This design note introduces the USB power manager with PowerPath Control, which offers the fastest charge time with the lowest heat.
This document is Design Note 415 from Linear Technology Corporation, focusing on the LTC4088 integrated circuit. It explains how this device improves upon traditional battery charging methods by combining a buck mode synchronous switching regulator with a linear battery charger in a PowerPath topology.
The text details that while increasing charge current reduces time, it creates heat and limits power available to the system load in linear designs. The LTC4088 addresses these issues by regulating an intermediate voltage bus, allowing full 2.5W from a USB port to be used for both the system load and charging simultaneously. This results in reduced charge times and lower thermal constraints compared to standard linear chargers.
The LTC4088 reduces charge time and heat generation by using a switching regulator topology instead of a linear one.
It allows the full 2.5W to be made available to the system load while charging, provided the input current limit is not exceeded.