Current test discharge method and system based on active discharge and segmented control

Abstract

The invention provides a current test discharge method and system based on active discharge and segmented control, and the method comprises the steps: monitoring the voltage of an energy storage capacitor after the current test of a chip is completed; when the voltage is greater than a first threshold value, entering a constant-current discharge mode, and in the constant-current discharge mode, adjusting the grid voltage of the MOS tube according to the voltage value, and maintaining the discharge current to be a set value constantly; the voltage of the energy storage capacitor continues to be monitored, when the voltage is smaller than a first threshold value and larger than a second threshold value, an exponential decay mode is switched, and in the exponential decay mode, the voltage of the grid electrode of the MOS tube continues to be adjusted; when the voltage is smaller than the second threshold value, the MOS tube is closed, and the discharging process is completed. The technical problems of non-uniform energy release, large transient impact, long discharge time and the like existing in a traditional discharge mode are effectively solved through precise control of two stages of constant current discharge and exponential decay.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor, in particular to a current test discharging method and system based on active discharge and segmented control. BACKGROUND

[0002] In the field of integrated circuit testing, the rapid and safe discharge of energy storage capacitor after chip current test is a key link to ensure test accuracy and equipment reliability. The existing technology mainly adopts three discharge schemes: passive discharge resistor, mechanical relay switching and single-stage constant current discharge. Although the passive discharge resistor has a simple structure, it is slow in discharging in large-capacity energy storage systems due to the discharge time constant τ = R·C, which seriously affects the test efficiency; the mechanical relay switching method has a short service life (less than 10 5 seconds) and slow response (milliseconds) due to the problem of contact arc, which is difficult to meet the demand of high-frequency testing; the single-stage constant current discharge is fast, but it is easy to cause voltage overshoot phenomenon in the discharge process, which may cause potential damage to the chip and test equipment.

[0003] At present, these discharge schemes have two defects: one is in terms of efficiency, the discharge time usually accounts for 30%-50% of the entire test cycle, for example, in the 100A current test scenario, the discharge time is more than 500 milliseconds, which seriously restricts the test throughput and production efficiency; the second is in terms of safety, residual voltage exceeding 5V is easy to trigger subsequent test misjudgment, and arc discharge phenomenon may damage the probe or chip pin, increasing equipment maintenance cost. With the increasing demand for integrated circuit testing, especially in high-current and high-speed test scenarios, a more efficient and safer energy storage capacitor discharge method is urgently needed. SUMMARY

[0004] The purpose of the present application is to solve the technical problems of low efficiency, long discharge time and easy damage to the chip in the discharge process of the energy storage capacitor in the chip current test of the prior art.

[0005] In a first aspect, the present application provides a current test discharging method based on active discharge and segmented control, comprising: monitoring the voltage of the energy storage capacitor after the chip current test is completed; when the voltage is greater than a first threshold value, entering a constant current discharge mode, in which the MOS tube gate voltage is adjusted according to the voltage value to maintain the discharge current constant at a set value; continuously monitoring the voltage of the energy storage capacitor, and when the voltage is less than the first threshold value and greater than a second threshold value, switching to an exponential decay mode, in which the MOS tube gate voltage is continuously adjusted; when the voltage is less than the second threshold value, the MOS tube is turned off, and the discharge process is completed.

[0006] Further, the set value is 60%-90% of the test current.

[0007] Further, the MOS transistor includes a first MOS transistor and a second MOS transistor. In the constant current discharge mode, the first MOS transistor is used for discharging and adjusting the gate voltage thereof. When switching to the exponential decay mode, the first MOS transistor is turned off and the second MOS transistor is turned on, and the exponential decay discharge is realized by adjusting the gate voltage of the second MOS transistor.

[0008] Further, in the constant current discharge mode, the discharge current is monitored in real time by a current sensor, and the gate voltage of the first MOS transistor is adjusted according to the monitoring result, forming a closed-loop control.

[0009] Further, in the exponential decay mode, the discharge current I(t) = I0 x , Where I0 is the current value when switching to the exponential decay mode, τ is the time constant, and t is the time elapsed since the exponential decay stage.

[0010] Further, the voltage change rate of the energy storage capacitor is calculated in real time, and the required time constant τ is determined according to the voltage change rate.

[0011] Further, in the exponential decay mode, the gate voltage of the second MOS transistor is dynamically adjusted by querying a pre-stored corresponding relationship table of the gate voltage of the second MOS transistor and the time constant.

