阅读说明：本技术 比较器阈值电压选择电路及方法 (Comparator threshold voltage selection circuit and method ) 是由 陈玺 王健安 付东兵 陈光炳 刘璐 李飞 沈晓峰 季瑾月 于 2021-07-07 设计创作，主要内容包括：本发明提供一种比较器阈值电压选择电路及方法中,在本发明的比较器阈值电压选择方法中,先提供多个备选阈值电压,再将比较器的理想阈值电压与多个备选阈值电压逐一比较判定,能快速有效地选择出略小于理想阈值电压的备选阈值电压作为比较器的阈值电压,基于失调电压的偏差值的逐渐逼近,能有效地对阈值电压进行校正,消除了失调电压对比较器输出结果准确性的影响,进而消除了系统上的失码问题；且整个比较器阈值电压选择电路为基于比较器的简单结构,不改变流水级模数转换器中Sub-ADC电路结构,不需要增加额外的运算单元,因此,该电路结构可以适配在任何流水级模数转换器中,在流水级模数转换器电路上电时自动选择合适的比较器阈值,适用范围广。(The invention provides a comparator threshold voltage selection circuit and a method, wherein in the comparator threshold voltage selection method, a plurality of alternative threshold voltages are provided firstly, then an ideal threshold voltage of a comparator is compared with the alternative threshold voltages one by one for judgment, the alternative threshold voltage slightly smaller than the ideal threshold voltage can be selected quickly and effectively as the threshold voltage of the comparator, and the threshold voltage can be effectively corrected based on the gradual approximation of the offset value of offset voltage, so that the influence of the offset voltage on the accuracy of the output result of the comparator is eliminated, and the code missing problem of a system is further eliminated; and the whole comparator threshold voltage selection circuit is a simple structure based on a comparator, the Sub-ADC circuit structure in the pipeline analog-to-digital converter is not changed, and an additional operation unit is not required to be added, so that the circuit structure can be adapted to any pipeline analog-to-digital converter, a proper comparator threshold is automatically selected when the pipeline analog-to-digital converter circuit is powered on, and the application range is wide.)

1. A comparator threshold voltage selection circuit for selecting a threshold voltage of a comparator in a pipelined analog-to-digital converter, comprising:

a threshold voltage generation module, one end of which is connected with a first voltage and the other end of which is connected with a second voltage, and which provides N alternative threshold voltages to the outside;

the input end of the path selection module is connected with the threshold voltage generation module, the output end of the path selection module is connected with the inverting input end of the comparator, the N alternative threshold voltages are connected to the inverting input end of the comparator one by one, and the on-off states of the alternative threshold voltages are controlled by a control end;

the input end of the judgment module is connected with the output end of the comparator, the output end of the judgment module is connected with the control end of the channel selection module, and the on-off states of the N alternative threshold voltages are controlled according to the output of the comparator;

the non-inverting input end of the comparator is connected with an ideal threshold voltage, and N is an integer larger than 1.

2. The comparator threshold voltage selection circuit according to claim 1, wherein the threshold voltage generation module includes N +1 resistors, N +1 resistors are sequentially connected in series to form a resistor string, one end of the resistor string is connected to the first voltage, the other end of the resistor string is connected to the second voltage, and a common end of two adjacent resistors outputs one of the alternative threshold voltages.

3. The comparator threshold voltage selection circuit of claim 2, wherein N +1 resistors have the same resistance, and the difference between two adjacent candidate threshold voltages is equal to the offset voltage deviation value of the comparator.

4. The comparator threshold voltage selection circuit according to claim 1 or 3, wherein the path selection module comprises N control switches arranged in parallel, input terminals of the N control switches are connected with the N candidate threshold voltages in a one-to-one correspondence, and output terminals of the N control switches are connected with an inverting input terminal of the comparator.

5. The comparator threshold voltage selection circuit according to claim 4, wherein the decision module includes a counter and a state machine, an input terminal of the counter is connected to an output terminal of the comparator, an output terminal of the counter is connected to an input terminal of the state machine, an output terminal of the state machine is connected to control terminals of the N control switches, and the state machine controls on-off states of the N control switches respectively.

