Page 573 – Electronics-Lab.com

Minimal ATSAMD21 Computer is Arduino compatible

Posted on 12 March, 201912 March, 2019 by mixos

This project describes how to build an ATSAMD21-based computer on a prototyping board using the minimum number of components, and program it from the Arduino IDE. David Johnson-Davies writes:

I give two alternative methods of uploading a bootloader to the bare ATSAMD21 chip using the Arduino IDE. You can then program the minimal ATSAMD21 computer from the Arduino IDE via the USB port, like any other Arduino board.

If you’re looking for something more powerful than the ATmega328 in the Arduino Uno a good choice is the ATSAMD21. This is an ARM Cortex M0+ processor with up to 256 KB flash memory, 32 KB RAM, and a 48 MHz clock, so it’s substantially better equipped than the ATmega328. In addition it has a USB interface built in, so there’s no need for a separate chip to interface to the serial port.

Minimal ATSAMD21 Computer is Arduino compatible – [Link]

Bootstrap Circuit in the Buck Converter explained

Posted on 12 March, 201912 March, 2019 by mixos

This application note explains the step-up circuit using a bootstrap capacitor. In buck converters, this circuit is used when the high-side switch is the N-ch MOSFET.

The configuration of the circuit in proximity to a buck converter depends on the polarity of the high-side switch.When a P-ch MOSFET is used for the high-side switch, there are advantages over using a N-ch MOSFET, such as the capability of driving the switch with input voltage VINas the gate voltage, as well as voltage reduction and obtainment of the maximum duty. On the contrary, the use of a P-ch MOSFET requires a larger chip area for passing the same current.The use of an N-ch MOSFET for the high-side switch requires a gate voltage of VIN+ Vth (threshold voltage of the N-ch MOSFET) or higher. A step-up circuit is required because the gate voltage is higher than VIN. This circuit is configured with an internal diode and an external bootstrap capacitor (charge pump type). The total cost, including the cost of the external bootstrap capacitor, can be lowered because the chip area can be reduced compared with the P-ch MOSFET, as mentioned above.

Bootstrap Circuit in the Buck Converter explained – [PDF]

Infineon Technologies XDPL8221 Digital PFC+Flyback Controller

Posted on 12 March, 201912 March, 2019 by mixos

The emerging trend of smart lighting and Internet of Things, requires a new generation of LED drivers. Infineon Technologies AG introduces the new member of its XDP LED series, the XDPL8221 for cost-effective dual-stage drivers with advanced features. This device combines a quasi-resonant PFC and a quasi-resonant flyback controller with primary side regulation together with a communication interface. A comprehensive set of configurable protection mechanisms (standard and sophisticated) ensure safe, reliable and robust LED driver for a large set of use cases. The new driver IC will be showcased at the APEC 2019 exhibition in Anaheim, CA.

The XDPL8221 combines advanced functions, such as multi control featuring constant voltage, constant current and limited power as configurable operating parameters. The result is a versatile, high performance LED driver.

The performance of the XDPL8221 helps to design more efficient devices. This driver IC supports full functionality for both AC and DC input in the nominal input voltage range of 100 V_AC to 277 V_AC or 127 V_DC to 430 V_DC. Depending on the actual situation, the built-in digital control selects the best mode of operation. It can switch between quasi-resonant, discontinuous conduction or active burst modes.

The XDPL8221 FB can be configured to operate in Constant Voltage (CV), Constant Current (CC) or Limited Power (LP) mode offering a large degree of flexibility.

The XDPL8221 UART interface with a command set enables control of the functions of the device and provides status information. This enables numerically exchanged real-time data. This data can be used for monitoring or additional local control functions.

This driver IC can be dimmed flicker free below one percent, while the current is still regulated with a high accuracy. The chip also offers a dim-to-off function to keep the device in a standby mode when the light is off with a low standby power (less than 100 mW, depending on driver design).

Reduced bill of materials (BOM) and increased flexibility minimize the overall system cost. The XDPL8221 comes in a DSO-16 package and, with a wide tool support, it is easy to design-in. This accelerates the design cycle and shortens time-to-market.

