12Vdc Input, 2.1A USB Charger for Smart Phones and Tablets Reference Design


Design files


This reference design takes a 12Vdc input (20V max) and generates a 5V/2.1A output for charging smart phone and tablets. The TPS54240 provides a cost effective yet efficient solution for the DC/DC conversion. The TPS2561A provides a precision current limit to protect the device being charged during over load conditions. The CSD25302 provides a gated latch that protects against output over-voltage conditions.

  • Complete USB charging solution
  • The TPS54240 provides a low cost yet high efficiency (~90%) DC/DC conversion.
  • The TPS2561A provides a precision current limit to protect the device from over load conditions.
  • The design implements a latching type output over-voltage protection.
Output voltage options PMP7371.1
Vin (Min) (V) 8
Vin (Max) (V) 20
Vout (Nom) (V) 5
Iout (Max) (A) 2.1
Output Power (W) 10.5
Isolated/Non-Isolated Non-Isolated
Input Type DC
Topology Buck- Non Sync

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.

SLUU914.PDF (3470 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

TIDC320.ZIP (249 K)

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

SLUU915.PDF (69 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Buck converters (integrated switch)

TPS542403.5V to 42V Input, 2.5A Step-Down Converter with Eco-Mode

Data sheet document-pdfAcrobat PDF open-in-new HTML
USB power switches & charging port controllers

TPS2561A2-ch, 0.25-2.8A adj. ILIMIT (tuned for 2.3±0.2A), 2.5-6.5V, 44mΩ USB power switch, active-high

Data sheet document-pdfAcrobat PDF

Technical documentation

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Type Title Date
Test report PMP7371 Test Results Mar. 28, 2012

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