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AS3658

Data Sheet Confidential - Detail ed Descri ption-Power Management Functions

8.5

Smooth switchover Power Management Overview

Figure 12. Power Source Management Architecture

The power source management architecture handles the smooth transitions between the two chargers (USB Charger

on VBUS, DCDC Step Down charger or Linear Charger on VCHARGER) and the battery. It takes care about the

system power supply VSUPPLY and its power requirements.

There are following operating conditions possible

1. No Charger connected

The internal switch SINT and the (optional) external switch MBATSW are closed and VSUPPLY is directly supplied by

VBAT. Because of the very low impedance of the switches the energy losses are minimized.

2. The active charger can deliver more current than the system requires

The system is directly supplied by the charger and the remaining energy can be used to charge the battery (CC/CV

charger). In case of deeply discharged batteries, the system is always immediately started and the internal current

source between VSUPPLY and VBAT delivers the trickle current to the battery.

3. The current limited (e.g. for USB with 500mA) charger cannot deliver the current, the system requires

In this case, the ideal diode starts conducting and delivers the remaining current to the system

The transitions between the different power states are done autonomously by the AS3658 allowing an uninterrupted

operation of the system.

The blocks are described in more detail in the following sections.

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AS3658 датащи(PDF) 42 Page - ams AG