Features

UART interface to control driver output and reading operating status
Flicker-free output dimming by analog reduction of driving current down to 1%
Integrated two stage digital controller allows a reduced number of external parts, optimizes Bill of Materials (BOM) and form factor
Two-stage design eliminates AC ripple on output
Supports universal AC and DC input voltage (90V_rms to 305V_rms) nominal
High efficiency up to 90%
Multi-control output
- Constant Current (CC)
- Constant Voltage (CV)
- Limited Power (LP)
Performance and protection related driver parameters are configurable via UART interface allowing for design flexibility and optimization
Low harmonic distortion (Total Harmonic Distortion (THD) <15%) down to 30% nominal load

Integrated 600V high voltage start-up cell ensures fast time to light (<250ms)
Configurable Adaptive Temperature Protection
Automatic switching of the Power Factor Correction (PFC) between Quasi-Resonant Mode (QRM) and Discontinuous Conduction Mode (DCM)
Automatic switching of the Flyback (FB) between QRM, DCM and Active Burst Mode (ABM)
Pulse Width Modulation (PWM) dimming input
Comprehensive set of protection features with configurable reaction like auto-restart or latch
- Output over-voltage protection (open load)
- Output under-voltage protection (output short)
- VCC over- and under-voltage lockout
- Input over- and under-voltage protection
- Bus over- and under-voltage protection
- Over-current protection for both PFC and FB stages
Package
- PG-DSO-16
- 10mm x 4mm

Applications

Flicker free LED driver for indoor or outdoor applications
Multi-mode LED driver for connected lighting
Smart LED driver
Wired or wireless connected LED driver

Documentation

XDPL8221 Digital PFC+Flyback Controller

Application Notes

Availability

The new XDPL8221 is now available. More information is available at www.infineon.com/xdpl8221.

Khadas VIM2 v1.4 SBC gets an array of upgrades

Posted on 12 March, 201912 March, 2019 by mixos

Shenzhen Wesion has recently launched Khadas VIM2 v1.4 with various improvements they neatly describe in a PDF document.

Currently there are three versions of Khadas VIM2 (v1.2) boards:

VIM2 Basic – 2GB DDR4, 16GB eMMC flash, Ampak AP6356S wireless module with 802.11 b/g/n/ac WiFi 5, and Bluetooth 4.1 connectivity
VIM2 Pro – 3GB DDR4, 32GB eMMC flash, Ampak AP6359SA wireless module with 802.11 b/g/n/ac with RSDB and Bluetooth 4.2 connectivity
VIM2 Max – 3GB DDR4, 64GB eMMC flash, Ampak AP6359SA wireless module with 802.11 b/g/n/ac with RSDB and Bluetooth 4.2 connectivity

The latest Changes:

AP6398S 802.11ac Wi-Fi (Pro / Max), with Bluetooth 5.0
Updated fan header to support the 3705 Cooling Fan
Thinner transformer H5120NL to support the New VIM Heatsink
Better airflow, and quieter cooling when combined with the DIY Case
Khadas TST, enter upgrade mode simply by pressing a button
Refer to this PDF Guide to see all changes from v1.2 to v1.4

Wi-Fi Module:

Pro / Max: AP6398S w/ BT 5.0
Basic: AP6356S w/ BT 4.1

Features:

Excellent performance: Amlogic S912 1.5GHz 64-bit Octa-Core CPU, T820MP3 GPU, and up to 3GB DDR4 & 64GB eMMC.
Unlimited connectivity: 2X2 MIMO AP6398S (Pro / Max) 802.11ac Wi-Fi, 5.x Bluetooth, Gbit Lan and a USB-C(2.0) port.
Advanced Specs: WOL(Wake on Lan) and RSDB Wi-Fi will improve the user experience steps forward.
Maker friendly: Equipped with 40-pin GPIO header, cooling fan slot and a programmable MCU.
Multimedia experts: HDMI2.0a and a powerful VPU with 10-bit 4K H.265/VP9@60fps playback support.
Tiny form factor: Thin and light with a dimensions of credit card.

Multi O/S Supported

Android 7.1
Google Fuchsia OS
Linux Mainline
LibreELEC 8.9 and later version
Ubuntu 16.04 and later version

More details at Khadas Website and Documentation.

