CN112345909B - Detection method, detection circuit and reset circuit - Google Patents
Detection method, detection circuit and reset circuit Download PDFInfo
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- CN112345909B CN112345909B CN201910726231.3A CN201910726231A CN112345909B CN 112345909 B CN112345909 B CN 112345909B CN 201910726231 A CN201910726231 A CN 201910726231A CN 112345909 B CN112345909 B CN 112345909B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/24—Arrangements for measuring quantities of charge
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Abstract
The invention provides a detection method of a reset circuit, which comprises the following steps: a. the charge storage unit receives a certain amount of first charge; b. acquiring a first voltage Vout output by the nonlinear unit based on a first charge received by the charge storage unit, inputting the first voltage to a reset judgment unit for reset judgment, and transmitting a judgment result to a reset unit; c. detecting the second voltage V' out output by the nonlinear unit again after the delay of the preset time, thereby judging whether the charge resetting unit resets the charge storage unit according to the result of the voltage detection twice; d. changing a first charge amount received by the charge storage unit, and repeating the steps b and c to obtain a plurality of pairs of voltage data respectively; e. and detecting and judging the reset circuit according to the voltage data. The detection method and the detection circuit provided by the invention can detect and judge the folding integral reset circuit so as to ensure that the reset circuit can accurately finish reset.
Description
Technical Field
The invention relates to the technical field of microelectronics, in particular to a detection method of a reset circuit, a detection circuit of the reset circuit and the reset circuit with a detection function.
Background
An image sensor, or photosensitive element, is a device that converts an optical image into an electronic signal, and is widely used in digital cameras and other electronic optical devices.
Image sensor designs are always aimed at improving image contrast, resolution, dynamic range, etc., while different reset modes can have a significant impact on the performance of the image sensor. Because the pixel end voltages of different working periods are inconsistent, the voltage is influenced by the voltage before reset after the traditional voltage reset mode is reset, and the image information of the previous frame is remained, so that the image tailing is shown.
The folding integral is to calculate the total charge transferred from the photosensitive element (e.g. photodiode) to the charge storage unit (e.g. integrating capacitor) by adopting a charge reset mode and by adopting an accumulated reset mode. The reset mode overcomes the image tailing phenomenon caused by the traditional voltage reset mode, thereby improving the imaging quality of the image.
The above-described reset mode using integral folding, the calculation of the total charge amount depends on the charge amount accurately per reset and the capacitance instant measurement voltage. The source follower in the reset circuit has nonlinearity, the specific execution condition of the reset circuit cannot be accurately determined, and whether charge reset is started according to preset conditions is difficult to evaluate.
In summary, it is needed to design a detection method of a reset circuit and a corresponding detection device to solve the above-mentioned problems.
Disclosure of Invention
In a first aspect of the embodiments of the present invention, there is provided a detection method of a reset circuit, the reset circuit including:
a charge storage unit for storing the received first charge;
a nonlinear unit comprising at least one nonlinear element, said nonlinear unit being connected to said charge storage unit for isolating and following a voltage of said charge storage unit;
the reset judging unit is connected to the nonlinear unit and is used for generating a signal for indicating the reset unit to work according to the output of the nonlinear unit; and
the reset unit is connected with the reset judging unit and the charge storage unit and is used for resetting the charge storage unit according to the signal output by the reset judging unit;
the detection method comprises the following steps:
a. the charge storage unit receives a certain amount of first charge;
b. acquiring a first voltage Vout output by the nonlinear unit based on a first charge received by the charge storage unit, inputting the first voltage to a reset judgment unit for reset judgment, and transmitting a judgment result to a reset unit;
c. detecting the second voltage V' out output by the nonlinear unit again after the delay of the preset time, thereby judging whether the charge resetting unit resets the charge storage unit according to the result of the voltage detection twice;
d. changing a first charge amount received by the charge storage unit, and repeating the steps b and c to obtain a plurality of pairs of voltage data respectively;
e. and detecting and judging the reset circuit according to the voltage data.
In one embodiment of the present invention, the reset circuit further includes a signal conversion unit, the charge storage unit is connected to the signal conversion unit through a first switch, the signal conversion unit is configured to generate a first charge according to an input signal conversion and transmit the first charge to the charge storage unit, and the changing the first charge amount received by the charge storage unit includes: changing the amount of signal input in the signal conversion unit and/or changing the time when the first switch is turned on.
