MCP1630
SEPIC Automotive LED Driver
Reference Design
© 2011 Microchip Technology Inc.
DS51955A
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ISBN: 978-1-61341-606-8
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DS51955A-page 2
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
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
© 2011 Microchip Technology Inc.
DS51955A-page 3
MCP1630 Sepic Automotive LED Driver Reference Design
DS51955A-page 4
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER 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. This number is located on the bottom of each
page, in front of the page number. The numbering convention for the DS number is
“DSXXXXXA”, where “XXXXX” is the document number and “A” is the revision level of the
document.
For the most up-to-date information on development tools, see the MPLAB® IDE online help.
Select the Help menu, and then Topics to open a list of available online help files.
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.
© 2011 Microchip Technology Inc.
DS51955A-page 5
MCP1630 Sepic Automotive LED Driver Reference Design
CONVENTIONS USED IN THIS GUIDE
This manual uses the following documentation conventions:
DOCUMENTATION CONVENTIONS
Description
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
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...
the Output window
the Settings dialog
select Enable Programmer
“Save project before build”
A dialog button
A tab
A number in verilog format,
where N is the total number of
digits, R is the radix and n is a
digit.
A key on the keyboard
Click OK
Click the Power tab
4‘b0010, 2‘hF1
Italic Courier New
Sample source code
Filenames
File paths
Keywords
Command-line options
Bit values
Constants
A variable argument
Square brackets [ ]
Optional arguments
Curly brackets and pipe
character: { | }
Ellipses...
Choice of mutually exclusive
arguments; an OR selection
Replaces repeated text
Represents code supplied by
user
DS51955A-page 6
Examples
File>Save
Press <Enter>, <F1>
#define START
autoexec.bat
c:\mcc18\h
_asm, _endasm, static
-Opa+, -Opa0, 1
0xFF, ‘A’
file.o, where file can be
any valid filename
mcc18 [options] file
[options]
errorlevel {0|1}
var_name [,
var_name...]
void main (void)
{ ...
}
© 2011 Microchip Technology Inc.
Preface
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 following 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)
THE MICROCHIP WEB SITE
Microchip provides online support via our web site at www.microchip.com. This web
site is used as a means to make files and information easily available to customers.
Accessible by using your favorite Internet browser, the web site contains the following
information:
• Product Support – Data sheets and errata, application notes and sample
programs, design resources, user’s guides and hardware support documents,
latest software releases and archived software
• General Technical Support – Frequently Asked Questions (FAQs), technical
support requests, online discussion groups, Microchip consultant program
member listing
• Business of Microchip – Product selector and ordering guides, latest Microchip
press releases, listing of seminars and events, listings of Microchip sales offices,
distributors and factory representatives
CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels:
•
•
•
•
Distributor or Representative
Local Sales Office
Field Application Engineer (FAE)
Technical Support
Customers should contact their distributor, representative or field application engineer
(FAE) for support. Local sales offices are also available to help customers. A listing of
sales offices and locations is included in the back of this document.
Technical support is available through the web site at: http://support.microchip.com
© 2011 Microchip Technology Inc.
DS51955A-page 7
MCP1630 Sepic Automotive LED Driver Reference Design
DOCUMENT REVISION HISTORY
Revision A (September 2011)
• Initial Release of this Document.
DS51955A-page 8
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
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:
© 2011 Microchip Technology Inc.
This application uses a Peak Current Mode Control. Use only the MCP1630
device option for this board.
DS51955A-page 9
MCP1630 Sepic Automotive LED Driver Reference Design
1.2
FEATURES
The MCP1630 Sepic Automotive LED Driver Reference Design has the following
features:
• Compact size with high output power
• Can operate in Buck (step-down) or Boost (step-up) mode
• Sustains voltage stresses typically found in automotive products:
42 VIN for 180 ms
• High efficiency over the entire operating input and output voltage ranges:
85% typical
• Maximum Output Current = 350 mA; this value can be modified with minor
changes in hardware
• Maximum Output Power = 18W
• Optional software dimming control for both methods: PWM or Current mode
• Preprogrammed source code
• The switching frequency, maximum duty cycle and the MCP1630 reference
voltage can be modified in firmware
• Additional application functions can be implemented in firmware
1.3
DEVICE SUMMARY
The MCP1630 Sepic Automotive LED Driver Reference Design uses the following
devices:
• MCP1630 High-Speed Pulse-Width Modulator IC – When used in conjunction with
a microcontroller, the MCP1630 controls the power system duty cycle to provide
output current and/or voltage regulation.
