Microchip Technology MCP1252 User Manual

Charge pump backlight led demo board

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MCP1252 Charge Pump

Backlight LED Demo Board

User's Guide

DS51551A

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Page 2 Smart Serial, SmartTel, Total Endurance and WiperLock are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies.
Page 3: Table Of Contents
1.1 Introduction ..................... 5 1.2 What is the MCP1252 Charge Pump Backlight LED Demo Board? ....6 1.3 What the MCP1252 Charge Pump Backlight LED Demo Board kit includes . 6 Chapter 2. Installation and Operation ................7 2.1 Introduction ..................... 7 2.2 Features ......................
Page 4 MCP1252 Charge Pump Backlight LED Demo Board User’s Guide NOTES: © 2005 Microchip Technology Inc. DS51515A-page iv...
Page 5: Preface
• Customer Support • Document Revision History DOCUMENT LAYOUT This document describes how to use the MCP1252 Charge Pump Backlight LED Demo Board. The manual layout is as follows: • Chapter 1. “Product Overview” – Important information about the MCP1252 Charge Pump Backlight LED Demo Board.
Page 6 { ... RECOMMENDED READING This user's guide describes how to use MCP1252 Charge Pump Backlight LED Demo Board. The following Microchip documents are available and recommended as supplemental reference resources. MCP1252/3 Data Sheet, “Low Noise, Positive Regulated Charge Pump”, (DS21752) This data sheet provides detailed information regarding the MCP1252/3 product family.
Page 7 The Development Systems Information Line numbers are: 1-800-755-2345 – United States and most of Canada 1-480-792-7302 – Other International Locations DOCUMENT REVISION HISTORY Revision A (May 2005) • Initial Release of this Document. © 2005 Microchip Technology Inc. DS51551A-page 3...
Page 8 MCP1252 Charge Pump Backlight LED Demo Board User’s Guide NOTES: © 2005 Microchip Technology Inc. DS51551A-page 4...
Page 9: Chapter 1. Product Overview
LED applications. Light intensity is controlled uniformly through the use of ballast resistors. The peak intensity is set by the feedback (FB) to the the MCP1252-ADJ. Dimming is accomplished by pulse-width modulating the shutdown pin of the device.
Page 10: What Is The Mcp1252 Charge Pump Backlight Led Demo Board
The MCP1252 allows the input voltage to be lower or higher than the the output voltage by automatically switching between buck and boost operation. This makes it especially...
Page 11: Chapter 2. Installation And Operation
LEDs. A PIC10F206 microcontroller in a SOT23 package is used to provide an enable signal to the MCP1252. It also accepts a push button input that allows the user to adjust the white LEDs to five different light intensities, in addition to placing the system in a standby mode that consumes less than 1 µA of current (typ.).
Page 12: Getting Started
(<1 µA) until the S1 button is pressed by the user. The MCP1252 Charge Pump Backlight LED Demo Board does not need a power switch or power jumper because of the “standby” or “sleep” mode of the PIC10F206 microcontroller.
Page 13 There are 5 levels of LED intensity (plus the “off” state). The intensity of the LEDs are controlled via the SHDN input pin of the MCP1252. A Pulse-Width Modulated (PWM) signal is generated by the PIC10F206 and routed to the SHDN input pin of the MCP1252.
Page 14 MCP1252 Charge Pump Backlight LED Demo Board User’s Guide The WAKE routine tests the GPIO push button input to determine if the button has been pressed. If it has, the program goes to the INC_MODE subroutine to set the new LED intensity mode.
Page 15: Appendix A. Schematic And Layouts