[0012] The second aspect of the present application provides a current test discharge system based on active discharge and stage control, comprising: An active discharge module for realizing a constant current discharge mode and an exponential decay mode; A discharge control module for receiving a discharge instruction, monitoring the voltage of an energy storage capacitor and generating a control signal; A current monitoring module for monitoring the discharge current; Wherein, the discharge control module adjusts the gate voltage of the MOS transistor in the active discharge module according to the voltage of the energy storage capacitor and the feedback signal of the current monitoring module, so that the discharge process goes through the constant current discharge mode, the exponential decay mode and the off mode in turn.

[0013] Further, the active discharge module further includes a discharge resistor connected in series with the MOS transistor.

[0014] Further, the discharge control module stores a mapping table of the gate voltage of the MOS transistor and the time constant for parameter query in the exponential decay mode.

[0015] Compared with the prior art, the present application at least has the following beneficial effects: by accurate control of two stages of constant current discharge and exponential decay, technical problems such as uneven energy release, large transient impact and long discharge time of traditional discharge modes are effectively improved. In the high voltage interval, the constant current discharge mode is used to quickly discharge a large part of energy, which not only ensures the discharge efficiency, but also avoids the impact of excessive current on the system; when the voltage drops to the first threshold, it is automatically switched to the exponential decay mode, and the current is smoothly decayed by dynamically adjusting the MOS tube gate voltage, which effectively suppresses the voltage backflow and electromagnetic interference in the low voltage region, and at the same time shortens the total discharge time and improves the utilization rate of the test equipment. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0017] Figure 1 A step schematic diagram of the current test discharge method based on active discharge and segmented control in an embodiment of the present application; Figure 2 A flowchart schematic diagram of the current test discharge method based on active discharge and segmented control in an embodiment of the present application; Figure 3 A module schematic diagram of the current test discharge system based on active discharge and segmented control in an embodiment of the present application.

[0018] Among them, D1-first MOS tube; D2-second MOS tube; R1-first discharge resistor; R2-second discharge resistor; TVS-voltage suppressor; C1-energy storage capacitor. DETAILED DESCRIPTION

[0019] The present application will be described in more detail below with reference to the accompanying drawings, in which the preferred embodiments of the present application are shown, it should be understood that those skilled in the art can modify the present application described herein while still achieving the advantageous effects of the present application. Therefore, the following description should be understood as widely known by those skilled in the art, and not as a limitation on the present application.

[0020] It is to be understood that the terminology used herein such as first and second, and the like, is merely for distinguishing one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises" and / or "comprising," or any variation thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process or method. Additionally, unless otherwise specified, all ranges are inclusive of the recited values and operable endpoints.

[0021] The application is described in more detail in the following passages with reference to the drawings. The advantages and features of the application will become more apparent from the following description. It should be noted that the drawings are in very simplified form and are not drawn to precise scale, only for the purpose of facilitating a convenient, clear explanation of embodiments of the application.

[0022] Embodiment one In a first aspect of the application, a current test discharge method based on active bleeding and segmented control is provided, please refer to Figures 1-3 , comprising: monitoring the voltage of the energy storage capacitor C1 after chip current test is completed; when the voltage is greater than a first threshold value, entering a constant current discharge mode, in which the MOS tube gate voltage is adjusted according to the voltage value to maintain the discharge current constant at a set value; continuing to monitor the voltage of the energy storage capacitor C1, and when the voltage is less than the first threshold value and greater than a second threshold value, switching to an exponential decay mode, in which the MOS tube gate voltage is continuously adjusted; when the voltage is less than the second threshold value, the MOS tube is turned off, and the discharge process is completed.

[0023] Specifically, after the chip current test is completed, when the voltage is greater than the first threshold value, the system first enters the constant current discharge mode, the MOS tube gate voltage is dynamically adjusted to maintain a constant discharge current, and most of the energy in the energy storage capacitor C1 is quickly released. When the capacitor voltage is less than the first threshold value but greater than the second threshold value, it is automatically switched to the exponential decay mode, the MOS tube gate voltage is continuously adjusted, the current is smoothly attenuated according to the exponential law, and the backwash phenomenon in the low voltage region is avoided. Finally, when the voltage is less than the second threshold value, the MOS tube is turned off to complete the entire discharge process.

[0024] The segmented control method ingeniously combines the high efficiency of constant current discharge and the smoothness of exponential decay, quickly discharges energy in the high voltage interval, and realizes the smooth transition of current in the low voltage interval, effectively avoiding parasitic oscillation and electromagnetic interference caused by voltage drop. By actively adjusting the gate voltage of the MOS tube to replace the traditional passive discharge or mechanical switching mode, not only the discharge speed is improved and the test period is shortened, but also the safety and reliability of the discharge process are ensured.

