Tag Archives: Power

ESPurna-H, A Compact Open Source Hardware Wireless Power Wall Switch

Controlling your AC loads using wireless power switch is not a new concept. Several commercial products from several vendors can be found on the market such as Xiaomi’s Mi Smart Socket Plug, SAMSUNG’s SmartThings Power Outlet and Sonoff Pow WiFi Switch from ITEAD.

Using ESP8266 makes the building of a customized WiFi power switch more affordable especially if you start with Sonoff Pow WiFi Switch design and you use a special Arduino C firmware called ESPurna developed by Xose (tinkerman) which is an open source firmware for ESP8266 based wireless switches such as Sonoff POW and many others.

After Xose has built the software ــ ESPurna, he decided to build his own smart switch board to meet his special needs. ESPurna-H electronic design is very similar to Sonoff POW’s one; it uses ESP12 module as a controller and as WiFi transceiver.


AC power monitoring is done using HLW8012 IC which is also present in Sonoff POW. This IC monitors both voltage and current of the AC power, and output RMS voltage, current and active power encoded as a 50% duty cycle square wave where the frequency is proportional to the magnitude. I should mention that ESPurna supports interfacing with HLW8012. In addition AC load is enabled/disabled by using a 10A relay.

ESPurna-H uses HLK-PM01 AC-DC step-down power supply module. The 100-240 VAC input range so the board can be used anywhere in the world and the good performance made Xeos select this module.

HLK-PM01 Inside (Image Source ــ lygte-info.dk )
HLK-PM01 Inside (Image Source ــ lygte-info.dk )
HLK-PM01 Inside (Image Source ــ lygte-info.dk )
HLK-PM01 Inside (Image Source ــ lygte-info.dk )

ESPurna-H has another option to enable/disable the relay using a capacitive touch switch using TTP223 module.

Xose designed the board with Eagle CAD and released the schematics, PCB layout and other hardware design files on Github.

Source: cnx-software


In order to synthesize chlorates and perchlorates in the home lab it is always good to have a way to regulate the current flowing through the electrolyte. Because the load is purely resistive the simplest solution is a small PWM (Pulse Width Modulation) regulator. So I decided to make my own.

PWM Power Regulator – [Link]

LTC5596 – 100MHz to 40GHz Linear-in-dB RMS Power Detector


The LTC5596 is a high frequency, wideband and high dynamic range RMS power detector that provides accurate, true power measurement of RF and microwave signals independent of modulation and waveforms. The LTC5596 responds in an easy to use log-linear 29mV/dB scale to signal levels from –37dBm to –2dBm, at accuracy better than ±1dB error over the full operating temperature range and RF frequency range, from 200MHz to an unprecedented 30GHz. In addition, the device’s response has ±1dB flatness within this frequency range. A wider frequency range can be used, from 100MHz to 40GHz, however with slightly reduced accuracy at the frequency extremes. Its RF input is internally 50Ω matched from 100MHz to 40GHz, making the device very easy to use at any band within its useful frequency range.

LTC5596 – 100MHz to 40GHz Linear-in-dB RMS Power Detector – [Link]

The SilentSwitcher, A Quiet Mains-free Power Supply

Audio projects become smaller over time with the rapid advancement of technology. A traditional power supply is still considered large compared to audio projects size constraints and it may not fit such delicate applications that need to deliver a good sound with zero noise.

Jan Didden, audio specialist who is known for his own publications Linear Audio, has came up with a new idea that can help in perfecting audio projects. The SilentSwitcher is a 55 x 31 mm special power supply module designed to supply clean power to high-end analog and digital audio circuits.


“One goal of this power supply that it doesn’t need to connect to the mains, you can use it with a USB charger or with a power bank… All problems with ground loops and mains born noise are not existing”- Jan Didden, the designer of The SilentSwitcher

The SilentSwitcher uses a combination of switching and linear regulators to generate a stable and noise-free supply voltage. The module can be powered from a 5V USB adapter, or from a 5V power bank for complete isolation. It delivers ±150 mA and a choice of 6V, 5V or 3.3V at 0.5 A to benefit most of your applications. The absolute maximum input voltage is 12VDC but in normal operation it is preferable to limit it to 10VDC.

Output specifications:

  • Outputs (analog): +15 and -15 VDC at 150mA* each;
  • Output (6/5/3.3V): selectable 6, 5 or 3.3 VDC at 0.5A*;
  • Output noise (6/5/3.3V): less than 1mV broadband
  • Output impedance (analog): less than 10mΩ (+15V) and 80mΩ (-15V) at 20kHz
  • Output impedance (6/5/3.3V): less than 3mV drop with 100mA current step.

15V output at 150mA are provided thanks to the very low noise linear regulators of Texas Instruments TPS7A47, TPS7A33 that suppress all the noise from the switching regulator by a factor of one thousand even at 1 Megahertz. Such chips have driven zero noise to switcher technology and have shown incredible quiet and low noise performance.

