Microchip Technology MCP1630 NiMH Guide

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©2011 Microchip Technology Inc. DS51955A
MCP1630
SEPIC Automotive LED Driver
Reference Design

DS51955A-page 2 ©2011 Microchip Technology Inc.
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MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
©2011 Microchip Technology Inc. DS51955A-page 3
Table of Contents
Preface ........................................................................................................................... 5
Introduction...............................................................................................................5
Document Layout .....................................................................................................5
Conventions Used in this Guide ...............................................................................6
Recommended Reading...........................................................................................7
The Microchip Web Site ...........................................................................................7
Customer Support ....................................................................................................7
Document Revision History.................................................................................... 8
Chapter 1. Product Overview
1.1 Introduction ........................................................................................................9
1.2 Features ..........................................................................................................10
1.3 Device Summary .............................................................................................10
1.4 Technical Specifications ..................................................................................11
1.5 Functional Description .....................................................................................12
1.6 What the MCP1630 SEPIC Automotive LED Driver Reference Design
Kit Includes ......................................................................................................... 12
Chapter 2. Installation and Operation
2.1 Getting Started ................................................................................................13
2.2 Setup Procedure .............................................................................................13
2.3 Evaluating the Application ...............................................................................15
2.4 Firmware Description .......................................................................................15
2.5 Programming the PIC12F683 Microcontroller ............................................... 16
Appendix A. Schematic and Layouts
A.1 Introduction .....................................................................................................17
A.2 Board – Schematic ..........................................................................................18
A.3 Board – Top Copper and Pads .......................................................................19
A.4 Board – Top Copper Pads and Silk .................................................................20
A.5 Board – Top Silk and Pads .............................................................................21
A.6 Board – Bottom Copper and Pads ................................................................ 22
Appendix B. Bill of Materials (BOM)
Appendix C. Firmware Flowchart
C.1 MCP1630 SEPIC Automotive LED Driver Reference Design
Firmware Flowchart ............................................................................................ 25
Appendix D. Test Points and Waveforms
D.1 Test Points Description ...................................................................................27
D.2 Waveforms Examples ................................................................................... 28
Worldwide Sales and Service .................................................................................... 34

MCP1630 Sepic Automotive LED Driver Reference Design
DS51955A-page 4 ©2011 Microchip Technology Inc.

MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
©2011 Microchip Technology Inc. DS51955A-page 5
Preface
INTRODUCTION
This chapter contains general information that will be useful to know before using the
MCP1630 SEPIC Automotive LED Driver Reference Design User’s Guide. Items
discussed in this chapter include:
• Document Layout
• Conventions Used in this Guide
• Recommended Reading
• The Microchip Web Site
• Customer Support
• Document Revision History
DOCUMENT LAYOUT
This document describes how to use the MCP1630 SEPIC Automotive LED Driver
Reference Design User’s Guide as a development tool to emulate and debug firmware
on a target board. The manual layout is as follows:
•Chapter 1. “Product Overview” – Important information about the MCP1630
SEPIC Automotive LED Driver Reference Design.
•Chapter 2. “Installation and Operation” – This chapter includes a detailed
description of each function of the demonstration board and instructions for how to
begin using the board.
•Appendix A. “Schematic and Layouts” – Shows the schematic and layout
diagrams for the MCP1630 SEPIC Automotive LED Driver Reference Design.
•Appendix B. “Bill of Materials (BOM)” – Lists the parts used to build the
MCP1630 SEPIC Automotive LED Driver Reference Design.
•Appendix C. “Firmware Flowchart” – Shows the board flowchart.
•Appendix D. “Test Points and Waveforms” – Describes the main test points
and waveforms for the MCP1630 SEPIC Automotive LED Driver Reference
Design.
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
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Select the Help menu, and then Topics to open a list of available online help files.

