Abstract: In this paper, a control circuit design scheme of automatic dimming sun visor is proposed. The EC-SPD dimming glass that can flexibly adjust the light transmittance is used to replace the traditional car sun visor. The 12 V DC circuit in the cab of a heavy commercial vehicle is used to supply power. The microcontroller generates the corresponding pulse width modulation (PWM) signal according to the light intensity data detected by the GY-302 digital light sensor. Under the control of the PWM signal, the bridge circuit converts 12 V DC power in the driver into 0～10 V AC power, which is then transmitted to the dimming glass to realize the shading function of the sun visor according to different light intensity. In addition to the automatic adjustment function, the circuit also supports the manual key adjustment function. This design has the advantages of low cost, small size, flexible control, etc. It is convenient to integrate into the cab of a heavy commercial vehicle. Through simple series parallel improvement and simple modification of other traditional glass in the cab, it can complete the integration with the intelligent cabin, and improve driving safety and riding comfort.

Key words: Automatic dimming; Sun visor; EC-SPD dimming glass; PWM

摘要： 文章提出一种自动调光遮阳板的控制电路设计方案，使用可以灵活调节透光度的 EC-SPD 调光玻璃代替传统汽车遮阳板，使用某重型商用车驾驶室内 12 V 直流电路供电，单 片机根据 GY-302 数字型光敏传感器所检测到的光强数据产生对应的脉冲宽度调制（PWM） 信号，在 PWM 信号的控制下，桥式电路将驾驶内的 12 V 直流电转换成 0～10 V 交流电，然 后输送给调光玻璃，实现遮阳板根据不同光照强度进行不同程度的遮光功能。除自动调节功 能外，该电路同时支持手动按键调节功能。该设计具有成本低廉、体积小巧、控制灵活等优 点，方便集成到某重型商用车驾驶室内部，通过简单的串并联改进和驾驶内其他传统玻璃的 简单改装即可完成与智能座舱的融合，提升驾驶安全与乘坐的舒适性。

关键词: 自动调光；遮阳板；EC-SPD 调光玻璃；PWM