Why Driver Solutions Outperform DOB Solutions in Certification Compliance

I. Certification Challenges Stemming from Structural Differences
1. Electrical Isolation Requirements (Safety Isolation)

• Driver Solution:
  Utilizes independent isolated power modules (e.g., Flyback, LLC topology). Physical isolation between primary high voltage (AC 230V) and secondary low voltage (DC) is achieved via transformers (compliant with EN 61347 double/reinforced insulation).
  Certification bodies can directly validate isolation transformer parameters like creepage distance (≥5.5mm) and electrical clearance (≥3mm), meeting EN 62471 standards.

• DOB Solution:
  Lacks physical isolation transformers. High-voltage AC (L/N) connects directly to the PCB light board, relying solely on linear/quasi-linear ICs (e.g., SCT2xxx series) for step-down.
  Requires strict insulation between high-voltage components and touchable enclosures (e.g., housing openings must satisfy IP ratings per EN 60598-1). In practice, PCB routing, potting defects, or heatsink misalignment often cause isolation failure, leading to certification rejection.

2. EMC Interference Suppression

• Driver Solution:
  Dedicated power housing provides effective radiated emission (30MHz-1GHz) shielding.
  Built-in π-filter (common-mode choke + X/Y capacitors) significantly suppresses conducted emissions (150kHz–30MHz), easing compliance with EN 55015.

• DOB Solution:
  High-voltage AC directly coupled to the light board generates broadband noise from switching transients (e.g., IC dv/dt), creating radiation sources.
  Limited space for EMC filters necessitates PCB layout optimization (e.g., ground plane isolation), yet emissions often exceed limits by 6–10dB (e.g., 68dBμV at 1.2MHz vs. 55dBμV quasi-peak limit). Requires repeated redesigns and potting for shielding, increasing costs and timelines.

II. Certification Testing Pitfalls
1. Safety Compliance (CE-LVD Case)

• Hi-POT Test (4kV AC): DOB prone to creepage along aluminum substrates, causing leakage current (>5mA).

• Thermal Test (EN 62493): Poor heatsinking (e.g., thermal paste >0.2mm) leads to IC junction temperatures >130°C (limit: 120°C), forcing bulky heatsinks that reduce luminaire efficacy.

• Fault Testing: DOB vulnerable to component shorts (e.g., IC failure outputting 220V directly), failing EN 62477 single-point fault safety.

2. EMC Test Failures
Real DOB bulb test data:

III. Certification Agencies’ Implicit Barriers
1. Technical Documentation Review

• Driver: Pre-certified power module certificates (e.g., IEC 61347 + EN 62384) simplify luminaire evaluation.

• DOB: Requires full PCB documentation (layouts, insulation paths), doubling prep time.

2. Production Consistency Risks

• Driver: High manufacturing consistency (e.g., Meanwell products); no retesting after certification.

• DOB: Process-dependent (e.g., ±10% copper foil variance); changing suppliers triggers recertification.

IV. Engineering Cost Comparison

Note: European agencies (e.g., TÜV) charge DOB double fees for extra UL 94 V0 potting validation and UL 796 substrate checks.

V. Technical Recommendations
If DOB is unavoidable:

1. Use pre-certified ICs (e.g., Infineon ICL8105 with 650V MOS/protections).

2. Adopt triple-insulation Al substrates (thermal conductivity ≥2.0W/mK, withstand >6kV), spacing per IEC 60664-1.

3. Add GND guard rings (>2mm clearance from high-voltage traces).

Preferred Alternatives:

• Non-isolated Buck drivers (e.g., TI LM3463) for cost/EMC balance.

• Modular DOB (e.g., Philips Fortimo SLM) with pre-certification.

Conclusion
Driver solutions dominate certifications due to proven isolation and EMC architectures. DOB demands trade-offs between cost and design complexity, only recommended for low-power (<10W) compact applications (e.g., candle lamps). For mission-critical projects, prioritize mature driver solutions for smoother certification.