MCP1630 Sepic Automotive LED Driver Reference Design
DS51955A-page 6 ©2011 Microchip Technology Inc.
CONVENTIONS USED IN THIS GUIDE
This manual uses the following documentation conventions:
DOCUMENTATION CONVENTIONS
Description Represents Examples
Arial font:
Italic characters Referenced books MPLAB®IDE User’s Guide
Emphasized text ...is the only compiler...
Initial caps A window the Output window
A dialog the Settings dialog
A menu selection select Enable Programmer
Quotes A field name in a window or
dialog
“Save project before build”
Underlined, italic text with
right angle bracket
A menu path File>Save
Bold characters A dialog button Click OK
A tab Click the Power tab
N‘Rnnnn A number in verilog format,
where N is the total number of
digits, R is the radix and n is a
digit.
4‘b0010, 2‘hF1
Text in angle brackets < > A key on the keyboard Press <Enter>, <F1>
Courier New font:
Plain Courier New Sample source code #define START
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File paths c:\mcc18\h
Keywords _asm, _endasm, static
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Bit values 0, 1
Constants 0xFF, ‘A’
Italic Courier New A variable argument file.o, where file can be
any valid filename
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[options]
Curly brackets and pipe
character: { | }
Choice of mutually exclusive
arguments; an OR selection
errorlevel {0|1}
Ellipses... Replaces repeated text var_name [,
var_name...]
Represents code supplied by
user
void main (void)
{ ...
}

Preface
©2011 Microchip Technology Inc. DS51955A-page 7
RECOMMENDED READING
This user’s guide describes how to use the MCP1630 SEPIC Automotive LED Driver
Reference Design User’s Guide. Other useful documents are listed below. The follow-
ing Microchip documents are available and recommended as supplemental reference
resources.
• MCP1630/MCP1630V Data Sheet – “High-Speed, Microcontroller-Adaptable,
Pulse Width Modulator” (DS21896)
• PIC12F683 Data Sheet – “8-Pin Flash-Based, 8-Bit CMOS Microcontrollers
with nanoWatt Technology” (DS41211)
• MCP1790 Data Sheet – “70 mA, High Voltage Regulator” (DS22075)
• MCP1415/16 Data Sheet – “Tiny 1.5A, High-Speed Power MOSFET Driver”
(DS22092)
• AN1137 – “Using the MCP1631 Family to Develop Low-Cost
Battery Chargers” (DS01137)
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Technical support is available through the web site at: http://support.microchip.com

MCP1630 Sepic Automotive LED Driver Reference Design
DS51955A-page 8 ©2011 Microchip Technology Inc.
DOCUMENT REVISION HISTORY
Revision A (September 2011)
• Initial Release of this Document.

MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
©2011 Microchip Technology Inc. DS51955A-page 9
Chapter 1. Product Overview
1.1 INTRODUCTION
The MCP1630 Sepic Automotive LED Driver Reference Design is a step-up/down,
Switch mode, DC-DC converter used for powering LED applications. The demo board
provides a 350 mA (700 mA, with hardware modification) constant current source.
Other output currents can be obtained with minor modifications to the board
components’ values.
The MCP1630 Sepic Automotive LED Driver Reference Design sustains the
high-voltage peaks that can be found in typical automotive applications. This board
provides useful information about typical high-voltage applications that can be found in
the automotive field.
The MCP1630 Sepic Automotive LED Driver Reference Design utilizes Microchip’s
MCP1630 high-speed, Pulse-Width Modulator (PWM) device. The 8-pin MCP1630
device contains all the analog components necessary for a peak current switch-mode
control loop, including an error amplifier, a PWM comparator and a high-current driver
output pin. The switching frequency and the maximum duty cycle for the MCP1630 are
determined by an external clock source.
An 8-pin PIC12F683 microcontroller is used to provide a 330 kHz switching clock for
the MCP1630 device. In addition, the PIC12F683 firmware supervises the input and
output voltage, and can optionally dim the LEDs when a button is attached.
In this reference design, the MCP1630 device is used for Peak Current Mode Control
in a SEPIC power train circuit. Because the duty cycle exceeds 50%, a ramp generator
provides an additional reference signal to the MCP1630 for slope compensation.
Note: This application uses a Peak Current Mode Control. Use only the MCP1630
device option for this board.