Tag Archives: Shunt

Current-sense amp integrates precision shunt resistor, in single package

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150710edne-ti-ina250_09jul15

by Graham Prophet @ edn-europe.com:

Texas Instruments says it is making, “high-accuracy measurement more attainable with the first current-sense amplifier to integrate a high-precision, low-drift 2 mΩ shunt resistor,” – the device can cut calibration effort, system cost, and footprint for test and measurement, communications load monitoring, and power supplies.

For highly accurate measurements over a wide temperature range, TI’s INA250 integrates the shunt resistor with a bi-directional, zero-drift current-sense amplifier to support both low-side and high-side implementations. It enables high-accuracy current measurements at common-mode voltages that can vary from 0 to 36V. The family of devices will be available in four output scales; 200, 500 and 800 mV/A, and 2 V/A; the maximum current through the shunt resistor is 10A at the full rated temperature of 125C, or 15A at up to 85C. Its accuracy and low drift reduce or may even eliminate designers’ calibration effort for many systems. This integration also enables lower system cost and a smaller board footprint compared to alternative solutions.

Current-sense amp integrates precision shunt resistor, in single package – [Link]

Using traces as resistors

Hex81Fu

NsN writes:

A while ago I needed some small value resistors as current shunts and I started wondering about the feasibility of using traces as resistors.
There are many theoretical reasons as to why copper traces make bad shunt resistors, but I found surprisingly little practical data.

The traces are (from left to right):
– 20 mil wide, 1221 mil long, should be ~30mOhms
– 6 mil wide, 611 mil long, ~50mOhms
– 12 mil wide 1221 mil long, 50 mOhms
– 6 mil wide 1221 mil long, 100 mOhms

Using traces as resistors – [Link]

Current sense circuit collection

AppNote1-600x362

Here is a PDF document from Linear Technology, featuring current sense circuits for different applications, including High side, low side, level shifting, high and low voltage, fault sensing, etc: [via]

Sensing and/or controlling current flow is a fundamental requirement in many electronics systems, and the techniques to do so are as diverse as the applications them-selves. This Application Note compiles solutions to current sensing problems and organizes the solutions by general application type. These circuits have been culled from a variety of Linear Technology documents.

Current sense circuit collection – [Link]

20 Amps DC Ammeter

20 Amps DC Ammeter using very low value resistance of 0.01 Ω

  • Supply voltage. symmetric power (+ -12)
  • Maximum current measure. 20A
  • With Possibility of increasing the measurement range
  • Resolution 10mA

20 Amps DC Ammeter – [Link]

TL431: Cost-effective shunt regulator solution

The TL431 is a three-terminal adjustable shunt regulators, with specified thermal stability over applicable automotive, commercial, and military temperature ranges. The output voltage can be set to any value between Vref (approximately 2.5 V) and 36 V, with two external resistors.

Features:

  • Operation from -40°C to 125°C
  • Reference voltage tolerance at 25°C
  • 1%: A grade
  • 2%: standard grade
  • Low output noise
  • 0.2-Ω typical output impedance
  • Sink-current capability: 1 mA to 100 mA
  • Adjustable output voltage: Vref to 36 V

TL431: Cost-effective shunt regulator solution – [Link]