MCP1252 CHARGE PUMP BACKLIGHT LED DEMO BOARD USER’S GUIDE Appendix A. Schematic and Layouts INTRODUCTION This appendix contains the following schematics and layouts for the MCP1252 Charge Pump Backlight LED Demo Board: • Board – Schematic • Board – Top Assembly Drawing •...
Page 16: Board - Schematic
MCP1252 Charge Pump Backlight LED Demo Board User’s Guide BOARD – SCHEMATIC © 2005 Microchip Technology Inc. DS51551A-page 12...
Page 17: Board - Top Assembly Drawing
Schematic and Layouts BOARD – TOP ASSEMBLY DRAWING © 2005 Microchip Technology Inc. DS51551A-page 13...
Page 18: Board - Top Layer + Silk-Screen
MCP1252 Charge Pump Backlight LED Demo Board User’s Guide BOARD – TOP LAYER + SILK-SCREEN © 2005 Microchip Technology Inc. DS51551A-page 14...
Page 19: Board - Bottom Layer (From Top)
Schematic and Layouts BOARD – BOTTOM LAYER (FROM TOP) © 2005 Microchip Technology Inc. DS51551A-page 15...
Page 20 MCP1252 Charge Pump Backlight LED Demo Board User’s Guide NOTES: © 2005 Microchip Technology Inc. DS51551A-page 16...
Page 21: Appendix B. Bill-Of-Materials (Bom)
MCP1252 CHARGE PUMP BACKLIGHT LED DEMO BOARD USER’S GUIDE Appendix B. Bill-Of-Materials (BOM) TABLE B-1: BILL-OF-MATERIALS (BOM) Reference Description Manufacture MFG PART # ® CAP .1UF 25V CERAMIC Panasonic – ECG ECJ-2VB1E104K X7R 0805 ® CAP 1.0UF 10V CERAMIC Kemet...
Page 22 MCP1252 Charge Pump Backlight LED Demo Board User’s Guide NOTES: © 2005 Microchip Technology Inc. DS51515A-page 18...
Page 23: Appendix C. 00016R1.Asm Source Code
Appendix C. 00016R1.asm Source Code DEVICE FIRMWARE Software License Agreement The software supplied herewith by Microchip Technology Incorporated (the “Company”) is intended and supplied to you, the Company’s customer, for use solely and exclusively with products manu- factured by the Company.
Page 24 ;on time before unit swithces back to sleep ;variables mode = 0x13 ;current mode ( high, med, lo ) counter = 0x14 ;hi and low time counter debounce = 0x15 ;debounce counter flag = 0x16 ;debounce control flags © 2005 Microchip Technology Inc. DS51551A-page 20...
Page 25 STATUS, TO goto wake btfss STATUS, PD goto wake goto init_vars ;initialize vars init_vars movlw 0xFF movwf timerh movwf timerl movlw led_hi_on ;calculate off times based on time remaining in PWM period © 2005 Microchip Technology Inc. DS51551A-page 21...
Page 26 ;clear new mode flag movlw 0x01 subwf mode, w btfsc STATUS, Z goto led_off movlw 0x02 subwf mode, w btfsc STATUS, Z goto led_low movlw 0x03 subwf mode, w btfsc STATUS, Z goto led_med © 2005 Microchip Technology Inc. DS51551A-page 22...
Page 27 ;turn on LED(s) for a set time movlw led_medhi_on call delay bcf GPIO, pwm ;turn off LED(s) fo a set time movf led_medhi_off, w call delay call bounce btfss flag, new_mode goto led_medhi goto mode_select ;medium brightness routine © 2005 Microchip Technology Inc. DS51551A-page 23...
Page 28 0x00 ;not yet bsf flag, new_mode incf mode, f ;a valid press has been detected bcf flag, timer_ena ;prevent timer from incrementing to prevent cycling though modes by holding debounce bounce00 retlw 0x00 © 2005 Microchip Technology Inc. DS51551A-page 24...
Page 30: Worldwide Sales And Service
Tel: 765-864-8360 Fax: 886-3-572-6459 Fax: 765-864-8387 Los Angeles Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 San Jose Mountain View, CA Tel: 650-215-1444 Fax: 650-961-0286 Toronto Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509 04/20/05 © 2005 Microchip Technology Inc. DS51551A-page 26...
Page 31 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Microchip MCP1252DM-BKLT...

Microchip Technology MCP1252 User Manual

Preface

Chapter 1. Product Overview

Chapter 2. Installation and Operation

Appendix A. Schematic and Layouts

Appendix B. Bill-Of-Materials (BOM)

Appendix C. 00016R1.Asm Source Code

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