6. A method for selecting threshold voltage of comparator in pipeline analog-to-digital converter is used for selecting threshold voltage of comparator in pipeline analog-to-digital converter, and is characterized by comprising the following steps:

providing an ideal threshold voltage and N alternative threshold voltages, wherein the N alternative threshold voltages form an incremental arithmetic series, and the ideal threshold voltage is the median of the arithmetic series;

comparing the candidate threshold voltages with the ideal threshold voltage in sequence from the first item of the arithmetic progression until finding one candidate threshold voltage smaller than the ideal threshold voltage, and taking the corresponding candidate threshold voltage as the threshold voltage of the comparator;

and the tolerance of the arithmetic progression is the offset voltage deviation value of the comparator, and N is an integer greater than 1.

7. The comparator threshold voltage selection method of claim 6, wherein the step of sequentially comparing the candidate threshold voltages with the ideal threshold voltage in order starting from the first entry of the arithmetic progression until a candidate threshold voltage smaller than the ideal threshold voltage is found comprises:

connecting the ideal threshold voltage to a non-inverting input end of the comparator;

and sequentially connecting the alternative threshold voltages to the inverting input end of the comparator from the first item of the arithmetic progression in sequence, and comparing the alternative threshold voltages with the ideal threshold voltage until finding one alternative threshold voltage smaller than the ideal threshold voltage.

8. The method according to claim 7, wherein when comparing the candidate threshold voltages with the ideal threshold voltage, each candidate threshold voltage is compared with the ideal threshold voltage n times, the count is increased by one if the output of the comparator is 1 after one comparison is completed, the threshold voltage selection is finished if the output count of the comparator reaches a set value m after the n comparisons are completed, the candidate threshold voltage is smaller than the ideal threshold voltage, and the corresponding candidate threshold voltage is used as the threshold voltage of the comparator; wherein m is an integer greater than 1, n is an integer greater than 2, and m is less than or equal to n.

9. The method according to claim 8, wherein if the candidate threshold voltages smaller than the ideal threshold voltage are not found after the N candidate threshold voltages are compared with the ideal threshold voltage, the voltage range of the candidate threshold voltages needs to be increased, and the candidate threshold voltages with smaller values are provided to be compared with the ideal threshold voltage until one candidate threshold voltage smaller than the ideal threshold voltage is found.

Technical Field

The present invention relates to the field of integrated circuit technologies, and in particular, to a comparator threshold voltage selection circuit and method.

Background

The high-speed high-precision analog-to-digital converter adopts a pipeline architecture so as to simultaneously meet the requirements of speed and precision. In the pipeline stage analog-to-digital converter, the comparator is mainly used for building a Sub-analog-to-digital converter (Sub-ADC), as shown in fig. 1, a non-inverting input terminal of the comparator 130 is connected to an input voltage Vin, an inverting input terminal of the comparator 130 is connected to a threshold voltage Vref provided by the threshold voltage generating module 110 through the path selecting module 120, one of core indexes of the comparator is an offset voltage Vo caused by a circuit structure and a production process, and a large offset voltage Vo makes a comparison decision between the input voltage Vin and the threshold voltage Vref at the input terminal of the comparator 130 wrong, so that an output signal of the pipeline stage is over-measured, and finally appears as an analog-to-digital converter integral differential nonlinear error/integral nonlinear error (DNL/INL) code loss. Therefore, the offset voltage of the comparator must be ensured to be sufficiently small to meet the design requirement from the aspect of circuit structure design or by using a correction means.

Currently, the correction concept of the offset voltage mainly obtains the offset value of the offset voltage through different calculation methods, and incorporates the offset value into the threshold voltage of the comparator, so as to eliminate the influence. However, these different calculation methods require a decision voltage, so additional circuits are used to perform the auxiliary operation, which adds to the complexity of the circuit implementation, such as the technical solution of 201610444100.2 "a comparator offset voltage self-correction circuit".

In view of the above, a technical solution for correcting the threshold voltage of the comparator with simple circuit structure and high reliability is needed.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a threshold voltage selection scheme for a comparator, which is used to solve the above-mentioned technical problems.

