Sampling feedback circuit, source meter and electronic equipment

Abstract

The utility model discloses a sampling feedback circuit, a source meter and electronic equipment, the circuit comprises a sampling circuit, the sampling circuit comprises a diode D1 and a sampling resistor Rs which are mutually connected in parallel; a differential amplifier; and the error driving circuit comprises a switch S1, a sampling hold circuit, a reference generation circuit and an error comparison circuit. The output end of the reference generation circuit is connected with the first input end of the error comparison circuit, the output end of the differential amplifier is connected with the second input end of the error comparison circuit, the output end of the sampling hold circuit is connected with the third input end of the error comparison circuit, and the output end of the error comparison circuit is used for outputting error driving signals. According to the invention, the accurate current sampling signal can be acquired as the error driving signal in the range switching process, and the output stability of the source meter during range transition is improved.

Description

Technical Field

[0001] The utility model relates to the field of source meter sampling, in particular to a sampling feedback circuit, a source meter and electronic equipment. Background Art

[0002] The source meter is a commonly used instrument in measurement and control technology. It can output voltage source, current source, electronic load, measure voltage, current, resistance, diode, etc. It can replace power supply, load and measuring instruments.

[0003] During the testing of semiconductor devices, the power supply output range is very wide, so the current sampling circuit of the source meter has multiple ranges. During the range switching of current sampling, the current current sampling signal needs to be collected as the error driving signal to achieve a smooth transition of the range switching.

[0004] The source meter uses resistor sampling to achieve current sampling. Existing resistor sampling has very obvious defects in the source meter. If the sampling resistor is a resistor with a larger resistance value, the power consumption of the sampling resistor itself is too large when the current is large, affecting the stability and safety of the circuit. If the sampling resistor is a resistor with a smaller resistance value, the voltage generated when the current is small is very small, making it difficult to sample. Therefore, during the range switching process, if the current is too large or too small, it is impossible to obtain an accurate current sampling signal as an error driving signal, resulting in unstable output of the source meter during the range transition. Utility Model Content

[0005] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a sampling feedback circuit, a source meter and an electronic device, which can obtain an accurate current sampling signal as an error driving signal during the range switching process, thereby improving the output stability of the source meter during the range transition.

[0006] According to the sampling feedback circuit of the embodiment of the first aspect of the utility model, used for a source meter, the sampling circuit includes: a sampling circuit, the sampling circuit includes a diode D1 and a sampling resistor Rs, the positive electrode of the diode D1 is connected to one end of the sampling resistor Rs, and the negative electrode of the diode D1 is connected to the other end of the sampling resistor Rs; a differential amplifier, the positive electrode of the diode D1 is connected to the non-inverting end of the differential amplifier, and the negative electrode of the diode D1 is connected to the inverting end of the differential amplifier; an error driving circuit, the error driving circuit includes a switch S1, a sampling and holding circuit, a reference generating circuit and an error comparison circuit, the output end of the differential amplifier is connected to the input end of the sampling and holding circuit through the switch S1, the output end of the sampling and holding circuit is connected to the input end of the reference generating circuit, the output end of the reference generating circuit is connected to the first input end of the error comparison circuit, the output end of the differential amplifier is connected to the second input end of the error comparison circuit, the output end of the sampling and holding circuit is connected to the third input end of the error comparison circuit, and the output end of the error comparison circuit is used to output an error driving signal.

[0007] According to some embodiments of the present invention, the sampling circuit further includes a diode D2 , wherein an anode of the diode D2 is connected to a cathode of the diode D1 , and a cathode of the diode D2 is connected to an anode of the diode D1 .

[0008] According to some embodiments of the present utility model, the sampling circuit also includes a follower U4 and a follower U5; the positive electrode of the diode D1 is connected to the input end of the follower U4, and the output end of the follower U4 is connected to the in-phase end of the differential amplifier; the negative electrode of the diode D1 is connected to the input end of the follower U5, and the output end of the follower U5 is connected to the inverting end of the differential amplifier.

