Constant current source circuit and a sampling circuit

摘要

A constant current source circuit includes a main circuit, wherein the main circuit includes a first three-terminal regulator, a transistor, a sample resistor and a load, an output terminal of the first three-terminal regulator is connected with a control Electrode of the transistor, a reference Electrode of the transistor is connected with a voltage input terminal, a working Electrode is connected with one end of the load, and the other end of the load is connected with one end of the sample resistor, and the other end of the sample resistor and an input terminal of the first three-terminal regulator are connected to a reference potential, respectively, wherein the constant current source circuit further includes an adjusting unit that includes a voltage stabilizing unit, a fourth resistor and a fifth resistor.

主权项

1. A constant current source circuit comprising a main circuit, wherein the main circuit comprises a first three-terminal regulator, a transistor, a sample resistor and a load, an output terminal of the first three-terminal regulator is connected with a control Electrode of the transistor, a reference Electrode of the transistor is connected with a voltage input terminal, a working Electrode is connected with one end of the load, and the other end of the load is connected with one end of the sample resistor, and the other end of the sample resistor and an input terminal of the first three-terminal regulator are connected to a reference potential, respectively, wherein the constant current source circuit further comprises an adjusting unit that comprises a voltage stabilizing unit, a fourth resistor and a fifth resistor, wherein the voltage stabilizing unit generates a second reference voltage higher than a first reference voltage of the first three-terminal regulator and supplies the second reference voltage to an adjusting terminal of the first three-terminal regulator through the fourth resistor, and the fifth resistor is connected between the adjusting terminal of the first three-terminal regulator and a node that is between the load and the sample resistor.