4s battery charger reference design


Design files


This reference design is for 4-cell battery charging applications such as vacuum robot or robotic lawn mower, etc. It employs the buck battery charger BQ25672 with a wide input and output range for 1-4 cell battery charging. External ship FET is introduced to minimize the battery leakage current by totally disconnecting all system load from batteries when on standby. The reference design uses a two-layer board to optimize cost and achieve 35-mm x 35-mm small board dimensions.

  • Support 4s battery with 16.8-V maximum regulation voltage and 2.5-A charging current
  • Robust ESD protection: pass 15-kV ESD test
  • System power on/off without additional external components
  • Small size solution (board dimensions 35 mm x 35 mm)
  • Two-layer board to optimize cost
Output voltage options PMP40937.1
Vin (Min) (V) 17
Vin (Max) (V) 19
Vout (Nom) (V) 16
Iout (Max) (A) 2.5
Output Power (W) 40
Isolated/Non-Isolated Non-Isolated
Input Type DC
Topology Buck- Synchronous

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.

TIDT184.PDF (966 K)

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

TIDM984.PDF (224 K)

Detailed schematic diagram for design layout and components

TIDM985.PDF (116 K)

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

TIDM986.PDF (203 K)

Detailed overview of design layout for component placement

TIDM988.ZIP (850 K)

Files used for 3D models or 2D drawings of IC components

TIDCG34.ZIP (507 K)

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

TIDM987.PDF (1044 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Buck converters (integrated switch)

TPS543024.5-V to 28-V Input, 3-A Output, EMI Friendly Synchronous Step-Down Converter

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

TLV733P300-mA, capacitor-free, low-IQ, low-dropout voltage regulator with enable

Data sheet document-pdfAcrobat PDF open-in-new HTML
Power muxes

TPS21212.7-V to 22-V, 56-mΩ, 4.5-A, power mux with seamless switchover

Data sheet document-pdfAcrobat PDF

Technical documentation

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Type Title Date
Test report 4s Battery Charger Solution For Vacuum Robot Reference Design Dec. 21, 2021

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