TIDA-00781 Reference Design

Texas Instruments

12W SEPIC Power Supply Reference Design for Industrial Applications


The TIDA-00781 is a 12W SEPIC power supply reference design for industrial applications. It takes 12V nominal input voltage: and generates a 12V @ 1A output with 92% peak efficiency. The SEPIC converter topology allows voltage step-up and step-down conversion. The design covers a wide input range of 2.5V to 20V with a minimum start-up input voltage of 3.5V. When using a noisy 12V supply: the design can operate uninterrupted while maintaining a regulated 12V output. The reference design features the LM3481 as the SEPIC controller and uses a single coupled inductor to achieve compact solution size. The component area of the SEPIC is about 39 x 26 mm (1.5 x 1 inch). The reference board is layout-optimized for improved EMI performance.The design can also use the output voltage to operate: which means after the output voltage reaches 12V under normal operating conditions: the input voltage can be reduced to as low as 2.5V with the system still maintaining output voltage regulation within 5%. Note that at input voltage of 2.5V: the high input current causes the inductor to heat up to over 130 °C so this is not a recommended operating condition.

  • Input: 2.5V to 20V (3.5V minimum start-up): IC capable up to 48V inputOutputs: 12V @ 1A12W total output powerPeak efficiency 92%Switching frequency 500kHzOutput voltage ripple less than 50mVCompact 4 layer board: 1oz outer: 0.5oz inner copper layersBoard Size: 76.2x54.8mm; solution size: 710.3 mm2
  • Process analytics
Product Categories
  • Power management

End Equipment Reference Diagrams


Part Number Name Companion Part
LM3481 LM3481 Buy Datasheet

Bill Of Materials

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Design File

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Test Data

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Other Documents

Title Updated Type Size (KB)
TIDA-00781 Gerber 19 Oct 2015 ZIP 318
TIDA-00781 BOM 19 Oct 2015 PDF 103
TIDA-00781 Schematic 19 Oct 2015 PDF 261