How do you find the current sensing 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.
How is an op amp used for high side current sensing?
Using An Op Amp for High-Side Current Sensing Tim Claycomb, Marc Liu High-side current sensing is used in a wide range of applications such as battery chargers or overcurrent protection. Figure 1 displays a typical high-side current sensing schematic. The shunt resistor, Rshunt, is placed between the bus voltage and the system load creates
How does a differential current sense amplifier work?
Current-sense amplifiers such as the AD8210 amplify the small differential input voltage in the following manner. The input terminals are connected to the differential amplifier, A1, by R1 and R2. A1 nulls the voltage appearing across its own input terminals by adjusting the current through R1 and R2 with transistors Q1 and Q2.
Why do we need high side current sensing?
In motor-control configurations (Figures 2 and 3), placing the shunt on the motor phase means that current in the shunt resistor could flow both ways; therefore, a bidirectional current sensor is necessary. The designer who studies the choices for the high-side current-sensing function will find a variety of options from many semiconductor vendors.
How are the input terminals connected to the differential amplifier?
The input terminals are connected to the differential amplifier, A1, by R1 and R2. A1 nulls the voltage appearing across its own input terminals by adjusting the current through R1 and R2 with transistors Q1 and Q2. When the input signal to the AD8210 is 0 V, the currents in R1 and R2 are equal.