• PIC12F683 Microcontroller (8-bit MCU) – Used to generate the MCP1630’s
reference voltage, the oscillator signal at 330 kHz, and to provide additional
software functions.
• MCP1790 HV LDO Regulator – Used to supply the regulated voltage to the
PIC12F683 and MCP1630. The MCP1790 is capable of delivering 70 mA and
sustaining 42V surge voltage on input for 180 ms (30 seconds repetition rate).
• MCP1416 – Is a high-speed MOSFET driver, capable of providing 1.5A of peak
current for driving the switching power transistor.
DS51955A-page 10
© 2011 Microchip Technology Inc.
Product Overview
1.4
TECHNICAL SPECIFICATIONS
• Input Voltage = 9V to 16V (surge voltage of 42V for maximum 180 ms, 30 seconds
repetition rate)
• Software Configurable Under Voltage Lock-Out Circuit (UVLO) and Over Voltage
Lock-Out Circuit (OVLO) (8V and 17V default thresholds)
• Software Configurable Load Disconnect Protection
• Typical Output Current = 350 mA
• Maximum Output Current = 700 mA (with hardware modifications)
• Typical Output Power = 18W (maximum 20W at TA = +25°C)
• Fully Protected Against Short-Circuit and No-Load Condition
Figure 1-1 shows a simplified block diagram of the application.
MCP1790
OUT IN
GND
+5V
+VIN
Surge
Protection
7
4
Ramp Generator
Slope Compensation
Circuit
MCP1416
MCP1630
OSC
CS
5 GND
MOSFET
Driver
VEXT
OUTPUT
DRIVER
PWM
COMP
6
3
CS
FB
1
VIN Sense
EA
REF
COMP
SEPIC Power Train
2
8
Compensation Network
ISENSE
LED String
Current
Sense
Resistor
+5V
1
CLOCK
VDD
5 GP2
2
GP5
Aux.
Dimming
4 GP3 GP1 6
7
GP4 3
GP0
VSS
8
FIGURE 1-1:
Reference
Voltage Filter
VIN Sense
PIC12F683
MCP1630 Sepic Automotive LED Driver Reference Design Block Diagram.
© 2011 Microchip Technology Inc.
DS51955A-page 11
MCP1630 Sepic Automotive LED Driver Reference Design
1.5
FUNCTIONAL DESCRIPTION
The MCP1630 device provides all the analog functions necessary to implement a Peak
Current Mode PWM DC-DC Converter. The power train is based on the Single-Ended
Primary Inductor Converter (SEPIC) topology. This topology offers the buck-boost
functionality and also has non-pulsating input current.
The converter provides adjustable constant current at the output, necessary to drive
high-power LED applications.
The MCP1630 PWM controller requires an external clock for operation. This clock is
provided by an external 8-bit microcontroller, PIC12F683. The PWM frequency and the
maximum duty cycle are set by this clock.
The output (load) current is sensed with a 0.5Ω shunt resistor (R17 and R18). The
voltage across this shunt resistor is compared with the reference voltage by the
MCP1630 device’s PWM controller.
The reference voltage for the MCP1630 device is also provided by PIC12F683, at the
VREF pin (Pin 8). R4, R3 and C2 form a low-pass filter that smooths the PWM signal
produced by the PIC® microcontroller. The maximum output current is set by the R4
and R3 voltage dividers. The duty cycle of the PWM signal is adjusted in eight steps.
The output current is calculated with Equation 1-1:
EQUATION 1-1:
V REF
I OUT = -----------0.5
Where:
R3
V REFmax = ⎛⎝ ---------------------⎞⎠ × 5V = 178 mV
R3 + R4
178mV
I OUTmax = ----------------- = 357mA
0.5
Because the operating duty cycle is bigger than 50%, a slope compensation circuit is
required to avoid subharmonic oscillations that occur in Peak Current mode controllers.