To achieve the above and other related objects, the present invention provides a comparator threshold voltage selection circuit for selecting a threshold voltage of a comparator in a pipeline analog-to-digital converter, including:

a threshold voltage generation module, one end of which is connected with a first voltage and the other end of which is connected with a second voltage, and which provides N alternative threshold voltages to the outside;

the input end of the path selection module is connected with the threshold voltage generation module, the output end of the path selection module is connected with the inverting input end of the comparator, the N alternative threshold voltages are connected to the inverting input end of the comparator one by one, and the on-off states of the alternative threshold voltages are controlled by a control end;

the input end of the judgment module is connected with the output end of the comparator, the output end of the judgment module is connected with the control end of the channel selection module, and the on-off states of the N alternative threshold voltages are controlled according to the output of the comparator;

the non-inverting input end of the comparator is connected with an ideal threshold voltage, and N is an integer larger than 1.

Optionally, the threshold voltage generation module includes N +1 resistors, the N +1 resistors are sequentially connected in series to form a resistor string, one end of the resistor string is connected to the first voltage, the other end of the resistor string is connected to the second voltage, and a common end of two adjacent resistors outputs one of the alternative threshold voltages.

Optionally, the resistances of the N +1 resistors are equal, and the difference between the two adjacent candidate threshold voltages is equal to the offset voltage deviation value of the comparator.

Optionally, the path selection module includes N control switches arranged in parallel, input ends of the N control switches are connected to the N candidate threshold voltages in a one-to-one correspondence manner, and output ends of the N control switches are connected to an inverting input end of the comparator.

Optionally, the determination module includes a counter and a state machine, an input end of the counter is connected to an output end of the comparator, an output end of the counter is connected to an input end of the state machine, an output end of the state machine is connected to control ends of the N control switches, and the state machine controls on-off states of the N control switches respectively.

Secondly, to achieve the above and other related objects, the present invention further provides a method for selecting a threshold voltage of a comparator in a pipeline analog-to-digital converter, including:

providing an ideal threshold voltage and N alternative threshold voltages, wherein the N alternative threshold voltages form an incremental arithmetic series, and the ideal threshold voltage is the median of the arithmetic series;

comparing the candidate threshold voltages with the ideal threshold voltage in sequence from the first item of the arithmetic progression until finding one candidate threshold voltage smaller than the ideal threshold voltage, and taking the corresponding candidate threshold voltage as the threshold voltage of the comparator;

and the tolerance of the arithmetic progression is the offset voltage deviation value of the comparator, and N is an integer greater than 1.

Optionally, the step of sequentially comparing the candidate threshold voltages with the ideal threshold voltage in order starting from the first item of the arithmetic progression until finding one candidate threshold voltage smaller than the ideal threshold voltage comprises:

connecting the ideal threshold voltage to a non-inverting input end of the comparator;

and sequentially connecting the alternative threshold voltages to the inverting input end of the comparator from the first item of the arithmetic progression in sequence, and comparing the alternative threshold voltages with the ideal threshold voltage until finding one alternative threshold voltage smaller than the ideal threshold voltage.

Optionally, when comparing the candidate threshold voltages with the ideal threshold voltage, each candidate threshold voltage is compared with the ideal threshold voltage n times, if the output of the comparator is 1 after one comparison is completed, the count is increased by one, if the output count of the comparator reaches a set value m after n comparisons are completed, the threshold voltage selection is finished, the candidate threshold voltages are smaller than the ideal threshold voltage, and the corresponding candidate threshold voltages are used as the threshold voltages of the comparator; wherein m is an integer greater than 1, n is an integer greater than 2, and m is less than or equal to n.

Optionally, if after the N candidate threshold voltages are compared with the ideal threshold voltage, the candidate threshold voltage smaller than the ideal threshold voltage is not found yet, the voltage value range of the candidate threshold voltage needs to be increased, and the candidate threshold voltage with a smaller value is provided to be compared with the ideal threshold voltage until a candidate threshold voltage smaller than the ideal threshold voltage is found.