In one embodiment of the present invention, the reset judging unit is a comparator, the comparator has a reference voltage Vref,
the step d includes:
obtaining Vout of at least one group of output voltages which are not in a preset range; and
obtaining Vout of at least one group of output voltages in a preset range; wherein the preset range is determined according to the reference voltage.
In one embodiment of the present invention, the step of detecting and judging the reset circuit according to the plurality of pairs of voltage data includes judging whether the reset circuit is normally started, including:
when Vout is not within the preset range, vout=v 'out, and when Vout is within the preset range, vout < V' out, the reset circuit is started normally, otherwise, the reset circuit is not started normally.
In one embodiment of the present invention, further comprising: calibrating the nonlinear unit to obtain a corresponding relationship between voltage input and voltage output of the nonlinear unit;
the step d further comprises: and obtaining Vout of at least two groups of output voltages in a preset range.
In one embodiment of the present invention, the step of detecting and determining the reset circuit according to the plurality of pairs of voltage data further includes determining whether the charge amounts of the second charges transferred to the charge storage unit are the same each time the charges are reset, including:
according to the voltage input-output curve of the nonlinear unit, the output voltage Vout and the corresponding V ' out, obtaining an input voltage Vin corresponding to each group of output voltage Vout and a V ' in corresponding to the V ' out;
calculating whether the difference value of any two groups of input voltages Vin and corresponding V' in is the same when Vout is in a preset range, if the difference value is the same, judging that the charge quantity of the second charge transferred to the charge storage unit is the same when reset is performed each time, otherwise, the charge quantity of the second charge transferred to the charge storage unit is different when reset is performed each time;
wherein the second charge is of opposite polarity to the first charge.
In one embodiment of the present invention, the step of detecting and judging the reset circuit according to the plurality of pairs of voltage data further includes determining whether the amount of charge transferred to the second charge in the charge storage unit at each reset is a preset value based on a difference between the capacitance of the charge storage unit and the input voltage of the corresponding nonlinear unit before and after the reset when the amount of charge transferred to the second charge in the charge storage unit at each reset is the same;
and comparing and judging according to the calculated charge quantity of the second charge transferred to the charge storage unit with a preset value.
In one embodiment of the invention, the method further comprises the step of resetting the charge storage unit before the charge storage unit receives a certain amount of the first charge amount each time.
In one embodiment of the invention, the nonlinear unit is connected to the charge storage unit through a second switch.
In a second aspect of the embodiments of the present invention, there is provided a detection circuit of a reset circuit including: a charge storage unit for storing the received first charge; a nonlinear unit connected to the charge storage unit for isolating and following a voltage of the charge storage unit; the reset judging unit is connected to the nonlinear unit and is used for generating a signal for indicating the reset unit to work according to the output of the nonlinear unit; the reset unit is connected with the reset judging unit and the charge storage unit and is used for resetting the charge storage unit according to the signal output by the reset judging unit;
the detection circuit includes:
the logic control unit is used for controlling the charge storage unit to receive a certain amount of first charges, acquiring a first voltage Vout output by the nonlinear unit based on the first charges received by the charge storage unit, inputting the first voltage to the reset judgment unit for reset judgment, and transmitting a judgment result to the reset unit; the second voltage V' out output by the nonlinear unit is detected again after a delay of a preset time; the charge storage unit is also used for changing the first charge quantity received by the charge storage unit, and repeating the steps to respectively acquire a plurality of pairs of voltage data; and detecting and judging the reset circuit according to the voltage data.
In one embodiment of the present invention, the detection circuit further includes a voltage input unit, and the voltage input unit is connected to an input end of the nonlinear unit through a third switch circuit, and is configured to provide an adjustable voltage as an input of the nonlinear unit, so as to obtain a correspondence between a voltage input and a voltage output of the nonlinear unit.
In one embodiment of the present invention, the logic control unit performs detection and judgment on the reset circuit according to the plurality of pairs of voltage data, including judging whether the reset circuit is normally started, whether the charge amount of the second charge transferred to the charge storage unit at each time of charge reset at the time of normal start of the reset circuit is the same, and determining whether the charge amount of the second charge transferred to the charge storage unit at each time of reset is a preset value.
