Power integrations InnoSwitch3-Pro User manual

Power Integrations
5245 Hellyer Avenue, San Jose, CA 95138 USA.
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Title
Getting Started with InnoSwitch
TM 3-Pro
Code Library using Arduino
Author
Applications Engineering Department
Document
Number
Application Note 77 (AN-77)
Date
September 6, 2018
Revision
1.0
Summary
InnoSwitch3-Pro is a digitally controllable CV/CC QR Flyback Switcher IC with integrated
High Voltage MOSFET, Synchronous Rectification and FluxLink Feedback.
RDK-641 is a reference design board rated for 40W output power and is programmable
from 3V to 20V output voltage. This reference design features an on board PIC16F18325
microcontroller and uses the InnoSwitch3-Pro integrated power supply IC.
This application note describes use of Arduino code libraries provided by Power
Integrations to develop control logic and firmware for customizing RDK-641.
Information presented in this application note was used to develop firmware for Arduino
UNO.
PATENT INFORMATION
The products and applications illustrated herein (including transformer construction and circuits external to the products) may
be covered by one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned
to Power Integrations. A complete list of Power Integrations' patents may be found at www.powerint.com. Power Integrations
grants its customers a license under certain patent rights as set forth at https://www.power.com/company/intellectual-
property-licensing/.

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Table of Contents
Introduction ................................................................................................................31
System Requirements................................................................................................42
Hardware Overview....................................................................................................53
Headers and Jumpers Settings...........................................................................53.1
InnoSwitch3-Pro Arduino Code Library......................................................................74
Library Installation...............................................................................................74.1
Library Installation Complete...............................................................................84.2
Library Examples ................................................................................................94.3
Folder Contents........................................................................................................115
File Description.................................................................................................125.1
Application Example.................................................................................................146
Step-By-Step Procedure...................................................................................146.1
Header Files Inclusion ...............................................................................146.1.1
Class Instance Creation.............................................................................146.1.2
InnoSwitch3-Pro Initialization.....................................................................146.1.3
Basic Control Functions ..............................................................................156.1.4
Basic Code Examples..................................................................................166.1.5
Building the Project ..................................................................................................187
Arduino board selection ....................................................................................187.1
Select the Active Com Port...............................................................................187.2
Verify / Compile.................................................................................................197.3
Upload...............................................................................................................197.4
Demonstration of Operation.....................................................................................208
Running the Program........................................................................................208.1
Constant voltage operation...............................................................................218.2
Constant current operation................................................................................218.3
Doxygen Documentation..........................................................................................229
Opening html file...............................................................................................229.1
Viewing the API Functions................................................................................239.2
Functions summary...........................................................................................249.3
Functions definition...........................................................................................259.4
Examples..........................................................................................................269.5
Revision History....................................................................................................2710

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Introduction1
This application note describes the structure and the application interface of the
InnoSwitch3-Pro Arduino Code Library as well as using it on a demo application. The
code was designed to be highly portable to other microcontroller platforms, and was
written in C++ language to be compatible with the Arduino library standards. This demo
application runs on Reference Design RDK-641 (Figure 1) and Arduino UNO (Figure 3).
Figure 1 –RDK-641 Board Top
Figure 2 –RDK-641 Board Bottom
1
2
3
4
5
6
7
8
9
10

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The RDK-641 board’s key features are indicated on the table below
Figure 3 –Arduino Uno Rev 3
System Requirements2The following are required to run the InnoSwitch3-Pro Arduino demo application
Arduino Software version 1.8.2 or later
Arduino UNO Rev3 SMD
RDK –641 Board rev C
InnoSwitch3-Pro Arduino Library version 1.0.0
Number
Description
Label
1
AC Input Terminals
TP1, TP2
2
DC Output Terminals
TP3, TP4
3
MCU GPIO Headers
J8
4
Green LED Indicator
D5
5
Pickit3 Programming Header
J5
6
Push Buttons
SW1, SW2
7
uVCCand I2C Isolation Jumpers
J3, J6, J7
8
External Interface Header
J4
9
PIC16F18325 microcontroller
U3
10
InnoSwitch3-Pro IC
U1
SCL
SDA
GND

