Designing a Li-Ion and USB Power Circuit with Built-in Charging

This video series will take you step by step through how to design a circuit that can be powered from a USB input (5V) or from a Lithium Ion battery cell and output a regulated 5V. The design includes a battery charging circuit and a circuit that automatically isolates the battery from the power bus when USB power is applied.

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In part one we review the overall plan for the design, go over Li-ion battery cell basics, and give a crash course on boost switching voltage regulators.

Battery university link: https://batteryuniversity.com/

In part two we go into detail on our boost switching regulator design using Texas Instruments TPS61202 5-V fixed output voltage boost converter.

Link to TI’s TPS61202 product page: https://www.ti.com/product/TPS61202?qgpn=tps61202

In part three we look at the battery charging circuit and the power source isolation circuit

Link to MAX1898 battery charging IC datasheet: https://www.mouser.com/datasheet/2/256/MAX1898-1515496.pdf

In part 4 we look at the PCB layout for our circuits and we see a demo of our circuits in action

Circuit Block Diagram