Current Sense Amplifiers

Current sense amplifiers are integrated circuits with operational amplifiers and sense resistors that are used in measuring the amplitude and direction of current in circuits. There are many types of amplifiers. Examples include a differential current sense amplifier, high-accuracy current-sense amplifier, high-side current sense amplifier, and a high voltage current sense amplifier. A differential current sense amplifier is generally used for battery-operated devices that require both charge and discharge currents to be monitored. A high-accuracy current-sense amplifier facilitates current sharing between various DC/DC converter modules in addition to current sensing. As this causes various modules to be paralleled, current sharing ensures reliable operation. A high-side current sense amplifier employs a high-side monitor that is connected directly to the power source. A high-side current sense amplifier can identify any failure downstream and also initiate appropriate corrective measures. A high-side current sense amplifier can measure load current as well as tolerate any level of high voltage within the limitations in the external parts of the equipment. Other current sense amplifiers are also commonly available.

There are several ways in which current sense amplifiers function. A current sense amplifier magnifies voltage, provides high bandwidth, and facilitates shifting of levels and bidirectional current measurement. A differential current sense amplifier produces a single output voltage, which helps in accurately measuring the current’s direction and magnitude regardless of polarity. The magnitude of output voltage is always proportional to that of sense voltage. A high-accuracy current-sense amplifier requires a resistor less than or equal to 2m for minimizing power dissipation. Recently, current sharing has gained tolerance by 10% of the output current. High-side current sense amplifier employs a 32V current monitor for measuring the load current up to 30mA and can work within the range of 32V to 76Vof DC. A high voltage current sense amplifier can accommodate high voltage levels used in industries, which can even be beyond 76Vof DC. Current sense amplifiers are designed and manufactured to meet most industry specifications.

Current sense amplifiers are used in many applications. Examples include power management and automotive applications. Current sense amplifiers can also be used in cellular infrastructure equipment, portable PCs, high-end routers, battery chargers, and accurate current sources. Current sense amplifiers should adhere to International Organization for Standardization (ISO) and National Institute of Standards and Technology (NIST) standards.

• Programmable Current Loop
  The DACOUT of the FGD40xx can be used to design a programmable current loop from 4 to 20mA (4mA when DACOUT=0, 20mA when DACOUT=2.5V). The DC voltage output of the DACOUT has a voltage range of -2.500...
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• Precision RTD Instrumentation for Temperature Sensing
  AN1154 Precision RTD Instrumentation for Temperature Sensing SOLUTION Author: Ezana Haile Microchip Technology Inc. This solution uses a common reference voltage to bias the RTD and the ADC which...
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• The Problem With Current Limit
  Traditional current limiting circuits may not offer the operational amplifier the protection it needs to be reliable in an application circuit. The problems associated with one traditional current...
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Part Numbers for Current Sense Amplifiers