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Hardware Overview3
The Reference Design (RDK-641) hardware consists of an 8-bit Microchip microcontroller
(PIC16F18325), interface headers and the user interface elements: two push buttons and
a green LED.
The InnoSwitch3-Pro can be controlled using it’s on board microcontroller or by an
external I2C Master through the interface header.
This Demo Application does not use the on board microcontroller but an Arduino Uno as
an I2C Master and InnoSwitch3-Pro as slave device.
SDA and SCL lines pull-up resistors R24 and R23 respectively are available on the
board. The output of the InnoSwitch3-Pro provides 3.6V pull up voltage from its μVCC
output pin.
To further ease in development, the following documents are available and
recommended as supplemental reference resources I2C
RDR-641 - 40 W Variable Output (3 V to 8 V, 5 A; 8 V –20 V Constant Power)
Supply Using InnoSwitch3-Pro and Microchip’s PIC16F18325 Microcontroller
AN-74 InnoSwitch3-Pro Programming Manual
Headers and Jumpers Settings 3.1
The table provides the description for each jumper available on the board.
Jumper
Description
Settings
J3
uVCC and MCU
Supply Jumper
If connected the uVCC output pin of the InnoSwitch3-Pro
will provide power to the on board microcontroller and
provide pull up voltage to the I2C lines
J6 , J7
I2C Lines
Isolation
Jumper
The user can select whether or not the SDA and SCL lines
from the MCU will be connected to the InnoSwitch3-Pro
The following headers are also available on the board.
Header
Description
Settings
J4
InnoSwitch3-Pro I2C lines
Header
When J6 and J7 are removed, an external I2C
Master can be connected through these header
J5
PICkit3 Programming
Header
For MCU Firmware Update using PICkit3 In-
Circuit Debugger/Programmer
J8
MCU GPIO Header
This can be used as Debug Pins

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By configuring the I2C lines isolation jumpers, the RDK-641 board can be controlled using
Arduino UNO.
Connection details:
Remove Jumpers J6 and J7 and retain Jumper J3
Connect J4 to Arduino Uno I2C lines (SDA, SCL and GND).
Make sure to check the I2C labels of J4 and Arduino UNO board
Wires on the Image above
oBlue –SDA
oRed –SCL
oBlack –GND

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InnoSwitch3-Pro Arduino Code Library4
To simplify the technicalities on controlling the InnoSwitch3-Pro, a simple code library is
provided as a reference.
The library contains all the registers needed for controlling the device. These registers
are organized as Command Registers and Telemetry registers. Command registers are
sent to the device for performance control and Telemetry Registers are for reading back
values.
Computation Macros are presented to aid in set point calculations. Register default values
are also defined to simplify writing to the required registers at device initialization.
The InnoSwitch3-Pro Arduino code library is available from the Power integrations
website.
https://ac-dc.power.com/design-support/articles/innoswitch3-pro-code-library-api-arduino/
Library Installation 4.1
Full installation guide can be found on the link below
https://www.arduino.cc/en/Guide/Libraries
In the Arduino IDE, navigate to Sketch > Include Library > Add .ZIP Library . At the top
of the drop down list, select the option to "Add .ZIP Library''.
Navigate to the .zip file's location and open it.

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Library Installation Complete4.2
Images below shows the InnoSwitch3-Pro library was added to the Arduino Library

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For windows users, the library can be viewed on this directory:
C:\Users\username\Documents\Arduino\libraries\
Library Examples4.3
The Library will be available to use in sketches, File > Examples

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Folder Contents5
The InnoSwitch3-Pro Arduino Code library consists of various folders and files as shown
below
Folder and files summary:
Examples - Contains the InnoSwitch3-Pro Main Application Examples (*.ino)
Documentation - Contains the Doxygen HTML Documentation
*.cpp and .h - Library source and header files
Library.properties - Arduino Library files format
Keywords.txt - List of keywords for the library, provided syntax coloring
Main.dox - Doxygen file
README.md - Compatibility list

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File Description 5.1
The Arduino Code library is layered and modular, implemented in, ‘Clock Driver’,
‘InnoSwitch3-Pro Driver’ and ‘InnoSwitch3-Pro API’. The Library architecture block
diagram is schematically presented in Figure3
Below is a brief description of each layer:
InnoSwitch3-Pro API
Simple Control Interface to control InnoSwitch3-Pro. This handles
Command Sequences and Timings, Register Settings, Threshold
Calculations, Parity Implementation, Telemetry
Related Files:
Inno3Pro.h - Contains the core of the library
Inno3Pro.cpp
Config.h - Contains the Configuration Parameters of the Library
InnoSwitch3-Pro Driver
Manages the I2C Packet format based on the InnoSwitch3-Pro Datasheet
for Write and Read Transactions
Built using Arduino Wire Library
Related Files:
Drv_I2C.cpp
Drv_I2C.h
Clock Driver
Module used for generating delays and timings involved for InnoSwitch3-
Pro Control.
Built using Arduino ‘millis()’ and ‘micros()’ functions
Related Files:
Drv_Rtc.cpp
Drv_Rtc.h
Application
Application Layer
Related Files:
Inno3Pro_Basic.ino
Inno3Pro_Basic_Volts_Amps_OV_UV.ino

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Figure 3 –Firmware Architecture

