The EVAL-CN0556-EBZ is a programmable buck or boost power supply featuring an adjustable buck output of 2 V to 14 V, 35 A, and adjustable boost output of 14 V to 56 V, 10 A. The design allows the mode of operation to externally controlled or automatically selected. Six independent control loops regulate input and output voltage in both directions, as well as provide input and output current limit programming and monitoring.
The system input and output voltages and currents are monitored and controlled through analog I/O. Using an analog I/O module, a single board computer such as a Raspberry Pi platform can receive telemetry information to control the board remotely.
The input and output voltages and current limits of the CN0556 can be controlled through software. Interfacing CN0556 with the CN0554 analog I/O module enables full control capability. For the device to run, the SD card should be loaded with Analog Devices Kuiper Linux, a distribution based on Raspbian from the Raspberry Pi Foundation. It incorporates Linux device drivers for ADI products as well as tools and other software products designed and created with ease of use in mind. The reasoning behind creating this distribution is to minimize the barriers to integrating ADI hardware devices into a Linux-based embedded system.
Access to the embedded system can be through a remote PC connected either via LAN cable or Wi-Fi.
In order to control the EVAL-CN0556-EBZ from the Raspberry Pi, you need to install ADI Kuiper Linux on an SD card. Complete instructions, including where to download the SD card image, how to write it to the SD card, and how to configure the system are provided at Kuiper Images.
There is an available Wiki Page which explains in detail on how to download and flash the SD card using Windows or Linux OS: 'Configuring the SD Card for Raspberry Pi Projects' in the Formatting and Flashing SD Cards using Windows.
For the Linux kernel to identify the device connected to the expansion header, update the device tree overlay. A Device Tree Overlay contains information about additional connected hardware, the EVAL-CN0556-EBZ for this case. The overlay file is already included in the SD card and just needs to be matched to the EVAL-CN0556-EBZ.
Follow the procedure under 'Configuring the SD Card for Raspberry Pi Projects' in the Analog Devices Kuiper Linux page, substituting the following lines in config.txt
This brings up the file in the terminal. Scroll down until the line that begins with “dtoverlay” is found; then, whatever it currently is, change it to:
Need to add overlay here since it isn't in Kuiper
dtoverlay=rpi-cn0556
PyADI-IIO is a python abstraction module for ADI hardware with IIO drivers to make them easier to use. This module provides device-specific APIs built on top of the current libIIO python bindings. These interfaces try to match the driver naming as much as possible without the need to understand the complexities of libIIO and IIO.
Follow the step-by-step procedure on how to install, configure, and set up PyADI-IIO and all necessary packages and modules found in pyadi-iio: Device Specific Python Interfaces for IIO Drivers.
Using 3.3 V from the on-board LDO
At P1, check if the shunt placed is in correct position. The shunt should be placed correctly to short Pins 3 and 4. If it is not in proper placement, move the shunt to the correct position before performing the rest of the tests.
Disabling Current Sharing Capability
The CN0556 enables a masterless fault-tolerant mechanism for sharing output current, following below configuration:
Share Capability | ISHARE pin | IGND pin |
---|---|---|
ENABLED | ISHARE shorted to IGND with RSHARE resistor in between | |
DISABLED | Shorted to INTVCC | Shorted to AGND |
By default, this capability is disabled in CN0556.
The EVAL-CN0556-EBZ can be programmed to function in buck or boost mode. Follow below steps to check the buck and boost converter functionality of the EVAL-CN0556-EBZ when connected to the EVAL-CN0554-RPIZ, and its capability to control and monitor the input and output voltage and current.
Warning: The following steps involve high DC voltages. Follow instructions carefully to prevent hot plugging, which may damage the device by an overvoltage transient.
By default, the example script sets the board into Buck Mode and sets its parameters to its maximum values.
You may try to adjust the values after this test. Refer to the table of ranges appropriate for each control function.
~/pyadi-iio/examples/cn0556_examples $ python cn0556_example_buck.py
The CN0556 buck mode pyadi-iio example script enables the user to control the input and output parameters of the board, as well as to measure the current and voltage at the input and output terminals. The summary of the CN0556 functions for Buck Mode can be found below:
Parameter | pyadi-iio Function | Description | Minimum Value | Maximum Value | |
---|---|---|---|---|---|
Write Functions | V1 Input Voltage | my_cn0556.set_buck_input_volt(value) | sets the buck input voltage value | 14 V | 56 V |
V1 Undervoltage | my_cn0556.set_buck_input_undervolt(value) | set the buck input undervoltage value | 12 V | 54 V | |
V2 Output Voltage | my_cn0556.set_buck_output_volt(value) | sets the buck output voltage value | 2 V | 14 V | |
V1 Input Current Limit | my_cn0556.set_buck_input_current_lim(value) | sets the buck input current limit value | 0.07 A | 10 A | |
V2 Output Current Limit | my_cn0556.set_buck_output_current_lim(value) | sets the buck output current limit value | 0 A | 35 A | |
Read Functions | Input Voltage at V1 | my_cn0556.measure_buck_input_volt() | measures the buck input voltage at V1 side | approx. 14 V to 56 V | |
Output Voltage at V2 | my_cn0556.measure_buck_output_volt() | measures the buck output voltage at V2 side | approx. 2 V to 14 V | ||
Input Current at V1 | my_cn0556.measure_buck_input_current() | measures the buck input current at V1 side | approx. 0.07 A to 10 A | ||
Output Current at V2 | my_cn0556.measure_buck_output_current() | measures the buck output current at V2 side | approx. 0 A to 35 A |
Warning: The following steps involve high DC voltages. Follow instructions carefully to prevent hot plugging, which may damage the device by an overvoltage transient.
By default, the example script sets the board into Boost Mode and sets its parameters to its maximum values.
You may try to adjust the values after this test. Refer to the table of ranges appropriate for each control function.
~/pyadi-iio/examples/cn0556_examples $ python cn0556_example_boost.py
The CN0556 boost mode pyadi-iio example script enables the user to control the input and output parameters of the board, as well as to measure the current and voltage at the input and output terminals. The summary of the CN0556 functions for Boost Mode can be found below:
Parameter | pyadi-iio Function | Description | Minimum Value | Maximum Value | |
---|---|---|---|---|---|
Write Functions | V2 Input Voltage | my_cn0556.set_boost_input_volt(value) | sets the boost input voltage value | 10 V | 14 V |
V2 Undervoltage | my_cn0556.set_boost_input_undervolt(value) | sets the boost input undervoltage value | 8 V | 12 V | |
V1 Output Voltage | my_cn0556.set_boost_output_volt(value) | sets the boost output voltage value | 14 V | 56 V | |
V2 Input Current Limit | my_cn0556.set_boost_input_current_lim(value) | sets the boost input current limit value | 0 A | 35 A | |
V1 Output Current Limit | my_cn0556.set_boost_output_current_lim(value) | set the boost output current limit value | 0.07 A | 10 A | |
Read Functions | Input Voltage at V2 | my_cn0556.measure_boost_input_volt() | measures the boost input voltage at V2 side | approx. 10 V to 14 V | |
Output Voltage at V1 | my_cn0556.measure_boost_output_volt() | measures the boost output voltage at V1 side | approx. 14 V to 56 V | ||
Input Current at V2 | my_cn0556.measure_boost_input_current() | measures the boost input current at V2 side | approx. 0 A to 35 A | ||
Output Current at V1 | my_cn0556.measure_boost_output_current() | measures the boost output current at V1 side | approx. 0.07 A to 10 A |
EVAL-CN0556-EBZ Design & Integration Files
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