[0009] According to some embodiments of the present utility model, the sampling and holding circuit includes a capacitor C1, a comparator U1, a comparator U2, a diode D3 and a diode D4, one end of the switch S1 is connected to the non-inverting end of the comparator U1, the non-inverting end of the comparator U1 is grounded through the capacitor C1, the inverting end of the comparator U1 is grounded through the resistor R5, the output end of the comparator U1 is respectively connected to the positive electrode of the diode D3 and the negative electrode of the diode D4, the negative electrode of the diode D3 is connected to the inverting end of the comparator U1, the positive electrode of the diode D4 is connected to the third input end of the error comparison circuit through resistors R7, R8 and R9 connected in series in sequence, and the positive electrode of the diode D4 is connected to the negative electrode of the diode D3 through a resistor R6; the non-inverting end of the comparator U1 is connected to the non-inverting end of the comparator U2, the inverting end of the comparator U2 is connected to the common end of the resistor R7 and the resistor R8, and the output end of the comparator U2 is connected to the input end of the reference generation circuit.

[0010] According to some embodiments of the present utility model, the reference generating circuit includes a comparator U3, the output end of the sampling and holding circuit is connected to the inverting end of the comparator U3 through a resistor R10, the non-inverting end of the comparator U3 is grounded, the output end of the comparator U3 is connected to the first input end of the error comparison circuit, the output end of the comparator U3 is connected to the inverting end of the comparator U3 through a resistor R11, and the resistance values ​​of the resistor R10 and the resistor R11 are equal.

[0011] According to some embodiments of the present utility model, the error comparison circuit includes a resistor R12, a resistor R13, a resistor R14 and a resistor R15 connected in series in sequence, the output end of the reference generation circuit is connected to an end of the resistor R15 away from the resistor R14, the output end of the differential amplifier is connected to a common end of the resistor R13 and the resistor R14, the output end of the sampling and holding circuit is connected to an end of the resistor R12 away from the resistor R13, the common end of the resistor R12 and the resistor R13 serves as a first error signal output end, and the common end of the resistor R14 and the resistor R15 serves as a second error signal output end.

[0012] The source meter according to the embodiment of the second aspect of the utility model includes the above-mentioned sampling feedback circuit.

[0013] An electronic device according to an embodiment of the third aspect of the utility model includes the above-mentioned source meter.

[0014] The sampling feedback circuit, source meter and electronic device according to the embodiments of the utility model have at least the following beneficial effects:

[0015] In the embodiment of the utility model, a diode D1 connected in parallel with a sampling resistor Rs is arranged in the sampling circuit. When the current is large, the current mainly flows through the diode D1; when the current is small, the current mainly flows through the sampling resistor Rs. Since the current mainly flows through the diode D1 when the current is large, the sampling resistor Rs can be selected to have a larger resistance value. When the current range is large, no large power consumption is generated, which improves the stability and safety of the circuit. At the same time, the current sampling signal can be accurately obtained when the current is small. At the beginning of the range transition, the current sampling signal output by the sampling circuit is amplified by the differential amplifier, and one path enters the error comparison circuit, and the other path enters the sampling and holding circuit through the switch S1. When the current sampling signal is stable, the switch S1 is disconnected, and the sampling and holding circuit inputs the held current sampling signal into the reference generation circuit and the other path into the error comparison circuit. The reference generation circuit forms a reference signal according to the current sampling signal and inputs it into the error comparison circuit. The error comparison circuit obtains an error driving signal according to the three-path signal, and the source meter adjusts the output according to the error driving signal to ensure the stability of the output during the range switching process. The present application can obtain an accurate current sampling signal as an error driving signal during the range switching process, thereby improving the output stability of the source meter during the range transition.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1 is a schematic diagram of a sampling feedback circuit in an embodiment of the present application;

[0019] Figure 2 is a circuit diagram of a sampling feedback circuit in an embodiment of the present application;

[0020] Figure 3 is a circuit diagram of a sampling and holding circuit and a reference generating circuit in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] In the description of the present invention, it should be understood that the descriptions involving orientation, such as the orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In the description of the present utility model, "a plurality" means more than two. If there is a description of "first" or "second", it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0024] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0025] It should be noted that the application scenario of this application is the sampling during the range switching transition of the source meter. The working time of the range switching transition is very short, about within 10mS.

