DEMO MANUAL DC2467A
LTC2970
Dual Power Supply Monitor Linduino Shield
with LTC3604 and LT3581 Regulators
Description
The DC2467 Linduino
®
shield is a demonstration system
for the
LTC
®
2970
dual power supply monitor and margin-
ing controller. The LTC2970 provides a rich set of features
for monitoring and controlling two power rails, including
monitoring supply voltage and current, detecting faults in
voltage and current, margining the supply voltage high or
low, measuring temperature, and turning the supplies on
and off through GPIO pins. It is fully accessible through
the built-in I
2
C bus, which allows it to communicate with
an external microcontroller or other I
2
C bus master.
The DC2467 Linduino shield operates in conjunction with
a Linduino One (DC2026) and with a DC1613 controller.
The Linduino is a microcontroller that comes with a full
library of existing C code examples, as well as the capa-
bility to run custom C code to control the LTC2970. The
DC1613 enables a PC running LTpowerPlay
®
to access
the LTC2970 on the DC2467. Linduino and LTpowerPlay
cooperate to enable code development and debugging in
one convenient system.
On the DC2467 board, two DC/DC switching regulators
provide +5V and –5V power outputs and demonstrate
how the LTC2970 monitors and controls power supplies
in a system. The LTC2970 fully controls both regulators.
The LTC3604 is a buck regulator with integrated switches,
configured to step down the +12V input to +5V at 1A. The
LT3581 is a multifunction switching regulator, configured
here as an inverting DC/DC converter producing –5V at –1A.
DC2467 Features
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Demonstrate the Capabilities of the LTC2970
Two Onboard Power Supplies: +5V and –5V
Monitor Supply Voltage and Current
Adjust Supply Voltage Higher or Lower on Command
Monitor Voltage and Current Faults with Adjustable
Thresholds
Monitor LTC2970 Die Temperature
Connect to both Linduino and LTpowerPlay
Demonstrate C Code Available for the LTC2970
DC2467 Shield
Linduino One (DC2026)
USB-to-I
2
C/SMBus/PMBus Controller (DC1613)
+12V Power Supply
2 USB Cables
DC2467 Hardware Required
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Design files for this circuit board are available at
http://www.linear.com/demo/DC2467A
L,
LT, LTC, LTM, Linear Technology, Linduino, LTpowerPlay and the Linear logo are registered
trademarks and QuikEval is a trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
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DEMO MANUAL DC2467A
Description
I
2
C TURRETS
I
2
C ACTIVITY LED
I
2
C ALERT LED
+5V OUTPUT
DC1613
CONNECTOR
GPIO LEDS
LTC2970
–5V OUTPUT
POWER LEDS
DC2467 BOARD
performance summary
Table 1. LTC2970 Performance Summary
PARAMETER
12VIN Supply Input Voltage Range
VDD Regulator Voltage Range
ADC Total Unadjusted Error
ADC Input Range
ADC Resolution
ADC Conversion Time
Margining DAC Resolution
Temperature Sensor Resolution
I
2
C Serial Clock Frequency
Resolution = 8.192V/16384
V
IN
= 3V
CONDITIONS
VALUE
8V to 15V
4.75V to 5.25V
±0.5%
0V to 6V
500μV/LSB
33.3ms
8-bits
0.25°C/LSB
10kHz to 400kHz
Table 2. DC2467 Performance Summary
PARAMETER
VOUT_CH0
IOUT_CH0 (Max)
VOUT_CH0 Servo Range
VOUT_CH1
IOUT_CH1 (Max)
VOUT_CH1 Servo Range
Untrimmed
T = 25°C
CONDITIONS
Untrimmed
T = 25°C
VALUE
+5V ±50mV
1A
±0.8V
–5V ±50mV
–1A
±0.75V
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DEMO MANUAL DC2467A
LinDuino Quick start
Make sure that the Linduino software is properly installed
on your PC, then get started quickly developing code for
the LTC2970 with these easy steps.
1. Follow the Linduino installation instructions in the
DC2026 demo manual.
