User Guide

2115i/2116/2116i (RH-66)

Baseband Description and Troubleshooting

Figure 11: Charging circuitry

Charger Detection

Connecting a charger creates voltage on the VCHAR input of the UEMC. Charging starts

when the UEMC detects the VCHAR input voltage level above 2 V (VCHdet+ threshold).

The VCHARDET signal is generated to indicate the presence of the charger for the

software. The energy management (EM) software controls the charger identification/

acceptance. The charger recognition is initiated when the EM software receives a

”charger connected” interrupt. The algorithm basically consists of the following three

steps:

1. Check that the charger output (voltage and current) is within safety limits.

2. Identify the charger as a 2- or 3-wire charger.

3. Check that the charger is within the charger window (voltage and current).

Over temperature

detection

Watchdog

PWM generator

Switch driver

Control logic

Current

sensing/limit

Comp

UEMC

VCHAR

VCHAR in

VCHAR out

Vmstr

VBATT

VBATT lim

PWM

Battery

VBATT