[0026] Reference Figure 1 and Figure 2 As shown, a sampling feedback circuit for a source meter includes: a sampling circuit, a differential amplifier and an error driving circuit. The sampling circuit includes a diode D1 and a sampling resistor Rs, the positive electrode of the diode D1 is connected to one end of the sampling resistor Rs, the negative electrode of the diode D1 is connected to the other end of the sampling resistor Rs, the positive electrode of the diode D1 is connected to the non-inverting end of the differential amplifier, and the negative electrode of the diode D1 is connected to the inverting end of the differential amplifier. The error driving circuit includes a switch S1, a sampling and holding circuit, a reference generating circuit and an error comparison circuit, the output end of the differential amplifier is connected to the input end of the sampling and holding circuit through the switch S1, the output end of the sampling and holding circuit is connected to the input end of the reference generating circuit, the output end of the reference generating circuit is connected to the first input end of the error comparison circuit, the output end of the differential amplifier is connected to the second input end of the error comparison circuit, the output end of the sampling and holding circuit is connected to the third input end of the error comparison circuit, and the output end of the error comparison circuit is used to output an error driving signal.

[0027] In the embodiment of the utility model, a diode D1 connected in parallel with a sampling resistor Rs is arranged in the sampling circuit. When the current is large, the current mainly flows through the diode D1; when the current is small, the current mainly flows through the sampling resistor Rs. Since the current mainly flows through the diode D1 when the current is large, the sampling resistor Rs can be selected to have a larger resistance value. When the current range is large, no large power consumption is generated, which improves the stability and safety of the circuit. At the same time, the current sampling signal can be accurately obtained when the current is small. At the beginning of the range transition, the current sampling signal output by the sampling circuit is amplified by the differential amplifier, and one path enters the error comparison circuit, and the other path enters the sampling and holding circuit through the switch S1. When the current sampling signal is stable, the switch S1 is disconnected, and the sampling and holding circuit inputs the held current sampling signal into the reference generation circuit and the other path into the error comparison circuit. The reference generation circuit forms a reference signal according to the current sampling signal and inputs it into the error comparison circuit. The error comparison circuit obtains an error driving signal according to the three-path signal, and the source meter adjusts the output according to the error driving signal to ensure the stability of the output during the range switching process. The present application can obtain an accurate current sampling signal as an error driving signal during the range switching process, thereby improving the output stability of the source meter during the range transition.

[0028] In this embodiment, the sampling circuit is used to obtain a real-time current sampling signal, and the end connected to the positive electrode of the diode D1 is used as the input end of the sampling circuit, and the end connected to the negative electrode of the diode D1 is used as the output end of the sampling circuit, that is, when the source meter outputs, the current enters from the input end and is output from the output end. The sampling circuit of the present application uses a diode and a sampling resistor in parallel to perform current sampling. When the current is large, the current basically flows through the diode. According to the volt-ampere characteristic curve of the diode, different currents flowing through the diode will produce different voltage drops. When the current is small, the current basically flows through the resistor. Therefore, the sampling resistor Rs can use a resistor with a larger resistance value, such as a resistor of 1KΩ-1MΩ, to form a larger sampling voltage. For example, if the sampling resistor Rs is a 100KΩ resistor, since the voltage drop is 0.7V when the current flowing through the diode D1 is 1A, when the current is 1A, the diode has only a 0.7V voltage drop, and the current flowing through the sampling resistor Rs is 0.7V / 100K=7uA, while when the current is small, such as a current of 1uA, the voltage across the sampling resistor Rs = 100K*1uA=0.1V, at which time the diode D1 has not reached the conduction condition and the two are connected in parallel. Therefore, the present application connects the diode and the sampling resistor in parallel to form a sampling circuit that can accurately collect current sampling signals for both large and small currents.

