MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide © 2009 Microchip Technology Inc.
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MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL USER’S GUIDE Table of Contents Preface ........................................................................................................................... 1 Introduction............................................................................................................ 1 Document Layout .................................................................................................. 1 Conventions Used in this Guide .............
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide NOTES: DS51812B-page 4 © 2009 Microchip Technology Inc.
MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL USER’S GUIDE Preface NOTICE TO CUSTOMERS All documentation becomes dated, and this manual is no exception. Microchip tools and documentation are constantly evolving to meet customer needs, so some actual dialogs and/or tool descriptions may differ from those in this document. Please refer to our web site (www.microchip.com) to obtain the latest documentation available. Documents are identified with a “DS” number.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide CONVENTIONS USED IN THIS GUIDE This manual uses the following documentation conventions: DOCUMENTATION CONVENTIONS Description Arial font: Italic characters Represents Referenced books Emphasized text A window A dialog A menu selection A field name in a window or dialog A menu path MPLAB® IDE User’s Guide ...is the only compiler...
Preface RECOMMENDED READING This user's guide describes how to use MCP73871 Demo Board with Voltage Proportional Current Control. Other useful documents are listed below. The following Microchip documents are available and recommended as supplemental reference resources. • MCP73871 Data Sheet - “Stand-Alone System Load Sharing and Li-Ion / Li-Polymer Battery Charge Management Controller”, DS22090 This data sheet provides detailed information regarding the MCP73871 product family.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide DOCUMENT REVISION HISTORY Revision B (November 2009) Initial Release of this Document. • Updated Section 2.2 “Features” with information on the Voltage Proportional Current Control Input Voltage. • Added footnote to Table 2-1. • Updated Section 2.3.3 “Voltage Proportional Charge Control (VPCC) Function”. • Added Section 2.3.3.1 “Example”. Revision A (April 2009) • Initial Release of this Document.
MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL USER’S GUIDE Chapter 1. Product Overview 1.1 INTRODUCTION The MCP73871 Demo Board with Voltage Proportional Current Control is designed to demonstrate Microchip's stand-alone linear Li-Ion battery charger with system power path and load sharing management control solution. The MCP73871 integrates the required elements to meet design challenges when developing new Li-Ion / Li-Polymer batteries powered products.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide 1.2 WHAT IS THE MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL? The MCP73871 Demo Board with Voltage Proportional Current Control demonstrates the features of Microchip’s MCP73871 “Stand-Alone System Load Sharing and Li-Ion / Li-Poly Battery Charge Management Controller”.The MCP73871 Demo Board with Voltage Proportional Current Control is designed to deliver minimum 1.
MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL USER’S GUIDE Chapter 2. Installation and Operation 2.1 INTRODUCTION The MCP73871 Demo Board with Voltage Proportional Current Control demonstrates Microchip's standalone linear Li-Ion battery charger with system power path and load sharing management control solution. The system load is also powered by the Li-Ion battery when the input power is disconnected.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide 2.3 GETTING STARTED The MCP73871 Demo Board with Voltage Proportional Current Control is fully assembled and tested for charging a single-cell Li-Ion or Li-Polymer battery with or without system load. 2.3.1 Power Input and Output Connection 2.3.1.1 POWERING THE MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL 1. Connect the positive battery terminal to VBAT+ (TP4) and negative battery terminal to GND (TP1 or TP5).
Installation and Operation Charge Current (mA) 1000 900 800 700 600 500 400 300 200 100 0 1 1 3 5 7 9 11 13 15 17 19 Programming Resistor (kΩ) FIGURE 2-1: (RPROG1). MCP73871 Charge Current (IOUT) vs. Programming Resistor Amp Meter 0V – 5V Power Source Volt Meter R 5Ω 10W © 2009 Microchip Technology Inc. Microchip Battery Charge Management Controller 100 μF GND FIGURE 2-2: VBAT+ VBAT- Simulated Battery Load.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide 5V DC Power Supply min 2A Resistive Load or E-Load Battery or Battery Emulation Circuit FIGURE 2-3: MCP73871 Top Board and Application Circuit.
Installation and Operation 2.3.3 Voltage Proportional Charge Control (VPCC) Function If the input voltage drops to a preset value, determined by the threshold established at the VPCC input (1.23V at pin #2), due to a limited amount of input current or input source impedance, the battery charging current is reduced. The VPCC control tries to reach a steady state condition where the system load has priority and the battery is charged with the remaining current.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide 2.3.4 Temperature Monitoring Option The MCP73871 device monitors continuously the battery temperature during a charge cycle by measuring the voltage between the THERM and VSS pins. An internal current source provides the bias for most common 10 kΩ negative-temperature coefficient thermistors (NTC). The MCP73871 device compares the voltage at the THERM pin to factory set thresholds of 1.24V and 0.25V, typically.
MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL USER’S GUIDE Appendix A. Schematic and Layouts A.1 INTRODUCTION This appendix contains the following schematics and layouts for the MCP73871 Demo Board with Voltage Proportional Current Control: • • • • Board – Schematic Board – Top Silk and Pads Board – Top Metal Layer Board – Bottom Layer © 2009 Microchip Technology Inc.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide BOARD – SCHEMATIC M A.2 DS51812B-page 18 © 2009 Microchip Technology Inc.
Schematic and Layouts A.3 BOARD – TOP SILK AND PADS © 2009 Microchip Technology Inc.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide A.4 BOARD – TOP METAL LAYER DS51812B-page 20 © 2009 Microchip Technology Inc.
Schematic and Layouts A.5 BOARD – BOTTOM LAYER © 2009 Microchip Technology Inc.
MCP73871 Demo Board with Voltage Proportional Current Control User’s Guide NOTES: DS51812B-page 22 © 2009 Microchip Technology Inc.
MCP73871 DEMO BOARD WITH VOLTAGE PROPORTIONAL CURRENT CONTROL USER’S GUIDE Appendix B. Bill of Materials (BOM) TABLE B-1: Qty BILL OF MATERIALS (BOM) Reference Description Manufacturer Part Number 3 C1, C2, C3 CAP CERAMIC 4.
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