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.
Which is the current sense resistor in the freewheeling loop?
Current sense resistor in the freewheeling loop is adopted for a fast response valley current mode. RDS(ON) of the low-side MSOFET can be used as the current sense resistor, which can improve the efficiency while the sensing accuracy may be worse.
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
Which is better a current sense amplifier or a CMR amplifier?
The current-sense amplifiers, with their transistor input structure, can obtain a better match, so that CMR, no longer dependent on input resistor matching, can typically be specified above 100 dB, except at low values of common-mode voltage.
What is the DC range of a current sense amplifier?
This specification defines the DC voltage range at the input of an amplifier with respect to ground. Current sense amplifiers are typically designed to support common-mode voltages well beyond the chip supply voltage.
Can a difference amplifier be used for low side sensing?
Difference amplifiers, however, can be used for high-side current sensing in the presence of high common-mode voltages at the expense of drawing current from the system bus supply. They can also be used for low-side sensing and negate the effects of parasitic resistances to ground.
How does a comparator in a sense amplifier work?
A comparator senses the high current range and shorts out the larger sense resistor. Now only the high range sense amplifier outputs a voltage. Figure 40.215. The current sense amplifier shown in Figure 434. 2 amplifies the voltage across a small value sense resistor by the ratio of the current source resistors (R2/R1).