Source measurement circuit and voltage output method

Abstract

The invention relates to a source measurement circuit and a voltage output method, the source measurement circuit comprises a voltage output module, an acceleration module, a current detection module and a load module, the voltage output module is connected with the load module through the current detection module, and the acceleration module is connected with the current detection module in parallel; the voltage output module is used for outputting a first voltage signal, and the first voltage signal represents the voltage at the two ends of the load module; the acceleration module is used for accelerating the process that the first voltage signal reaches the target voltage; and the acceleration module is in a conducting state in the change process of the first voltage signal, and is in a cut-off state after the first voltage signal reaches the target voltage. According to the source measurement circuit, the acceleration module accelerates the process that the voltage at the two ends of the load module reaches the target voltage, the output slew rate is improved, and the establishment time of the output voltage is shortened.

Description

Technical Field

[0001] This invention relates to the field of source meter technology, and in particular to a source measurement circuit and voltage output method. Background Technology

[0002] In existing source meter circuits, because they frequently need to measure minute currents below 1uA, the current sensing resistor in the circuit is often configured with a large resistance value to ensure measurement accuracy. However, due to the excessively large resistance value and the presence of parasitic capacitance in the circuit, the RC charging and discharging effect results in a long voltage settling time across the load, severely impacting the efficiency of the source meter circuit's output voltage. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention discloses a source measurement circuit and a voltage output method. The source measurement circuit accelerates the process of the voltage across the load module reaching the target voltage through an acceleration module, thereby increasing the output slew rate and shortening the output voltage settling time.

[0004] To achieve the above objectives, the present invention provides a source measurement circuit, which includes a voltage output module, an acceleration module, a current detection module, and a load module. The voltage output module is connected to the load module through the current detection module, and the acceleration module is connected in parallel with the current detection module. The voltage output module is used to output a first voltage signal, which represents the voltage across the load module. The acceleration module is used to accelerate the process of the first voltage signal reaching the target voltage; the acceleration module is in a conducting state during the change of the first voltage signal, and in a cut-off state after the first voltage signal reaches the target voltage.

[0005] In an optional embodiment, the source measurement circuit further includes a differential amplifier module connected in parallel with the current detection module; The differential amplifier module is used to convert the differential voltage across the current detection module into a second voltage signal characterizing the load current after the first voltage signal reaches the target voltage. The load current is the current flowing through the load module.

[0006] In an optional embodiment, the acceleration module includes a first branch and a second branch connected in parallel. The first branch includes a first resistor and a first diode connected in series, and the second branch includes a second resistor and a second diode connected in series. The resistance values ​​of the first resistor and the second resistor are much smaller than the resistance value of the current detection module.

[0007] In an optional embodiment, the anode of the first diode is connected to the first resistor, and the cathode of the first diode is connected to the load module; the anode of the second diode is connected to the load module, and the cathode of the second diode is connected to the second resistor.

[0008] In an optional embodiment, during the rise of the first voltage signal, the first branch is in a conducting state, the second branch is in a cut-off state, the current detection module is connected in parallel with the first branch, and the current output by the voltage output module flows to the load module through the current detection module and the first branch. The current flowing through the current detection module is less than the current flowing through the first branch.

[0009] In an optional embodiment, during the decrease of the first voltage signal, the first branch is in a cutoff state, the second branch is in a conduction state, the current detection module is connected in parallel with the second branch, the current flowing through the load module flows through the current detection module and the second branch to the voltage output module, and the current flowing through the current detection module is less than the current flowing through the second branch.

[0010] In an optional embodiment, the acceleration module further includes a pull-up resistor, a pull-down resistor, a positive voltage source, and a negative voltage source; a first end of the pull-down resistor is connected to the anode of the first diode, and a second end of the pull-down resistor is connected to the negative voltage source; a first end of the pull-up resistor is connected to the cathode of the second diode, and a second end of the pull-up resistor is connected to the positive voltage source.

[0011] In an optional embodiment, after the first voltage signal rises to the first target voltage, the cathode voltage of the first diode is equal to the first target voltage. The pull-down resistor and the negative voltage source make the anode voltage of the first diode less than the cathode voltage of the first diode. Both the first branch and the second branch are in the off state. The current output by the voltage output module flows to the load module through the current detection module.

