TIDA-010932

24-VAC power stage reference design with battery backup

TIDA-010932

Design files

Overview

This reference design provides a high efficiency power stage solution for smart thermostats and other gateway building automation end equipment using a 24 VAC power source. This power stage takes a 24-VAC input and produces a 5 V and 3.3 V 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 brownout. The boosterpack formfactor allows the designer to evaluate this power architecture with other launchpads and includes an LED driver and current sensing capabilities.

Features
  • 24-VAC or USB to 3.3-V power rail
  • Dynamic power path and battery power assist
  • Independent battery charging and load path
  • High efficiency over entire load current range
  • Power rail current monitoring
  • USB overcurrent 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.

PDF | HTML
TIDUF26.PDF (5782 KB)

Reference design overview and verified performance test data

TIDMBO5.PDF (538 KB)

Detailed overview of design layout for component placement

TIDMBO4.PDF (179 KB)

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

TIDMBO7.ZIP (1902 KB)

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

TIDCGF7.ZIP (2272 KB)

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

TIDMBO6.PDF (2012 KB)

PCB layer plot file used for generating PCB design layout

TIDMBO3.PDF (551 KB)

Detailed schematic diagram for design layout and components

Products

Includes TI products in the design and potential alternatives.

AC/DC & DC/DC converters (integrated FET)

TLV625682.5V-5.5V input, 1A high efficiency step-down buck converter in SOT23 and SOT563 package

Data sheet: PDF | HTML
AC/DC & DC/DC converters (integrated FET)

LMR36520SIMPLE SWITCHER® 4.2-V to 65-V, 2-A synchronous step-down converter with 26-uA IQ

Data sheet: PDF
Power muxes

TPS21161.6-V to 5.5-V, 40-mΩ, 2.5-A, low-IQ, priority power multiplexer

Data sheet: PDF | HTML
Battery charger ICs

BQ24072Standalone 1-cell 1.5-A linear battery charger, Power Path, 4.2-V VBAT and VOUT=VBAT + 225mV

Data sheet: PDF
ESD protection diodes

TPD1E10B0612-pF, ±5.5V, ±30-kV ESD protection diode in 0402 and SOD-523 package

Data sheet: PDF | HTML
Analog current-sense amplifiers

INA218026V, dual channel, 350kHz current sense amplifier

Data sheet: PDF | HTML
Backlight LED drivers

TPS9236038-V 1.2-A single channel LED backlight driver

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Design guide High-Efficiency 24-VAC to 5-V, 3.3-V Ref Design With Battery Backup and Charging PDF | HTML Jun 30, 2023

Related design resources

Reference designs

REFERENCE DESIGN
TIDA-01358 24-V AC Power Stage With Wide Vin Converter and Battery Backup Reference Design for Smart Thermostat TIDA-01395 24-V AC Power Stage With Wide Vin Converter and Battery Gauge Reference Design for Smart Thermostat

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