal in accordance with the second power. The feedback circuit feedbacks the output power from the output unit to the switching driving unit. The switching driving unit includes a high voltage regulator, a PWM generator for generating the PWM signal and supplying the PWM signal to a first switching device, and a UVLO/band gap unit for controlling the operation of the PWM generator.