The board sells at $99.90 and it is available on www.khadas.com

8 Channel Optically Isolated I/O Shield for Arduino Nano

Posted on 12 March, 2019 by mixos

This shield enables you to interface many different devices to Arduino Nano using optically isolated inputs/outputs. The circuit consists of 4 Input channels and 4 Output channels and all 8 I/O lines are optically isolated. This project can help in various industrial applications where EMI noise and high voltage lines can damage the Arduino Nano or other circuits connected to it. Circuit is built using 8 x 6N137 optocoupler. The 6N137 optocoupler can switch at frequency up to 10 MHz.

8 Channel Optically Isolated I/O Shield for Arduino Nano – [Link]

8 Channel Optically Isolated I/O Shield for Arduino Nano

Features

Supply of Arduino Nano 7-12V DC
Supply to Outputs of Optocoupler 5V DC
All Outputs are TTL 5V
Inputs 3.3V to 5V DC
4 Channel Inputs
4 Channel Outputs
PCB Dimensions 61.09 mm X 48.89 mm

Schematic

Parts List

Connections

Photos

6N137 Datasheet

Low Cost GL-USB150 Micro Router – A Potential Weapon in Disguise

Posted on 12 March, 201912 March, 2019 by Ayo Ayibiowu

Micro routers are portable USB mini routers used for cyber privacy or as access points. They are easy plug and play devices. GL.inet has introduced a low-cost micro router based on OpenWRT. The GL-USB150 micro router comes with the Qualcomm QCA9331 CPU, MIPS processor with the speed of 400 MHz, 64 MB DDR3 Ram is installed for system memory purpose. While the system storage is given 4 MB, that is a NOR flash type.

WiFi connectivity transmission rate is 150 Mbps at 2.4 GHz band with version 802.11 b/g/n. It is ready to be used with any USB port. Power is supplied via the USB port with standard 5V/1A, and power consumption less than 1 W. That’s even lower than counterpart routers of the same caliber.

Though the structure is minimized, which gives a lot of advantages in making it fit, on the other side, it has a few limitations. These limitations come in the shape of customization. Unlike other routers, this small router cannot be customized with additional extensions. There is no Ethernet port or extra USB port available. Just a USB port is enough to get on with its functionality. The USB port of power banks can also be used, as it only needs standard power input. Whether if you are running a computer or laptop with USB port, or portable USB power bank and charger, it can be plugged into a standard USB port.

GL-USB150 micro router specifications

CPU – Qualcomm QCA9331 (Atheros AR9331) MIPS processor @ 400MHz
System Memory – 64MB DDRII
Storage – 16MB NOR Flash
Connectivity – 2.4GHz 802.11b/g/n WiFi up up 150Mbps transmission rate
Power input – 5V/1A via USB port
Power consumption – <1W
Dimension – 82x24x11mm
Weight – 10 grams

There is no need to download and install drivers to make it compatible with every device you connect it to. Pre-installed OpenWRT gives freedom from that hectic work. OpenWRT software will make it plugged in as Linux OS, that is ready to be used. Slim and smart routers are the future. With the advancement in software and operating system, comes advancement in connectivity and power consumption as well.

Upon its connection to the computer via a USB port, it will work as a USB ethernet adapter automatically directing the user’s traffic through (I smell something here). Primary internet connection can be changed over to it very easily. In case the user wants to use a different WIFI connection, then no need to plug it off. Just keep it plugged in a while changing the connectivity to the secondary one.

When inserted into a Windows or Linux computer it boots to Linux then registers itself to the host (your client’s) computer as a USB Ethernet device. It becomes the default route to the network. This causes the PC to direct all it’s traffic through this device as opposed to the WiFi or Ethernet it was intended to be using. The router then joins a predetermined WiFi access point which it uses as it’s path to the Internet.

By setting this router to be accessible via the Tor Network you can access it remotely, usually even if the router is deployed behind a firewall or cable modem.

Although the device looks small, it’s a potential tool for the unjust hacker. As demonstrated by Mason Jeffers, the micro-router can be used as a penetration tool and with is USB Pendrive lookalike shape, it can easily camouflage as a standard flash drive to the unknown host. Imagine plugging this to a server, or some critical infrastructure, it can easily be used to maintain a backdoor into a network system.

