ADC (Analog to Digital Converter) real-time calibration device, control method of ADC real-time calibration device and electronic equipment

Abstract

The embodiment of the invention discloses an ADC real-time calibration device, a control method and electronic equipment, and relates to the field of power circuits. The stable reference signal is generated through the band-gap reference circuit, and the performance of an ADC (analog-to-digital converter) in a complex environment is remarkably optimized through the technology. For reference voltage instability caused by external factors such as voltage fluctuation and temperature change, the technology can effectively counteract gain errors generated by the reference voltage instability, the precision and reliability in the ADC conversion process are ensured, and therefore the calibration precision is greatly improved. The band-gap reference signals are seamlessly integrated and converted in the gap when the ADC executes a normal conversion task, the continuous working process of the ADC does not need to be interrupted in the process, and efficient utilization of resources and smoothness of operation are achieved.

Description

Technical Field

[0001] The invention relates to the field of power supplies, and in particular to an ADC real-time calibration device, a chip and an electronic device. Background Art

[0002] ADC is the abbreviation of Analog-to-Digital Converter, which is mainly used to convert continuously transmitted analog signals into digital signals, so that digital systems (such as central processing units MCU) can quickly process and analyze the transmitted information. Analog signals refer to information expressed by continuously changing physical quantities, such as temperature, humidity, pressure, voltage, current, etc. The signal collected by the ADC module is a continuous analog signal (voltage or current), which changes continuously within a certain range. The result of the ADC module conversion is a discontinuous digital signal (0 / 1 sequence), which often has different degrees of deviation. The most common are the gain error introduced by the change of the reference voltage and the offset error introduced by the change of the reference ground.

[0003] Generally speaking, when ADC is calibrated, a ground signal is continuously sampled inside the ADC, and the bias error of the ADC in the current situation is obtained through the conversion result of this reference ground. This method can eliminate the bias error introduced by the reference ground, but cannot eliminate the gain error introduced by the reference signal change. In addition, this method requires continuous sampling of the ground signal, which has poor real-time calibration and cannot achieve the purpose of real-time calibration during the normal operation of the ADC. Summary of the invention

[0004] The embodiments of the present application provide an ADC real-time calibration device, a chip, and an electronic device, which can reduce power consumption and simplify circuit structure. The technical solution is as follows:

[0005] In a first aspect, an embodiment of the present application provides an ADC real-time calibration device, comprising:

[0006] A bandgap reference circuit, a first switch circuit, a second switch circuit, an analog-to-digital conversion circuit and a main control circuit, wherein the first switch circuit is provided with a first input terminal, a second input terminal, a control terminal and an output terminal, and the second switch circuit is provided with an input terminal, a control terminal, a first output terminal and a second output terminal;

[0007] The first switch circuit is provided with a first input terminal and a second input terminal, the first input terminal is connected to the analog signal source, the second input terminal is connected to the bandgap reference signal, the output terminal of the first switch circuit is connected to the input terminal of the analog-to-digital converter, and the control terminal of the first switch circuit is connected to the main control circuit;

[0008] The reference end of the analog-to-digital conversion circuit is connected to the reference circuit, the control end of the analog-to-digital conversion circuit is connected to the main control circuit, the output end of the analog-to-digital conversion circuit is connected to the input end of the second switch circuit, the first output end of the second switch circuit is connected to the main control circuit, the second output end of the second switch circuit is connected to the external circuit, the calibration end of the analog-to-digital converter is connected to the main control circuit, and the control end of the second switch circuit is connected to the main control circuit;

[0009] In the calibration operation state, the main control circuit instructs the second input terminal and the output terminal of the first switch circuit to be turned on through the control terminal of the first switch circuit, instructs the first input terminal and the first output terminal of the second switch circuit to be turned on through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; the analog-to-digital conversion circuit performs analog-to-digital conversion on the bandgap reference signal from the bandgap reference circuit to obtain a conversion result, the main control circuit calculates a calibration coefficient according to the conversion result, and sends the calculated calibration coefficient to the analog-to-digital conversion circuit through the calibration terminal, so that the analog-to-digital conversion circuit updates the currently stored calibration coefficient;

[0010] Under normal operating conditions, the main control circuit instructs the first input terminal and the output terminal of the first switch circuit to be connected through the control terminal of the first switch circuit, instructs the input terminal and the second output terminal of the second switch circuit to be connected through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; the analog-to-digital conversion circuit receives an analog signal from an analog signal source, and converts the analog signal into a digital signal using a currently stored calibration coefficient, and outputs the digital signal to an external circuit for processing.