In a third aspect of the embodiment of the present invention, there is provided a reset circuit with a detection function, including a reset circuit, the reset circuit including: a charge storage unit for storing the received first charge; a nonlinear unit connected to the charge storage unit for isolating and following a voltage of the charge storage unit; the reset judging unit is connected to the nonlinear unit and is used for generating a signal for indicating the reset unit to work according to the output of the nonlinear unit; the reset unit is connected with the reset judging unit and the charge storage unit and is used for resetting the charge storage unit according to the signal output by the reset judging unit; and the detection circuit of the reset circuit provided by the embodiment.
In the technical scheme provided by the embodiment of the invention, the detection method of the reset circuit receives a certain amount of first charges through the charge storage unit; acquiring a first voltage Vout output by the nonlinear unit based on a first charge received by the charge storage unit, inputting the first voltage to a reset judgment unit for reset judgment, and transmitting a judgment result to a reset unit; detecting the second voltage V' out output by the nonlinear unit again after the delay of the preset time, thereby judging whether the charge resetting unit resets the charge storage unit according to the result of the voltage detection twice; changing the first charge quantity received by the charge storage unit, and repeating the steps to obtain a plurality of pairs of voltage data respectively; and detecting and judging the reset circuit according to the voltage data. Therefore, when the folding integral reset circuit is used for resetting to overcome the image tailing phenomenon caused by the traditional voltage reset mode, the detection method and the detection circuit provided by the invention can be used for detecting and judging the folding integral reset circuit so as to ensure that the reset circuit can accurately finish resetting.
Drawings
Fig. 1 schematically shows a schematic configuration of a reset circuit;
fig. 2 schematically illustrates a flowchart of a detection method of a reset circuit according to an embodiment of the present invention
Fig. 3 schematically illustrates a schematic diagram of a detection circuit structure of a reset circuit according to an embodiment of the present invention;
fig. 4 schematically illustrates a schematic diagram of a detection circuit structure of another reset circuit according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to overcome the problem, the charge resetting mode by adopting folding integration can avoid the problem of traditional image tailing, thereby improving the imaging quality of the image.
The working principle of folding integration is that a charge resetting mode is adopted, the photodiode receives radiation to generate charge to transfer to a capacitor, the voltage on the capacitor starts to drop until the voltage is smaller than or equal to the reference voltage Vref of a comparator, the comparator turns over, signals are folded, the next integration is carried out, and the process is circulated until the integration is completed. However, in practical use, it is not possible to accurately determine the execution of the reset circuit, for example, whether the reset is started according to a preset condition, whether the amount of charge reset each time is the same, and the specific value of the amount of charge reset are difficult to evaluate, and especially, when the reset circuit is disposed in a chip, it is more difficult to know and control the execution of the reset circuit.
Based on the above-mentioned problems, the present invention provides a method for detecting a reset circuit, which performs a series of orderly control on the reset circuit, so as to detect the performance of the reset circuit.
Referring to fig. 1, the reset circuit 100 according to the present invention generally includes a charge storage unit 120, a nonlinear unit 140, a reset judging unit 160, and a reset unit 180. Wherein the charge storage unit 120 is configured to store the received first charge; the nonlinear unit 140 comprises at least one nonlinear element, the nonlinear unit 140 being connected to the charge storage unit 120 for isolating and following the voltage of the charge storage unit 120; the reset judging unit 160 is connected to the nonlinear unit 140, and is configured to generate a signal for indicating the reset unit to operate according to the output of the nonlinear unit 140; and a reset unit 180, connected to the reset judging unit 160 and the charge storage unit 120, for resetting the charge storage unit 120 according to the signal output by the reset judging unit 160. The nonlinear unit 140 includes at least one nonlinear element, where an input signal and an output signal of the nonlinear element 140 have a nonlinear relationship, and the nonlinear element includes a source follower and a buffer.
Referring to fig. 2, a method 200 for detecting a reset circuit is used for detecting the reset circuit 100, and the method 200 includes the following steps:
step a. Control the charge storage unit 120 to receive a certain amount of the first charge. In a specific embodiment, an amount of charge may be transferred to the charge storage unit 120 in different ways, for example, the photo-energy converted charge may be transferred to the charge storage unit 120 by means of photoelectric conversion.