This means you can walk into any your customer’s building and just push a small innocent looking USB device into a computer then watch and manipulate it’s traffic from the comfort of your home. You would also have access to a full blown Linux box in this network which you could use to mount any number of attacks.

This lightweight and easy to use micro router GL-USB150 is now available for purchase for $29 at Amazon and AliExpress. It comes open source and programmable in OpenWRT. More information is available on the product page.

The Compact BOXER-6405U: The Gateway to Industry 4.0

Posted on 12 March, 201912 March, 2019 by mixos

AAEON, an award winning manufacturer of embedded PC solutions, is proud to announce the BOXER-6405U, a turn-key rugged embedded PC built to be flexible and adaptable to a wide range of Industry 4.0 applications, including machine vision, AI edge computing, and industrial IoT gateway.

The BOXER-6405U is built to be a go-anywhere, work-anywhere solution. Rugged design gives it a wide operating temperature range from -20°C to 50°C. It’s palm-sized compact size, only 37mm thick, allows it to squeeze into tight operating spaces, and it’s wide voltage input range of 9V to 24V allow it to easily integrate with industrial power sources. The BOXER-6405U even comes with wall-mount brackets to ensure it’s ready to install wherever you need it.

The BOXER-6405U features an Intel N3350 processor with 2G DDR3L 1600 memory and up to 32 GB eMMC storage onboard. The BOXER-6405U comes with four USB 3.0 and two Intel i211AT Gigabit Ethernet ports, perfect for machine vision applications. The BOXER-6405U has two internal expansion bays, one full-sized Minicard and one half-sized Minicard, supporting a wide range of options including AI modules such as AAEON’s own AI Core X with Intel Movidius Myriad X VPU. With support for WiFi or 4GLTE cards, the BOXER-6405U can also be used for remote edge computing or as an industrial IoT gateway.

The BOXER-6405U is a rugged turn-key solution that is ready to go out of the box. With AAEON’s manufacturer support, it can even be tailored to meet the specific needs of your application.

The BOXER-6405U is a cost effective solution for tough industrial environments,” said Ken Pan, Product Manager with AAEON’s System Platform Division. “It’s a compact embedded computer built for vertical market applications such as machine vision and industrial gateway.

more information on: www.aaeon.com

Google Coral – An i.MX8M dev board with Edge TPU AI chip

Posted on 8 March, 20198 March, 2019 by Rik

Single board computers are not a new wonder anymore and the market has already experienced so many different devices based on numerous SoC and SOM. So, why should we be excited this time about the launch of a $150 “Coral Dev Board”? Well, there are multiple reasons – but the most important one is, the Coral Dev Board is manufactured by Google – a relatively new player in the consumer market of SBC and i.MX8M dev boards. Also, the dev board along with a USB accelerator stick is built around Google’s Edge TPU, their purpose-built ASIC designed to run machine learning inference at the edge.

So, what is the Edge TPU? The Edge TPU is a small ASIC designed and built by Google that provides high-performance ML inferencing with a low power cost. For example, it can execute state-of-the-art mobile vision models such as MobileNet v2 at 100+ fps, in a power efficient manner. This allows you to add fast ML inferencing to your embedded AI devices in a power-efficient and privacy-preserving way. For more information on this ASIC, check out googles official documentation.

The NXP i.MX8m based Coral Dev Board appears to be an open-spec design. It would join other open-spec i.MX8M SBCs such as the HummingBoard Pulse. Like SolidRun’s Pulse, the Coral is a sandwich-style board with a removable computer module. The big difference from the expanding field of i.MX8M boards are that the Coral SOM module integrates Google’s Edge TPU neural network co-processor.

The Edge TPU is a stripped-down version of Google’s TPU Unit designed to run TensorFlow Lite ML models on Arm Linux based IoT gateways running on boards like the Coral. The gateways connect to Google Cloud services that are optimized with full-strength Cloud TPU chips to work together via Google’s new Cloud IoT Edge framework. Edge TPU enables concurrent execution of multiple AI models per frame on a high-resolution video at 30fps.