[0029] In this embodiment, the function of the differential amplifier is to amplify the current sampling signal to facilitate the processing and identification of the subsequent circuit. The error driving circuit is to compare the reference signal with the real-time current sampling signal to form an error driving signal to control the output of the source meter, ensuring that the output of the source meter is stable during the range switching process. Switch S1 is to avoid the current sampling signal from suddenly changing due to load changes, interference, jitter, instability, etc. in the process. Switch S1 is only closed at the beginning of the range switching. When the signal of the sampling and holding circuit is stable, switch S1 is disconnected. The function of the sampling and holding circuit is mainly to keep the sampled signal until the range transition is completed. The sampling and holding circuit outputs the signal to the reference generation circuit. The function of the reference generation circuit is to perform absolute value calculation on the signal input by the sampling and holding circuit and form a reference signal with equal positive and negative values. The purpose of forming a reference signal with equal positive and negative values ​​is that the current of the source meter has two directions, so the sampled signal has positive and negative values.

[0030] In this embodiment, the function of the error comparison circuit is to compare the two reference signals with the output signal of the differential amplifier in real time. When the reference signal is the same as the output signal of the differential amplifier, the error signal output is 0, indicating that the current output has not changed. When the reference signal is inconsistent with the output signal of the differential amplifier, an error drive signal is generated, and the output is adjusted according to the error drive signal, thereby achieving the purpose of stabilizing the source meter output.

[0031] In some embodiments of the present invention, the sampling circuit further includes a diode D2 , wherein the anode of the diode D2 is connected to the cathode of the diode D1 , and the cathode of the diode D2 is connected to the anode of the diode D1 .

[0032] In this embodiment, the sampling circuit includes a forward-connected diode D1 and a reverse-connected diode D2, both of which are connected in parallel with the sampling resistor Rs. Because the source meter is a four-quadrant, there are two situations of positive and negative current, so two diodes with inconsistent directions are required to be connected in parallel at both ends of the sampling resistor Rs, and accurate current sampling signals can be obtained in the positive current and negative current range switching states.

[0033] It should be understood that when the current is positive, the end connected to the anode of the diode D1 is used as the input end of the sampling circuit, and the end connected to the cathode of the diode D1 is used as the output end of the sampling circuit; when the current is negative, the end connected to the anode of the diode D2 is used as the input end of the sampling circuit, and the end connected to the cathode of the diode D2 is used as the output end of the sampling circuit.

[0034] In some embodiments of the present invention, the sampling circuit also includes a follower U4 and a follower U5; the positive electrode of the diode D1 is connected to the input end of the follower U4, and the output end of the follower U4 is connected to the non-inverting end of the differential amplifier; the negative electrode of the diode D1 is connected to the input end of the follower U5, and the output end of the follower U5 is connected to the inverting end of the differential amplifier.

[0035] In this embodiment, a follower is provided between the sampling circuit and the differential amplifier, so as to avoid the current consumption of the subsequent circuit and thus reduce the output precision, and further improve the stability of the source meter output.

[0036] In some embodiments of the present invention, reference Figure 2 As shown, the sampling and holding circuit includes a capacitor C1, a comparator U1, a comparator U2, a diode D3 and a diode D4, one end of the switch S1 is connected to the non-inverting end of the comparator U1, the non-inverting end of the comparator U1 is grounded through the capacitor C1, the inverting end of the comparator U1 is grounded through the resistor R5, the output end of the comparator U1 is respectively connected to the positive electrode of the diode D3 and the negative electrode of the diode D4, the negative electrode of the diode D3 is connected to the inverting end of the comparator U1, the positive electrode of the diode D4 is connected to the third input end of the error comparison circuit through resistors R7, R8 and R9 connected in series in sequence, and the positive electrode of the diode D4 is connected to the negative electrode of the diode D3 through the resistor R6; the non-inverting end of the comparator U1 is connected to the non-inverting end of the comparator U2, the inverting end of the comparator U2 is connected to the common end of the resistors R7 and R8, and the output end of the comparator U2 is connected to the input end of the reference generation circuit.

