Universal uP Controlled Battery Charger 24Vin 10 Aout max, 5/12V 2A & 5V 4A, 2 USB Ports Ref Design


Design files


BQ24745 is a host controlled synchronous buck battery charger capable of charging batteries at up to 19.2V and up to 8 A normally, extended to 10 A with use of 8 mOhm battery sense resistor. The power train is capable of 8 A with convection only cooling and 10 A with moderate fan cooling (~200 LFM). The Test Report includes Thermal images for both cases. While the design shows a 28 pin MSP430 as the host, any processor with SMBus capability will work. A 5/12V 2A auxiliary converter using TPS54335, and 5V 4A with TPS40170 with 2x CSD18504 are provided. For the two USB ports, the design provides TPS2561A for power switching and TPS2513A for control. A linear TPS70933 provides the 3.3V for the MSP430 and interface signals. A rich Test Interface allows full testing of hardware in the absence of software and then provides multiple interface choices for software development.

  • Host controlled 10 A charger off 24 Vin
  • MSP430 controller shown, but can work off other processors with SMBus capability
  • Power train can be verified without  processor 
  • 5/12 V 2A and 5V 4A with two USB ports & 3.3V uP power provided
  • All parts on top side for ease of testing / battery discharge switch provided
  • Schematic, BOM, layout and Test Report focusing on Battery charger
Output voltage options PMP9668.1 PMP9668.2 PMP9668.3 PMP9668.4 PMP9668.5 PMP9668.6
Vin (Min) (V) 21.6 21.6 21.6 4.5 4.5 4.5
Vin (Max) (V) 26.4 26.4 26.4 5.5 5.5 5.5
Vout (Nom) (V) 12.6 5 12 3.3 5 5
Iout (Max) (A) 10 4 2 .1 2 2
Output Power (W) 126 20 24 .33 10 10
Isolated/Non-Isolated Non-Isolated Non-Isolated Non-Isolated Non-Isolated Non-Isolated Non-Isolated
Input Type DC DC DC DC DC DC
Topology Buck- Synchronous Buck- Synchronous Buck- Synchronous Linear Regulator USB Switch USB Switch

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.

TIDUA06.PDF (1326 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


Detailed overview of design layout for component placement


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

TIDREZ8.PDF (3092 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Battery charger ICs

BQ24745SMBus up to 4 cell level 2 Buck battery chager to support Multiple battery chemistries

Data sheet document-pdfAcrobat PDF
Buck controllers (external switch)

TPS401704.5 V to 60 V Wide-Input Synchronous PWM Buck Controller

Data sheet document-pdfAcrobat PDF open-in-new HTML
Buck converters (integrated switch)

TPS54335A4.5V to 28V Input, 3A, Synchronous, Step-Down Converter with Eco-mode

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TPS709150-mA, 30-V, ultra-low-IQ, low-dropout voltage regulator with reverse current protection and enable

Data sheet document-pdfAcrobat PDF open-in-new HTML
N-channel MOSFETs

CSD18504Q5A40-V, N channel NexFET™ power MOSFET, single SON 5 mm x 6 mm, 6.6 mOhm

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

TPS2513ADual USB Dedicated Charging Port Controllers

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 PMP9668 Test Results May 27, 2015

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