Step b, the first voltage Vout output by the nonlinear unit 140 is obtained, and is input to the reset judging unit 160 to perform reset judgment, and the judgment result is transmitted to the reset unit 180.
Step c, detecting the second voltage V' out outputted from the nonlinear unit 140 again after a delay of a predetermined time, thereby judging whether the charge resetting unit 180 resets the charge storage unit 120 according to the result of detecting the voltage twice. After a delay of a predetermined time, if the reset unit 180 resets the charge storage unit 120, the voltage value V' out, which is followed by the nonlinear unit 140 after the reset of the charge storage unit 120, is acquired at this time.
Step d. Changing the first charge amount received by the charge storage unit 120, and repeating the steps b and c to obtain a plurality of pairs of voltage data, respectively.
The reset circuit 100 further includes a signal conversion unit 190 (not shown), the charge storage unit 120 is connected to the signal conversion unit 190 through a first switch, the signal conversion unit 190 is configured to generate a first charge according to the input signal conversion and transmit the first charge to the charge storage unit 120, and the changing the first charge amount received by the charge storage unit 120 includes: changing the amount of signal input in the signal conversion unit 190 and/or changing the time when the first switch is turned on. For example, when the input signal is illumination, changing the amount of input signal may be by changing the illumination time and/or illumination intensity; when the input signal is pressure, the pressure applying time and/or the pressure magnitude can be changed.
By changing the charge amount of the charge storage unit 120 a plurality of times, thereby changing the following voltage value of the nonlinear unit 140, and then by determining the different voltage values and the predetermined threshold value a plurality of times by the reset determining unit 160, different determination results are obtained, and the reset unit 180 completes the reset or does not reset of the charge storage unit 120 according to the signal transmitted by the reset determining unit 160.
And e, detecting and judging the reset circuit 100 according to the plurality of pairs of voltage data.
The method comprises the steps of detecting and judging a reset circuit according to a plurality of pairs of voltage data, and judging the working state of the reset circuit qualitatively, wherein if the reset circuit is normally started, and the charge quantity of second charges transferred to the charge storage unit at each time of charge reset is the same; and quantitatively judging the working state of the reset circuit, for example, when the charge quantity of the second charge transferred to the charge storage unit is the same each time the charge is reset, further determining whether the charge quantity of the second charge transferred to the charge storage unit is a preset value or not each time the charge is reset.
Further details regarding the qualitative determination of the reset circuit 100 are provided below. Whether the reset circuit 100 is normally started or not is judged, whether the reset circuit 100 performs reset or not when the reset condition is satisfied, and whether the reset circuit 100 does not perform reset or not when the reset condition is not satisfied is required. Therefore, determining whether the reset circuit 100 is normally started according to the plurality of pairs of voltage data specifically includes: at least one set of voltage data is acquired when the charge storage unit 120 completes the reset, and at least one set of voltage data is acquired when the charge storage unit 120 does not perform the reset.
The reset determination unit 160 is exemplified as a comparator, and will be described below. Wherein the comparator has a reference voltage Vref. Therefore, when acquiring multiple sets of voltage data, vout of at least one set of output voltages not within a preset range needs to be acquired; and obtaining Vout of at least one group of output voltages within a preset range; wherein the preset range is determined according to the reference voltage. For example, when the first charge is negative, the preset range of the output voltage is equal to or less than the reference voltage of the comparator; when the second charge is positive, the preset range of the output voltage is equal to or greater than the reference voltage of the comparator. When Vout is not within the preset range, vout=v 'out, and when Vout is within the preset range, vout < V' out, the reset circuit is started normally, otherwise, the reset circuit is not started normally.
On the basis of completing the qualitative judgment of the reset circuit 100, a more accurate qualitative judgment of the reset circuit 100 is further described. That is, it is detected whether the reset charge amount is the same every time the reset circuit 100 is reset. At this time, the step d further includes: and obtaining Vout of at least two groups of output voltages in a preset range. According to the voltage input-output curve of the nonlinear unit, the output voltage Vout and the corresponding V ' out, obtaining an input voltage Vin corresponding to each group of output voltage Vout and a V ' in corresponding to the V ' out; calculating whether the difference value of any two groups of input voltages Vin and corresponding V' in is the same when Vout is in a preset range, if the difference value is the same, judging that the charge quantity of the second charge transferred to the charge storage unit is the same when reset is performed each time, otherwise, the charge quantity of the second charge transferred to the charge storage unit is different when reset is performed each time; wherein the second charge is of opposite polarity to the first charge.
