Aperture controlling system

An aperture controlling system, comprising:

• a lens module comprising a plurality of lenses and an aperture positioned between two adjacent lenses;
• a CMOS image sensor aligned with the lens module;
• a brightness encoder configured for extracting brightness information sensed by the CMOS image sensor and converting the brightness information into digital codes;
• and
• an aperture driving circuit comprising a D/A converter, a motor coil driving circuit, an environment sensing module, a benchmark voltage generator and a motor mechanically connected to the aperture, the motor coil driving circuit comprising a voltage comparator, an input of the D/A converter being coupled to the brightness encoder, an output of the D/A converter being coupled to an inverting input of the voltage comparator, the D/A converter being configured for converting the digital codes output by the brightness encoder into a first voltage, an input of the benchmark voltage generator being coupled to the environment sensing module, an output of the benchmark voltage generator being coupled to the non-inverting input of the voltage comparator and the motor, an output of the voltage comparator being connected to the motor;
• wherein the environment brightness sensing module is configured for measuring the brightness of the environment and storing a plurality of digital codes, each of the digital codes corresponds to one brightness value of the environment, the benchmark voltage generator is configured for converting the digital codes outputted from the environment brightness sensing module into a second voltage, the voltage comparator is configured for comparing the first voltage and the second voltage to control the motor to rotate the aperture counterclockwise or rotate the aperture clockwise.