[0012] In an optional embodiment, after the first voltage signal drops to the second target voltage, the anode voltage of the second diode is equal to the second target voltage. The pull-up resistor and the positive voltage source make the cathode voltage of the second diode greater than the anode voltage of the second diode. Both the first branch and the second branch are in the off state. The current flowing through the load module flows to the voltage output module through the current detection module.

[0013] In an optional embodiment, the voltage output module includes a signal source, a first operational amplifier, and a second operational amplifier. The signal source is connected to the non-inverting input of the first operational amplifier, the output of the first operational amplifier is connected to the non-inverting input of the second operational amplifier via the current detection module, and the output of the second operational amplifier is connected to the inverting input of the first operational amplifier.

[0014] On the other hand, this application also provides a voltage output method, which is applied to the source measurement circuit as described above, the method comprising: The voltage output module outputs a first voltage signal, which represents the voltage across the load module. The acceleration module accelerates the process of the first voltage signal reaching the target voltage; the acceleration module is in a conducting state during the change of the first voltage signal, and in a cut-off state after the first voltage signal reaches the target voltage.

[0015] Implementing the embodiments of the present invention has the following beneficial effects: The source measurement circuit disclosed in this invention accelerates the process of the voltage across the load module reaching the target voltage through an acceleration module. The voltage output by the voltage output module represents the voltage across the load module. During the voltage change across the load module, the acceleration module is in a conducting state. The acceleration module provides a bypass by being connected in parallel with the current detection module, which shortens the settling time of the output voltage of the source measurement circuit and improves the output slew rate.

[0016] Furthermore, after the voltage across the load module stabilizes to the target voltage, the acceleration module is in the off state, causing the current sensing module to be connected in series with the load module. At this time, the current flowing through the current sensing module is equal to the current flowing through the load module. The differential amplifier module can output a voltage signal characterizing the load current based on the differential voltage across the current sensing module, without affecting the measurement accuracy of the load current. Moreover, since the stability of the voltage across the load module, i.e., the output voltage, is a prerequisite for load current measurement, the shortened settling time of the output voltage will also shorten the settling time of the load current, i.e., the measurement current. Through the source measurement circuit of this invention, the output slew rate can be improved without sacrificing the load current measurement accuracy, and the settling time of the output voltage and the measurement current can be shortened, thereby improving the testing capability of the source measurement circuit. Attached Figure Description

[0017] To more clearly illustrate the source measurement circuit described in this invention, the accompanying drawings required for the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the output voltage and measured current of a conventional source meter circuit provided for an embodiment of the present invention; Figure 2 This is a schematic diagram of a source measurement circuit provided in an embodiment of the present invention; Figure 3 A schematic diagram of the output voltage and measured current of a source measurement circuit provided in an embodiment of the present invention; Figure 4 This is a schematic flowchart of a voltage output method provided in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0021] In existing current meter circuits, because they frequently need to measure minute currents below 1uA, the current sensing resistor is often configured with a relatively large resistance value to ensure measurement accuracy. However, due to the excessively large resistance value and the presence of parasitic capacitance in the circuit, the RC charging and discharging effect results in a longer settling time for the voltage and current across the load. Figure 1 As shown, Figure 1 This invention provides a schematic diagram of the output voltage and measured current waveforms of a conventional source meter circuit, where the red line represents the voltage across the load, and the green line represents the voltage characterizing the load current. Figure 1 As can be seen, the voltage settling time across the load is over 10µs, and the voltage characterizing the load current takes over 15µs to settling, which seriously affects the efficiency of the source meter circuit output voltage and current measurement.

[0022] The following combination Figure 2 as well as Figure 3 This specification provides a detailed description of a source measurement circuit provided in an embodiment.

[0023] In the embodiments described in this specification, Figure 2 This is a schematic diagram of a source measurement circuit provided in an embodiment of the present invention, such as... Figure 2 As shown, the source measurement circuit includes a voltage output module, an acceleration module, a current detection module, and a load module. The voltage output module is connected to the load module through the current detection module, and the acceleration module is connected in parallel with the current detection module. The voltage output module is used to output a first voltage signal, which represents the voltage across the load module. The acceleration module is used to accelerate the process of the first voltage signal reaching the target voltage; the acceleration module is in a conducting state during the change of the first voltage signal, and in a cut-off state after the first voltage signal reaches the target voltage.

