CISPR 25 Class 5 Rated Multi-Output Power Supply with Pre-Boost for Automotive Cluster Unit


Design files


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
Output voltage options PMP9477.1 PMP9477.2 PMP9477.3
Vin (Min) (V) 4.5 4.5 4.5
Vin (Max) (V) 38 38 38
Vout (Nom) (V) 2.8 1.8 5
Iout (Max) (A) 2 2 2
Output Power (W) 5.6 3.6 10
Isolated/Non-Isolated Non-Isolated Non-Isolated Non-Isolated
Input Type DC DC DC
Topology Buck- Integrated Switch Buck- Integrated Switch Buck- Non Sync
?? View video with transcript Video

A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDU604.PDF (1405 K)

Test results for the reference design, including efficiency graphs, test prerequisites and more


Detailed schematic diagram for design layout and components


Complete listing of design components, reference designators, and manufacturers/part numbers

TIDC706.ZIP (211 K)

Design file that contains information on physical board layer of design PCB

TIDRBC9.PDF (1399 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Boost controllers (external switch)

LM34812.97V to 48V High-Efficiency Controller for Boost, SEPIC and Flyback

Data sheet: PDF | HTML
Buck converters (integrated switch)

LM260033A Switching Regulator with High Efficiency Sleep Mode

Data sheet: PDF | HTML
Buck converters (integrated switch)

LM26420Dual 2 A, high-efficiency synchronous DC/DC converter

Data sheet: PDF | HTML

Technical documentation

No results found. Please clear your search and try again.
View all 1
Type Title Date
Test report PMP9477 Test Results Oct. 16, 2014

Support & training

TI E2E™ forums with technical support from TI engineers

View all forum topics

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​