Monolithic Power Systems, Inc. · NASDAQ:MPWR
Monolithic Power Systems — Technical Presentation (June 2020)
12 slides from Monolithic Power Systems's technical presentation, June 2020
Slide 1: Automotive Lighting Design and EMI Best Practices
Automotive Lighting Design and EMI Best Practices Ralf Ohmberger, Applications Engineer, MPS Francesc Estragués, Applications Engineer, MPS June 2020
Slide 2: Agenda
Agenda Introduction What Is So Tricky about Lighting Power Supplies? Improving the Design at the Schematic Level Component Selection Tips to Solve EMC Issues with Good Layout Layer Stack Open Q&A
Slide 3: Introduction to Automotive LED Lighting
Introduction to Automotive LED Lighting LED lighting is gaining popularity in the automotive market because it offers: • High efficiency • Flexibility of design High & Low Beam DRL Matrix • Dimming and dynamic signalling • More control Signaling Dome Lamp Ambient 1 to 5 LED Puddle Light CHMSL Dynami
Slide 4: What Is So Tricky about Lighting Power Supplies?
What Is So Tricky about Lighting Power Supplies? Great design brings interesting challenges. Emissions 200cm <58V VIN to LED- … MPQ24833-B 400cm Loop Interferences
Slide 5: Improving the Design at the Schematic Level
Improving the Design at the Schematic Level 3 4 1 Differential 200cm filter µH … Common Differential nF Mode µF Filter Filter nF 2 400cm Loop nH pF 1. A differential mode input filter attenuates the fundamental frequency and low-frequency harmonics. 2. The output filter provides two-fold benefit in
Slide 6: Component Selection
Component Selection Start of Winding 1 3 2 200cm µH 4 … nF µF nF 3 nH pF 1. Ferrite beads suffer greatly from DC current saturation. Apply a 66% or greater derating when choosing the part (e.g. 2A max on a 6A rated ferrite bead). 2. Capacitors are also affected by DC bias. In a typical car battery s
Slide 7: Tips to Solve EMC Issues with Good Layout
Tips to Solve EMC Issues with Good Layout Important concepts: 𝑐 • The user only needs to be concerned with structures that are larger than λ/10 of the signals λ= 𝑓 being worked with (signal tracks, enclosure openings, antenna structures, etc). • Radiated immunity test injects signals up to 6GHz…
Slide 8: Tips to Solve EMC Issues with Good Layout
Tips to Solve EMC Issues with Good Layout Not Recommended Recommended NTC 300000 𝑓> 0.018 𝑥 10 Potential issues occur with noise signals greater than 1.6GHz L = 18mm Routed in Internal Layer IC Pin (Bottom Layer)
Slide 9: Tips to Solve EMC Issues with Good Layout
Tips to Solve EMC Issues with Good Layout WideNTC Current Loops Due Sufficient Via Spacing to Insufficient Via Spacing Internal Layer Internal Layer GND Plane GND Plane Power IC Power IC Enough spacing Overlapping return between vias allow Return paths may create for copper to flood Currents crossta
Slide 10: Layer Stack
Layer Stack Inductance from any trace to its return plane depends on Prepreg thickness and trace width At any point of a given signal trace, there is a certain amount of inductance to its return in the plane underneath nH·inch Use 50-250µm between signal (Width of trace) Layer and GND plane! Mils So
Slide 11: Layer Stack
Layer Stack Top Layer Internal Layer 1 Prepreg Thickness: 50µm to 250µm Bottom Layer Internal Layer 2 Copper Thickness: • External Layer: 70µm (2oz) • Internal Layer: 35µm (1oz) • By minimizing prepreg thickness the magnetic fields radiated by the converter are reduced. • 70µm Cu thickness helps dis
Slide 12: Questions?
Questions? MES
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