[0011] In a second aspect, the present application provides an electronic device, comprising the above-mentioned ADC real-time calibration device.

[0012] In a third aspect, the present application provides a control method for an ADC real-time calibration device, which is applied to the above-mentioned ADC real-time calibration device, and the method includes:

[0013] In the calibration operation state, the main control circuit instructs the second input terminal and the output terminal of the first switch circuit to be turned on through the control terminal of the first switch circuit, instructs the first input terminal and the first output terminal of the second switch circuit to be turned on through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; the analog-to-digital conversion circuit performs analog-to-digital conversion on the bandgap reference signal from the bandgap reference circuit to obtain a conversion result, the main control circuit calculates a calibration coefficient according to the conversion result, and sends the calculated calibration coefficient to the analog-to-digital conversion circuit through the calibration terminal, so that the analog-to-digital conversion circuit updates the currently stored calibration coefficient;

[0014] Under normal operating conditions, the main control circuit instructs the first input terminal and the output terminal of the first switch circuit to be connected through the control terminal of the first switch circuit, instructs the input terminal and the second output terminal of the second switch circuit to be connected through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; the analog-to-digital conversion circuit receives an analog signal from an analog signal source, and converts the analog signal into a digital signal using a currently stored calibration coefficient, and outputs the digital signal to an external circuit for processing.

[0015] The beneficial effects brought about by the technical solutions provided by some embodiments of the present application include at least:

[0016] By using a bandgap reference circuit to generate a stable reference signal, this technology significantly optimizes the performance of ADC (analog-to-digital converter) in complex environments. In the face of reference voltage instability caused by external factors such as voltage fluctuations and temperature changes, this technology can effectively offset the resulting gain error, ensuring the accuracy and reliability of the ADC conversion process, thereby greatly improving the accuracy of calibration. In the gap between the ADC performing normal conversion tasks, the bandgap reference signal is seamlessly integrated and converted. This process does not need to interrupt the continuous workflow of the ADC, achieving efficient resource utilization and smooth operation. This non-invasive calibration strategy enables the real-time acquired gain coefficient to be immediately applied to the next ADC conversion, which not only reduces calibration lag, but also greatly enhances the real-time response capability of ADC calibration, ensuring the immediacy and accuracy of data conversion, and laying a solid foundation for high-precision data acquisition and processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a structural diagram of an ADC real-time calibration device provided in an embodiment of the present application;

[0019] Figure 2 It is a flow chart of a calibration method of an ADC real-time calibration device provided in an embodiment of the present application;

[0020] Figure 3 It is a timing diagram of the calibration process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] See also Figure 1 The present invention provides a structural schematic diagram of an ADC real-time calibration device according to an embodiment, comprising: a bandgap reference circuit, a first switch circuit K1, a second switch circuit K2, an analog-to-digital conversion circuit and a main control circuit, wherein the first switch circuit K1 is provided with a first input terminal, a second input terminal, a control terminal and an output terminal, and the second switch circuit K2 is provided with an input terminal, a control terminal, a first output terminal and a second output terminal. The first switch circuit K1 selects one of the two input terminals to conduct with the output terminal based on a channel switching signal of the control terminal. The second switch circuit K2 selects one of the two output terminals to conduct with the input terminal based on a channel switching signal of the control terminal. The bandgap reference circuit is used to generate a bandgap reference signal.

[0023] The connection relationship between the above components is as follows: the first input terminal of the first switch circuit K1 is connected to the analog signal source ( Figure 1 The analog signal source is used to generate the analog signal to be converted, the second input end of the first switch circuit K1 is connected to the bandgap reference circuit, the control end of the first switch circuit K1 is connected to the main control circuit, and the output end of the first switch circuit K1 is connected to the input end of the analog-to-digital conversion circuit. The reference end of the analog-to-digital conversion circuit is connected to the reference circuit, and the reference circuit is used to generate a reference signal V refThe output end of the analog-to-digital conversion circuit is connected to the input end of the second switch circuit K2, the control end of the analog-to-digital conversion circuit is connected to the main control circuit, and the calibration end of the mode conversion circuit is connected to the main control circuit. The first output end of the second switch circuit K2 is connected to the main control circuit, and the second output end of the second switch circuit K2 is connected to the external circuit.