[0024] In the embodiments of this specification, the voltage output module includes a signal source VG1, an operational amplifier U2, and an operational amplifier U4. The voltage output by the signal source VG1 is connected to the non-inverting input of the operational amplifier U2. The output voltage of the operational amplifier U2 is connected to the non-inverting input of the operational amplifier U4 after passing through a current detection module. The output voltage of the operational amplifier U4 is connected to the inverting input of the operational amplifier U2 to form a negative feedback loop. The voltage at the output terminal OUT is the voltage across the load module, i.e., the first voltage signal. The voltage across the load module is equal to the output voltage of the signal source VG1.

[0025] In the embodiments described in this specification, a load module refers to a device that needs to be subjected to a specific voltage (or current) and simultaneously has its current (or voltage across its terminals) measured. Figure 2 Taking resistor R2 as an example, the load module can actually be different devices in different application scenarios.

[0026] In the embodiments described in this specification, the current sensing module is used to convert the current signal flowing through the load module, which cannot be directly measured, into a voltage signal that is easy to measure accurately. Figure 2 Taking the current sensing module as an example with current sensing resistor R21, the current sensing module can actually be different devices in different application scenarios.

[0027] In the embodiments described in this specification, the acceleration module is used to accelerate the process of the OUT terminal output voltage reaching stability. Specifically, during the process of the OUT terminal output voltage change, that is, before the OUT terminal output voltage reaches stability, the acceleration module is in a conducting state. The acceleration module provides a bypass by being connected in parallel with the current sensing module, thereby shortening the time required for the OUT terminal output voltage to reach stability. After the OUT terminal output voltage reaches stability, the acceleration module is in a cutoff state. At this time, the current sensing module is connected in series with the load module, and the current flowing through the current sensing module is equal to the current flowing through the load module.

[0028] In the embodiments described in this specification, the source measurement circuit further includes a differential amplifier module, which is connected in parallel with the current detection module; The differential amplifier module is used to convert the differential voltage across the current detection module into a second voltage signal characterizing the load current after the first voltage signal reaches the target voltage. The load current is the current flowing through the load module.

[0029] In the embodiments of this specification, the differential amplifier module includes operational amplifiers U5, U6, and U7. The differential amplifier module is used to convert the differential voltage across the current sensing module into a single-ended voltage IM. That is, the output voltage at the IM terminal represents the current flowing through the current sensing module. After the output voltage at the OUT terminal reaches stability, the acceleration module is in the off state. The current sensing module is connected in series with the load module, and the current flowing through the current sensing module is equal to the current flowing through the load module. At this time, the output voltage at the IM terminal represents the current flowing through the load module, that is, the load current. The load current can be obtained according to IM = G * I * R21, where IM is the second voltage signal, G is the voltage gain of the differential amplifier module, I is the load current, and R21 is the resistance of the current sensing module. The acceleration module can shorten the time required for the output voltage at the OUT terminal to reach stability, and thus also shorten the time required for the output voltage at the IM terminal to reach stability, that is, shorten the settling time of the load current.

[0030] In the embodiments of this specification, the source measurement circuit mainly realizes the functions of outputting voltage and measuring current. The output voltage function refers to outputting a first voltage signal, which is the voltage across the load module (i.e., the voltage across the load module) = the output voltage of the OUT terminal = the output voltage of the signal source VG1. The current measurement function refers to outputting a second voltage signal, which is the output voltage of the IM terminal. The second voltage signal is related to the load current, and the load current can be determined based on the second voltage signal, thus realizing the measurement of the load current.

[0031] In this embodiment, after the voltage across the load module stabilizes to the target voltage, the acceleration module is in the off state, so that the current flowing through the current sensing module is equal to the current flowing through the load module. The differential amplifier module outputs a voltage signal representing the load current based on the differential voltage across the current sensing module, which does not affect the measurement accuracy of the load current. In addition, since the stability of the output voltage is a prerequisite for load current measurement, shortening the settling time of the output voltage will also shorten the settling time of the load current.