A ramp generator is constructed with Q1 and the associated components. The ramp is
then summed with the inductor current, measured across R9 and R10 resistors.
A 100V VDS MOSFET transistor is also used in this application. The MCP1416
MOSFET driver drives the gate of this transistor. This is necessary because the
high-voltage transistors usually have high gate charge and also require at least 7V for
gate-to-source voltage.
Note:
1.6
The MCP1416 MOSFET driver must be protected against input voltage
surges. This protection is ensured by R6 and D1.
WHAT THE MCP1630 SEPIC AUTOMOTIVE LED DRIVER REFERENCE
DESIGN KIT INCLUDES
The MCP1630 Sepic Automotive LED Driver Reference Design includes:
• MCP1630 Sepic Automotive LED Driver Reference Design (102-00323)
• Important Information Sheet
DS51955A-page 12
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
Chapter 2. Installation and Operation
2.1
GETTING STARTED
The MCP1630 Sepic Automotive LED Driver Reference Design is fully assembled and
tested. The board requires the use of an external input voltage source (9V to 16V) and
an external LED load, provided by Microchip.
2.1.1
Additional Tools Required for Operation
1. A DC power supply, a bench supply that can produce 12V, 2.5A, is recommended
to operate the board at the full rated power.
2. An oscilloscope and/or a multi-meter to observe the waveforms and measure the
electrical parameters (optional).
2.2
SETUP PROCEDURE
To operate the MCP1630 Sepic Automotive LED Driver Reference Design, the
following steps must be completed:
1. Attach an LED load (or dummy load) to the Output Connector J3 (observe the
polarity).
2. Attach the push button to the J1 header (between Pins 3 and 4 is optional).
3. Connect a power supply to the Input Connector J2 (observe the polarity).
Detailed instructions are provided below for each step.
WARNING
Please observe the polarity for all steps to avoid board damage.
2.2.1
Demo Board Output Current Configuration
The board is configured to deliver a maximum of 350 mA to the LEDs’ load. UVLO and
OVLO thresholds are set to 8V and 17V, respectively. The maximum output voltage is
set to be approximately 55V.
2.2.2
Connecting the Load
A string of up to sixteen white LEDs (1W each) can be powered by this board. The
LED's string must be mounted on an appropriate heat sink to keep the maximum
junction temperature at safe level (consult the LED data sheet for details). The
maximum current delivered by the board to the LED's string is set to 350mA and the
maximum output voltage is 55V.
The LED's string can be replaced by a resistor of 150Ω and 20W dissipated power
(dummy load). In this case, the power delivered to the load will be about 18W.
Connect the LEDs’ string to the J3 connector. It is very important to use the correct
polarity (see Figure 2-1).
© 2011 Microchip Technology Inc.
DS51955A-page 13
MCP1630 Sepic Automotive LED Driver Reference Design
(+)LOAD
+VIN
GND
(-)LOAD
Connect a
push button
between
Pin 3 and
Pin 4
FIGURE 2-1:
2.2.3
Power Supply and Load Connection Diagram.
Connecting the Dimming Push Button (optional)
The Dimming Push Button provides the option to adjust the LEDs’ luminous intensity
in eight steps. Connect the Dimming Push Button to the J1 header between GND
(Pin 3) and Pin 4.
2.2.4
Powering the Board
Connect a power supply to J2 to power up the MCP1630 Sepic Automotive LED Driver
Reference Design. Ensure that the power supply has the (+) terminal connected to the
J2 terminal block at Pin 1 (left), and the (–) terminal connected to Pin 2 (right). The input
voltage source should be limited to a range from 9V to 16V. Ensure that the chosen
power supply can provide enough current at the selected voltage to properly power the
LEDs.
For 12V input voltage, the current drain will be around 1.8A at full load (18W).
Note:
DS51955A-page 14
This board has no Thermal Shut-Down function implemented. Please
ensure that the load is properly cooled.
© 2011 Microchip Technology Inc.
