With the advancement of the times and the development of science and technology, people's lives are gradually becoming intelligent. Smart homes are gradually appearing in people's lives, and they usually have two functions of intelligent control and security. With the development of smart homes and smart communities, IoT technology is becoming more and more widely used. Weak current controllers have a wide range of applications in indoor and outdoor sensor control and indoor home appliances. This paper studies the weak current controller in smart home and finds that the mains (220 VAC) is easy to affect it, so the circuit back-end chip is easily damaged or directly damaged. Based on this, this paper designs a back-end controller suitable for the smart home control system and a low-voltage protection circuit in the communication module. Through experiments and analysis, it is found that it has the function of circuit protection.