How to use diversion resistance measurement circuit current

In recent years, the demand for multi -functional and high -security electronic circuits for using current measurement technology has increased. We will introduce a method to detect current using diversion resistance in this article, and actually run the current detection circuit to view its detection effect.

Measure current value to ensure the safe operation of the circuit

At present, the demand for multifunctional and high security equipment has been increasing. These equipment needs to use the current measurement technology for the updated electronic circuit suitable for its configuration.

For example, monitoring circuits for detecting overcurrent and running abnormal circuits and stopping operations are safely stopped, function circuits for battery charging and battery capacity detection, and current monitoring circuits that are also very important for motor control. Therefore, current monitoring technology is for current monitoring technology for Modern circuit design is essential.

Next, we will introduce a method of detecting the current, and actually run the current detection circuit to view its effect.

Basic knowledge of current detection circuit and diversion resistance

Ultra -low resistance patch resistance for current detection (PMR)

Ultra -low -resistance patch resistance/long -sided electrode (PML) for current detection

You may think that the current detection circuit is complicated, but in principle, it is just a simple circuit that uses the "Ohm Law", and Ohm's law is a very basic theoretical knowledge in the electronic circuit field. Candid in a resistor used for current detection, and the voltage drop of the resistance is converted into a current value through Ohm's law to achieve current detection.

The resistance for current detection is called "diversion resistance"

Dialing resistance is an electronic component used to measure and detect current. The resistance range is 100 μΩ to hundreds of mΩ. Ideally, you should use the resistance value as low as possible, but in actual operation, you should choose the appropriate resistance value according to the amplifier coefficient and detection target range of the operator.

And if the low -resistance resistance is used, the voltage drop is small, and the microcontroller will be difficult to detect the voltage, so at this time, a high -precision calculation amplifier with a low -input offset voltage should be used to detect the current.

The current detection circuit using diversion resistors and computing amplifiers is called "current detection amplifier".

In addition, the "diversion" of the diversion resistance refers to "avoiding, turning away." The initial refers to the connection of the resistance to expand the measurement range of analog current. The patch resistance that is recently used for current detection is called a diversion resistance. Although the usage has changed, the phenomenon of this name remains unchanged.

Connect the diversion resistance to the differential amplifier circuit

In principle, the current detection circuit using a diversified resistor is a simple circuit that measures only the voltage. However, because the voltage of the diversion resistance is small, the circuit that can amplify the voltage at a high precision is needed. Therefore, we use the differential amplifier circuit with an operational amplifier.

For the calculation amplifier for current detection, please choose a high -precision operational amplifier with a low -input offset voltage. Because the offset voltage can cause measurement errors when detecting the small voltage value, please use the "high -precision calculation amplifier" as low as possible as possible, or the "zero drift amplifier" that can automatically adjust the input offset voltage.

shunt resistor current measurement