Tag Archives: voltage

Low-side I/V sensing IC, with internal power calculation

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Maxim Integrated has posted details of the MAX44299, a low-side current, voltage, and power monitoring circuit that provides an analogue output current proportional to the measured current, voltage, and the internally calculated instantaneous power. The power monitor offers high precision and integration in tiny size.

Instantaneous power is calculated internally by multiplying the load current and a fraction of the load voltage set by an external resistive divider. All three outputs are scaled to a full-scale current of 100 µA. An additional output current of 100 µA is available at the reference (REF) output; this current can be used to create a reference voltage for the ADC that is being used to measure the power, voltage, and current signals.

Low-side I/V sensing IC, with internal power calculation – [Link]

How-to use PWM to Generate Analog Voltage in Digital Circuits

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Maurizio @ emcelettronica.com tipped us with his latest article on how to generate analog voltages using a microcontroller.

Many times, designers are faced with the need of generating analogue or analog voltage levels in purely digital circuits. Although the market provides today a very broad range of dedicated digital-to-analogue converters, putting such a device in the schematic has a negative impact on the overall cost of the system.

How-to use PWM to Generate Analog Voltage in Digital Circuits – [Link]

USB Power Meter

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Daniel Grießhaber @ hackaday.io has published his build of a USB power meter. His device is based on ATTiny 85 mcu and 0.96″ OLED Display and is able to measure voltage, current and power output from USB port.

Since USB has become more and more a power delivery standard, it would be nice to have a convenient way to measure the power consumption these devices need. Of course there are already power meters out there, but they are just boring or don’t have all the features I like.

USB Power Meter – [Link]

Generating Analog Voltage with Digital Circuit

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Maurizio show us how to generate an analog voltage using a microcontroller and some resistors.

The purpose of this article is how to generate analog voltage with digital circuit. Although the market provides today a very broad range of dedicated digital-to-analogue converters, putting such a device in the schematic has a negative impact on the overall cost of the system. There are however, cheap methods of creating the required voltage levels, and even of generating pseudo-analogue signals, using purely digital means.

Generating Analog Voltage with Digital Circuit – [Link]

Isolated Circuit Digitally Indicates 120-/220-V Line Voltage

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Edward K. Miguel @ electronicdesign.com has published a circuit that has output high when the votlage in input is 220V and output low when the voltage is 110V. This is often useful on motor control and power supply systems.

The circuit illustrated in the figure monitors the ac line and provides a basic output indicating whether it is at 120 V or 220 V, with the output at the transistor collector going low for 120-V and high for 220-V inputs.

Isolated Circuit Digitally Indicates 120-/220-V Line Voltage – [Link]

Protecting the USB from over voltage and overcurrent threats

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An application note from Littelfuse about USB protection.

This application note addresses the various requirements for protecting the Universal Serial Bus (USB) from overcurrent and overvoltage environmental threats. The solutions presented cover both USB 1.1 and the higher speed USB 2.0 circuitry. Specific emphasis is placed on USB 2.0 with information directed at hot connection over current conditions and electrostatic discharge (ESD) induced in the USB system.

Protecting the USB from over voltage and overcurrent threats – [Link]

Analog Devices AD587KN 10V reference chip

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SteelCity Electronics published an article about Analog Devices AD587KN 10V reference:

I recently got hold of an Analog Devices AD587KN high precision 10.000V reference chip.
This model of chip has an output value of 10.000V ± 5mV (that is, an output value of 9.995V to 10.005V) straight out of the factory. A voltage drift of 10ppm/°C at 25°C meaning that the output voltage will drift by 10μV for each 1°C the chip is exposed to. Additionally, the chip has a voltage trim input, so if you have access to a precision voltmeter, the chip’s output value can be adjusted even closer to 10.000V.
Alternatively, the chip’s output can be trimmed to a value of 10.24V. You may think that a value of 10.24V seems like a strangely familiar number. A value of 1024 is the decimal representation of 10bits, that is 2∧10 = 1024. Why would I want a voltage reference that outputs a value of 10.24V? Because it makes any ADC or DAC conversions much simpler.

Analog Devices AD587KN 10V reference chip  – [Link]

Lowest-drift bandgap voltage reference reaches 1.5ppm/°C, offers low dropout

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by Graham Prophet @ edn-europe.com:

LT6657 is a family of ultra-stable bandgap voltage references that exhibits less than 1.5ppm/°C of temperature drift. Reinforcing this performance, the device has only 0.5ppm p-p of low frequency noise, less than 30 ppm of long term drift and 35 ppm of thermal hysteresis.

The LT6657 is fully specified for –40°C to 125°C and was designed for the most demanding high performance instrumentation, test equipment and automotive systems. The LT6657’s buffered output can source and sink up to 10 mA. The LT6657 can operate on a supply voltage from as low as 50 mV above the output, up to 40V, and with a supply current of only 1.2 mA. In shutdown mode, power consumption is reduced to 4 µA. Load regulation error is less than 6 ppm/mA and line regulation error is less than 4 ppm/V, both under worst case conditions.

Lowest-drift bandgap voltage reference reaches 1.5ppm/°C, offers low dropout – [Link]

 

Voltage indicator transitions between colours

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by Einar Abell @ edn.com:

This Design Idea gives two versions of an indicator light that changes from green to red as a battery discharges. There are many circuits that do this sort of thing, but all the ones I have seen are too complex and costly for my taste. This DI shows a method that uses an absolute minimum of low cost parts: a dual-color LED and four other parts.

Voltage indicator transitions between colours – [Link]

USB power supply active load tester

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Sasa Karanovic has designed and built a DIY USB power Supply active load tester, that is available at GitHub:

USB Power supply Active Load Tester or short PAL Tester is unit designed for testing the quality of the power supplies.
Idea was to create low-cost, precise device for simultaneous measurement of Voltage and Current drawn from the device under test.

USB power supply active load tester – [Link]