As described above, the comparator threshold voltage selection circuit and method of the present invention have at least the following advantages:

firstly, a plurality of alternative threshold voltages are provided, then the ideal threshold voltage of the comparator is compared with the alternative threshold voltages one by one for judgment, the alternative threshold voltage slightly smaller than the ideal threshold voltage can be quickly and effectively found out to be used as the threshold voltage of the comparator, the threshold voltage is corrected, the influence of offset voltage on the accuracy of the output result of the comparator is eliminated, and the code missing problem on a system is further eliminated; and the whole comparator threshold voltage selection circuit is a simple structure based on a comparator, the circuit structure of a Sub-ADC in the pipeline analog-to-digital converter is not changed, and an additional operation unit is not required to be added, so that the circuit structure can be adapted to any pipeline analog-to-digital converter, a proper comparator threshold is automatically selected when the pipeline analog-to-digital converter circuit is powered on, and the application range is wide.

Drawings

Fig. 1 is a schematic structural diagram of a sub-analog-to-digital converter in a pipeline-level analog-to-digital converter in the prior art.

FIG. 2 is a schematic diagram of a comparator threshold voltage selection circuit according to the present invention.

Fig. 3 is a schematic diagram of a comparator threshold voltage selection circuit according to an embodiment of the invention.

FIG. 4 is a schematic diagram showing steps of a comparator threshold voltage selection method according to the present invention.

FIG. 5 is a diagram illustrating an output state of the determining module according to an embodiment of the invention.

110. 210-threshold voltage generation module, 120, 220-path selection module, 230-decision module, 130, 240-comparator, VDD-operating voltage, GND-ground, V_OOffset voltage, Vref-threshold voltage, Vin-input voltage, V_PA first voltage, V_MA second voltage, V₁、V₂、…、V_N-1And V_N-alternative threshold voltage, V₀-ideal threshold voltage, R₁、R₂、…、R_NAnd R_N+1Resistance, S₁、S₂、…S_N-1And S_N-a control switch, V_O1、V_O2、…、V_ON-1And V_ON-a control terminal of the control switch.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 2 to 5. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated. The structures, proportions, sizes, and other dimensions shown in the drawings and described in the specification are for understanding and reading the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined in the claims, and are not essential to the art, and any structural modifications, changes in proportions, or adjustments in size, which do not affect the efficacy and attainment of the same are intended to fall within the scope of the present disclosure.

As shown in fig. 2, the present invention provides a comparator threshold voltage selection circuit for selecting a threshold voltage of a comparator in a pipeline analog-to-digital converter, including:

a threshold voltage generation module 210 connected to the first voltage V_PThe other end is connected with a second voltage V_MProviding N alternative threshold voltages externally, i.e. alternative threshold voltage V₁、V₂、…、V_N-1And V_N；

A path selection module 220, the input end of which is connected with the threshold voltage generation module 210, the output end of which is connected with the inverting input end of the comparator 240, and the N alternative threshold voltages (namely alternative threshold voltage V)₁、V₂、…、V_N-1And V_N) One-to-one connected to the inverting input terminal of the comparator 240 and alternative threshold voltage V₁、V₂、…、V_N-1And V_NIs controlled by the control end V in one-to-one correspondence with the on-off state_O1、V_O2、…、V_ON-1And V_ONControl of (2);

a decision module 230 with an input end connected to the output end of the comparator 240 and an output end connected to the control end of the path selection module 220, for controlling the N candidate threshold voltages V according to the output of the comparator 240₁、V₂、…、V_N-1And V_NOn-off state of (c);

wherein the non-inverting input terminal of the comparator 240 is connected to the ideal threshold voltage V₀And N is an integer greater than 1.

