MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design User’s Guide © 2011 Microchip Technology Inc.
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MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN Table of Contents Preface ........................................................................................................................... 5 Introduction............................................................................................................ 5 Document Layout .................................................................................................. 5 Conventions Used in this Guide ......................
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design NOTES: DS51999A-page 4 © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN 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.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design CONVENTIONS USED IN THIS GUIDE This manual uses the following documentation conventions: DOCUMENTATION CONVENTIONS Description Represents Examples Arial font: Italic characters Initial caps Quotes Underlined, italic text with right angle bracket Bold characters N‘Rnnnn Text in angle brackets < > Courier New font: Plain Courier New Referenced books Emphasized text A window A dialog A menu selection A field name in a window or dialog A m
Preface RECOMMENDED READING This user’s guide describes how to use the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design. Other useful documents are listed below. The following Microchip document is available and recommended as a supplemental reference resource. • MCP1640/B/C/D Data Sheet – “0.65V Start-up Synchronous Boost Regulator with True Output Disconnect or Input/Output Bypass Option” (DS22234) THE MICROCHIP WEB SITE Microchip provides online support via our web site at www.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design NOTES: DS51999A-page 8 © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN Chapter 1. Product Overview 1.1 INTRODUCTION This chapter provides an overview of the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design and covers the following topics: • MCP1640 Short Overview • What is the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design? • What Does the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design Kit Include? 1.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design 1.2.1 MCP1640 Key Features • Up to 96% Typical Efficiency • 800 mA Typical Peak Input Current Limit: - IOUT > 100 mA @ 1.2V VIN, 3.3V VOUT - IOUT > 350 mA @ 2.4V VIN, 3.3V VOUT - IOUT > 350 mA @ 3.3V VIN, 5.0V VOUT • Low Start-up Voltage: 0.65V, typical 3.3V VOUT @ 1 mA • Low Operating Input Voltage: 0.35V, typical 3.3VOUT @ 1 mA • Adjustable Output Voltage Range: 2.0V to 5.5V • Maximum Input Voltage ≤ VOUT < 5.
Product Overview 1.3 WHAT IS THE MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN? The MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design is designed to demonstrate the MCP1640 device’s high-voltage boost capability above its typical output range of 5.5V. This board boosts the low-voltage input to 12V and up to 70 mA load. By changing the sense resistors (RT and RB on Figure 1-2), a lower/higher output than 12V will be obtained.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design NOTES: DS51999A-page 12 © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN Chapter 2. Installation and Operation 2.1 INTRODUCTION The MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design is developed to demonstrate how the MCP1640 device can operate as a high output voltage DC-DC converter when powered from two batteries. This reference design allows boosting from the input range of 2.0V-5V to an output higher than 5.5V of the typical MCP1640 application.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design 80.0 Efficiency (%) 75.0 70.0 65.0 60.0 VIN = 2.4V 55.0 VIN = 3.0V 50.0 50 0 45.0 40.0 10 Maximu um Load Current (mA) FIGURE 2-1: 3.0V Input. 20 30 40 Load Current (mA) 50 Efficiency vs. Load Current for 12V Output at 2.4V and 80 70 60 50 40 30 20 10 0 2 2.4 2.8 3.2 3.6 Input Voltage (V) FIGURE 2-2: DS51999A-page 14 Maximum Load Current vs. Input Voltage at 12V Output. © 2011 Microchip Technology Inc.
Installation and Operation 2.2 GETTING STARTED The MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design is fully assembled and tested to evaluate and demonstrate the MCP1640 family of products. 2.2.1 Powering the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design The extended input range of the MCP1640 Input Boost Converter is 2.0 to 5.0V input. Good efficiency is obtained by supplying from two cells (primary and secondary batteries).
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design The board has several test points that help engineers analyze the switch node’s waveforms or MCP1640’s output: • The high-voltage switch node test point (SWH). • The test point of the MCP1640 device’s switch node (SWL). • VO test point shows the MCP1640 device’s VOUT pin (this output is unregulated). The difference between SWH and SWL signals is their amplitude.
Installation and Operation FIGURE 2-5: MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design Test Points (SWH, SWL), Inductor (IL) and Load Current (IOUT) Waveforms for 60 mA Load and 2.4V Input in Continuous mode. 2.2.3 How Does the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design Works? The board was designed to boost low voltage from two alkaline cells or NiCd/NiMH cells to high voltage.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design Attention should be paid to the values of the sense resistors. When testing the board for other output voltage, a potential issue with higher value resistors is environmental contamination, which can create a leakage current path on the PCB. This will affect the feedback voltage and the output voltage regulation. Engineers should use resistors that are larger than 1 MΩ with precaution.
MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN Appendix A. Schematic and Layouts A.1 INTRODUCTION This appendix contains the following schematics and layouts for the MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design: • • • • Board – Schematic Board – Top Silk and Pads Board – Top Copper and Pads Board – Bottom Copper and Pads © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design BOARD – SCHEMATIC MCP1640 VOUT Notes: * Do not populate in case of instability, use 2k or 3k resistors CIN 10µ L 4μ7 VIN 2 1 2µ2 10µ COUT VOUT A.2 DS51999A-page 20 © 2011 Microchip Technology Inc.
Schematic and Layouts A.3 BOARD – TOP SILK AND PADS © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design A.4 BOARD – TOP COPPER AND PADS DS51999A-page 22 © 2011 Microchip Technology Inc.
Schematic and Layouts A.5 BOARD – BOTTOM COPPER AND PADS © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA Two Cells Input Boost Converter Reference Design NOTES: DS51999A-page 24 © 2011 Microchip Technology Inc.
MCP1640 12V/50 mA TWO CELLS INPUT BOOST CONVERTER REFERENCE DESIGN Appendix B. Bill of Materials TABLE B-1: Qty BILL OF MATERIALS (BOM)(1) Reference Description Manufacturer ® Part Number 1 CIN CAP. CER 10 µF 6.3V X5R 20% 0603 TDK Corporation C1608X5R0J106M 1 COUT CAP. CER 10 µF 16V X5R 0805 TDK Corporation C2012X5R1C106M 1 CL CAP. CER 2.2 µF 6.3V X5R 20% 0603 TDK Corporation C1608X5R0J225M 1 D SCHOTTKY RECT. 40V 0.
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