Introduction to the principle of a high-precision current source circuit

In analog circuit design, it is necessary to use a current source as a load or bias circuit.

The common method is to use a current mirror mirrored bandgap reference circuit to generate an IPTAT current proportional to temperature, or directly use a bandgap reference voltage as a current source. Drive voltage. The current sources generated by these methods are susceptible to temperature changes, channel modulation effects, and semiconductor chip production processes. As a result, the accuracy of the current source is not high, and the performance of the circuit is greatly affected by the changes of these parameters. Therefore, more and more attention is paid to the high-precision current source, and the research work in this area has also achieved rapid development.

A high-precision current source circuit that converts the bandgap reference voltage generated by the bandgap reference voltage circuit, which is independent of temperature and power supply voltage, into a high-precision reference current independent of temperature and voltage through V/I conversion. The high-precision current mirror structure generates the required mirror current, which effectively suppresses the influence of temperature, power supply voltage, load impedance changes and interference on the current source.

The high-precision current source is a model abstracted from the actual power supply. Its terminal button can always provide a certain current to the outside regardless of the voltage across it. The current source has two basic properties: First, it provides Is the current at a fixed value I or a certain time function I(t) has nothing to do with the voltage across it. Second, the current of the current source itself is determined, and the voltage across it is arbitrary.

The ATS-2000C series is a high-precision current source with a maximum output current of 3A, high-precision, high-stability current output, continuously adjustable, with an accuracy of up to 5½ digits, a minimum current resolution of 20 pA, and a four-quadrant precision current source. It is widely used in the fields of chip and sensor detection, electronic testing and design verification, instrument calibration and so on.

Through the above introduction, I believe that you have a clear understanding of the circuit principles of high-precision current sources. If you want to know more about current sources and voltage sources, you can click Aigtek's official website www.aigtek.com.

Xi'an Antai Electronic Technology Co., Ltd. (Aigtek) is a domestic high-tech enterprise specializing in R&D, production and sales of measuring instruments. The company is committed to the research of related industry test solutions with power amplifiers, measurement calibration products, wiring harness testers and other products as the core, and provides users with competitive test solutions. Aigtek has become a broad product line in the industry and has a considerable scale. Supplier of equipment and equipment.