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Why are current sense amplifiers called current shunt amplifiers?
Current Sense Amplifiers are special-purpose amplifiers that output a voltage that is proportional to the current flowing in the power rail. Current sense amplifiers are also called current shunt amplifiers because it uses a shunt resistor in the power rail that provides a small voltage drop when current flows through the resistor.
Why do we use a low side current amplifier?
The advantages of Low side current measurements are, it is simple to implement because the sense voltage across the current shunt resistor is in the GND referenced. In this configuration, a low voltage current sense amplifier can be used due to the small voltage drop across the shunt resistor.
How does a high side current sense amplifier work?
Same as Low side current sense, a high side current measurement uses the same current shunt resistor but the placement takes place between the power source and the active load. In the below images, high current sense amplifier circuits are shown. The above circuits are practical examples of the High side current sensing technique.
What kind of impedance do I need for differential probe?
So I decided to go with a “traditional” differential amplifier with op-amp in front to get a nice high impedance for this improvise differential probe. Here’s a simple schematic of my circuit: (Op-amp have 12v supply) To my surprise, the reading on the 5 ohm shunt resistor is way off the real reading (measure with a multimeter).
When do you need a current sense amplifier?
Current-sense amplifiers with this architecture are generally useful only if input common-mode voltage remains above 2 V or 3 V, and if the application doesn’t require that the input common-mode voltage go all the way to ground (or below).
How are high side shunts used in motor control?
High-side shunt in typical solenoid control. Figure 2. High-side shunt in H-bridge motor control. Figure 3. High-side shunts in 3-phase motor control. In all configurations shown above, the pulse-width-modulated (PWM) common-mode voltage at the shunt resistor—which monitors the load current—is swinging over the whole range from ground to battery.
What kind of voltage does an op amp support?
A normal op-amp supports a small range of common-mode voltage that is not suitable for the precision level current sensing operations. But in the case of current sense amplifiers, the common-mode voltage ranges much wider than the actual supply voltage of the amplifier.