App note: Miniature, precision negative reference requires no precision resistors

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App note from Maxim Integrated creating voltage negative reference from charge-pump inverter plus positive voltage reference combo. Link here (PDF)

This application note discusses how to build a negative voltage reference without using external resistors or a negative supply by simply combining a simple charge-pump inverter and a positive output voltage reference.

App note: Simple test method for estimating the stability of linear regulators

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Tips from ROHM Semiconductor to estimate the stability of linear regulator using simple step response method. Link here (PDF)

Low drop-out (LDO) regulators developed back in the age when large-capacitance multi-layer ceramic capacitors (hereinafter, MLCCs) were uncommon cause a phase delay, leading to oscillation when connected to a low-ESR capacitor like an MLCC. Often, MLCCs are used to save board space and prolong the lives of electronic components. A resistor placed in series in the circuit increases apparent ESR and establishes a phase lead that enable the use of an MLCC as an output capacitor. Phase margin measurement is practical on an LDO having variable output voltage, since its feedback loop is outwardly exposed. However, on a fixed output voltage LDO, the phase margin cannot be measured because of its closed loop circuit.

Op amp on the Moon: Reverse-engineering a hybrid op amp module

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Ken Shirriff has written an article on reverse engineering a hybrid op amp module:

I recently obtained a mysterious electronic component in a metal can, flatter and slightly larger than a typical integrated circuit.1 After opening it up and reverse engineering the circuit, I determined that this was an op amp built for NASA in the 1960s using hybrid technology. It turns out that the development of this component ties connected several important people in the history of semiconductors, and one of these op amps is on the Moon.

See the full post on his blog.

Piggybacking USB onto an industrial push button

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Glen Akins has written an article detailing his USB-connected big red button project:

In this project, I mount the electronics from my single-key USB keyboard project to the back of an industrial mushroom push button switch. The finished big red button now activates my screensaver with a single overly-large button press. The biggest issues in this project were where to mount the USB electronics and how to connect the USB cable between the button and my computer.

More details on Photons, Electrons, and Dirt blog.

Resistive load, constant-current power supplies, and a 3D printed desk lamp

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Dr. Scott M. Baker published a new build:

In this video, I build a 3D Printed Desk lamp. The basic design came from Thingiverse, but I repurposed my LM2576 Constant-Current design to serve as a dimmer.  It all started when I found an interesting lamp on thingiverse, which used 75mm air hose segments from another model to make a flexible articulating desk lamp. What appealed to me about this project is the size of it, and the use of COB LED panels, which I’ve been wanting to experiment with.

See the full post on his blog.

Check out the video after the break.

App note: Receiving S/PDIF audio stream with the STM32F4/F7/H7 series

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App note from STMicroelectronics about electrically connecting an external S/PDIF stream to an STM32 with an S/PDIFRX interface peripheral, Link here (PDF)

The Sony/Philips Digital Interface Format (S/PDIF) is a point-to-point protocol for serial and uni-directional transmission of digital audio through a single transmission line for consumer and professional applications. The transmission of data can be done in several ways, by electrical or optical means.

The S/PDIFRX peripheral embedded in STM32 devices is designed to receive an S/PDIF flow compliant with IEC-60958 and IEC-61937, which define the physical implementation requirements as well as the coding and the protocol. These standards support simple stereo streams up to high sample rates, and compressed multi-channel surround sound, such as those defined by Dolby or DTS.

App note: Addressing power supply challenges for after-market electronics and infrastructure

Addressing Power Supply Challenges for After-Market Electronics and Infrastructure

This application note discusses key market trends and customer needs that are presenting new challenges for power supply design for after-market technologies and transport infrastructure automation. This piece will also examine solutions to address these challenges, with a special emphasis on power architecture. Link here

After-market automotive products have driven remarkable innovation, from infotainment and telematics to advanced driver assistance systems (ADAS). Features like GPS, rear-view cameras, and parking sensors are now common in vehicles. There is also a continuous rollout of novel after-market technologies being developed by companies worldwide. Fleet management, on-board diagnostics, heads-up display, and freight control/monitoring are just a few examples of technologies found in cars and trucks, trains, ships, avionics, and defense applications.

Wifi based DIY 5V switcher for led-lights

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Albert posted a detailed how-to on building DIY ESP-12F based USB-5V switcher:

5V powered 100LED circuit was consuming around ~1.8Watts(though 5.1Ohm series resistor was really hot) and the brightness of the LED’s were not bad, especially difference between first led and last led brightness didnt bother me it was hardly noticeable when seen from distance. So I decided to use them as a christmas decoration for my garden.
I wanted to use them with battery-bank as there was no power-outlet readily available(for the safety of my children, i would avoid any 230v circuit in my garden especially in wet weather). Also I wanted them to be switchable remotely to avoid going out in the freezing cold. Hence this is what i came up with.. an “ESP-12F based USB-5V switcher”

See the full post on his blog.