What is high side sensing?

This single–supply, high–side, low–cost current sensing solution detects load current between 50mA and 1A and converters it to an output voltage from 0.25V to 5V. High–side sensing allows for the system to identify ground shorts and does not create a ground disturbance on the load.

What is low side sensing?

Low-side current sensing is when the voltage is measured across a sense resistor that is placed between the load and ground. Figure 1 shows the configuration for low side current sensing.

How is high side current measured?

In their simplest form, such high-side monitors require a precision op amp and a handful of precision resistors. One common approach for high-side measurements has been the use of the classic differential amplifier, which is employed as a gain amplifier and a level shifter from the high side to ground ( 4).

What is common mode voltage?

Common-Mode Signals Defined Technically, a common-mode voltage is one-half the vector sum of the voltages from each conductor of a balanced circuit to local ground or common. An offset from signal common created in the driver circuit, or. A ground differential between the transmitting and receiving locations.

How do you measure current with a sensor?

Measurement principle: Since detection is performed by a winding, AC zero-flux sensors can measure only AC current. They cannot measure DC current. ic flux that remains is detected by the Hall element, and a secondary current is made to flow by the amp circuit so as to cancel out the magnetic flux Φ.

How does high side current sensing circuit work?

High-Side Current Sensing. As shown in Figure 2, high-side current sensing connects the sensing resistor between the power supply and load. The sensed voltage signal is amplified by subsequent op amp circuits to get the measurable VOUT.

What kind of sensor is needed for solenoid control?

In solenoid control (Figure 1) that uses a single control FET, the current is always flowing in the same direction, so a unidirectional current sensor will be sufficient.

What is the purpose of a current sensor?

A current sensor is a device that detects and converts current to an easily measured output voltage, which is proportional to the current through the measured path. There are a wide variety of sensors, and each sensor is suitable for a specific current range and environmental condition.

How is a current sensing resistor converted to voltage?

Among these sensors, a current sensing resistor is the most commonly used. It can be considered a current- to-voltage converter, where inserting a resistor into the current path, the current is converted to voltage in a linear way of V = I × R.

What is high-side sensing?

This single–supply, high–side, low–cost current sensing solution detects load current between 50mA and 1A and converters it to an output voltage from 0.25V to 5V. High–side sensing allows for the system to identify ground shorts and does not create a ground disturbance on the load.

How current is measured using sense resistor?

The most-common way to accurately make this measurement is by using a sense resistor of known value inserted in series with the load, then measuring the IR voltage drop across this resistor. By applying Ohm’s law, determination of the current flow is simple—or at least that’s how it seems.

Why do you need a resistor to measure current?

One of the principles of instrumentation is to use as little power from the circuit as is necessary, to reduce the ‘loading’ on the circuit. To that end, instrumentation on power circuits often use a “shunt” resistor, which is simply a high current, low resistance conductor, of accurately known resistance.

What’s the difference between high side and low side current sensing?

1. High-side and low-side current sensing refers to the placement of the current-sense resistor: between the positive supply and the load, or between the load and ground.

What’s the difference between high side and low side?

There are also potential ground loop problems. The voltage at V COM2 could be higher or lower than the voltage at V COM1, in which case current would flow between them, causing errors in the current measurements in R S1 and R S2. Finally, parasitic resistance R P makes the ground-loop problem even more sinister.

Are there any problems with low side sensing?

One problem with low-side current measurements is that the current sense circuitry will not detect a fault if it shorts the top of the sense resistor to ground. There is a more serious problem when low-side sensing is used to monitor multiple loads that can be switched on and off independently.

Why do we need high side sensing in amplifier?

High-side sensing is desirable in that it directly monitors the current delivered by the supply, which allows for the detection of load shorts. The challenge is that the amplifier’s input common-mode voltage range must include the load’s supply voltage, or Vbus.