[0037] In some embodiments of the present invention, reference Figure 2 and Figure 3 As shown, the reference generating circuit includes a comparator U3, the output end of the sampling and holding circuit is connected to the inverting end of the comparator U3 through a resistor R10, the non-inverting end of the comparator U3 is grounded, the output end of the comparator U3 is connected to the first input end of the error comparison circuit, the output end of the comparator U3 is connected to the inverting end of the comparator U3 through a resistor R11, and the resistance values ​​of the resistors R10 and R11 are equal.

[0038] In some embodiments of the present invention, reference Figure 2 As shown, the error comparison circuit includes a resistor R12, a resistor R13, a resistor R14 and a resistor R15 connected in series in sequence, the output end of the reference generation circuit is connected to an end of the resistor R15 away from the resistor R14, the output end of the differential amplifier is connected to a common end of the resistor R13 and the resistor R14, the output end of the sampling and holding circuit is connected to an end of the resistor R12 away from the resistor R13, the common end of the resistor R12 and the resistor R13 serves as a first error signal output end, and the common end of the resistor R14 and the resistor R15 serves as a second error signal output end.

[0039] The working principles of the sampling and holding circuit, the reference generation circuit and the error comparison circuit are described in detail below:

[0040] The current generates a voltage drop Vs through the sampling circuit, and then is input into the differential amplifier through the follower, whose gain is -G, and AFB=-G*Vs; when the range needs to be switched, the switch S1 will be closed in advance to charge the capacitor C1 to the voltage on it is AFB, and then the switch S1 will be opened.

[0041] The function of the sampling and holding circuit is to take the absolute value, as follows: the voltage on capacitor C1 is input to the in-phase terminals of comparator U1 and comparator U2 respectively, resistors R5 to R9 are equal resistances, point A is assumed to be the common endpoint of resistors R5 and R6, point B is the common endpoint of resistors R6 and R7, the voltage at point C is the common terminal voltage of resistors R7 and R8, and the voltage of capacitor C1 is V1. From the principle of negative feedback virtual short and virtual open, it can be seen that the voltage at point A is equal to the voltage at point C and equal to V1.

[0042] When the voltage V1 on capacitor C is positive, the output of comparator U1 is positive, diode D3 is turned on, and diode D4 is turned off. Since diode D4 is turned off, and VA=VC=V1, there is no current in resistors R6 and R7. Obviously, there is no current in resistors R8 and R9. Then IAFB equals V1. When the voltage V1 on capacitor C1 is negative, the output of comparator U1 is negative, diode D3 is turned off, and diode D4 is turned on. At this time, the voltage at point B can be calculated as VB=2*V1, and further calculation shows that IAFB=-V.

[0043] Comparator U3, R10, R11 constitute a reference generation circuit, that is, an inverting circuit. Since the resistance values ​​of resistor R10 and resistor R11 are equal, it can be obtained that NIAFB=-IAFB.

[0044] The voltage on capacitor C1 is then taken in absolute value and reversed to obtain the signal IAFB and the signal NIAFB, where IAFB = |AFB|, NIAFB = -|AFB|, one is the positive reference signal, and the other is the negative reference signal input to the error comparison circuit. AFB, IAFB and NIAFB are divided by voltage, and the four voltage-dividing resistors have equal resistance values, and the two error drive signals IAdrive and NIAdrive are obtained by voltage division.

[0045] When the range of the source meter is officially switched, the voltage and current control loops will not work, and the loops will switch to the circuit of the present application, so that the current I remains in the state before the range switching, preventing the output from being abnormal during the range switching process. After the range switching is completed, the voltage and current loops take over control again, and the circuit of the present application exits the control of the output and waits for the next range switching to work again.

[0046] The present application also relates to a source meter, comprising the sampling feedback circuit of the above embodiment.

[0047] The present application also relates to an electronic device, comprising the source meter of the above embodiment.

