Introduction
Modern dishwashers must not only perform basic functions such as washing and drying but also monitor parameters—including water temperature, water level, pressure, door lock status, and operating modes—in real-time, while facilitating data exchange between modules via communication interfaces like LIN and CAN.
However, the integration of additional electronic modules and interfaces exposes dishwasher circuitry to increasingly complex electrical environments:
- AC power inputs are susceptible to surges induced by lightning strikes and fluctuations in the power grid;
- Switching loads such as motors, heaters, and solenoid valves can generate transient overvoltages;
- User interaction with control panels can result in Electrostatic Discharge (ESD);
- Communication interfaces may experience data anomalies due to external interference.
Consequently, precise surge and ESD protection designs tailored to specific circuit locations are essential during the dishwasher development process.
I. Electrical Risks in Dishwasher Systems
| Dishwasher Systems | Electrical Risks |
| AC Input | Lightning surge, power transient |
| MCU Control Board | ESD, voltage spike |
| LIN/CAN Interface | ESD, transient interference |
| Touch Panel | Human ESD |
| Load Control | Switching spike |
Semiware offers system-level protection solutions—covering surge, ESD, and load control protection—for the various circuit modules found in smart dishwashers, including power supply, communication, human-machine interface (HMI), and load control systems.
II. Semiware Complete Circuit Protection Solution for Smart Dishwashers
2.1 Surge Protection Design for AC 220V Input
Dishwashers typically connect directly to the household AC power grid, making the AC input one of the most critical points for system protection.
While external lightning strikes may not hit the appliance directly, induced surges can travel through the power grid and enter the unit. Additionally, the starting and stopping of high-power loads—such as internal motors and heaters—can generate repetitive transient voltages.
Semiware employs a combined GDT (Gas Discharge Tube) and MOV (Metal Oxide Varistor) protection scheme for the dishwasher's AC 220V input.
Solution Advantages:
- The GDT activates first, shunting the majority of the surge current to ground;
- The MOV subsequently absorbs residual energy and clamps the output voltage to a safe level;
- Downstream components—including power modules, MCUs, and control chips—are effectively protected.
Recommended Components：
2.2 ESD Protection Design for LIN Communication Interfaces
Smart dishwashers typically contain multiple control modules, such as:
- Main control board;
- Door lock control module;
- Sensor module;
- Motor control module.
These modules often communicate with one another via a LIN bus. Human body static electricity, transients generated during module hot-swapping, and power supply disturbances can all compromise system safety.
ESD protection devices require fast response times, low leakage current, and low parasitic capacitance.
Recommended Devices:
2.3 CAN Communication Interface Protection Design
High-end smart dishwashers utilize CAN networks to connect multiple control modules. CAN interfaces are susceptible to ESD and line surges; therefore, ESD diodes are recommended for protection.
Recommended Devices:
- SE23T20B24LB ESD Diode
2.4 ESD Protection for HMI Touch Controls and Buttons
Dishwashers typically employ capacitive touchscreens and LED displays; these areas subject to direct human contact are the most likely entry points for ESD.
Electrostatic discharge from the human body can reach several kilovolts; without protection, this may result in:
- MCU resets;
- Touch function malfunctions;
- Display failure.
Low-capacitance ESD protection devices are recommended:
2.5 Load Control Protection
Dishwashers contain numerous AC loads (such as heaters and drain pump motors), which are typically controlled via TRIACs.
Recommended TRIAC Devices：
Reference design:
To learn more about surge and ESD protection solutions for dishwashers, please visit: https://en.semiware.com/applications/dishwasher/
If you are designing smart dishwashers or other smart home appliances, the Semiware technical team can provide professional component selection support and customized circuit protection solutions tailored to your circuit architecture, operating environment, and protection requirements.
Please contact us for further application support.