Installation and Operation
2.2.5
Using the Reference Board
When the board is powered up, it supplies the maximum output current (350mA). The
user has the option to adjust this output current connecting an external push button
(see Figure 2-1). The push button controls the output current in eight steps from 0 to
350mA.
The board has Under Voltage Lock-Out and Over Voltage Lock-Out protections. The
thresholds are set in firmware and are 8 VDC and 17 VDC, respectively.
The board is protected for the No-Load condition. The typical threshold value is 55 VDC
for the output voltage.
Note:
2.3
It is not recommended to operate the board without a proper load
connected to the output. The maximum power at the output must be limited
to 19W at ambient temperature.
EVALUATING THE APPLICATION
The best way to evaluate the MCP1630 Sepic Automotive LED Driver Reference
Design is to dig into the circuit and measure the voltages and currents with a Digital
Voltage Meter (DVM), and probe the board with an oscilloscope.
Additional tools are necessary to evaluate some technical parameters of the board
(temperature of power components, ability to withstand surge voltage pulse on input,
EMI).
Some typical voltage and waveforms are provided in Appendix D. “Test Points and
Waveforms”.
The firmware program of the PIC12F683 can also be edited to modify the operation of
the application.
2.4
FIRMWARE DESCRIPTION
The PIC12F683 is preprogrammed with firmware to operate the system, as described
in the previous sections. The firmware flow diagram is shown in Appendix
C. “Firmware Flowchart”. The program is simple and straightforward.
The TRISIO register controls the direction of the GPIO pins, and is configured to set
GP2 (oscillator pulses to the MCP1630) and GP5 (VREF voltage to MCP1630) as output
ports. GP1 and GP4 are configured as analog inputs. These inputs are used to
measure the input and output voltages.
The Capture/Compare/PWM (CCP) block is used to generate the master clock for the
MCP1630 device. This module is configured for PWM mode operation. The PWM
period can be calculated by writing to the PR2 register. The PWM duty cycle is specified
by writing to the CCPR1L register and to the CCP1CON<5:4> bits. A resolution, up to
10-bit, is available. The CCPR1L contains the eight MSbs, while the CCP1CON<5:4>
contains the two LSbs. This 10-bit value is represented by the
CCPR1L:CCP1CON<5:4> bits. The switching frequency is set to 330 kHz.
The reference voltage for the MCP1630 device is produced by the software PWM. This
allows the user to adjust the LED’s intensity in eight steps.
The No-Load condition protection is provided by using the internal comparator. If the
output voltage is too high, an interrupt occurs and the master clock for PWM operation
is disabled.
The internal ADC is used to monitor the input voltage. If the input voltage is too low or
too high, the board will be in a “Power Off” condition.
The Soft Start feature is also provided in this firmware. The duty cycle is gradually
increased until it reaches the maximum value.
© 2011 Microchip Technology Inc.
DS51955A-page 15
MCP1630 Sepic Automotive LED Driver Reference Design
2.5
PROGRAMMING THE PIC12F683 MICROCONTROLLER
The firmware package provides the source and .hex files for the LED driver.
The board is factory programmed with the LED driver firmware. UVLO, OVLO
thresholds and dimming steps can be modified. The source code is commented
extensively and helps the user to define the board.
This firmware was developed using MPLAB® Integrated Development Environment
and HI-TECH C® for the PIC10/12/16 MCU Family (v9.7).
Header J1 provides in-system circuit programming. Follow the next steps to program
the board:
1. Connect the PICkit™ 3 to the USB port.
2. Connect the PICkit 3 device to the board at J1 pin. Ensure the polarity is correctly
applied.
3. Open the project00323.prj file with MPLAB Integrated Development
Environment.
4. Select Programmer from the menu bar, click Select Programmer and choose
PICkit 3 from the submenu list.
5. Return to the Programmer menu and select Settings. From the Properties
window that appears, click the Power tab.
Set the voltage to 5V and select the “Power target circuit from PICkit 3” check
box. Press Apply.
6. On the warning message that appears click, OK.
7. From the Programmer menu, choose Program. Check the Output window if the
programming was performed without errors.
The board is now ready to operate.
