Offset compensation structure suitable for large-dynamic-range logarithmic amplifier

A logarithmic amplifier, a technology with a large dynamic range, which is used in amplification control, amplifier combination, differential amplifiers, etc., and can solve the problems of easy DC mismatch, out-of-tolerance digital amplifier parameters, and high overall gain of the limiting amplifier.

CN114400978AActive Publication Date: 2022-04-26NO 24 RES INST OF CETC
3 Cites 2 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2022-04-26

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention belongs to the field of integrated circuits, and particularly relates to an offset compensation structure of a large-dynamic-range logarithmic amplifier chip. The offset compensation structure comprises a first-stage limiting amplifier, a multi-stage limiting amplifier, a transconductance detection unit, a constant current source and a feedback current source; the first-stage limiting amplifier is respectively connected with the input positive end and the input negative end of a differential signal, and the output positive end and the output negative end of the differential signal are connected with the input positive end and the input negative end of the multi-stage limiting amplifier; the constant current source is connected with the input negative end of the multi-stage limiting amplifier, and the feedback current source is connected with the input positive end of the multi-stage limiting amplifier; the transconductance detection unit is connected with the output negative end and the output positive end of the multi-stage limiting amplifier; according to the invention, the transconductance detection unit is used for obtaining a difference result between the voltage of the output positive end and the voltage of the output negative end, the feedback current is generated through the feedback current source, the current of the constant current source compensates the direct current working point change of the first-stage limiting amplifier caused by the feedback current, and the effect of stabilizing the working of the limiting amplifier is achieved.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention belongs to the field of integrated circuits, in particular to an offset compensation structure of a logarithmic amplifier chip with a large dynamic range. Background technique

[0002] The topology of a high dynamic range log amp is as figure 1 As shown, it uses six limiting amplifiers connected in series, and rectification is performed at the output of each limiting amplifier, and the rectified current is added to obtain the total rectified current, and then the rectified current signal is converted into an output voltage through the transimpedance output stage . Through this structure, an output voltage that has a linear relationship with the input power can be obtained.

[0003] The structure of the limiting amplifier is as figure 2 As shown, it is essentially a differential pair with a resistor as a load. Q1 and Q2 constitute a differential input pair of transistors, and the bases of Q1 and Q2 are respectively connected to the po...

Examples

Embodiment Construction

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0028] The following will be combined with Figure 4 , to describe the embodiment of the present invention in detail, Figure 4 It is an offset compensation structure according to an embodiment of the present invention. The offset compensation structure mainly includes a first-stage limiting amplifier, a multi-stage limiting amplifier, a transconductance detection unit, a constant current source and a feedback current source; wherein, the first The first-stag...