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Application Example6
This section describes the step-by-step procedures for setting up the Arduino
sketch for InnoSwitch3-Pro.
Step-By-Step Procedure 6.1
Header Files Inclusion6.1.1
The library header files contain all of the function declarations and macro definitions.
This must be included in the main page as shown.
Class Instance Creation6.1.2
Construct a Class instance to call the functions inside Inno3Pro_Application.
Constructing a Class instance of Inno3Pro_Rtc is Optional.
InnoSwitch3-Pro Initialization6.1.3
Before continuous execution of the main code, the status of System Ready Signal is
monitored to ensure the InnoSwitch3-Pro is ready to receive I2C commands. Afterwards
initialization commands are sent to the device to configure the default settings. This
initialization routine disables the watchdog timer and Fast VI Limit. UVL timer is also
initialized to 64ms.
The 400 kHz clock frequency for I2C communication is set-up on initialization.

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Basic Control Functions6.1.4
Updates the Output Voltage and Constant Current Setting
Follows a certain sequence of I2C commands in order to avoid inadvertent triggering
of UV or OV faults
Controls the VOUT pin strong bleeder when Decreasing the voltage from High to Low
Setting
Automatically updates the Over Voltage (OVA) and Under Voltage (UVA) settings
OVA is 124% of CV Setpoint
UVA is Fixed to 3V Setting
Inno3Pro.Inno3Pro_Write_VI( Volts, Amps )
Updates the Output Voltage without Bleeder Control
Inno3Pro.Inno3Pro_Write_Volts( Volts )
Sets the Constant Current Setting
Inno3Pro.Inno3Pro_Write_Amps( Amps )
Sets the Over Voltage Setting
Inno3Pro.Inno3Pro_Write_Over_Volts( Value )
Sets the Under Voltage Setting
Inno3Pro.Inno3Pro_Write_Under_Volts( Value )
Sets the Cable Drop Compensation Value
Inno3Pro.Inno3Pro_Write_Cable_Drop_Comp( Value )
Sets the Constant Output Power Threshold
Inno3Pro.Inno3Pro_Write_Volt_Peak( Value )
Used for Turning On or Off the Bus Voltage Switch
Inno3Pro.Inno3Pro_Vbus_Switch_Control( Value )
Used for Turning On or Off the VOUT pin strong bleeder
The BLEEDER must not be enabled for extended period of time to prevent excessive
power dissipation in the controller
Inno3Pro.Inno3Pro_Bleeder_Enable ( Value )

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Basic Code Examples6.1.5
Example 1 - Inno3Pro_Basic.ino6.1.5.1
Demonstrates the basic usage of InnoSwitch3-Pro Arduino Library.
Initial commands are sent using the InnoSwitch3-Pro Initialization Routine.
The Main Routine using write VI sets the output voltage to 5V and constant current
current to 5.1A.
Cable Drop Compensation is programmed to 300mV.
Constant power is knee voltage is set to 7V and then Vbus Switch is turned ON
This code example is presented on “examples\Inno3Pro_Basic\Inno3Pro_Basic.c”
Copy and paste these contents to your Arduino sketch.

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Example 2 - Inno3Pro_Basic_Volts_Amps_OV_UV.ino6.1.5.2
Demonstrates the basic usage of InnoSwitch3-Pro Arduino Library.
Initial commands are sent using the InnoSwitch3-Pro Initialization Routine.
Output Over voltage is set to 6.2V and Output Under voltage is programmed to 3.6V
The Main Routine sets the output voltage to 5V and constant current current to 5.1A.
Cable Drop Compensation is programmed to 300mV.
Constant power is knee voltage is set to 7V and then Vbus Switch is turned ON
This code example is presented on “examples\Inno3Pro_Basic_Volts_Amps_OV_UV\
Inno3Pro_Basic_Volts_Amps_OV_UV.ino”
Copy and paste these contents to your Arduino sketch.

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Building the Project7
Arduino board selection7.1 Under tools menu, Select Arduino UNO board
Make sure your Arduino Uno is already connected to your computer
through the usb port
Select the Active Com Port7.2 Under tools menu, Select the correct port
For Arduino UNO, the name will appear next to the serial port

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Verify / Compile7.3 Click the check icon to Verify
After few seconds , “Done Compiling” should show up on the Notification Area
This means the sketch is ready for uploading to the Arduino board
Upload7.4 Click the Arrow icon to Upload
After few seconds , “Done Uploading” should show up on the Notification Area
This means the upload was successful

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Demonstration of Operation8
Running the Program8.1
This section demonstrates code Example 1 or Example 2 in action.
Upon power up, the Arduino program is uploaded to InnoSwitch3-Pro.
100VAC was applied to the AC input terminals and output terminals were connected
to a Chroma DC electronic load. Arduino Uno board is connected to a USB port.