Also, the description will be given taking the use of a comparator as the reset judging unit 160 as an example. The charge amount of each reset is judged and compared, so that at least two sets of voltage data when the reset is completed are required to be acquired. In order to determine whether the amount of charge in each reset is the same, it is also necessary to acquire a voltage input/output curve of the nonlinear unit 140. It should be noted that, calibration of the input and output voltages of the nonlinear unit 140 may be a calibration method that is conventional in the art, and will not be described in detail herein.
According to the voltage input-output curve of the nonlinear unit, the output voltage Vout and the corresponding V ' out, obtaining an input voltage Vin corresponding to each group of output voltage Vout and a V ' in corresponding to the V ' out;
calculating whether the difference value of any two groups of input voltages Vin and corresponding V' in is the same when Vout is in a preset range, if the difference value is the same, judging that the charge quantity of the second charge transferred to the charge storage unit is the same when reset is performed each time, otherwise, the charge quantity of the second charge transferred to the charge storage unit is different when reset is performed each time; wherein the second charge is of opposite polarity to the first charge.
When the amount of charge per reset is the same, the reset circuit 100 may further perform quantitative determination, that is, determination as to whether or not the amount of charge transferred to the second charge in the charge storage unit is a predetermined value, if the amount of charge per reset is the same. Determining whether the charge amount transferred to the second charge in the charge storage unit at each reset is a preset value based on the difference between the capacitance of the charge storage unit and the input voltage of the nonlinear unit corresponding to the charge storage unit before and after the reset; and comparing and judging according to the calculated charge quantity of the second charge transferred to the charge storage unit with a preset value.
When the charge storage unit 120 is an integrating capacitor, the charge amount Qreset of the second charge transferred to the charge storage unit each time can be calculated according to the following formula:
Qreset＝Cint·ΔV＝Cint·(V’in-Vin)；
wherein Cint is the capacitance of the integrating capacitor, and Δv is the voltage difference between the integrating capacitor before and after each reset; and then comparing and judging according to the calculated charge quantity transferred to the second charge in the charge storage unit with a preset value.
Therefore, the detection method provided by the invention not only can judge whether the reset circuit 100 works normally or not and judge whether the charge amount of the second charge transferred to the charge storage unit is the same or not, but also can quantitatively and precisely monitor the specific value of the charge amount of the second charge transferred to the charge storage unit each time. Thus, the performance of the reset circuit 100 located in the chip can be accurately evaluated, and the interference of the nonlinearity of the nonlinear unit 140 to the test of the reset circuit is avoided.
Further, to ensure the accuracy of detection, the charge storage unit 120 may be reset at each detection. For example, after calibration of the nonlinear unit 140 is completed, before whether the charge reset circuit 100 is tested for normal operation, the charge storage unit 120 needs to be reset first to ensure that the charge storage unit 120 has the same condition before each test, so as to avoid interference with detection of the charge reset circuit 100 of the present invention. On the other hand, when the photoelectric conversion unit is used to transfer charges to the photoelectric storage unit in the reset circuit 100, in order to ensure the detection accuracy, the photoelectric conversion unit needs to be reset during each detection, so as to ensure that the photoelectric conversion unit has the same condition before each test, and avoid interference to the detection of the charge reset circuit 100 of the present invention.
Referring to fig. 3, the present invention further provides a detection circuit 300 of the reset circuit, which is configured to implement the functions corresponding to the detection method 200. The detection circuit 300 is used for detecting the reset circuit 100, and includes a logic control unit 320. The logic control unit 320 is configured to control the charge storage unit to receive a certain amount of the first charge, obtain a first voltage Vout output by the nonlinear unit based on the first charge received by the associated charge storage unit, input the first voltage to the reset judgment unit to perform a reset judgment, and transmit a judgment result to the reset unit; the second voltage V' out output by the nonlinear unit is detected again after a delay of a preset time; the charge storage unit is also used for changing the first charge quantity received by the charge storage unit, and repeating the steps to respectively acquire a plurality of pairs of voltage data; and detecting and judging the reset circuit according to the voltage data.
