Patent ID: 7319360

Claim:
A modulator, comprising: a power supply; a feedback device; a differential amplifier, coupled to said power supply for inputting a reference voltage and a feedback voltage outputted from said feedback device, and if said feedback voltage is lower than said reference voltage, said differential amplifier will output a low level signal, and if said feedback voltage is higher than said reference voltage, said differential amplifier will output a high level signal; a first transistor, coupled to said feedback device and said power supply for receiving said low level signal and said high level signal transmitted from said differential amplifier, and if said low level signal is received, then said first transistor will be electrically connected and supply a power to said feedback device; and a second transistor, connected to a voltage detector and a diode, and said voltage detector being coupled to an output voltage (VOUT), and said diode being coupled to said power supply, and said second transistor being set between said differential amplifier and said first transistor, and said voltage detector continues detecting the output voltage (VOUT) between said feedback device and said first transistor; wherein if said output voltage (VOUT) value is lower than a predetermined voltage value, then said voltage detector will issue a signal to drive said second transistor to limit a gate-source voltage (VGS) of said first transistor within a voltage difference of said diode, so as to lower the impetus of said first transistor and reduce a sudden climb with an excessively high output voltage.