User Guide

After Sales
Technical Documentation
Handsfree Desktop Charger CHH–7
Original, 11/94 Page 3
HANDSFREE DESKTOP CHARGER CHH–7
CONTENTS
Page No
Introduction 5
Technical Summary 5
Operation 5
List of Modules 5
Basic Specifications 6
Technical Specifications 6
Modes of Operation 6
DC Characteristics 7
AC Characteristics 8
External Signals and Connections 9
Internal Signals and Connections 11
Mechanical Characteristics 12
User Interface Features 12
Charge States and Charge Control 13
Charge Indication to User 13
Environmental Conditions 15
Temperature Conditions 15
Functional Description 16
Circuit Description (DC3H) 18
Control Logic 18
Watchdog Function 21
Switch Mode Power Supply (SMPS) 21
Battery Charging 21
Spare Battery Discharging 22
Microphone Amplifier and Corresponding Switches 22
Speaker Amplifier and Corresponding Switches 22
Circuit Description (DC4H) 22