A power bank battery is charged when the wall power is available, after which it is used to charge external accessories when required. The most common topology of a battery charger is the step-down buck converter during the charging stage. When a battery is discharging to power up the external accessories, power flow is reversed and the converter operates as a boost converter.
Depending on the power flows, operating the converter in either buck or boost mode reduces the total solution size and cost. The overload protection scheme is crucial to ensure that the battery charger and battery operate safely. This application note from Texas Instruments discusses the overload protection schemes of a battery charger operating in OTG boost mode. In addition to the cycle-by-cycle current limit, the average output current protections are implemented in battery chargers.
To read the full paper, click here.
