Driven by the wave of automotive intelligence, in-car atmosphere lights have been upgraded from a single lighting function to a core element in shaping an immersive cockpit experience. However, in the face of complex on-board electrical environments (such as voltage fluctuations, multichannel load interference, etc.), its reliability faces technical challenges: transient energy shocks, power lines can be up to line-to-line surge voltage of 400V, and achieve μs level response, kW level surge absorption protection design within a limited PCB area (usually <10cm²). For the small area of the atmosphere lamp circuit board, to protect 400V surge is a challenge.

Shanghai Leimou EMC small brother in response to this problem, put forward a design scheme, for the power interface of the atmosphere lamp using TVS diode +PPTC device + anti-reverse diode compound topology, can achieve the dual function of line-to-line 400V surge clamping and overcurrent protection in a small space, such a scheme has been verified in the project.

The schematic diagram is as follows:

PTC (self-restoring fuse) : used for short circuit protection, according to the circuit current and voltage selection, you can choose 1206 series;

SKY fast recovery diode: anti-reverse action, according to the circuit current selection such as SS26A,SS210A,SS36A, SS310A, etc.

SD3002P4-3: High-power ESD diode for VCC, mainly to prevent 400V surge, for surge protection. Due to space display, DFN2020-3 package (size 2.0mmX2.0mm) is selected;

SMC24Q: ESD diode for CAN interface;

PESD1LIN: ESD diode for LIN interface.

Pre-understand the specific parameters, please contact EMC brother or Lei MAO sales staff.

1. Waveform diagram after clamping.

The 400V/8/20μs standard surge waveform was simulated by Lei-Mao Electronics SUG61005TB surge generator, and the surge voltage clamp was implemented by ESD protection device SD3002P4-3. After testing and verification, the voltage waveform after clamping is shown in the figure：

It can be seen that the original 400V surge voltage is clamped to 37.6V using SD3002P4-3, which can well protect the rear stage atmosphere lamp circuit.

3. SD3002P4-3 Measured data

The above data can be seen: SD3002P4-3 itself can fully resist 500V surge of 8/20μS waveform.

Therefore, even if you need to pass a 500V surge, you can choose this ESD diode.

1. Performance parameters of SD3002P4-3

High power Ppp: 5300W,

Strong anti-static ability: the air contact is ±30KV (the higher the better);

The peak current Ipp is large: the minimum is 160A, and the measured data in the above table reaches 224A current passing capacity (the larger the better);

Clamp voltage VC low: maximum 39V, with flyback function (the lower the better);

Leiditech is committed to becoming a leading brand in the supply of electromagnetic compatibility solutions and components, supplying ESD, TVS, TSS, GDT, MOV, MOSFET, Zener, inductors and other products. Lei MAO has an experienced R & D team, can provide personalized customized services according to customer needs, to provide customers with the best quality solutions.