DS51955A-page 16
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
Appendix A. Schematic and Layouts
A.1
INTRODUCTION
This appendix contains the following schematics and layouts for the MCP1630 Sepic
Automotive LED Driver Reference Design User’s Guide:
•
•
•
•
•
Board – Schematic
Board – Top Copper and Pads
Board – Top Copper Pads and Silk
Board – Top Silk and Pads
Board – Bottom Copper and Pads
© 2011 Microchip Technology Inc.
DS51955A-page 17
DS51955A-page 18
OSC
VREF
R2
C2
1U
TP2
OSC
2K7
C1
1500P
TP1
SLOPE
VREF = lout X Rsense
Rsense = 0.5
Q1
NDS7002A
R1
5.1K
+VIN_SENSE
VREF
+5V
R3
100k
+5V
ISENSE
C5
470P
8
4
7
2M7
3
TP3
CS
U2
3
IN
GND
4
2
VDD
NC
OUT
C8
1U
5
8
4 GP3/MCLR/VPP
PIC12F683
GP2/AN2/T0CKI/INT/COUT/CCP1
5
R7
OSC
TP5
DRIVE
C9
22P
1K
R8
DRAIN
TP6
D1
SMAZ15-13-F
1K
U3
MCP1416
VSS
1
R6
68/1W
GP0/AN0/CIN+/ICSPDAT/ULPWU 7
GP5/TICKI/OSC1/CLKIN
VDD
GND
IN
3 GP4/AN3/OSC2/CLKOUT GP1/AN1/CIN-/VREF/ICSPCLK 6
2
1
GND 5
CS
VEXT
6
1
C7
4.7u
Comp
MCP1630
R4
VREF
OSC IN
VIN
FB
10K
1500P
2
R5
U1
C6
100N
C4
C3
100N
OUT
U4
MCP1790
+5V
2.2u/100V
C10
R9
0.22
5
4
3
2
J1
1
R10
0.22
D2
C12
10u
L2
22uH
10BQ100
C11
10u
C13
2.2u
C14
2.2u
+VIN_SENSE
PROGRAMMING HEADER
DIMMING
Q2
BSC196N10NSG
L1
22uH
TP7
VIN+
R14
3.3K
R13
15K
R12
10K
R11
91K
C15
470P
OVP
R15
62K
ISENSE
10K
R16
TP9
VOUT+
TP8
VIN-
OUT
IN
R17
1
R18
1
TP10
ISENSE
J3
11
22
J2
1 1
2 2
A.2
+5V
SLOPE COMPENSATION CKT.
+5V
TP4
+5V
MCP1630 Sepic Automotive LED Driver Reference Design
BOARD – SCHEMATIC
© 2011 Microchip Technology Inc.
Schematic and Layouts
A.3
BOARD – TOP COPPER AND PADS
© 2011 Microchip Technology Inc.
DS51955A-page 19
MCP1630 Sepic Automotive LED Driver Reference Design
A.4
BOARD – TOP COPPER PADS AND SILK
DS51955A-page 20
© 2011 Microchip Technology Inc.
Schematic and Layouts
A.5
BOARD – TOP SILK AND PADS
© 2011 Microchip Technology Inc.
DS51955A-page 21
MCP1630 Sepic Automotive LED Driver Reference Design
A.6
BOARD – BOTTOM COPPER AND PADS
DS51955A-page 22
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
Appendix B. Bill of Materials (BOM)
TABLE B-1:
Qty
BILL OF MATERIALS (BOM)
Reference
Description
Manufacturer
Part Number
4
B1, B2, B3, B4
BUMPON HEMISPHERE .44X.20
CLEAR
3M
SJ-5303 (CLEAR)
2
C1,C4
CAPACITOR 1500P 50V COG 5%
SMD 0805
KEMET®
C0805C152J5GACTU
1
C2
CAPACITOR 1U 16V X7R 10%
SMD 0805
KEMET
C0805C105K4RACTU
2
C3, C6
CAPACITOR 100N 100V X7R 10%
SMD 0805
KEMET
C0805C104K1RACTU
2
C5, C15
CAPACITOR 470P 50V COG 5%
SMD 0805
KEMET
C0805C471J5GACTU
1
C7
CAPACITOR 4.7U 10V X7R 10%
SMD 0805
TAIYO YUDEN Co., Ltd. LMK212B7475KG-T
1
C8
CAPACITOR 1U 25V X7R 10%
SMD 0805
KEMET
C0805C105K3RACTU
1
C9
CAPACITOR 22P 50V COG 5%
SMD 0805
KEMET
C0805C220J5GACTU
3
C10, C13, C14
CAPACITOR 2.2U 100V X7R 10%
SMD 1210
KEMET
C1210C225K1R1C
2
C11, C12
CAPACITOR 10U 25V X7R 10%
SMD 1210
KEMET
C1210X106K3RACTU
1
D1
SMAZ15-13-F DIODE ZENNER
15V/1W SMD SMA
Diodes Incorporated®
SMAZ15-13-F
1
D2
10BQ100 DIODE SCHOTTKY 100V
1A SMB
Vishay
Intertechnology, Inc.
