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sonvu
Visitor
October 25, 2026
Question

Technical Guidance on Scaling ST AN2747 HID Ballast from 250W to 400W

Hi,

We are developing a 380W/400W electronic ballast for a Mercury UV lamp (Dymax 36970), based on the circuit topology presented in ST AN2747 – 250W HID Metal Halide Electronic Ballast.

Lamp specifications:

  • P/N: 36970 (Brand: DYMAX)

  • Rated power: 380W

  • Lamp voltage: 135V ±15V

  • Lamp current: 3.2A

  • AC input: 230V

We would appreciate technical guidance on the following questions:

  1. Topology: Is the AN2747 circuit suitable for scaling from 250W to 380–400W for a Mercury UV lamp?

  2. Power stage: Which components and design calculations need to be revised, particularly the PFC, MOSFETs/IGBTs, buck inductor, output capacitor, and gate drivers?

  3. Control: What changes are required for ignition, warm-up current limiting, and constant-power regulation?

Regards.

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