A constant current source circuit of negative resistance characteristic

Abstract

The invention discloses a constant current source circuit of negative resistance characteristic, comprising a voltage detection circuit, a constant current source and an output circuit. The constant current source provides current for the voltage detection circuit and the output circuit, and the current flowing through the constant current source is the sum of the current provided by the constant current source for the voltage detection circuit and the current provided by the constant current source for the output circuit. The voltage detection circuit has an absorption current which increases along with the rise of an operating voltage. The more current provided by the constant current source for the voltage detection circuit is absorbed by the voltage detection circuit, the less current is provided by the constant current source for the output circuit accordingly. The output circuit directly outputs the current provided by the constant current source for the output circuit, or outputs the current provided for the output circuit by the constant current source after amplification or reduction. The circuit of the invention can control the power consumption of the circuit when the operating voltage is high by provision of a small bias current.

Description

technical field [0001] The invention relates to constant current source technology, in particular to a constant current source circuit with negative resistance characteristics. Background technique [0002] DC constant current sources are widely used, and are widely used in integrated circuits, radio frequency amplifier circuits, audio power amplifier circuits, etc., and are generally used as bias circuits. [0003] Its characteristic is that when the power supply voltage or load changes, its output current requirement remains constant. The constant current source has a detailed analysis in the second edition of "Basics of Analog Electronics Technology" published by Higher Education Press and edited by Tong Shibai. The ISBN number of the book is 7-04-000868-8 / TN·53. In "Basics of Analog Electronics Technology", there are detailed constant current source textbooks in the last line on page 220 to the end of the fourth line on page 221, and in the subsection "3.2.2 Current Sou...

AI Technical Summary

Problems solved by technology

[0006] In practical applications, in special applications, the advantages of constant current sources have turned into disadvantages: in circuits where the power supply voltage cannot be stabilized, if a constant current source is used for bias, as the voltage rises, the operating current of the transistor used for amplification will remains unchanged, but the voltage rises, the tube consumption of the transistor will rise synchronously, and finally cause damage to the transistor, thereby causing damage to the circuit

[0007] Especially in the case of using a lithium polymer battery, the working voltage varies between the terminal voltage of the lithium polymer battery, that is, between 3.0V and 4.20V. When the lithium polymer battery is fully charged, it is 4.20V, and the discharge is almost over. It is about 3.0V to 2.7V; another example is automotive equipment, the working voltage varies between 12.6V and 14.4V. When working, the battery terminal voltage is around 12.6V; another example is the equipment using the mains, the mains is 220V AC, allowing ±10% variation, in fact, it is common for the mains to rise to 265VAC and above at night in many areas For example, the power supply of the audio power amplifier circuit is generally obtained by rectifying the commercial power after being stepped down by a transformer. Without voltage stabilizing equipment, the above problems will also occur.

Images