I. Background: White Goods Systems
Modern white goods—such as washing machines, refrigerators, and air conditioners—are intelligent systems that integrate precision microcontrollers (MCUs), sensors, and communication modules. Consequently, they are highly susceptible to damage from electrostatic discharge (ESD) and power surges.
II. Primary Sources of ESD and Surge Risks
1. Surges
External Sources: Primarily lightning strikes. Even if lightning does not directly strike a building, it can induce high voltages—reaching thousands of volts—on power lines, which then propagate through the power grid and infiltrate household appliances.
Internal Sources: High-power components within the appliances themselves—such as compressors and motors—can generate repetitive, lower-intensity surges within the internal circuitry during their startup and shutdown cycles.
2. Electrostatic Discharge (ESD)
Sources: Primarily concentrated in areas that users can directly touch, such as control panels, buttons, and communication interfaces (e.g., CAN/LIN buses).
III. Key Risk Areas in White Goods
| Module | Risk Type | Typical Issues |
| AC Input | Surge | Lightning-induced surges, power grid transients |
| Power Supply (PFC / DC-DC) | Surge / Transient | Power IC damage, voltage spikes |
| MCU Control Board | ESD | Reset, latch-up, system crash |
| Human Interface (Key / Touch Panel) | ESD | False triggering, no response |
| Communication Interfaces (LIN / CAN / UART) | ESD | Data corruption, communication failure |
| Motor Drive / Compressor | Surge | Back EMF, voltage spikes |
| Triac-Controlled Loads (Heater / Valve / Lamp) | Surge | dv/dt false triggering, load-induced spikes |
IV. Semiware’s System-Level Protection Solutions
To address these challenges, Semiware offers a comprehensive protection solution that covers the entire system—from the AC power inlet to signal ports and load control circuits.
1. Surge Protection for AC Power Inlets
Design Objectives:
- Withstand lightning-induced surges (IEC 61000-4-5)
- Suppress power grid transients
- Protect downstream PFC / DC-DC stages
Recommended Solution: Employ a coordinated protection scheme utilizing Gas Discharge Tubes (GDTs) and Metal Oxide Varistors (MOVs).
Component Selection:
| Part Number | Device Type | Key Specs |
| SG2R05B3600 | Gas Discharge Tube (GDT) | 3600V, 3kA, Φ5.5mm |
| SG2R08B3600 | Gas Discharge Tube (GDT) | 3600V, 3kA, Φ8.0mm |
| SG2R05B600 | Gas Discharge Tube (GDT) | 600V, 5kA, Φ5.5mm |
| 14D561K | Varistor (MOV) | 560V, 4.5kA, 150J, 360pF, 14D |
Solution Description:
- When a lightning surge occurs, the Gas Discharge Tube (GDT) rapidly breaks down and conducts, shunting the vast majority of the surge current (up to 3kA) to ground and clamping the voltage to a low level.
- The residual surge voltage is then absorbed by the Metal Oxide Varistor (MOV). With its faster response time, the MOV further clamps the voltage to a level that downstream circuits (such as PFC and DC/DC converters) can safely withstand. 2. Communication Interface ESD Protection
2. ESD Protection for Communication Interfaces
Sources of Risk:
- LIN — Long-distance cabling; ESD coupling from external modules
- CAN — Differential long-distance cabling; Industrial/motor interference; Common-mode surges
Recommended Solution: Low-capacitance ESD Diode
Component Selection:
| Part Number | Device Type | Key Specs |
| PESD1LIN | ESD Diode | +15/-24V, ±8kV, 13pF, 0.05µA, SOD-323 |
| SE23T20B24LB | TVS Diode Array | 24V, ±20kV, 13pF, 1µA, SOT-23 |
Solution Description:
The PESD1LIN is specifically designed for LIN buses; with a capacitance as low as 13pF, it ensures signal integrity while withstanding ±8kV ESD strikes, thereby protecting the transceiver chip.
3. Key (Button) ESD Protection
Sources of Risk:
- Human Body Static Discharge (±8kV to ±15kV)
- Discharge in Dry Environments
Recommended Solution: Low-Capacitance ESD Diode
Component Selection:
| Part Number | Device Type | Key Specs |
| SE5D10B5.0A | ESD Diode | 5V, ±8kV, 15pF, 1µA, SOD-523 |
Solution Description:
- The SE5D10B5.0A features an operating voltage of just 5V, perfectly matching the I/O voltage levels of the MCU.
- With its ±8kV protection capability and low capacitance of 15pF, it effectively safeguards the MCU against electrostatic damage without compromising the user experience.
4. Load Control
Sources of Risk:
- dv/dt False Triggering
- Inductive Load Kickback
- Superimposed Power Grid Transients
Recommended Solution: 800V Triacs
Component Selection:
| Part Number | Device Type | Key Specs |
| STF8A80CW | Triac | 8A, 800V, 35mA, TO-220F |
| STA16A80BW | Triac | 16A, 800V, 50mA, TO-220A |
Solution Description:
The STF8A80CW and STA16A80BW feature a high breakdown voltage of 800V and robust current-handling capabilities (8A/16A). Their high dv/dt immunity effectively suppresses switching noise, ensuring stable operation in harsh electromagnetic environments and preventing equipment failure caused by false triggering.
V. Circuit Block Diagram
ESD-snd-Surge-Protection-for-White-Goods.jpg" alt="Comprehensive ESD and Surge Protection Solutions for White Goods" title="Comprehensive ESD and Surge Protection Solutions for White Goods" alt="" class="wp-image-17166"/>VI. Advantages of Semiware Protection Solutions
- Compliance with IEC 61000-4-2 / 4-5 standards
- Comprehensive protection (Power Supply + Interfaces + Loads)
- Components specifically matched to real-world application scenarios
- Balances cost-effectiveness with reliability
👉 If you are developing white goods such as washing machines, air conditioners, or smart appliances, we can help you build a complete ESD & surge protection solution from schematic to BOM level.
Contact us for:
- Application-specific device selection
- Reference design support
- Samples and datasheets
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