In lighting, power supply, and industrial control systems, surge protection is the first line of defense for product reliability. However, in real-world applications, differential mode (DM) and common mode (CM) surge strategies are often confused or misapplied, resulting in insufficient protection and frequent product failures.
Boarden Electronics takes the lead in introducing the BIS (Boarden Isolation Surge Protector), a patented isolated surge protection component that overcomes the technical challenges of balancing isolation and CM surge suppression. It provides more reliable protection for LEDs, drivers, and industrial systems.
DM vs. CM Surges: Not Just a Directional Difference
| Surge Type | Current Path | Source | Protection Focus |
|---|---|---|---|
| Differential Mode (DM) | L ↔ N | Lightning induction, power switching | L-N spike suppression |
| Common Mode (CM) | L/N → PE | Lightning, EMI coupling, ground potential shifts | L/N-to-ground residual voltage control |
DM surges are usually clamped by MOVs or TVS diodes. In contrast, CM surges act along the ground path and are often neglected—yet they are a major cause of system failures in outdoor and industrial lighting.
Industry Challenges: 3 Major CM Protection Weaknesses
- Unstable Protection Voltage: Traditional GDTs often vary ±20% in triggering voltage, leading to poor consistency.
- High Residual Voltage: GDT+MOV solutions commonly leave CM residual voltages >3200V—exceeding the breakdown threshold of standard aluminum PCBs (2000–2500V).
- Slow Response & False Triggering: GDTs can misfire and fail to meet the stability and consistency demands of high-density LED systems.
Boarden’s BIS Solution: Redefining CM Surge Protection
Boarden’s BIS offers five key advantages over conventional GDT solutions:
| Feature | BIS Performance | Compared to GDT |
|---|---|---|
| 🔧 Voltage Consistency | ±10% tolerance | ±20% deviation |
| ⚡ Response Speed | Rapid surge suppression | Slow and prone to false triggers |
| 📉 Residual Voltage | CM residual voltage as low as 1900–2200V | Often exceeds 3200V |
| 🔁 Stability | Maintains performance after repeated surges | GDTs easily degrade |
| ⚙️ Impedance Matching | Matches MOV for stable voltage division | Often mismatched, leading to failure |
BIS in Action: CM Protection for Outdoor & Industrial Lighting
In non-isolated or linear LED drivers, CM surges can travel through aluminum PCBs and stress the insulation layers. Most PCBs used in lighting products have a withstand voltage under 2500V. Without BIS, traditional solutions can easily cause breakdowns.
📌 Recommended Boarden Configuration
- Models: DS602-S (SMB package), BR602-LM (DO-27 package)
- Works with MOVs to form a low residual voltage CM protection loop
- Verified to keep full-lamp residual voltage under 2200V and pass EN60598 standards
Differential Mode BIS (DM-BIS): Upgrade for RCD Snubber Circuits
BIS can also be used for DM surge protection as an alternative to traditional RCD snubber designs. By connecting resistors across BIS and the CMS-series MOVs, a stable voltage divider is created to clamp L-N overvoltages and minimize triggering errors.
⚠️ Note: DM-BIS is currently designed for post-bridge circuits with up to 200A surge current. It does not require mandatory safety certification, making it ideal for flexible applications in LED drivers and small power supplies.
Design Tips and Debugging Suggestions
| Item | Suggestion |
|---|---|
| PCB Layout | MOV voltage sampling should be placed before FR1/FR2 to avoid high residuals |
| System Verification | Run ≥10 sets of actual surge + withstand tests for batch reliability |
| MOV Matching | Ensure correct voltage grade to avoid BIS premature or delayed triggering |
| Applicable Power Type | Supports non-isolated and linear PSU designs (better stability in linear) |
From Component Selection to System Validation, Boarden BIS Sets a New Standard
As traditional GDTs face increasing limitations in voltage accuracy, response consistency, and residual voltage control, Boarden’s BIS series offers a replicable, scalable solution for both common and differential mode surge protection—ideal for LED lighting, power systems, and industrial electronics.
📩 For product datasheets, free samples, or technical consultation, feel free to reach out via WeChat (4027704).
