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CN-122001380-A - Electronic circuit and method for suppressing offset variations in a buffer

CN122001380ACN 122001380 ACN122001380 ACN 122001380ACN-122001380-A

Abstract

The present invention relates to an electronic circuit and method for suppressing offset variations in a buffer.

Inventors

  • AMIN JEMILI
  • S. BECKER

Assignees

  • 罗伯特·博世有限公司

Dates

Publication Date
20260508
Application Date
20251106
Priority Date
20241107

Claims (11)

  1. 1. Electronic circuit (1) for suppressing offset variations in a buffer (2) for providing an electrical output signal, comprising: A buffer (2) configured for providing an electrical output signal based on an input signal at an input of the electronic circuit (1), wherein the buffer (2) is arranged in a main path of the electronic circuit (1), Wherein the electronic circuit (1) further comprises an auxiliary path arranged in parallel with the main path and comprising at least the following elements: -an electronic amplifier (3) connected to an input to generate a conditioning signal for the buffer (2) based on the input signal, and -An arrangement of chopping switches (5) to minimize, in particular to suppress, offset variations in the auxiliary path by the arrangement of chopping switches (5).
  2. 2. Electronic circuit (1) according to claim 1, characterized in that the electronic amplifier (3) is an integrating amplifier.
  3. 3. Electronic circuit (1) according to claim 1 or 2, characterized in that the output signal of the buffer (2) is determined at least in part by a regulation signal of the auxiliary path, wherein the buffer (2) is in particular configured as a folded cascode amplifier.
  4. 4. Electronic circuit (1) according to any of the preceding claims, characterized in that the electronic amplifier (3) minimizes an error between an input signal of the buffer (2) and an input signal of the electronic amplifier (3) by means of the adjustment signal, in particular to 0 or towards 0.
  5. 5. Electronic circuit (1) according to any of the preceding claims, characterized in that the offset variation is minimized, in particular suppressed, in an auxiliary path such that an input of the auxiliary path is modulated by manipulation of an arrangement of the chopper switches (5).
  6. 6. Electronic circuit (1) according to claim 5, characterized in that the auxiliary path has at least two capacitances (4) for reducing noise in the auxiliary path by the at least two capacitances (4), wherein the offset of the auxiliary path is preferably triangulated using the at least two capacitances (4) within the scope of modulation.
  7. 7. Electronic circuit (1) according to any of the preceding claims, characterized in that the electronic circuit (1) is arranged for handling the capacitive sensor (6), in particular as a reference for SIGMA DELTA analog-to-digital converter (7).
  8. 8. Electronic circuit (1) according to claim 7, characterized in that the buffer is configured as a reference buffer to convert an input signal in the form of a high-resistance reference voltage into an output signal in the form of a low-resistance source voltage.
  9. 9. A method (100) for suppressing offset variations in a buffer (2), comprising: -providing (101) an electronic circuit (1) according to any of the preceding claims, -Generating (102) a regulating signal by the electronic amplifier (3) based on the input signal, wherein the regulating signal represents an error between the input signal of the buffer (2) and the input signal of the electronic amplifier (3), wherein the generated regulating signal is fed to the buffer (2) to suppress offset variations.
  10. 10. The method (100) of claim 9, wherein, The method (100) further comprises: -modulating the input of the auxiliary path by manipulation of the arrangement of chopping switches (5), in particular based on a predefined clock signal, wherein the offset of the auxiliary path is triangulated using at least two capacitances (4).
  11. 11. The method (100) according to claim 9 or 10, wherein, The method (100) further comprises: -handling and/or operating a capacitive sensor (6) with the use of an electronic circuit (1) according to any one of claims 1 to 8, in particular as a reference for SIGMA DELTA analog-to-digital converters (7).

Description

Electronic circuit and method for suppressing offset variations in a buffer Technical Field The present invention relates to an electronic circuit and method for suppressing offset variations in a buffer. Background The reference buffer is an important component of the electronic signal processing chain. These buffers have the task, inter alia, of converting a reference voltage, which is typically high-resistance (i.e. having a high resistance), into a voltage of low resistance (i.e. having a low resistance). One reason is that low resistance voltages can better drive other electronic components such as resistors, capacitors, or inductors without significant voltage drops (also known as "IR Drop"). "IR Drop" refers to the voltage loss caused by the flow of current in a resistor. Each electronic component may have so-called random telegraph noise. Random telegraph noise (Random Telegraph Noise, RTN) is a form of noise signal that occurs in electronic components, especially in semiconductors such as transistors. It is a random ripple noise characterized by abrupt switching of an electrical signal between two or more discrete states. These states may be caused by the capture and release of carriers at defective points or so-called "traps" in the material. For example, the reference buffer may suddenly have an additional offset source in its input pair, which source disappears again, for example, within a few seconds, or takes another discrete value. Chopper modulation may be used to combat random telegraph noise signals, but is not a suitable solution when used in certain systems, because the signal is not removed, but is only modulated, especially when the signal is used as a reference for a so-called SIGMA DELTA analog-to-digital converter. This may significantly degrade performance by demodulation of quantization noise. Furthermore, it is often desirable that the signal be permanently available. Moreover, noise is also often a parameter to be optimized. Disclosure of Invention The subject of the invention is an electronic circuit for suppressing offset variations in a buffer and a method for suppressing offset variations in a buffer. Other features and details of the invention are found in the preferred embodiments, the description and the drawings. The features and details described in connection with the electronic circuit according to the invention are of course also applicable here in connection with the method according to the invention and vice versa, so that the disclosure in relation to the invention is always made mutually. The subject of the invention is in particular an electronic circuit, in particular a reference buffer, for suppressing offset variations in a buffer for providing an electrical output signal, comprising: A buffer configured to provide an electrical output signal based on an input signal at an input of the electronic circuit, wherein the buffer is arranged in a main path of the electronic circuit, wherein the buffer may also be referred to and understood as a reference buffer (Referenzbuffer or Referenzpuffer) or may be configured as a reference buffer, such as a reference buffer for a SIGMA DELTA analog-to-digital converter, Wherein the electronic circuit further comprises an auxiliary path arranged in parallel with the main path and comprising at least the following elements: An electronic amplifier, in particular an operational amplifier, particularly preferably a transconductance amplifier, which is connected to the input for generating a regulating signal for the buffer on the basis of the input signal, so that the buffer can advantageously provide an output signal with suppressed offset variations using the regulating signal, and -An arrangement of chopping switches to minimize, in particular to suppress, offset variations in the auxiliary path by the arrangement of chopping switches, wherein the arrangement of chopping switches preferably comprises at least two and further preferably three chopping switches. The offset variations in the electronic circuit relate in particular to variations in the quiescent direct current or direct voltage applied to the amplifier, i.e. for example a buffer according to the invention, or other electronic circuit, to influence the output signal. The variations may be caused by variations in the circuit elements or by external factors such as temperature or component aging. Offset variations may affect the accuracy and stability of the output signal. The reference buffer in this context is used in particular for converting a high-resistance reference voltage into a low-resistance source, wherein the high-resistance reference voltage corresponds in particular to the input signal and the low-resistance source corresponds in particular to the output signal. This low resistance is for example necessary to keep the reference voltage stable and load-carrying so that it can drive a resistor, capacitor or inductor accurately and without voltage loss