[0032] In the embodiments of this specification, the acceleration module includes a first branch and a second branch connected in parallel. The first branch includes a first resistor and a first diode connected in series, and the second branch includes a second resistor and a second diode connected in series. The resistance values ​​of the first resistor and the second resistor are much smaller than the resistance value of the current detection module.

[0033] In the embodiments described in this specification, such as Figure 2 As shown, the acceleration module includes a first branch and a second branch connected in parallel. The first branch includes a first resistor R25 and a first diode D3, and the second branch includes a second resistor R26 and a second diode D5. The resistance values ​​of the first resistor R25 and the second resistor R26 are much smaller than the resistance value of the current sensing module. For example, the resistance value of the current sensing resistor R21 is 1MΩ, and the resistance values ​​of the first resistor R25 and the second resistor R26 are both 220Ω. Therefore, during the change of the first voltage signal, the acceleration module can provide a low-impedance path. The current flowing through the acceleration module is greater than the current flowing through the current sensing module. The current output by the operational amplifier U2 mainly flows through the acceleration module, thereby reducing the impact of the RC charging and discharging effect between the current sensing module and the parasitic capacitor on the settling time of the output voltage and the measured current. The settling time of the output voltage refers to the time required for the output voltage to reach stability, and the settling time of the measured current refers to the time required for the measured current to reach stability.

[0034] In the embodiments of this specification, parasitic capacitance exists in the source measurement circuit. Parasitic capacitance refers to the capacitive effect that is unintentionally generated and inherent between actual circuit elements, wires or device pins. The parasitic capacitance in the source measurement circuit mainly comes from the lead line from the output terminal of operational amplifier U2 to the current detection module to the load module, the load module, the input terminals of all operational amplifiers, and the filter capacitors (including capacitors C20, C21, and C19).

[0035] The resistance value of the acceleration module in the embodiments of this specification is much smaller than that of the current sensing module. During the change of the first voltage signal, the acceleration module can provide a low impedance path. The current output by the voltage output module mainly flows through the acceleration module, thereby reducing the impact of the RC charging and discharging effect between the current sensing module and the parasitic capacitor on the settling time of the output voltage and the measured current, and shortening the settling time of the output voltage and the measured current.

[0036] In the embodiments described in this specification, the anode of the first diode is connected to the first resistor, and the cathode of the first diode is connected to the load module; the anode of the second diode is connected to the load module, and the cathode of the second diode is connected to the second resistor.

[0037] In the embodiments described in this specification, such as Figure 2 As shown, the anode of the first diode D3 is connected to the first resistor R25, and the cathode of the first diode D3 is connected to the load module. The anode of the second diode D5 is connected to the load module, and the cathode of the second diode D5 is connected to the second resistor R26. That is, the first branch includes the forward resistor R25 and the forward diode D3, and the second branch includes the reverse resistor R26 and the reverse diode D5. The conduction directions of the first branch and the second branch are opposite, corresponding to different changes in the first voltage signal. Specifically, during the process of the first voltage signal rising from low to high, the first branch is on and the second branch is off; during the process of the first voltage signal falling from high to low, the second branch is on and the first branch is off.

[0038] The acceleration module in the embodiments of this specification includes two branches with opposite conduction directions. During the process of the first voltage signal rising from low to high, the first branch acts as a low-impedance path, shortening the output voltage rise setup time; during the process of the first voltage signal falling from high to low, the second branch acts as a low-impedance path, shortening the output voltage fall setup time.

[0039] In the embodiments of this specification, during the rise of the first voltage signal, the first branch is in a conducting state, the second branch is in a cut-off state, the current detection module is connected in parallel with the first branch, and the current output by the voltage output module flows to the load module through the current detection module and the first branch. The current flowing through the current detection module is less than the current flowing through the first branch.

[0040] In the embodiments of this specification, during the rise of the first voltage signal from low to high, the first branch is turned on and the second branch is turned off. The current sensing module is connected in parallel with the first branch. In addition to flowing to the output terminal OUT through the original current sensing module, the current output by the operational amplifier U2 also flows to the output terminal OUT through the first resistor R25 and the first diode D3. Since the resistance of the first resistor R25 is much lower than the resistance of the current sensing module, and the first diode D3 is turned on, the current output by the operational amplifier U2 mainly flows through the first branch. The current flowing through the first branch is greater than the current flowing through the current sensing module. At this time, the RC charging and discharging effect between the current sensing module and the parasitic capacitor has a very weak impact on the settling time of the output voltage and the measured current, and the rise time of the first voltage signal is greatly shortened.