The logic control unit 320 performs detection and determination on the reset circuit 100 according to the plurality of pairs of voltage data, including determining whether the reset circuit is normally started, whether the charge amounts of the second charges transferred to the charge storage unit during each reset of the charges in the reset circuit are the same during normal start, and determining whether the charge amounts of the second charges transferred to the charge storage unit during each reset are preset values.
Referring to fig. 3, the detection circuit 300 further includes a voltage input unit 340, connected to an input end of the nonlinear unit through a third switch circuit, configured to provide a controllable voltage as an input of the nonlinear unit, and obtain a corresponding relationship between a voltage input and a voltage output of the nonlinear unit.
Referring to fig. 4, a specific reset circuit detection circuit 400 is disclosed. The reset circuit shown in fig. 4 receives radiation by using a photodiode to generate a first charge, the photodiode is connected with a capacitor C through a first switch TX, a voltage source follower is connected with the capacitor C through a second switch s_sf, the source follower is sequentially connected with a comparing unit and a charge reset unit, and the charge reset unit is connected with the capacitor C. The voltage input unit V_SF_current passes through the third switch-! The s_sf is connected to the input of the source follower. The output end of the photodiode is connected with the first reset circuit through a fourth switch TX_anti, and the upper polar plate of the capacitor is connected with the second reset circuit through a fifth switch S_rst.
The detection method of the present invention will be described in detail with reference to FIG. 4.
Before the reset circuit starts to detect, the first switch and the second switch are turned off, and the fourth switch and the fifth switch are turned off. Firstly, closing a third switch, providing voltage input for a voltage source follower through a voltage input unit V_SF_cut, and further obtaining an input and output curve of the voltage source follower through measuring the output of the voltage source follower, namely finishing the calibration of the voltage source follower.
After the calibration of the voltage source follower is completed, before the reset circuit starts to test, the photoelectric conversion unit, namely the photodiode and the capacitor, are reset firstly, so that the same conditions of the photoelectric conversion unit and the charge storage unit before each test are ensured, and the interference to the charge reset circuit is avoided.
The whole test process is as follows:
(1) And (5) calibrating the voltage source follower, and obtaining the Vout-Vin curve.
(2) The fourth switch tx_anti is closed to reset the photodiode, and the fifth switch s_rst is closed to reset the capacitor C.
(3) Then, the fourth switch tx_anti is turned off, the fifth switch s_rst is turned off, the first switch TX is turned on for a certain time t1, and charges generated by the light received by the photodiode are transferred to the capacitor C through the first switch TX.
(4) And closing the second switch S-SF, reading the voltage Vout1 of the capacitor C through the output end of the voltage source follower, outputting the voltage to the comparison unit, comparing the voltage with the reference voltage Vref of the comparison unit, and determining whether to transfer the preset charge into the capacitor C by the charge resetting unit according to the comparison result output by the comparison unit.
(5) After a preset time, the current voltage of the capacitor C is read through the output end of the voltage source follower, and the output value V' out1 is output after passing through the voltage follower.
(6) The above steps (2) - (5) are repeated, wherein the illumination condition is different in each step (3), for example, the time for closing TX is different or the radiation intensity of the illumination diode is different, so as to change the amount of charge transferred to the capacitor C, and thus the voltage thereof. Thereby obtaining a plurality of groups of output voltages Vout and corresponding V' out.
(7) And detecting and judging the reset circuit according to the acquired multiple groups of voltage data.
The judgment basis is as follows:
taking the first charge as negative charge as an example, when Vout > Vref, the reset circuit is not started, the charge amount of the capacitor C is not changed, and vout=v' out; when Vout is less than or equal to Vref, the reset circuit is started, the charge reset unit injects charge into the capacitor, the voltage of the capacitor C is increased, and Vout is smaller than V' out; when the test result meets the conditions, the reset circuit is normally started. Similarly, when the first charge is positive, and Vout < Vref, the reset circuit is not started, and the charge amount of the capacitor C is not changed, where vout=v' out; when Vout is more than or equal to Vref, the reset circuit is started, the charge reset unit injects charges into the capacitor, the voltage of the capacitor C is reduced, and Vout is more than V' out; when the test result meets the conditions, the reset circuit is started normally
On the basis of normal starting of the reset circuit, it is further judged whether the charge amount of the second charge transferred to the charge storage unit at each time of reset is the same. The specific judgment basis is as follows: the amount of charge injected into the capacitor C at each reset is fixed to Qreset: qreset=cint·Δv; wherein Cint is the capacitance of capacitor C, which is constant; deltaV is the voltage difference between the capacitor C before and after the charge injection. Therefore, if the input voltages corresponding to any two groups of output voltages vout+.vref are set to Vini and V 'ini, vinj and V' inj, and if V 'ini-vini=v' inj-Vinj, it is indicated that the charge amount injected each time is a fixed value.
