As video doorbells become more popular, the challenge of powering these devices using traditional home wiring and mechanical doorbells grows. Littelfuse, an industrial technology manufacturing company dedicated to powering a sustainable, connected, and safer world, recently introduced the CPC2501M, a powerful, self-driven, normally closed solid-state relay optimized for chime bypass in video doorbell systems.
About CPC2501M
The CPC2501M is designed to replace discrete relay circuits and is the first application-specific integrated circuit (ASIC) in the Littelfuse portfolio for this function. The self-driven, normally closed solid-state relay architecture allows independent operation without external microcontroller or software control, greatly simplifying circuit design.
Source from Littelfuse
The product integrates self-protection logic, a fault timer, and solid-state switching functions. It uses a compact 6x6 mm QFN package. The thermally optimized design not only simplifies the integration process of video doorbells but also significantly improves the system's reliability and safety.
"The CPC2501M chime bypass relay allows video doorbell manufacturers to make their products compatible with existing residential wiring systems," said Hugo Guzman, product marketing manager for Littelfuse's integrated circuit division. "End users can use existing doorbell boxes to replace doorbell buttons with new video doorbell units without professional installation or additional wiring."
CPC2501M Feature
Integrated self-driving logic that operates without an external microcontroller or software control
Built-in fault protection timer (approximately 17 seconds) automatically resets in case of prolonged button press or chime fault, improving system reliability
High-performance switch withstands 60 Vp bidirectional voltage and 1.84A RMS continuous load current
Peak current capability of 5A to handle startup and surge conditions
Thermally optimized 6x6 mm QFN-16 package saves PCB space for compact module design
It can be mounted behind a standard 8-24V AC doorbell transformer
Applications of CPC2501M
Visual doorbells require a continuous power supply and instantaneous high power, but traditional mechanical doorbell transformers cannot meet both requirements. CPC2501M solves this problem by creating a current bypass path when the bell is not in operation and immediately shutting down the path when the bell is in operation, ensuring a continuous power supply to the camera unit while retaining the bell function without complex modifications.
CPC2501M is not only optimized for bell bypass in visual doorbell systems. Its applications also include:
Building automation control: voltage-controlled switches for lighting and temperature control systems
IoT devices: power management of voltage-controlled drivers (such as sensor nodes)
Security systems: security equipment that requires compact, high-reliability switches
By integrating multiple protection and logic functions, this product significantly improves device durability and operating performance in consumer and industrial application environments while simplifying the design and installation process.
Conclusion
Littelfuse CPC2501M solves the compatibility problem of smart doorbells in traditional wiring systems through hardware-level integration and intelligent bypass logic, while expanding into the field of industrial automation with high reliability. Its "plug and play" feature reduces the user's installation threshold, reflects Littelfuse's technical integration capabilities in solid-state relay innovation, and provides a cost-effective power management solution for smart homes and IoT devices.