[0041] In the embodiments described in this specification, when the output voltage rises from low to high, the first diode is forward biased and conducts, providing a low-impedance path for the output current of the voltage output module, thereby improving the forward slew rate and shortening the rise-up time of the source measurement circuit output voltage.

[0042] In the embodiments of this specification, during the process of the first voltage signal decreasing, the first branch is in the off state, the second branch is in the on state, the current detection module is connected in parallel with the second branch, the current flowing through the load module flows through the current detection module and the second branch to the voltage output module, and the current flowing through the current detection module is less than the current flowing through the second branch.

[0043] In the embodiments described in this specification, during the process of the first voltage signal decreasing from high to low, the first branch is cut off, the second branch is turned on, the current sensing module is connected in parallel with the second branch, the operational amplifier U2 draws current, and the discharge current of the load module flows to the output terminal of the operational amplifier U2 through the original current sensing module, as well as through the second resistor R26 and the second diode D5. Since the resistance value of the second resistor R26 is much lower than the resistance value of the current sensing module, and the second diode D5 is turned on, the discharge current of the load module mainly flows through the second branch. The current flowing through the second branch is greater than the current flowing through the current sensing module. At this time, the RC charging and discharging effect between the current sensing module and the parasitic capacitor has a very weak impact on the settling time of the output voltage and the measured current, and the fall time of the first voltage signal is greatly shortened.

[0044] In the embodiments described in this specification, when the output voltage decreases from high to low, the second diode is forward biased and conducts, providing a low-impedance path for the discharge current of the load module, thereby improving the negative slew rate and shortening the settling time of the output voltage drop of the source measurement circuit.

[0045] In the embodiments of this specification, the acceleration module further includes a pull-up resistor, a pull-down resistor, a positive voltage source, and a negative voltage source; the first end of the pull-down resistor is connected to the anode of the first diode, and the second end of the pull-down resistor is connected to the negative voltage source; the first end of the pull-up resistor is connected to the cathode of the second diode, and the second end of the pull-up resistor is connected to the positive voltage source.

[0046] In the embodiments described in this specification, such as Figure 2 As shown, the acceleration module also includes a pull-up resistor R39, a pull-down resistor R40, a positive voltage source V15, and a negative voltage source V16. One end of the pull-down resistor R40 is connected to the anode of the first diode D3, and the other end is connected to the negative voltage source V16. One end of the pull-up resistor R39 is connected to the cathode of the second diode D5, and the other end is connected to the positive voltage source V15. The function of the pull-down resistor R40 and the negative voltage source V16 is to pull down the anode voltage of the first diode D3 to change the on / off state of the first branch. The function of the pull-up resistor R39 and the positive voltage source V15 is to pull up the cathode voltage of the second diode D5 to change the on / off state of the second branch.

[0047] The embodiments in this specification change the on / off state of the first branch by using a pull-down resistor and a negative voltage source, and change the on / off state of the second branch by using a pull-up resistor and a positive voltage source. This ensures that both the first and second branches are in the off state after the output voltage of the source measurement circuit stabilizes, thus eliminating the influence of the acceleration module on the accuracy of the small current measurement under steady state.

[0048] In the embodiments of this specification, after the first voltage signal rises to the first target voltage, the cathode voltage of the first diode is equal to the first target voltage. The pull-down resistor and the negative voltage source make the anode voltage of the first diode less than the cathode voltage of the first diode. Both the first branch and the second branch are in the off state. The current output by the voltage output module flows to the load module through the current detection module.

[0049] In the embodiments of this specification, the first target voltage can be set according to the actual situation. After the first voltage signal rises to the first target voltage, that is, after the first voltage signal reaches stability, the negative voltage source V16 pulls down the anode voltage of the first diode D3 through the pull-down resistor R40, so that the anode voltage of the first diode D3 is lower than the cathode voltage, and the first diode D3 is cut off. At this time, both the first branch and the second branch are in the cut-off state. The current detection module is connected in series with the load module, and all the current output by the operational amplifier U2 flows to the load module through the current detection module. The current flowing through the current detection module is equal to the current flowing through the load module, so that the differential amplifier module can output a second voltage signal representing the load current based on the differential voltage across the current detection module.

