Main components of a lawn mowing robot

The lawn mower robot is an outdoor, intelligent device that mows lawns independently. With a precise and coordinated core system, it easily frees up hands and achieves efficient lawn maintenance. Its core components and functions are as follows:

Ÿ   Control unit: It issues orders through the main control chip (MCU) and algorithms and serves as the "command center" of the entire device.

Ÿ   Perception system: ultrasonic, laser obstacle avoidance sensors, GPS positioning sensors, boundary sensors and other "eyes and ears";

Ÿ   Power system: lithium battery pack, drive motor + cutting motor, motor drive module;

Ÿ   Auxiliary system: Wi-Fi, Bluetooth communication module, automatic charging dock, fault detection module.

The coordinated operation of each component of the lawn mowing robot enables it to independently complete lawn mowing. And doing a good job in electrostatic surge protection is to build a "safety barrier" for these components, avoiding equipment failure and performance degradation caused by static electricity or surges, and allowing the robot to stably exert its intelligent maintenance advantages for a long time

Shanghai Leiditech Electronic full-chain electrostatic surge protection solution

In response to the system architecture and application scenarios of intelligent lawn mowers, a full-chain electrostatic discharge and surge protection solution has been launched, effectively enhancing the reliability, safety and certification pass rate of lawn mower products.

Electrostatic protection scheme for communication interfaces

The intelligent lawn mower relies on communication interfaces such as USB, UART, and I²C for firmware upgrades, status feedback, and human-machine interaction. At the same time, it needs to frequently plug and unplug the charger to complete automatic recharging. These interfaces are exposed and are highly susceptible to static electricity from the human body.

• • Shanghai Leiditech provide the ultra-low capacitance ESD device ULC0524P, with a capacitance value of ≤0.4pF (IO-IO). It perfectly compatible with high-speed signals such as USB 3.0/Type-C, without affecting the data transmission rate, meeting the standard IEC61000-4-2 (Class 4), and has a protection capability of ±25kV for contact discharge and ±25kV for air discharge.
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  • UART offers a transmission speed of 115,200 bps. Leiditech Electronic uses discrete components for protection, which is convenient for design and placement and ensures signal integrity. ESDA33CP30, SMDA05CCN, ULC0542C complies with IEC61000-4-2, Grade 4.
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·         SPI offers a maximum transmission speed of 10Mbps. Leiditech Electronic uses the integrated device SMC12 for protection, which not only facilitates design and layout but also ensures signal integrity. It meets IEC61000-4-2, level 4, and has a protection capability of ±30kV for contact discharge and ±30kV for air discharge.

Sensor module electrostatic surge protection solution

The intelligent lawn mower is equipped with multiple sensors such as buttons, infrared proximity sensors, ToF distance measurement modules, and Hall position detection, which are used to achieve safe obstacle avoidance, automatic wake-up, and precise navigation. These highly sensitive analog/digital signal lines are extremely sensitive to static electricity.

• • For the control keys, Leiditech uses ordinary low-capacitance ESDA33CP30/ ESDA05CP30 discrete components for anti-static purposes, meeting IEC61000-4-2, Grade 4, and its protection capability can reach ±30kV for contact discharge and ±30kV for air discharge.
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  • For the power lines of optical sensors such as infrared and ToF, Leiditech uses SMBJ33CA for power surge protection, covering a voltage range of 10-30V, effectively clamping the surges at the front end and the overvoltage generated by the relays at the back end.

Surge protection solution for motor drive and power module:

Hub drive and cutter head motor are the power cores of lawn mowers. The MOSFET drive circuit generates high dv/dt transient voltages during start and stop, and the superposition of external surges can easily cause breakdown of power devices.

• • Leiditech recommends parallel high-reliability TVS devices at the MOSFET gate to quickly clamp overvoltage to a safe level. Typical VRWM selection: 15V to 18V, VC range: 24.4V to 29.2V. Such as SMBJ15A (VRWM15V/VC24.4V), SMBJ18A (VRWM18V/VC29.2V)
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l  Leiditech Electronic recommends adding TVS clamping and anti-reverse circuits at the DC-DC input end to isolate the reverse injection interference of motor noise on the control system.

l  For 24V power supply systems, Leiditech provide TVS devices with appropriate protection currents based on the environment where the power supply is located, meeting IEC61000-4-2, Grade 4, with contact discharge at 8KV and air discharge at 15KV.

l  To meet the IEC61000-4-5 surge test requirements, high-power TVS devices must be selected. The specific matching should be based on the surge test level to be passed. For detailed inquiries, please contact the Leiditech EMC team.

From a single TVS diode to the overall electrostatic surge protection architecture, Leiditech Electronic, with its profound technical accumulation and rich industry experience, provides reliable, efficient and compliant electrostatic and surge protection solutions for intelligent lawn mowers. We not only supply high-quality components, but also offer free electrostatic surge detection tests, customized selection suggestions and FAE on-site support, truly becoming a trusted EMC partner for our customers.