| 摘要 |
An aperture controlling system includes a CMOS image sensor, a brightness encoder, an aperture and an aperture driving circuit. The brightness encoder is used for extracting brightness information sensed by the CMOS image sensor and converting the brightness information into digital codes. The aperture driving circuit includes a D/A converter, a motor coil driving circuit, an environment sensing module, a benchmark voltage generator and a motor. The motor is mechanically connected to the aperture. The motor coil driving circuit includes a voltage comparator. The input and the output of the D/A converter are respectively coupled to the brightness encoder and the inverting input of the voltage comparator. The input and the output of the benchmark voltage generator are respectively coupled to the environment sensing module and the non-inverting input of the voltage comparator. The output of voltage comparator is connected to the motor. |