[0050] For example, if the first resistor R25 = 220Ω, the second resistor R26 = 220Ω, the pull-up resistor R39 = 2KΩ, the pull-down resistor R40 = 2KΩ, the positive voltage source V15 = +15V, the negative voltage source V16 = -15V, the current sensing module R21 = 1MΩ, the load module R2 = 10MΩ, and the first target voltage is +10V, then after the first voltage signal stabilizes at +10V, the load current I = V(OUT) / R2 = +1uA, the voltage at the output terminal (PIN6) of the operational amplifier U2 is V(PIN6) = V(OUT) + I*R21 = 11V. At this time, the anode voltage of the first diode D3 is (2K / 2.22K)*(+11V) + (0.22K / 2.22K)*(-15V) = +8.42V, the cathode voltage is +10V, and the first diode D3 is in the cutoff state.

[0051] In this embodiment, after the voltage across the load module stabilizes to the target voltage, the acceleration module is in a cutoff state, so that the current output by the voltage output module flows only through the current sensing module. At this time, the current flowing through the current sensing module is equal to the current flowing through the load module. The differential amplifier module outputs a voltage signal representing the load current based on the differential voltage across the current sensing module, which will not affect the measurement accuracy of the load current.

[0052] In the embodiments of this specification, after the first voltage signal drops to the second target voltage, the anode voltage of the second diode is equal to the second target voltage. The pull-up resistor and the positive voltage source make the cathode voltage of the second diode greater than the anode voltage of the second diode. Both the first branch and the second branch are in the off state. The current flowing through the load module flows to the voltage output module through the current detection module.

[0053] In the embodiments of this specification, the second target voltage can be set according to the actual situation. After the first voltage signal drops to the second target voltage, that is, after the first voltage signal reaches stability, the positive voltage source V15 pulls up the cathode voltage of the second diode D5 through the pull-up resistor R39, so that the cathode voltage of the second diode D5 is higher than the anode voltage, and the second diode D5 is cut off. At this time, both the first branch and the second branch are in the cut-off state. The current detection module is connected in series with the load module. All the current flowing through the load module flows through the current detection module to the output terminal of the operational amplifier U2. The current flowing through the current detection module is equal to the current flowing through the load module, so that the differential amplifier module can output a second voltage signal representing the load current based on the differential voltage across the current detection module.

[0054] For example, if the first resistor R25 = 220Ω, the second resistor R26 = 220Ω, the pull-up resistor R39 = 2KΩ, the pull-down resistor R40 = 2KΩ, the positive voltage source V15 = +15V, the negative voltage source V16 = -15V, the current sensing module R21 = 1MΩ, the load module R2 = 10MΩ, and the second target voltage is -10V, then after the first voltage signal stabilizes to -10V, the load current I = V(OUT) / R2 = -1uA, the voltage at the output terminal (PIN6) of the operational amplifier U2 is V(PIN6) = V(OUT) + I*R21 = -11V. At this time, the cathode voltage of the second diode D5 is (2K / 2.22K)*(-11V) + (0.22K / 2.22K)*(+15V) = -8.42V, the anode voltage is -10V, and the second diode D5 is in the cutoff state.

[0055] In this embodiment, after the voltage across the load module stabilizes to the target voltage, the acceleration module is in a cutoff state, so that the current output by the voltage output module flows only through the current sensing module. At this time, the current flowing through the current sensing module is equal to the current flowing through the load module. The differential amplifier module outputs a voltage signal representing the load current based on the differential voltage across the current sensing module, which will not affect the measurement accuracy of the load current.

[0056] In the embodiments of this specification, the voltage output module includes a signal source, a first operational amplifier, and a second operational amplifier. The signal source is connected to the non-inverting input of the first operational amplifier, the output of the first operational amplifier is connected to the non-inverting input of the second operational amplifier via the current detection module, and the output of the second operational amplifier is connected to the inverting input of the first operational amplifier.