On the basis that the charge amount of each reset is the same, whether the charge amount transferred into the capacitor C is a preset value or not can be further determined, and the calculation formula is as follows: qreset=cint·Δv=cint· (V ' inj-Vinj), where Cint is a constant, and V ' inj and Vinj are obtained from the inputs corresponding to the output voltage outputs V ' outj and Voutj on the Vout-Vin curve of the source follower. Thereby calculating a specific value of the amount of charge transferred to the second charge in the charge storage unit.
Further, the invention also provides a reset circuit with a self-detection function, which comprises a reset circuit, wherein the reset circuit comprises: a charge storage unit for storing the received first charge; a nonlinear unit connected to the charge storage unit for isolating and following a voltage of the charge storage unit; the reset judging unit is connected to the nonlinear unit and is used for generating a signal for indicating the reset unit to work according to the output of the nonlinear unit; the reset unit is connected with the reset judging unit and the charge storage unit and is used for resetting the charge storage unit according to the signal output by the reset judging unit; and a detection circuit of the reset circuit described in any one of the above.
The detection method, the detection circuit and the reset circuit with the self-detection function can accurately judge whether the charge reset of the reset circuit is started based on a preset condition by changing the voltage of the capacitor, further judge whether the charge quantity reset each time is the same, and further judge whether the specific value of the charge quantity reset each time is a preset fixed value, thereby accurately evaluating the performance of the reset circuit positioned in a chip and avoiding the interference to the test of the reset circuit due to the nonlinear error of the follower.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present invention without departing from the spirit or scope of the embodiments of the invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims and the equivalents thereof, the present invention is also intended to include such modifications and variations.
Claims (13)
1. A method of detecting a reset circuit, the reset circuit comprising:
a charge storage unit for storing the received first charge;
a nonlinear unit comprising at least one nonlinear element, said nonlinear unit being connected to said charge storage unit for isolating and following a voltage of said charge storage unit; the reset judging unit is connected to the nonlinear unit and is used for generating a signal for indicating the reset unit to work according to the output of the nonlinear unit;
and
the reset unit is connected with the reset judging unit and the charge storage unit and is used for resetting the charge storage unit according to the signal output by the reset judging unit;
the detection method is characterized by comprising the following steps of:
the charge storage unit receives a certain amount of first charges;
step b, obtaining a first voltage Vout output by the nonlinear unit based on the first charge received by the charge storage unit, inputting the first voltage to a reset judgment unit for reset judgment, and transmitting a judgment result to a reset unit;
c, detecting the second voltage V' out output by the nonlinear unit again after the delay of the preset time, so as to judge whether the reset unit resets the charge storage unit according to the result of the two detection voltages;
step d, changing the first charge quantity received by the charge storage unit, and repeating the step b and the step c to respectively obtain a plurality of pairs of voltage data;
and e, detecting and judging the reset circuit according to the voltage data.
2. The method of claim 1, wherein,
the reset circuit further comprises a signal conversion unit, the charge storage unit is connected with the signal conversion unit through a first switch, the signal conversion unit is used for generating first charges according to input signal conversion and transmitting the first charges to the charge storage unit, and the change of the first charge amount received by the charge storage unit comprises: changing the amount of signal input in the signal conversion unit and/or changing the time when the first switch is turned on.
3. The method of claim 1, wherein,
the reset judging unit is a comparator, the comparator has a reference voltage Vref, and the step d includes:
acquiring a first voltage Vout of which at least one group of output voltages is not in a preset range; and
acquiring a first voltage Vout of at least one group of output voltages in a preset range; wherein the preset range is determined according to the reference voltage.