In detail, as shown in fig. 2, the threshold voltage generation module 210 includes N +1 resistors, i.e., a resistor R₁、R₂、…、R_NAnd R_N+1Resistance R₁、R₂、…、R_NAnd R_N+1Sequentially connected in series to form a resistor string, one end of which is connected with a first voltage V_PThe other end is connected with a second voltage V_MAn alternative threshold voltage is output at the common end of two adjacent resistors, namely a resistor R₁And a resistor R₂Output an alternative threshold voltage V at the common terminal₁Resistance R₂And a resistor R₃Output an alternative threshold voltage V at the common terminal₂…, resistance R_NAnd a resistor R_N+1Output an alternative threshold voltage V at the common terminal_N。

Wherein the resistance values of the N +1 resistors are equal, i.e. the resistor R₁、R₂、…、R_NAnd R_N+1Are equal, and the difference between two adjacent candidate threshold voltages is equal to the offset voltage deviation value of the comparator 240, i.e., V₁-V₂＝V₂-V₃＝…＝V_N-1-V_NΔ; a first voltage V_PSecond voltage V for the theoretical value of the previous comparator threshold_MIdeal threshold voltage V for the design theoretical value of the next comparator threshold₀The theoretical value of the current comparator threshold is designed.

In detail, as shown in fig. 2, the path selection module 220 includes N control switches arranged in parallel, i.e., a control switch S₁、S₂、…S_N-1And S_NThe input ends of the N control switches are connected with the N alternative threshold voltages in a one-to-one correspondence manner, namely the control switch S₁And an alternative threshold voltage V₁Connect, control switch S₂And an alternative threshold voltage V₂Connection, …, control switch S_NAnd an alternative threshold voltage V_NThe outputs of the N control switches are connected to the inverting input of the comparator 240.

In detail, as shown in fig. 2, the determining module 230 includes a counter and a state machine, an input terminal of the counter is connected to an output terminal of the comparator 240, an output terminal of the counter is connected to an input terminal of the state machine, and an output terminal of the state machine is connected to control terminals of the N control switches, that is, the output terminal of the state machine is respectively connected to the control switches S₁Control terminal V_O1Control switch S₂Control ofEnd manufacturing V_O2… and control switch S_NControl terminal V_ONConnection, the state machine controls N to open S₁、S₂、…S_N-1And S_NThe on-off states of the switches are respectively controlled.

In an alternative embodiment of the present invention, as shown in fig. 3, N is 5, and the threshold voltage generating module 210 includes 6 resistors, i.e. the resistor R₁、R₂、R₃、R₄、R₅And R₆Resistance R₁、R₂、R₃、R₄、R₅And R₆Sequentially connected in series to form a resistor string, one end of which is connected with a first voltage V_PThe other end is connected with a second voltage V_MThe threshold voltage generation module 210 provides 5 alternative threshold voltages, i.e. alternative threshold voltages V, to the outside₁、V₂、V₃、V₄And V₅。

Correspondingly, as shown in fig. 3, the path selection module 220 includes 5 control switches arranged in parallel, i.e., a control switch S₁、S₂、S₃、S₄And S₄Control switch S₁And an alternative threshold voltage V₁Connect, control switch S₁Is connected to the inverting input of the comparator 240, controls the switch S₁Control terminal V_O1Connected with the output end of the judging machine in the judging module 230 and controlling the switch S₂And an alternative threshold voltage V₂Connect, control switch S₂Is connected to the inverting input of the comparator 240, controls the switch S₂Control terminal V_O2Connected with the output end of the judging machine in the judging module 230 and controlling the switch S₃And an alternative threshold voltage V₃Connect, control switch S₃Is connected to the inverting input of the comparator 240, controls the switch S₃Control terminal V_O3Connected with the output end of the judging machine in the judging module 230 and controlling the switch S₄And an alternative threshold voltage V₄Connect, control switch S₄Is connected to the inverting input of the comparator 240, controls the switch S₄Control terminal V_O4Connected with the output end of the judging machine in the judging module 230 and controlling the switch S₅And an alternative threshold voltage V₅Connect, control switch S₅Is connected to the inverting input of the comparator 240, controls the switch S₅Control terminal V_O5Connected to the output of the decision maker in decision block 230.