[0024] The working principle of the calibration device of the present application includes: in the calibration operation state, the main control circuit sends a channel switching signal to the control end of the first switch circuit K1 to control the conduction between the second input end and the output end of the first switch circuit K1, sends a work instruction signal to the control end of the analog-to-digital conversion circuit to instruct the analog-to-digital conversion circuit to start working, and sends a channel switching signal to the control end of the second switch circuit K2 to control the conduction between the input end and the first output end of the second switch circuit. In the calibration operation state, the bandgap reference circuit generates a bandgap reference signal, and the analog-to-digital conversion circuit performs analog-to-digital conversion processing based on the bandgap reference signal and the reference signal to obtain an analog-to-digital conversion result. The main control circuit calculates the gain coefficient based on the analog-to-digital conversion result, and updates the locally stored gain coefficient. In this way, the analog-to-digital conversion circuit in the normal operation state performs analog-to-digital conversion processing according to the gain coefficient stored in the main control circuit.

[0025] In some embodiments of the present application, the method for calculating the gain coefficient includes:

[0026] 1. Based on the voltage of the bandgap reference signal and the ideal reference voltage of the reference signal, an ideal conversion result of the bandgap reference signal is obtained.

[0027] Assume that the voltage of the bandgap reference signal is V bandgap The ideal reference voltage of the reference signal is V refideal , then the ideal conversion result DataIdeal of the bandgap reference signal is calculated as follows:

[0028] DataIdeal=(V bandgap / V refideal )×DataFull, where DataFull is the maximum digital result of the analog-to-digital conversion. For example, if the resolution is 16 bits, the value is 2^16-1=65535, and if the resolution is 8 bits, the value is 2^8-1=255.

[0029] 2. Based on the ideal conversion result and the actual conversion result of the bandgap reference signal, the actual reference voltage of the analog-to-digital conversion circuit is obtained.

[0030] Assuming that the actual conversion result of the bandgap reference signal is DataActual, the actual reference voltage V refactual The calculation formula is V refactual =V bandgap×(DataFull / DataActual).

[0031] 3. Based on the actual reference voltage of the analog-to-digital conversion circuit, the gain factor is calculated.

[0032] The gain coefficient Coeff acts on the analog-to-digital conversion result. The actual analog-to-digital conversion result multiplied by Coeff is the ideal analog-to-digital conversion result. The gain coefficient Coeff calculation formula is Coeff=(V bandgap / V refideal )×(DataFull / DataActual), where the ideal analog-to-digital conversion result is the conversion result obtained by the ideal reference voltage.

[0033] For example, assuming that the bit width of the analog-to-digital conversion circuit ADC is 12 bits, the maximum digital result is 2^12-1=4095, the ideal reference voltage is 3V, the actual reference voltage fluctuates from 3V to 2.9V, the voltage of the bandgap reference signal is 1.2V, and the actual conversion result is 1696. Apply the above steps:

[0034] 1. The ideal conversion result DataIdeal of the bandgap reference signal, DataIdeal=(1.2V / 3V)×4095=1638.

[0035] 2. The actual reference voltage V of the analog-to-digital conversion circuit refactual , V refactual =1.2V×(4095 / 1696)=2.897V.

[0036] 3. Gain coefficient Coeff, Coeff = (1.2V / 3V) × (4095 / 1696) = 0.9658

[0037] Finally, the gain coefficient is applied to the actual analog-to-digital conversion result. Taking the bandgap reference signal as an example, the conversion result after applying the gain coefficient is (1696×0.9658=1638), which is consistent with the ideal conversion result 1638. This shows the effect of real-time calibration. By applying the gain coefficient obtained by calibration, the gain error introduced by the reference voltage change is eliminated.

[0038] In some embodiments of the present application, a method for generating a bandgap reference signal by a bandgap reference circuit includes: adding two voltage signals with opposite temperature coefficients with appropriate weights within a chip to finally obtain a bandgap reference signal with a zero temperature coefficient. The bandgap reference signal is equivalent to a constant ruler, which is used to measure the change of the reference voltage, thereby realizing real-time calibration of the gain coefficient.