Jan Didden talking about his product

The well designed board will help in keeping all elements quiet and avoiding excess radiation. There are 2- and 3-pin headers on the PCB to connect the load, and a 2-pin header for an On/Off switch. The connection to the 5V source is through a B-type USB connector or a standard 2-pin screw-type connector block. You can mount the PCB on the back of your enclosure with a hole cut out for the USB-B – no further input wiring required.

The SilentSwitcher Connections
The SilentSwitcher Connections

This power supply will be a great companion for your project! No need to think about wiring or transformers, and you won’t face any issues like mains hum or mains earth loops.

The SilentSwitcher is live on a Kickstarter crowdfunding campaign and there are only few hours left to go! You can get your own SilentSwitcher for $59 and you will receive a fully assembled and tested board.

More details are provided at the campaign page and at Linear Audio website.

$14.5 All-Purpose Switched-Mode Power Supply

Switching technology devices and integrated circuits are growing fast providing solutions that obtain power for different kind of circuits and devices, and they are proposed in different variations. A useful little known kind which is suitable for mixed supply systems is called SEPIC,single-ended primary-inductor converter.

Torpedo is a switched-mode power supply with a SEPIC configuration which is produced by Open Electronics, an open source solutions producer and the brainchild of Futura Group Srl. It supports three different wide-range voltage sources, battery, USB, and external source from 3 to 20 volts with up to 1 A output current and integrated LiPo battery cell charger.

Torpedo Board
Torpedo Board

Torpedo comes with these features:

  • Triple power source, that is to say: the USB, the battery and an external one
  • Wide range of values as for the input voltage: from 3 to 20 volts
  • Minimum output current of 500mA, with the possibility to reach 1A and more, via an external source
  • High efficiency, above 70% and possibly above 80-90%
  • Single-cell LiPo battery charger incorporated
  • A transition from battery power to another source that is without interruptions
  • 5 V output with high stability, having a low ripple and when varying the load.

Torpedo’s circuit structure can be functionally divided into three different parts; Input Stage, Battery Charger, and SEPIC Converter.

At first, the Input Stage is composed of two diodes and a MOSFET transistor. This set forms a power source selector by allowing the highest voltage power source to pass through Vin pin and prevent it from going to another input having a lower voltage.

Torpedo Circuit Diagram
Torpedo Circuit Diagram

The Battery Charger is based on the MCP73831-2 integrated circuit, that is envisaged for charging single-cell LiPo batteries having a voltage of 4.2 volts. It comes with a red LED indicating the statues of charging, and a two-resistor bridge giving two different output current, 100mA and 500mA.

The SEPIC Converter in general is a DC/DC converter which control its output to be greater than, less than, or equal to that at its input. In Torpedo circuit, the SEPIC integrated circuit contains 1.2Mhz oscillator with variable duty cycle, a low-RDSON MOSFET, and a feedback circuit. This combination provides constant 5V output voltage from variant input voltage between 2.5V to 20V.

Torpedo is available for $14.5 from Open Electronics store, and its technical details are reachable here.

A Cost-efficient Super-Cascode SiC Switch

Coping with rapid technological advances and finding efficient energy solutions are the keys for development of power electronics of the future. A new research had been done in North Carolina State University about increasing the efficiency of high-power switches.

Silicon Carbide is a compound of silicon and carbon with chemical formula SiC. It is a wide bandgap (WBG) semiconductor, that allows devices to operate at much higher voltages, frequencies and temperatures than conventional semiconductor materials.

Researchers came up with a high voltage and high frequency silicon carbide (SiC) power switch that could cost much less than similarly rated SiC power switches. This research may guide to new applications in power converters like medium voltage drives, solid state transformers and high voltage transmissions and circuit breakers.

Semiconductor devices like the 15kV SiC MOSFET can lead to great potential applications in high voltage and high frequency power converters. However, these devices are not commercially available and their high cost displaces them from industry competition with other alternatives like the standard IGBT (Insulated-gate Bipolar Transistors) that are widely used, but in the same time they dissipate a lot of energy while switching on and off.

Loss Comparison between Silicon IGBT and SiC MOSFETs
Loss Comparison between Silicon IGBT and SiC MOSFETs

The new SiC power switch, called FREEDM Super-Cascode Switch, contains a series of 1.2kV SiC power devices to produce a 15 kV and 40 mA output that can transcend the 15 kV SiC MOSFET in ease of adoption and cost – since it costs only one third of the estimated high voltage SiC MOSFETs. In addition, this new switch is capable of operating in a wide range of temperatures and frequencies due to its proficiency in heat dissipation, which is considered an advantage in power devices.