10BQ100TRPBF
1
J1
CONN HEADER 5POS .100 VERT
TIN
Molex® Connector Corp. 22-03-2051
2
J2, J3
CONN TERM BLOCK 2.54MM 2POS Phoenix Contact
®
Wurth Group
1725656
7443551221
2
L1, L2
INDUCTOR POWER 22UH 6.0A
SMD
1
PCB
RoHS Compliant Bare PCB,
MCP1630 SEPIC Automotive LED
Driver Reference Design
1
Q1
NDS7002A MOSFET N-CH 60V
280MA SOT-23
Fairchild
Semiconductor®
NDS7002A
1
Q2
BSC196N10NS G MOSFET N-CH
100V 45A TDSON-8
Infineon
Technologies AG
BSC196N10NS G
1
R1
RESISTOR 5.1K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW08055K10FKEA
1
R2
RESISTOR 2.7K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW08052K70FKEA
Note 1:
—
104-00323
The components listed in this Bill of Materials are representative of the PCB assembly. The released
BOM used in manufacturing uses all RoHS-compliant components.
© 2011 Microchip Technology Inc.
DS51955A-page 23
MCP1630 Sepic Automotive LED Driver Reference Design
TABLE B-1:
Qty
BILL OF MATERIALS (BOM) (CONTINUED)
Reference
Description
Manufacturer
Part Number
1
R3
RESISTOR 100K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW0805100KFKEA
1
R4
RESISTOR 2.7M OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW08052M70FKEA
3
R5, R12, R16
RESISTOR 10K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW080510K0FKEA
1
R6
RESISTOR 68 OHM 1W 5%
SMD 2512
Vishay
Intertechnology, Inc.
CRCW251268R0JNEG
2
R7, R8
RESISTOR 1K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW08051K00FKEA
2
R9, R10
RESISTOR 0.22 OHM 1/2W 1%
SMD 1206
Vishay
Intertechnology, Inc.
RCWE1206R220FKEA
1
R11
RESISTOR 91K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW080591K0FKEA
1
R13
RESISTOR 15K OHM 1/4W 1%
SMD 1206
Vishay
Intertechnology, Inc.
CRCW120615K0FKEA
1
R14
RESISTOR 3.3K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW08053K30FKEA
1
R15
RESISTOR 62K OHM 1/8W 1%
SMD 0805
Vishay
Intertechnology, Inc.
CRCW120615K0FKEA
2
R17, R18
RESISTOR 1 OHM 1/4W 1%
SMD 1206
Vishay
Intertechnology, Inc.
CRCW12061R00FKEA
3
TP7, TP8, TP9
TEST POINT PC COMPACT SMT
Keystone® Electronics
Corp.
5016
1
U1
MCP1630 HIGH-SPEED uC
ADAPTABLE PWM CONTROLLER
MSOP10
Microchip
Technology Inc.
MCP1630-E/MS
1
U2
PIC12F683 8BIT FLASH
MICROCONTROLLER SOIC8
Microchip
Technology Inc.
PIC12F683-E/SN
1
U3
MCP1416 TINY 1.5A POWER
MOSFET DRIVER SOT23-5
Microchip
Technology Inc.