Follow the software installation and IDE configuration
instructions. These can be found on the Linduino main
web page and include instructions for downloading
and installing the Arduino software and downloading
and installing the LTSketchbook. Both of these steps
must be completed successfully before proceeding
further (see Note 1 at the end of this document). Begin
with this web page:
http://www.linear.com/solutions/linduino
This document assumes software running on a
Windows PC. LTpowerPlay only runs on Microsoft
Windows. Linux and Mac versions of the Arduino
software are available. While these usually work well
with the Linduino, they may have their own platform-
specific details and are not specifically addressed in
this document.
LTSketchbook is the complete code base for the
Linear Technology devices supported by the Linduino
platform. It includes library code, demonstration
sketches and HTML documentation. Download the
latest LTSketchbook.zip from:
http://www.linear.com/docs/43958
The LTSketchbook contains code for many Linear
Technology
®
ICs and demo boards, so it is important
to upload the specific DC2467 sketch to the Linduino
before using it. Below, we show how to do this (see
Note 5).
2. Plug in the Linduino
Attach the DC2467 to the DC2026 shield connector.
The DC2467 shield will plug into the top of the DC2026,
with corresponding pins lined up along both edges.
Figure 1 shows the proper arrangement.
Set the DC2467 jumpers as follows:
JUMPER
ASEL0
ASEL1
GPIO_CFG
SETTING
LO
LO
LO
Plug in the USB cable to the DC2026 and to the PC. The
USB connector powers the DC2026 and the LTC2970.
The DC2026 communicates with the PC through the
USB connection.
Plug in the +12V wall adapter power source. This is
necessary to supply power to the two onboard DC/DC
converters on the DC2467. +12V is not necessary to
power the LTC2970 and initiate I
2
C communication.
The voltage should remain between 8V and 15V.
Figure 1. DC2467 Shield Mounted on the DC2026 Linduino
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DEMO MANUAL DC2467A
LinDuino Quick start
3. Upload the Linduino sketch
The Linduino has a microcontroller with nonvolatile
flash program memory. It stores instructions that
execute upon power-up or reset. The contents of the
Linduino flash memory should be updated to talk to the
LTC2970. The LTSketchbook contains a demonstration
sketch for the DC2467.
Begin by opening the Arduino software. Select the
DC2467 sketch in the Arduino File menu (Figure 2):
File→Sketchbook→Part_Number→2000→2900→
2970→ DC2467
Ensure that the Arduino software is using the correct
COM port (see Note 3 at the end of this document).
Microsoft Windows communicates with the Linduino
through a serial port (COM port). You must tell the
Arduino software which COM port to use.
Tools→Port→COMxx
Note that every time you plug in the Linduino USB
connector your PC may select a different COM port
for it. Often the COM port number will be 5 or higher.
Press the arrow button at the top of the window to
compile and upload the sketch (Figure 3).
Figure 2. Open the DC2467 Sketch from the Sketchbook Menu
Figure 3. Press the Compile and Upload Button
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DEMO MANUAL DC2467A
LinDuino Quick start
4. Execute Linduino menu commands
Now the Linduino is running the desired code and
ready to command the LTC2970. The primary user
interface is the serial port, which sends and receives
simple ASCII characters to the PC and can act on
simple menu-driven inputs and return basic responses
(Figure 5).
Open the serial terminal by pressing the “Serial Moni-
tor” button at the top of the window (Figure 4). The
serial monitor opens in a new window.
When the Arduino software is configured correctly, the
Linduino prints a menu in the serial monitor window
(Figure 5). Select one of the menu actions by typing its
number in the command line at the top of the window
and pressing ENTER.
Figure 5. Serial Monitor Showing the Menu from the
Linduino and the DC2467
Figure 4. Press the Serial Monitor Button
The DC2467 Linduino sketch includes options for
exercising many of the features of the LTC2970. Each
option invokes a C-code procedure. When you select a
menu option the Linduino executes the code, sending
a series of commands over the I
2
C bus, then it stops,
freeing the bus for other traffic. This is important be-
cause it allows other I
2
C bus masters to communicate
with the LTC2970.
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