Coral Dev Board

The Coral Dev Board is a single-board computer with a removable system-on-module (SOM) that contains SOC, eMMC, wireless radios, and Google’s Edge TPU. It’s perfect for IoT devices and other embedded systems that demand fast on-device ML inferencing. The board has a layout that’s somewhat similar to the Raspberry Pi. It offers a 40-pin GPIO connector just like raspberry pi. The Coral SOM connects to the baseboard with 3x 100-pin connectors. The Coral board is equipped with a microSD slot, as well as GbE, USB 3.0 host, USB Type-C OTG, USB Type-C 5V power, and micro-USB 2.0 serial console ports. Media I/O includes a full-size, 4Kp60-ready HDMI 2.0a port and 4-lane MIPI-DSI and CSI interfaces via FFC connectors. It also features a good old 3.5mm audio jack.

The Coral Dev Board is a single-board computer with a removable system-on-module (SOM) that contains SOC, eMMC, wireless radios, and Google’s Edge TPU. It’s perfect for IoT devices and other embedded systems that demand fast on-device ML inferencing.

Google EdgeTPU ASIC — Google Edge TPU ASIC

Coral USB Accelerator

Google also unveils Coral USB Accelerator and PCIe Accelerator. The USB Accelerator is a plug-in USB stick that brings powerful ML inferencing capabilities to existing Linux systems. With the Edge TPU connected over USB 3.0 interface, it allows for quick prototyping of local AI applications. The USB accelerator can boost inference on any Linux machine, while the dev board’s array of pins and ports make it perfect for prototyping hardware and other experimental applications. The 65 x 30 mm² USB Accelerator can even work with a Raspberry Pi board, although only at USB 2.0 speeds. The stick computer is built around a 32-bit, 32MHz Cortex-M0+ chip with 16KB of flash and 2KB of RAM.

Google's Coral Accelerator — Google’s Coral USB Accelerator

The Coral USB Accelerator is a plug-in USB stick that brings powerful ML inferencing capabilities to existing Linux systems. With the Edge TPU connected over USB 3.0 interface, it allows for quick prototyping of local AI applications.

The development board is accompanied by the Coral Camera – built around a 5 megapixel (2582×1933 pixel) Omnivision OV5645 sensor. The camera is connected to the board using the CSI interface. The 25 x 25mm camera looks like below:

Now, let’s list the important specifications of the Coral Dev Board:

Processor (via Coral SOM):
- NXP i.MX8M (4x Cortex-A53 @ 1.5GHz)
- Vivante GC7000Lite/GC7000VLX for OpenGL/ES 3.1, OpenGL 3.0, Vulkan, OpenCL 1.2 GPU
- Cortex-M4 @ 266MHz
- separate Edge TPU Accelerator and crypto coprocessor
Memory/storage:
- 1GB LPDDR4 RAM (via Coral SOM)
- 8GB eMMC flash (via Coral SOM)
- MicroSD slot
Wireless (via Coral SOM): 802.11 b/g/n/ac 2×2 MIMO and Bluetooth 4.1 BLE
Networking: GbE port
Media I/O:
- HDMI 2.0a output port (4K)
- MIPI-DSI (4-lane)
- MIPI-CSI (4-lane)
- Optional 5-megapixel CSI camera
- 3.5mm audio jack
- 2x digital PDM microphones
- 4-pin terminal for stereo speakers
Other I/O:
- USB 3.0 host port
- USB 3.0 Type C OTG port
- USB 3.0 Type C 5V power port
- Micro-USB serial console port
Expansion: 40-pin GPIO connector
Power: 5v DC via USB Type-C; 2x PMICs via Coral SOM
Operating temperature: 0 to 50°C
Dimensions: 88.1 x 59.9 x 22.38 including fan (possibly 85 x 56mm)
Operating system: Debian Linux

The Coral Dev Board with Coral SOM is available for $150 at Google and Mouser, but currently only via phone orders. It should start shipping to early buyers within the week. The same schedule likely pertains to the $75 USB Accelerator. The Coral SOM and PCI-E Accelerator will be available later this year, with pricing undisclosed. More information on all these products may be found on Google’s Coral Beta website.