FREEDM Super-Cascode SiC Switch
FREEDM Super-Cascode SiC Switch

Since there is no high voltage SiC device commercially available at voltage higher than 1.7 kV, as Alex Huang said – Progress Energy Distinguished Professor, he assures that this solution paves the way for power switches to be developed in large quantities with breakdown voltages from 2.4 kV to 15 kV.

The research took place in North Carolina State’s FREEDM Systems Center which is funded by National Science Foundation. This center’s mission is to modernize the electric grid and mold the generation of leaders by providing all the needed software and hardware tools, funds, and partnerships with Industries. This project had also participated in IEEE Energy Conversion Conference & Expo on September 2016 and it was presented by Xiaoqing Song, a Ph.D. candidate at the FREEDM Systems Center under Huang’s supervision.

More research projects in the same field can be reached at the FREEDM Systems Center website and further details can be found at the university website.

Via: ScienceDaily

AEM10940, A High Efficient Power Management IC From e-peas

AEM10940 is a power management IC designed by e-peas to store power from photovoltaics (PVs) cells and thermoelectric generator (TEGs) into rechargeable power sources, such as Li-Ion batteries and thin film batteries. At the same time, it supplies the system with two different regulated voltages, the charging voltage and the system supply voltage.

e-peas is a startup based in Liège, Belgium. It works towards solutions to extend batteries life-time for IoT applications, by increasing the amount of harvested energy and reducing power consumption for each element in the system.

AEM10940 Block Diagram
AEM10940 Block Diagram

The AEM10940 features are:

  • Ultra low power start-up, which gives it the ability to operate with just 380 mV input voltages and 1 μW input power.
  • Ultra-low-power Boost regulator, whit operates with input voltages in a range of 100 mV to 2.5 V.
  • Integrated Low Drop-Out (LDO) regulator, drives a microcontroller at 1.8 V with up to 10 mA load current at low voltage supply, and drives a radio transceiver at configurable voltage from 2.2 V to 4.2 V with 80 mA load current.
  • Programmable overcharge and overdischarge protection
  • Suitable for any type of rechargeable battery or supercapacitor
The AEM10940 Evaluation Board
The AEM10940 Evaluation Board

e-peas introduces AEM10040 as an evaluation board that provides a laboratory-like environment for testing and analysing. It also simplifies the connections with power sources, storage elements, and the different loads. However, the evaluation board is not suitable for end-user applications.

More detailed information is reachable at the datasheet and the product official page.

Enhanced Wireless High Power Transmission

A group of developers in Elektor Labs have modified a high power wireless power transfer project, which originally developed by Würth Elektronik eiSos GmbH & Co. KG, an electronic and electromechanical components manufacturer in Europe, in an attempt to come up with an easy-to-achieve solution for wireless power transfer of more than 100 Watts without using any kind of controller or programmed elements.

The Original Transmitter and Receiver Circuits
The Original Transmitter and Receiver Circuits

The same circuit is used in both transmitter and receiver circuits. It is based on a resonant converter which generates a constant frequency according to the LC parallel resonant circuit. The resonant converter, also known as Zero Voltage Switching (ZVS) oscillator, has no power-loss elements and provide high efficiency response with up to 200 Watts of energy.

The Modified Transmitter and Receiver Circuits
The Modified Transmitter and Receiver Circuits

In the modified version, the gate driving circuit were replaced with a faster one which uses a separate power supply. Also a protection circuit consists of a PTC resettable fuse was added using a high-side current monitor IC, this will protect the whole circuit from damage by shutting down the converter.
This version delivers up to 50 Watts with 88% efficiency for 12-24 V supply voltage.

More details about this project are available here, including the bill of materials BOM, schematics, and how circuits work.

More information about original circuits are available here.

30A, PCB-level supply monitor has integrated 300 µΩ sense resistor

>Designed to simplify board-level energy measurements, the LTC2947 power and energy monitor for 0V to 15V DC supply rails eliminates the need for an external sense resistor to measure current. by Graham Prophet @ edn-europe.com

Choosing a sense resistor, Linear says, is not an easy task, especially when dealing with high currents, where available sense resistors can dissipate too much power, occupy a lot of board space or have a large impact on measurement accuracy. The LTC2947 integrates a 300 µΩ temperature-compensated sense resistor to alleviate these concerns, providing users with a simple 24 mm² solution that provides up to 1.2% accurate energy readings at up to ±30A.

30A, PCB-level supply monitor has integrated 300 µΩ sense resistor – [Link]

How to Build a Class-D Power Amp


Cezar Chirila @ allaboutcircuits.com shows how to build a Class-D amplifier which has amazing efficiency.

What is a Class-D audio power amplifier? The answer could be just a sentence long: It is a switching amplifier. But in order to fully understand how one works, I need to teach you all its nooks and crannies.

How to Build a Class-D Power Amp – [Link]