[0057] In the embodiments of this specification, the voltage output module includes a signal source VG1, a first operational amplifier U2, and a second operational amplifier U4. The signal source VG1 generates DC (direct current) and AC (alternating current) waveforms, which are connected to the non-inverting input terminal of the first operational amplifier U2. The output voltage of the first operational amplifier U2 is connected to the non-inverting input terminal of the second operational amplifier U4 (BUFFER) after passing through the current sensing resistor R21. The output voltage of the second operational amplifier U4 is connected to the inverting input terminal of the first operational amplifier U2 to form a negative feedback loop. Through the negative feedback mechanism, the voltage across the load module, i.e., the voltage at the output terminal OUT, is equal to the output voltage of the signal source VG1.

[0058] The voltage output module in the embodiments of this specification uses a negative feedback mechanism to make the voltage across the load module equal to the output voltage of the signal source, thereby realizing the high-precision and high-stability voltage output function of the source measurement circuit.

[0059] In the embodiments described in this specification, if the output voltage of the signal source VG1 is -10V to +10V, the resistance of the load module R2 is 10MΩ, the resistance of the current sensing resistor R21 is 1MΩ, and the voltage gain of the differential amplifier circuit is G=1, then according to IM = G * I * R21, the voltage at the output terminal OUT is also -10V to +10V, the load current I on the load resistor R2 is -1uA to +1uA, and the voltage IM is -1V to +1V. The waveforms of the output voltage at the OUT terminal and the output voltage at the IM terminal are as follows: Figure 3 As shown, the red line represents the output voltage at the OUT terminal, and the green line represents the output voltage at the IM terminal. Figure 3 As can be seen, the settling time of the output voltage at the OUT terminal has been shortened from more than 10us to less than 0.2us, and the settling time of the output voltage at the IM terminal has been shortened from more than 15us to less than 8us. This significantly reduces the settling time of the output voltage and measurement current of the source measurement circuit, and improves the testing capability of the source measurement circuit.

[0060] As can be seen from the above embodiments of the source measurement circuit provided by the present invention, the source measurement circuit of the present invention includes a voltage output module, an acceleration module, a current detection module, and a load module. The voltage output module is connected to the load module through the current detection module, and the acceleration module is connected in parallel with the current detection module. The voltage output module is used to output a first voltage signal, which represents the voltage across the load module. The acceleration module is used to accelerate the process of the first voltage signal reaching a target voltage. The acceleration module is in a conducting state during the change of the first voltage signal and in a cut-off state after the first voltage signal reaches the target voltage. The technical solution provided by the embodiments of this specification accelerates the process of the voltage across the load module reaching the target voltage through the acceleration module. The voltage output by the voltage output module represents the voltage across the load module. The acceleration module is in a conducting state during the change of the voltage across the load module. The acceleration module provides a bypass by being connected in parallel with the current detection module, which shortens the settling time of the output voltage of the source measurement circuit and improves the output slew rate. Furthermore, after the voltage across the load module stabilizes to the target voltage, the acceleration module is in the off state, causing the current sensing module to be connected in series with the load module. At this time, the current flowing through the current sensing module is equal to the current flowing through the load module. The differential amplifier module can output a voltage signal characterizing the load current based on the differential voltage across the current sensing module, without affecting the measurement accuracy of the load current. Moreover, since the stability of the voltage across the load module, i.e., the output voltage, is a prerequisite for load current measurement, the shortened settling time of the output voltage will also shorten the settling time of the load current, i.e., the measurement current. Through the source measurement circuit of this invention, the output slew rate can be improved without sacrificing the load current measurement accuracy, and the settling time of the output voltage and the measurement current can be shortened, thereby improving the testing capability of the source measurement circuit.

[0061] This application also provides a voltage output method, see [link to relevant documentation] Figure 4 , Figure 4 This is a flowchart illustrating a voltage output method provided in an embodiment of the present invention. The method is applied to the aforementioned source measurement circuit and includes: S401, the voltage output module outputs a first voltage signal, the first voltage signal representing the voltage across the load module; S402, the acceleration module accelerates the process of the first voltage signal reaching the target voltage; the acceleration module is in a conducting state during the change of the first voltage signal, and in a cut-off state after the first voltage signal reaches the target voltage.