[0039] In normal operation, the main control circuit sends a channel switching signal to the control end of the first switch circuit K1 to control the first input end and the output end of the first switch circuit K1 to conduct, sends a work instruction signal to the control end of the analog-to-digital conversion circuit to control the analog-to-digital conversion circuit to start working, and sends a channel switching signal to the control end of the second switch circuit K2 to control the input end and the second output end of the second switch circuit K2 to conduct. In normal operation, the analog-to-digital conversion circuit receives an analog signal from an analog signal source, and the voltage of the analog signal is recorded as V signal The analog-to-digital conversion circuit reads the current gain coefficient from the main control circuit, processes the analog signal according to the read gain coefficient and the reference signal received from the reference circuit to obtain a digital signal, and outputs the digital signal to the external circuit.

[0040] In some embodiments of the present application, the main control circuit includes: a channel switching circuit and an operation storage circuit;

[0041] The channel switching circuit is connected to the control end of the first switch circuit, the control end of the second switch circuit, the control end of the analog-to-digital conversion circuit and the operation storage circuit; the operation storage circuit is connected to the first output end of the second switch circuit and the calibration end of the analog-to-digital conversion circuit.

[0042] See also Figure 3 As shown, this is a waveform diagram of the ADC real-time calibration provided by the present application, in which ADC_CLK is the ADC clock signal, ADC_CHSEL is the ADC channel switching signal, CONV_STATE is the conversion initiated during normal ADC operation, CALI_STATE is the conversion initiated during ADC calibration operation, CALI_ENABLE is the start and end of the ADC calibration signal, and GAIN_COEFF is the gain coefficient.

[0043] It can be seen from the figure that before the ADC calibration signal is initiated, the ADC is in normal operation. During normal operation, the ADC converts the external input signal, and the channel selection corresponds to external signal 0 / external signal 1; after the ADC calibration signal is initiated, the ADC is in calibration operation. During calibration operation, the ADC converts the bandgap reference signal, and the channel selection corresponds to the reference signal; after the calibration signal ends, the gain coefficient is updated, and the new gain coefficient is immediately applied to the next ADC conversion.

[0044] The ADC real-time calibration circuit of the present application has the following technical effects.

[0045] High-precision calibration: Using a stable bandgap reference signal as the calibration reference effectively eliminates reference voltage changes caused by environmental factors such as voltage fluctuations and temperature changes, thereby significantly improving the accuracy of ADC conversion and reducing gain errors.

[0046] Real-time calibration capability: Through intelligent control of the switch circuit, the calibration operation is seamlessly performed during the normal operation of the ADC, ensuring that the calibration process does not affect the continuous operation of the ADC. At the same time, the calibration coefficient is updated in real time and applied to the next conversion, greatly improving the real-time and dynamic response capabilities of the calibration.

[0047] Flexibility and scalability: The master control circuit fully controls the first and second switch circuits and the analog-to-digital conversion circuit, so that the entire system can flexibly adjust the working mode according to actual needs, is easy to integrate into a wider range of electronic systems, and supports future functional expansion.

[0048] Efficient resource utilization: Fast switching between calibration and normal operation modes without additional calibration cycles or interruption of the ADC's normal conversion process, improving overall system efficiency and resource utilization.

[0049] Simplify design complexity: Through integrated hardware design and intelligent control logic, the complex process of traditional ADC calibration is simplified, the design difficulty and cost are reduced, and the reliability and market competitiveness of the product are improved.

[0050] The electronic device provided in the embodiments of the present application includes but is not limited to communication equipment, terminal equipment, computer equipment, etc. In addition to the above-mentioned ADC real-time calibration device, the electronic device may also include: a shell for accommodating various components, a display screen and an input device (for example: a keyboard, a mouse or a touch screen), etc.

[0051] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.