[0048] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A sampling feedback circuit for a source meter, characterized in that: include: A sampling circuit, wherein the sampling circuit comprises a diode D1 and a sampling resistor Rs, wherein the anode of the diode D1 is connected to one end of the sampling resistor Rs, and the cathode of the diode D1 is connected to the other end of the sampling resistor Rs; A differential amplifier, wherein the anode of the diode D1 is connected to the non-inverting terminal of the differential amplifier, and the cathode of the diode D1 is connected to the inverting terminal of the differential amplifier; An error driving circuit, the error driving circuit includes a switch S1, a sampling and holding circuit, a reference generating circuit and an error comparison circuit, the output end of the differential amplifier is connected to the input end of the sampling and holding circuit through the switch S1, the output end of the sampling and holding circuit is connected to the input end of the reference generating circuit, the output end of the reference generating circuit is connected to the first input end of the error comparison circuit, the output end of the differential amplifier is connected to the second input end of the error comparison circuit, the output end of the sampling and holding circuit is connected to the third input end of the error comparison circuit, and the output end of the error comparison circuit is used to output an error driving signal.

2. The sampling feedback circuit according to claim 1, characterized in that: The sampling circuit further includes a diode D2 , wherein an anode of the diode D2 is connected to a cathode of the diode D1 , and a cathode of the diode D2 is connected to an anode of the diode D1 .

3. The sampling feedback circuit according to claim 1, characterized in that: The sampling circuit also includes a follower U4 and a follower U5; the positive electrode of the diode D1 is connected to the input end of the follower U4, and the output end of the follower U4 is connected to the in-phase end of the differential amplifier; the negative electrode of the diode D1 is connected to the input end of the follower U5, and the output end of the follower U5 is connected to the inverting end of the differential amplifier.

4. The sampling feedback circuit according to claim 1, characterized in that: The sampling and holding circuit includes a capacitor C1, a comparator U1, a comparator U2, a diode D3 and a diode D4. One end of the switch S1 is connected to the non-inverting end of the comparator U1, the non-inverting end of the comparator U1 is grounded through the capacitor C1, the inverting end of the comparator U1 is grounded through a resistor R5, the output end of the comparator U1 is respectively connected to the positive electrode of the diode D3 and the negative electrode of the diode D4, the negative electrode of the diode D3 is connected to the inverting end of the comparator U1, the positive electrode of the diode D4 is connected to the third input end of the error comparison circuit through resistors R7, R8 and R9 connected in series in sequence, and the positive electrode of the diode D4 is connected to the negative electrode of the diode D3 through a resistor R6; the non-inverting end of the comparator U1 is connected to the non-inverting end of the comparator U2, the inverting end of the comparator U2 is connected to the common end of the resistor R7 and the resistor R8, and the output end of the comparator U2 is connected to the input end of the reference generation circuit.

5. The sampling feedback circuit according to claim 1, characterized in that: The reference generating circuit includes a comparator U3, the output end of the sampling and holding circuit is connected to the inverting end of the comparator U3 through a resistor R10, the non-inverting end of the comparator U3 is grounded, the output end of the comparator U3 is connected to the first input end of the error comparison circuit, the output end of the comparator U3 is connected to the inverting end of the comparator U3 through a resistor R11, and the resistance values ​​of the resistor R10 and the resistor R11 are equal.

6. The sampling feedback circuit according to claim 1, characterized in that: The error comparison circuit includes a resistor R12, a resistor R13, a resistor R14 and a resistor R15 connected in series in sequence, the output end of the reference generation circuit is connected to an end of the resistor R15 away from the resistor R14, the output end of the differential amplifier is connected to a common end of the resistor R13 and the resistor R14, the output end of the sampling and holding circuit is connected to an end of the resistor R12 away from the resistor R13, the common end of the resistor R12 and the resistor R13 serves as a first error signal output end, and the common end of the resistor R14 and the resistor R15 serves as a second error signal output end.

7. A source meter, characterized in that: The sampling feedback circuit comprises any one of claims 1 to 6.

8. An electronic device, characterized in that: Comprising the source table as claimed in claim 7.

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