4. The method of claim 3, wherein,
the step of detecting and judging the reset circuit according to the voltage data comprises judging whether the reset circuit is normally started or not, and the step of detecting and judging the reset circuit according to the voltage data comprises the following steps:
when the first voltage Vout is not within the preset range, vout=v 'out, and when the first voltage Vout is within the preset range, vout < V' out, the reset circuit is started normally, otherwise the reset circuit is not started normally.
5. The method of claim 3, wherein,
further comprises:
calibrating the nonlinear unit to obtain a corresponding relationship between voltage input and voltage output of the nonlinear unit;
the step d further comprises: and acquiring first voltages Vout of at least two groups of output voltages within a preset range.
6. The method of claim 5, wherein,
the step of detecting and judging the reset circuit according to the plurality of pairs of voltage data further includes judging whether the charge amounts of the second charges transferred to the charge storage unit are the same each time the charges are reset, including:
according to the voltage input-output curve of the nonlinear unit, the first voltage Vout and the corresponding second voltage V ' out, obtaining an input voltage Vin corresponding to each group of the first voltage Vout and a V ' in corresponding to the second voltage V ' out;
calculating whether the difference value of any two groups of input voltages Vin and corresponding V' in is the same when the first voltage Vout is in a preset range, if the difference value is the same, judging that the charge quantity of the second charge transferred to the charge storage unit is the same when the first voltage Vout is reset each time, otherwise, judging that the charge quantity of the second charge transferred to the charge storage unit is different when the first voltage Vout is reset each time;
wherein the second charge is of opposite polarity to the first charge.
7. The method of claim 6, wherein,
the step of detecting and judging the reset circuit according to the plurality of pairs of voltage data further comprises determining whether the charge amount of the second charge transferred to the charge storage unit is a preset value or not at each reset based on the difference value between the capacitance of the charge storage unit and the input voltage of the corresponding nonlinear unit before and after the reset when the charge amount of the second charge transferred to the charge storage unit at each reset is the same;
and comparing and judging according to the calculated charge quantity of the second charge transferred to the charge storage unit with a preset value.
8. The method of claim 1, wherein,
the method further includes resetting the charge storage unit before the charge storage unit receives a certain amount of the first charge amount each time.
9. The method of claim 1, wherein,
the nonlinear unit is connected with the charge storage unit through a second switch.
10. A detection circuit of a reset circuit, the reset circuit comprising:
a charge storage unit for storing the received first charge;
a nonlinear unit connected to the charge storage unit for isolating and following a voltage of the charge storage unit;
the reset judging unit is connected to the nonlinear unit and is used for generating a signal for indicating the reset unit to work according to the output of the nonlinear unit;
the reset unit is connected with the reset judging unit and the charge storage unit and is used for resetting the charge storage unit according to the signal output by the reset judging unit;
the detection circuit is characterized by comprising:
the logic control unit is used for controlling the charge storage unit to receive a certain amount of first charges, acquiring a first voltage Vout output by the nonlinear unit based on the first charges received by the charge storage unit, inputting the first voltage to the reset judgment unit for reset judgment, and transmitting a judgment result to the reset unit; the second voltage V' out output by the nonlinear unit is detected again after a delay of a preset time; the charge storage unit is also used for changing the first charge quantity received by the charge storage unit, and repeating the steps to respectively acquire a plurality of pairs of voltage data; and detecting and judging the reset circuit according to the voltage data.
11. The detecting circuit for reset circuit of claim 10, further comprising a voltage input unit connected to the input of said nonlinear unit through a third switching circuit for providing a controllable voltage as the input of said nonlinear unit, obtaining a correspondence of voltage input and output of said nonlinear unit.
12. The detecting circuit for a reset circuit according to claim 11, wherein the logic control unit performs detection judgment of the reset circuit based on the plurality of pairs of the voltage data, including judgment of whether the reset circuit is normally activated, whether an amount of charge transferred to the second electric charge in the electric charge storage unit at each time of electric charge reset at the normal activation of the reset circuit is the same, and determination of whether an amount of charge transferred to the second electric charge in the electric charge storage unit at each time of reset is a preset value.
13. A reset circuit with detection function is characterized in that,
detection circuit comprising a reset circuit according to any of claims 10-12.
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