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The PMP9477 design is a conducted EMI optimized multi-output power supply for automotive cluster units. The power supply has a pre-boost stage for cold crank and start-stop operation and two buck regulators. The pre-boost stage features the LM3481 boost controller and will start to operate and regulate a 9.5V output when the input voltage drops below 9.5V. It makes the design a wide input voltage range of 4.5V to 38V suitable for 12V automotive battery systems. The design has two buck regulators following the pre-boost to generate 3 output voltages: the first stage buck generates a 5V, 2A output using the LM26003, and the second stage generates two outputs of 2.8V, 2A and 1.8V, 2A using the LM26420 (the max output power is 15W). The LM26003 is a wide Vin non-synchronous buck regulator, and the LM26420 is a 5V input dual 2A, high frequency synchronous buck regulator. All three ICs are available in automotive grade versions, qualified in AEC-Q100 Grade 1. The board layout is optimized for improved conducted EMI performance. The power inductor in the pre-boost stage is utilized as an input EMI filter, and thus no additional filter components are required. The board is tested under the automotive EMC standard, CISPR 25, and its conducted emissions are in compliance with the CISPR 25 Class 5 requirements.
- Conducted EMI optimized PCB layout, no extra filter components needed
- In compliance with the CISPR 25 Class 5 conducted emissions standard
- 4.5V to 38V wide Vin range with pre-boost stage
- LM3481, LM26003 and LM26420 are all available in AEC-Q100 qualified versions
- Power enable/shutdown configurable via the jumper
- Circuit board is tested, and the design files and test report are included