[0062] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments, while other embodiments fall within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than those in the embodiments and still achieve the desired results. The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0063] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A source measurement circuit, characterized in that, The source measurement circuit includes a voltage output module, an acceleration module, a current detection module, and a load module. The voltage output module is connected to the load module through the current detection module, and the acceleration module is connected in parallel with the current detection module. The voltage output module is used to output a first voltage signal, which represents the voltage across the load module. The acceleration module is used to accelerate the process of the first voltage signal reaching the target voltage; The acceleration module is in a conducting state during the change of the first voltage signal and in a cut-off state after the first voltage signal reaches the target voltage.

2. The source measurement circuit according to claim 1, characterized in that, The source measurement circuit further includes a differential amplifier module, which is connected in parallel with the current detection module; The differential amplifier module is used to convert the differential voltage across the current detection module into a second voltage signal characterizing the load current after the first voltage signal reaches the target voltage. The load current is the current flowing through the load module.

3. The source measurement circuit according to claim 1, characterized in that, The acceleration module includes a first branch and a second branch connected in parallel. The first branch includes a first resistor and a first diode connected in series, and the second branch includes a second resistor and a second diode connected in series. The resistance values ​​of the first resistor and the second resistor are much smaller than the resistance value of the current detection module.

4. The source measurement circuit according to claim 3, characterized in that, The anode of the first diode is connected to the first resistor, and the cathode of the first diode is connected to the load module; the anode of the second diode is connected to the load module, and the cathode of the second diode is connected to the second resistor.

5. The source measurement circuit according to claim 4, characterized in that, During the rise of the first voltage signal, the first branch is in the on state, the second branch is in the off state, the current detection module is connected in parallel with the first branch, and the current output by the voltage output module flows to the load module through the current detection module and the first branch. The current flowing through the current detection module is less than the current flowing through the first branch.

6. The source measurement circuit according to claim 4, characterized in that, During the decrease of the first voltage signal, the first branch is in the off state, the second branch is in the on state, the current detection module is connected in parallel with the second branch, the current flowing through the load module flows through the current detection module and the second branch to the voltage output module, and the current flowing through the current detection module is less than the current flowing through the second branch.

7. The source measurement circuit according to any one of claims 3-6, characterized in that, The acceleration module further includes a pull-up resistor, a pull-down resistor, a positive voltage source, and a negative voltage source; the first end of the pull-down resistor is connected to the anode of the first diode, and the second end of the pull-down resistor is connected to the negative voltage source; the first end of the pull-up resistor is connected to the cathode of the second diode, and the second end of the pull-up resistor is connected to the positive voltage source.

8. The source measurement circuit according to claim 7, characterized in that, After the first voltage signal rises to the first target voltage, the cathode voltage of the first diode is equal to the first target voltage. The pull-down resistor and the negative voltage source make the anode voltage of the first diode less than the cathode voltage of the first diode. Both the first branch and the second branch are in the off state. The current output by the voltage output module flows to the load module through the current detection module.

9. The source measurement circuit according to claim 7, characterized in that, After the first voltage signal drops to the second target voltage, the anode voltage of the second diode is equal to the second target voltage. The pull-up resistor and the positive voltage source make the cathode voltage of the second diode greater than the anode voltage of the second diode. Both the first branch and the second branch are in the off state. The current flowing through the load module flows to the voltage output module through the current detection module.

10. The source measurement circuit according to claim 1, characterized in that, The voltage output module includes a signal source, a first operational amplifier, and a second operational amplifier. The signal source is connected to the non-inverting input of the first operational amplifier. The output of the first operational amplifier is connected to the non-inverting input of the second operational amplifier via the current detection module. The output of the second operational amplifier is connected to the inverting input of the first operational amplifier.

11. A voltage output method, characterized in that, The method is applied to the source measurement circuit as described in any one of claims 1-10, and the method includes: The voltage output module outputs a first voltage signal, which represents the voltage across the load module. The acceleration module accelerates the process of the first voltage signal reaching the target voltage; the acceleration module is in a conducting state during the change of the first voltage signal, and in a cut-off state after the first voltage signal reaches the target voltage.

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