24-V AC Power Stage With Wide Vin Converter and Battery Backup Reference Design for Smart Thermostat


Design files


The TIDA-01358 reference design provides a low BOM cost, high efficiency power stage solution for smart thermostats and other gateway building automation end equipment. This power stage takes a 24Vac input and produces a 5V and 3.3V output rail which can power additional point-of-load converters if added. The design provides LiPo battery charging and seamless switching to battery power during a 24Vac brownout. The power-path capability provides battery power assistance allowing system load transient to exceed the current limit of the 24Vac to DC system, allowing a lower cost Wide Vin buck to be utilized.

  • Battery backup
  • Independent battery charging and load path
  • Dynamic power path/battery power assist
  • High efficiency over entire load current range
  • USB over-curent compliant
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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.


Reference design overview and verified performance test data


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


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

TIDCD20.ZIP (502 K)

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

TIDRPC8.PDF (1283 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

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Technical documentation

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Type Title Date
* Design guide 24-V AC Power Stage With Wide VIN Converter and Battery Backup Ref Design (Rev. A) Feb. 06, 2017

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