The invention discloses a
voltage protection circuit. The
voltage protection circuit comprises a rectification circuit, a
voltage signal acquisition circuit, a voltage follower, an
optical coupler and a control module, wherein the rectification circuit is connected with an
AC power supply, an input end of the voltage
signal acquisition circuit is connected with the rectification circuit, an input end of the voltage follower is connected with the voltage
signal acquisition circuit, a positive
electrode of a
light emitting diode in the
optical coupler is connected with an output end of the voltage follower, a negative
electrode of the
light emitting diode is connected with an output negative
electrode line of the rectification circuit, a collector of a photosensitive
semiconductor in the
optical coupler is connected with a power supply through a
resistor, an emitter of the photosensitive
semiconductor is connected with the ground, an input end of the control module is connected with the collector of the photosensitive
semiconductor, an output end of the control module is connected with a control end of a controllable switch, the control module is used for controlling the controllable switch to be switched off when a
DC voltage output from the rectification circuit is not within a preset range, and the controllable switch is arranged on an output positive electrode line between the
AC power supply and a load, With the voltage protection circuit disclosed by the invention,
electrical isolation between an input end of the voltage follower and an output end of a photoelectrical coupler is achieved, no influence of an output
signal on the input end is generated, and the voltage protection circuit is high in anti-interference capability.