Meanwhile, as shown in fig. 4, the present invention further provides a comparator threshold voltage selection method, which is used for selecting a threshold voltage of a comparator in a pipeline analog-to-digital converter, and includes the steps of:

s1, providing ideal threshold voltage V₀With N alternative threshold voltages V₁、V₂、…、V_N-1And V_NAlternative threshold voltage V₁、V₂、…、V_N-1And V_NForming an increasing series of equal differences and having an ideal threshold voltage V₀Is the median of the arithmetic progression;

s2, starting from the first item of the arithmetic progression, sequentially setting the alternative threshold voltage V₁、V₂、…、V_N-1And V_NAnd an ideal threshold voltage V₀Making comparison until finding a slightly smaller than ideal threshold voltage V₀Alternative threshold voltage V of_jAnd corresponding alternative threshold voltage V_jAs the threshold voltage of comparator 240;

the tolerance of the arithmetic progression is the offset voltage deviation of the comparator 240, and N is an integer greater than 1.

Alternatively, starting from the first term of the arithmetic progression, the alternative threshold voltages V are sequentially applied in order₁、V₂、…、V_N-1And V_NAnd an ideal threshold voltage V₀Making comparison until finding a voltage less than ideal threshold voltage V₀Alternative threshold voltage V of_jStep S2 further includes:

s21, converting the ideal threshold voltage V₀The non-inverting input terminal of the comparator 240 is accessed;

s22, starting from the first item of the arithmetic progression, sequentially setting the alternative threshold voltage V₁、V₂、…、V_N-1And V_NSwitching in the inverting input of the comparator 240 and comparing the alternative threshold voltage V₁、V₂、…、V_N-1And V_NAnd an ideal threshold voltage V₀Based on the gradual approximation of the offset value of the offset voltage until a value slightly less than the ideal threshold voltage V is found₀Alternative threshold voltage V of_jWherein j is a positive integer less than or equal to N.

Optionally, after comparing the alternative threshold voltage V_iAnd an ideal threshold voltage V₀When the magnitude of (1) is larger, the alternative threshold voltage V_iAnd an ideal threshold voltage V₀After n comparisons, if the output of the comparator 240 after one comparison is 1, the count is increased by one, and if the output count of the comparator 240 after n comparisons reaches the set value m, the threshold voltage selection is ended, and the alternative threshold voltage V is set_iLess than ideal threshold voltage V₀And corresponding alternative threshold voltage V_iAs the threshold voltage of comparator 240; wherein m is an integer greater than 1, N is an integer greater than 2, m is less than or equal to N, and i is a positive integer less than or equal to N.

Further, if N candidate threshold voltages V₁、V₂、…、V_N-1And V_NAnd an ideal threshold voltage V₀After the comparison is completed, no voltage less than the ideal threshold voltage V is found₀This indicates that the offset voltage of the comparator 240 has exceeded the correction range, the voltage value range of the candidate threshold voltage needs to be increased, and a candidate threshold voltage with a smaller value and an ideal threshold voltage V are provided₀Making comparison until finding a slightly smaller than ideal threshold voltage V₀Alternative threshold voltages of (2).

In an alternative embodiment of the present invention, as shown in fig. 3 and 5, the comparator threshold voltage selection circuit shown in fig. 3 operates according to the following principle: the threshold value of the current comparator is judged and selected by five times, and if the judgment is finished at any time, the next circulation is not carried out;

stp1, first determination, counter clear, determination Module 230 output State 1 control switch S₅Conducting to control the switch S₁/S₂/S₃/S₄The non-inverting input of the comparator 240 is connected to the ideal threshold voltage V₀At this time, the ideal threshold voltage V₀Equal to the alternative threshold voltage V₃The inverting input of the comparator 240 is connected to the alternative threshold voltage V₅(ii) a If the output of the comparator 240 is 1, the output of the determining module 230 is maintained, and the counter is increased by one; the comparator 240 performs n comparisons, and if the counter reaches a set value m (m is less than or equal to n) after the n comparisons, the output of the determination module 230 is maintained, the threshold selection is ended, and the candidate threshold voltage V is set₅As the threshold voltage of comparator 240; if the counter does not reach the set value m, the output of the determination module 230 is changed, and the next selection is entered;