MCP1416T-E/OT
1
U4
MCP1790 70MA HIGH-VOLTAGE
REGULATOR SOT-223
Microchip
Technology Inc.
MCP1790-5002E/DB
Note 1:
The components listed in this Bill of Materials are representative of the PCB assembly. The released
BOM used in manufacturing uses all RoHS-compliant components.
DS51955A-page 24
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
Appendix C. Firmware Flowchart
C.1
MCP1630 SEPIC AUTOMOTIVE LED DRIVER REFERENCE DESIGN
FIRMWARE FLOWCHART
Interrupt
Start
GPIO Setup
GP5 -> Vref OUT
GP2 -> CLK OUT
GP4 -> Vin SENSE
GP1 -> OVP Input
Comparator Tripped
?
Yes
ADC Setup
PWM = OFF
FAULT = 1
CMIF = 0
No
Analog Comparator
Setup
PWM Setup
Enable Interrupts
No
No
Vref DC = 0
?
Timer Interrupt
?
Yes
Generate Vref
Signal PWM
PWM = OFF
Soft_Start = 1
Soft_Start =
1
?
Yes
No
TOIF = 0
Soft_Start()
Soft_Start = 0
RETI
Read Vin
No
Vin > Vin_min
Vin < Vin_max
?
PWM = OFF
FAULT = 1
Yes
FAULT = 1
?
No
Yes
FAULT = 0
Soft_Start()
Read Push-Button
Vref DC ++
No
Vref DC = 8
?
Yes
Vref DC = 0
© 2011 Microchip Technology Inc.
DS51955A-page 25
MCP1630 Sepic Automotive LED Driver Reference Design
NOTES:
DS51955A-page 26
© 2011 Microchip Technology Inc.
MCP1630 SEPIC AUTOMOTIVE LED
DRIVER REFERENCE DESIGN
Appendix D. Test Points and Waveforms
D.1
TEST POINTS DESCRIPTION
TABLE D-1:
TEST POINTS
Testpoint
Name
Description
TP1
RAMP
TP2
CLK
Master clock for PWM controller
TP3
CS
Current sense pin for PWM controller
TP4
+5V
Microcontroller and PWM controller supply voltage
Artificial ramp for Slope Compensation
TP5
DRIVE
Gate drive of Power MOSFET
TP6
DRAIN
Drain terminal of the Power MOSFET
TP7
+VIN
Input Voltage
TP8
GND
Board ground. All measurements are referred to this test point.
TP9
VOUT
Output Voltage
TP10
ISENSE
© 2011 Microchip Technology Inc.
Main current sense test point. The output current is estimated by dividing
the voltage from this test pint with 0.5.
DS51955A-page 27
MCP1630 Sepic Automotive LED Driver Reference Design
D.2
WAVEFORMS EXAMPLES
DS51955A-page 28
D.2.1
Clock Signal (TP 2)
D.2.2
Drive Signal (TP 5)
© 2011 Microchip Technology Inc.
Test Points and Waveforms
D.2.3
RAMP Signal (TP 1)
D.2.4
CS Signal (TP 3)
© 2011 Microchip Technology Inc.
DS51955A-page 29
MCP1630 Sepic Automotive LED Driver Reference Design
DS51955A-page 30
D.2.5
MOSFET DRAIN Signal (TP 6)
D.2.6
Main Inductor Current
© 2011 Microchip Technology Inc.
Test Points and Waveforms
D.2.7
Typical Output Ripple/Noise of the SEPIC Converter
D.2.8
Typical Step Response (Zero to Full Load)
© 2011 Microchip Technology Inc.
DS51955A-page 31
MCP1630 Sepic Automotive LED Driver Reference Design
D.2.9
Typical Efficiency vs Output Voltage
Efficiency vs. Output Voltage
86.0
Efficiency %
84.0
82.0
80.0
eff
78.0
76.0
74.0
72.0
0
10
20
30
40
50
60
Output Voltage (V)
DS51955A-page 32
© 2011 Microchip Technology Inc.
NOTES:
© 2011 Microchip Technology Inc.
DS51955A-page 33
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DS51955A-page 34
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© 2011 Microchip Technology Inc.