App note: Choose the right power supply for your FPGA

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Designing a power supply for FPGA includes multiple voltage, ripple management and power sequencing, here’s an app note from Maxim Integrated. Link here (PDF)

Field-programmable gate arrays (FPGAs) and complex programmable logic devices (CPLDs) require 3 to 15, or even more, voltage rails. The logic fabric is usually at the latest process technology node that determines the core supply voltage. Configuration, housekeeping circuitry, various I/Os, serializer/deserializer (SerDes) transceivers, clock managers, and other functions all have differing requirements for voltage rails, sequencing/tracking, and voltage ripple limits. An engineer must consider all of these issues when designing a power supply for an FPGA.

from Dangerous Prototypes http://ift.tt/2jEOgDR

App note: Current-sense amplifier doubles as a high common mode instrumentation amplifier

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Application note from Maxim intergrated on utilizing a boost converter and a current-sense amplifier to form a regulator that derives +5V from -48V without isolation. Link here (PDF)

Instrumentation amplifiers (IAs) are used where gain accuracy and dc precision are important, such as in measurement and test equipment. The downside of IAs is the cost. However, inexpensive current-sense amplifiers handle high common-mode voltages and share some traits with IAs. As a result, in some applications, such as a ground-referenced -48V to +5V power converter, current-sense amplifiers can replace IAs, thereby reducing cost.

from Dangerous Prototypes http://ift.tt/2BrwVbX

Free PCB coupon via Facebook to 2 random commenters

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook with a coupon code for the PCB drawer.
  • Limit one PCB per address per month, please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

from Dangerous Prototypes http://ift.tt/2A4CaKr

Bus timer project

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Limpkin published a new build:

For once, this project was not for me… it was for my wife !
Every morning she takes the bus then train to go to work. If she misses her train, she has to wait for more than 30 minutes for the next one. Not missing her bus is therefore quite important.
Where we live every bus station has a display letting you know in real time when the next bus will be there. My first thought was to reverse engineer its RF signal but something easier then came to mind.
In the very same bus stations, a small QR code brings you to a web page displaying the very same “minutes before bus arrival”… HTML parsing therefore made more sense given that I was fairly busy with other projects.

See the full post on his blog.

from Dangerous Prototypes http://ift.tt/2Algv4S

App note: Current sensing in metering applications using a pulse current sensor and ST metering devices

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App note from STMicroelectronics about current sensing using Rogowski coil together with STPMxx metering device. Link here (PDF)

This application note describes the benefits of a current sensing system for metering applications using STPMxx metering devices and a current sensor developed by Pulse Engineering Inc. (hereafter referred to as “Pulse current sensor”), based on the Rogowski coil principle. Following an overview of the Rogowski coil principle, the Pulse current sensor is introduced along with a comparison to other current measuring devices. This is followed by a presentation of the characteristics of the STPMxx family of metering devices, and the results of accuracy testing conducted using a demonstration board with the STPM01 and the Pulse current sensor.

from Dangerous Prototypes http://ift.tt/2AHGsek

App note: Watt-hour meter based on the STM32F101 microcontroller

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ARM Microcontroller based watt-hour meter implementation from STMicroelectronics. Link here (PDF)

This document describes, in detail, the hardware and software implementation of a watthour meter using the STM32F101 microcontroller. This cost effective watt-hour meter uses shunt with an operational amplifier as a current sensor, an embedded 12-bit ADC for current and voltage measurement, GPIO for LCD management, and a lot of other peripherals for communication, tamper detection, keyboard, and power disconnection. Powerful architecture of the STM32™ microcontroller allows sampling at 1 Msps. The high sampling rate makes it possible to use methods for ADC resolution enhancement.

from Dangerous Prototypes http://ift.tt/2A0OAXC

Free PCB coupon via Facebook to 2 random commenters

BP

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook with a coupon code for the PCB drawer.
  • Limit one PCB per address per month, please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

from Dangerous Prototypes http://ift.tt/2zUndyr