Patent ID: 9627993
Date: 2017-04-18
CPC Classifications: H02M

Claim:
1. An AC-DC conversion circuit, comprising: an inputting module used to input an AC voltage; a rectifying module used to transform the AC voltage to a DC voltage; a transforming module used to perform a transforming process; an outputting module used to output the DC voltage after the transforming process; a voltage detecting module used to detect the DC voltage outputted from the rectifying module; and a controlling module used to control whether the AC-DC conversion circuit works or not according to a detecting result of the voltage detecting module; wherein the rectifying module comprises: a rectifying bridge used to transform the AC voltage received by the inputting module to the DC voltage; and a first filtering capacitor used to filter the DC voltage; a terminal of the first filtering capacitor being connected with an output of the rectifying bridge, another terminal of the first filtering capacitor being connected with a ground; the outputting module comprises a second diode and a second filtering capacitor; a positive electrode of the second diode being connected with an output of the transforming module, a negative electrode of the second diode being connected with an output of the AC-DC conversion circuit, a terminal of the second filtering capacitor being connected with the negative electrode of the second diode, another terminal of the second filtering capacitor being connected with the ground; wherein the voltage detecting module comprisies a first comparator and a second comparator; a first input terminal of the first comparator being connected with the output of the rectifying bridge, a second input terminal of the first comparator receives a first reference voltage, and an output terminal of the first comparator outputs a first comparison signal; a second input terminal of the second comparator being connected with the output of the rectifying bridge, a first input terminal of the second comparator receives a second reference voltage, and an output terminal of the second comparator outputs a second comparison signal; wherein the controlling module comprises a first controlling device; the first controlling device comprises a first transistor and a second transistor, a controlling terminal of the first transistor receives the first comparison signal, an output terminal of the first transistor being connected with the ground, an input terminal of the first transistor being individually connected with a controlling terminal of the second transistor and a power, an input terminal of the second transistor being connected with the first filtering capacitor, and an output terminal of the second transistor being connected with the ground.