Claims

1. An ADC real-time calibration device, characterized in that: include: A bandgap reference circuit, a first switch circuit, a second switch circuit, an analog-to-digital conversion circuit and a main control circuit, wherein the first switch circuit is provided with a first input terminal, a second input terminal, a control terminal and an output terminal, and the second switch circuit is provided with an input terminal, a control terminal, a first output terminal and a second output terminal; The first switch circuit is provided with a first input terminal and a second input terminal, the first input terminal is connected to an analog signal source, the second input terminal is connected to the bandgap reference signal, the output terminal of the first switch circuit is connected to the input terminal of the analog-to-digital converter, and the control terminal of the first switch circuit is connected to the main control circuit; The reference end of the analog-to-digital conversion circuit is connected to the reference circuit, the control end of the analog-to-digital conversion circuit is connected to the main control circuit, the output end of the analog-to-digital conversion circuit is connected to the input end of the second switch circuit, the first output end of the second switch circuit is connected to the main control circuit, the second output end of the second switch circuit is connected to the external circuit, the calibration end of the analog-to-digital converter is connected to the main control circuit, and the control end of the second switch circuit is connected to the main control circuit; In the calibration operation state, the main control circuit instructs the second input terminal and the output terminal of the first switch circuit to be turned on through the control terminal of the first switch circuit, instructs the first input terminal and the first output terminal of the second switch circuit to be turned on through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; The analog-to-digital conversion circuit performs analog-to-digital conversion on the bandgap reference signal from the bandgap reference circuit to obtain a conversion result, the main control circuit calculates a calibration coefficient according to the conversion result, and sends the calculated calibration coefficient to the analog-to-digital conversion circuit through the calibration terminal, so that the analog-to-digital conversion circuit updates the currently stored calibration coefficient; In a normal operating state, the main control circuit instructs the first input terminal and the output terminal of the first switch circuit to be turned on through the control terminal of the first switch circuit, instructs the input terminal and the second output terminal of the second switch circuit to be turned on through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; The analog-to-digital conversion circuit receives an analog signal from an analog signal source, converts the analog signal into a digital signal using a currently stored calibration coefficient, and outputs the digital signal to an external circuit for processing.

2. The circuit according to claim 1, characterized in that The bandgap reference circuit adds two voltages with opposite temperature coefficients with appropriate weights within a chip to finally obtain a reference voltage with a zero temperature coefficient.

3. The circuit according to claim 1 or 2, characterized in that: The main control circuit calculates the calibration coefficient according to the conversion result, including: Calculate the ideal conversion result: DataIdeal = (V bandgap / V refideal )×DataFull; V bandgap is the voltage of the bandgap reference signal, V refideal is the ideal reference voltage, DataFull is the maximum digital result of analog-to-digital conversion; Calculate the actual reference voltage V refactual =V bandgap ×(DataFull / DataActual); DataActual is the actual conversion result of the reference bandgap signal; Calculate the gain coefficient: Coeff = (V bandgap / V refideal )×(DataFull / DataActual).

4. The device according to claim 1, characterized in that The main control circuit includes: a channel switching circuit and an operation storage circuit; The channel switching circuit is connected to the control end of the first switch circuit, the control end of the second switch circuit, the control end of the analog-to-digital conversion circuit and the operation storage circuit; the operation storage circuit is connected to the first output end of the second switch circuit and the calibration end of the analog-to-digital conversion circuit.

5. The device according to claim 1, characterized in that The bandgap reference circuit, the first switch circuit, the second switch circuit, the analog-to-digital conversion circuit and the main control circuit are arranged inside a chip.

6. A real-time ADC calibration method, characterized in that: The ADC real-time calibration device applied to any one of claims 1 to 5; In the calibration operation state, the main control circuit instructs the second input terminal and the output terminal of the first switch circuit to be turned on through the control terminal of the first switch circuit, instructs the first input terminal and the first output terminal of the second switch circuit to be turned on through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; The analog-to-digital conversion circuit performs analog-to-digital conversion on the bandgap reference signal from the bandgap reference circuit to obtain a conversion result, the main control circuit calculates a calibration coefficient according to the conversion result, and sends the calculated calibration coefficient to the analog-to-digital conversion circuit through the calibration terminal, so that the analog-to-digital conversion circuit updates the currently stored calibration coefficient; In a normal operating state, the main control circuit instructs the first input terminal and the output terminal of the first switch circuit to be turned on through the control terminal of the first switch circuit, instructs the input terminal and the second output terminal of the second switch circuit to be turned on through the control terminal of the second switch circuit, and instructs the analog-to-digital conversion circuit to start working through the control terminal of the analog-to-digital conversion circuit; The analog-to-digital conversion circuit receives an analog signal from an analog signal source, converts the analog signal into a digital signal using a currently stored calibration coefficient, and outputs the digital signal to an external circuit for processing.

7. An electronic device, characterized in that: The device comprises the ADC real-time calibration device as described in any one of claims 1 to 3.

Images