The top 10 linear voltage regulators according to SnapEDA

Posted on 8 March, 20198 March, 2019 by mixos

In electronics, linear voltage regulators are commonly used to stabilize voltages. Regardless of the input voltages or load conditions, they will provide fixed output voltages, thus protecting devices from fluctuating outputs, which can cause inefficient performance or even damage.

When designing a power supply for an application that requires a small difference between its input and output voltages, hardware designers should consider linear voltage regulators.

Simplicity and cost are the main advantages of using linear regulators over switching voltage regulators. Additionally, the absence of switching noise makes linear regulators particularly useful for audio and video communication, medical devices and other noise-sensitive applications.

On the downside, linear voltage regulators generate heat and their efficiency is rather poor, varying between 30% and 60%. This is why they are used mainly for low-powered devices and small differences between input and output voltages.

Compared to linear regulators, switching voltage regulators (also known as switch-mode regulators) are superior in terms of efficiency and generate much less heat, but are also more expensive and complex.

When choosing between different voltage regulators for your application, you should consider several factors, including their maximum input voltages, the differences between input and output voltages, current ratings, temperature ratings, and output noise.

Most of the linear voltage regulators in our Top 10 list have overcurrent and thermal protection. Most also have maximum input voltages ranging from 5.5V up to 40V and output voltages ranging from 3.3V to 15V. The most popular vendors for voltage regulators on SnapEDA are Diodes Inc, Richtek USA Inc, Microchip, STMicroelectronics, and Texas Instruments.

Let’s now take a look at the Top 10 Linear Voltage Regulators on SnapEDA!

#10 – LP2985-33DBVR by Texas Instruments

This low dropout regulator has 16V Maximum input voltage, 3.3V output voltage, 150mA output current, 280mV Dropout voltage and -40°C to 125°C junction temperature range. The average price across distributors: $0.60

#9 – L7805ACD2T by STMicroelectronics

This positive regulator has 35V maximum input voltage, 5V output voltage, 1.5A output current, 2V dropout voltage and 0°C to 125°C junction temperature range. The average price across distributors: N/A

#8 – L7805CV-DG by STMicroelectronics

This positive regulator has 35V maximum input voltage, 5V output voltage, 1.5A output current, 2V dropout voltage, and 0°C to 125°C junction temperature range. The average price across distributors: $0.52

#7 – REG1117 by Texas Instruments

This low dropout positive regulator has 15V maximum input voltage, 1.8V output voltage, 800mA output current and -40°C to 125°C junction temperature range. The average price across distributors: $2.02

#6 – L7805CV by STMicroelectronics

This positive regulator has 35V maximum input voltage, 5V output voltage, 1.5A maximum output current, 2V dropout voltage and 0°C to 125°C junction temperature range. The average price across distributors: $0.41

#5 – LD1117S33CTR by STMicroelectronics

This low drop voltage regulator has 15V maximum input voltage, 3.3V output voltage, 950mA maximum output current, 1V dropout voltage and -40°C to 125°C junction temperature range.The average price across distributors: $0.36

#4 – AP2112K-3.3TRG1 by Diodes Inc.

This positive regulator has 6V maximum input voltage, 3.3V output voltage, 600mA maximum output current, 0.4V Dropout voltage and -40°C to 85°C junction temperature range. The average price across distributors: $0.24

#3 – RT9193-33GB by Richtek USA Inc.

This low dropout regulator has 5.5V maximum input voltage, 3.3V output voltage, 300mA maximum output current, 0.3V dropout voltage, and -40°C to 125°C junction temperature range. The average price across distributors: $0.50

#2 – MIC29302WU by Microchip

This low dropout regulator has 26V maximum input voltage, 3.3V output voltage, 3A output current, 0.6V maximum dropout voltage, and -40°C to 125°C junction temperature range. The average price across distributors: N/A

#1- LM1117MP-3.3 by Texas Instruments

This low dropout regulator has 15V maximum input voltage, 3.3V output voltage, 800mA maximum output current, 1.2 dropout voltage, and 0°C to 125°C junction temperature range. The average price across distributors: N/A