stp2, second determination, clear counter, output State 2 of determination Module 230 causes control switch S₄Conducting to control the switch S₁/S₂/S₃/S₅The non-inverting input of the comparator 240 is connected to the ideal threshold voltage V₀The inverting input of the comparator 240 is connected to the alternative threshold voltage V₄(ii) a If the output of the comparator 240 is 1, the output of the determining module 230 is maintained, and the counter is increased by one; the comparator 240 performs n comparisons, and if the counter reaches a set value m (m is less than or equal to n) after the n comparisons, the output of the determination module 230 is maintained, the threshold selection is ended, and the candidate threshold voltage V is set₄As the threshold voltage of comparator 240; if the counter does not reach the set value m, the output of the determination module 230 is changed, and the next selection is entered;

stp3, third determination, clearing of the counter, output state 3 of the determination module 230, and controlling the switch S₃Conducting to control the switch S₁/S₂/S₄/S₅The non-inverting input of the comparator 240 is connected to the ideal threshold voltage V₀The inverting input of the comparator 240 is connected to the alternative threshold voltage V₃(ii) a If the output of the comparator 240 is 1, the output of the determining module 230 is maintained, and the counter is increased by one; the comparator 240 performs n comparisons, and if the counter reaches a set value m (m is less than or equal to n) after the n comparisons, the output of the determination module 230 is maintained, the threshold selection is ended, and the candidate threshold voltage is setV₃As the threshold voltage of comparator 240; if the counter does not reach the set value m, the output of the determination module 230 is changed, and the next selection is entered;

stp4, fourth determination, clearing of the counter, output state 4 of the determination module 230, and controlling the switch S₂Conducting to control the switch S₁/S₃/S₄/S₅The non-inverting input of the comparator 240 is connected to the ideal threshold voltage V₀The inverting input of the comparator 240 is connected to the alternative threshold voltage V₂(ii) a If the output of the comparator 240 is 1, the output of the determining module 230 is maintained, and the counter is increased by one; the comparator 240 performs n comparisons, and if the counter reaches a set value m (m is less than or equal to n) after the n comparisons, the output of the determination module 230 is maintained, the threshold selection is ended, and the candidate threshold voltage V is set₂As the threshold voltage of comparator 240; if the counter does not reach the set value m, the output of the determination module 230 is changed, and the next selection is entered;

stp5, fifth determination, counter clear, output state 5 of determination module 230 control switch S₁Conducting to control the switch S₂/S₃/S₄/S₅The non-inverting input of the comparator 240 is connected to the ideal threshold voltage V₀The inverting input of the comparator 240 is connected to the alternative threshold voltage V₁(ii) a If the output of the comparator 240 is 1, the output of the determining module 230 is maintained, and the counter is increased by one; the comparator 240 performs n comparisons, and if the counter reaches a set value m (m is less than or equal to n) after the n comparisons, the output of the determination module 230 is maintained, the threshold selection is ended, and the candidate threshold voltage V is set₁As the threshold voltage of comparator 240; if the counter does not reach the set value m, the output of the determining module 230 is in a state 0, which indicates that the offset voltage of the comparator 240 has exceeded the calibration range, and the calibration range may be increased by increasing the value range of the threshold voltage of the comparator 240, for example, the offset voltage of the comparator 240 may be more accurately eliminated by increasing the number of the alternative comparator threshold voltages.

In summary, in the comparator threshold voltage selection circuit and method provided by the invention, a plurality of candidate threshold voltages are provided, and then the ideal threshold voltage of the comparator is compared with the candidate threshold voltages one by one for judgment, so that the candidate threshold voltage slightly smaller than the ideal threshold voltage can be quickly and effectively selected as the threshold voltage of the comparator, and the threshold voltage can be effectively corrected based on the gradual approximation of the offset value of the offset voltage, the influence of the offset voltage on the accuracy of the output result of the comparator is eliminated, and the code missing problem on the system is further eliminated; and the whole comparator threshold voltage selection circuit is a simple structure based on a comparator, the Sub-ADC circuit structure in the pipeline analog-to-digital converter is not changed, and an additional operation unit is not required to be added, so that the circuit structure can be adapted to any pipeline analog-to-digital converter, a proper comparator threshold is automatically selected when the pipeline analog-to-digital converter circuit is powered on, and the application range is wide.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.