[0025] Further, the set value is 60%-90% of the test current.

[0026] Further, the first threshold value is 10V-20V; and the second threshold value is 0.5V-2V.

[0027] Specifically, the selection range of the set value is based on the following considerations: when the discharge current is less than 60% of the test current, the discharge time will be significantly prolonged, which cannot meet the test efficiency requirement; and more than 90% may cause MOS tube overheating or voltage backwash phenomenon. As a preferred embodiment, the set value can be dynamically adjusted by a programmable current source to adapt to different test current scenarios. For example, under the condition of 200A test current, the discharge current can be set to 160A (80%), which can ensure the discharge speed and avoid excessive stress on the device. Therefore, by limiting the proportional relationship between the discharge current and the test current, the discharge efficiency is optimized under the premise of ensuring the safety of the discharge. Compared with the existing single-stage constant current discharge, this set range can prevent voltage backwash caused by too fast discharge, and avoid the low efficiency problem of passive discharge resistor scheme.

[0028] In the present embodiment, the first threshold value is set to 10V-20V. When the voltage drops to the set threshold value, the discharge current changes from a constant value to an exponential decay. The second threshold value is set to 0.5V-2V. As a preferred embodiment, the first threshold value is 15V and the second threshold value is 1V, at which point the discharge efficiency and safety reach the best balance. In another embodiment, the threshold value can be adjusted according to different capacitance capacities, for example, for large-capacity capacitors, the first threshold value can be set to 18V and the second threshold value can be set to 1.5V.

[0029] Therefore, by setting two precise voltage threshold values, the segmented control of the discharge process is realized, solving the problems of incomplete discharge or over-discharge in the prior art. Compared with single-stage constant current discharge, this method realizes the discharge speed while avoiding damage to the test equipment caused by voltage backwash. Compared with passive discharge, the discharge time is significantly shortened.

[0030] Further, the MOS tube includes a first MOS tube D1 and a second MOS tube D2.

[0031] In the constant current discharge mode, the first MOS tube D1 is used for discharging and adjusting its gate voltage.

[0032] When switching to the exponential decay mode, the first MOS tube D1 is turned off and the second MOS tube D2 is turned on, and the exponential decay discharge is achieved by adjusting the gate voltage of the second MOS tube D2.

[0033] Further, in the constant current discharge mode, the discharge current is monitored in real time by a current sensor, and the gate voltage of the first MOS tube D1 is adjusted according to the monitoring result to form a closed-loop control.

[0034] Specifically, the current sensor can be implemented by a Hall effect sensor or a shunt resistor. In this embodiment, the current sensor is a Hall effect sensor with model ACS770LCB-200B. As a preferred embodiment, the Hall effect sensor converts the current signal into a voltage signal through an I / V conversion circuit, and inputs the voltage signal into the control unit after ADC sampling. Further, the control unit calculates the gate voltage adjustment amount through a PID algorithm, and drives the first MOS tube D1 gate driver after DAC conversion. The closed-loop control loop formed thereby can control the discharge current fluctuation within ±2%. For example, when the discharge current deviates due to load changes, the control unit can complete voltage adjustment within 100μs to maintain constant current.

[0035] By introducing a closed-loop control mechanism, the current instability problem caused by element parameter drift or load changes in the traditional open-loop constant current discharge mode is effectively improved. Compared with the passive discharge scheme, the closed-loop control improves the current stability and avoids the voltage kickback phenomenon caused by current fluctuation. Compared with the mechanical relay scheme, the electronic adjustment has a millisecond-level response speed and can adapt to high-frequency test requirements. By accurately maintaining the discharge current constant, both the discharge efficiency and the potential damage of overcurrent to the test equipment are ensured.

[0036] Further, in the exponential decay mode, the discharge current I(t)=I0× , where I0 is the current value when switching to the exponential decay mode, τ is the time constant, and t is the time elapsed since the exponential decay phase began.

[0037] Specifically, the voltage change rate of the energy storage capacitor C1 is calculated in real time, and the required time constant τ is determined according to the voltage change rate. In the exponential decay mode, the relationship between voltage and time follows an exponential function, and the voltage change rate (dV / dt) directly reflects the current discharge rate. By monitoring the actual voltage change rate, it can be determined whether the current time constant τ meets the expected value, which provides a real-time feedback mechanism for the system to adjust according to the actual discharge situation.

[0038] Further, in the exponential decay mode, the gate voltage of the second MOS tube D2 is dynamically adjusted by querying a pre-stored corresponding relationship table of the gate voltage of the second MOS tube D2 and the time constant.

[0039] Specifically, the pre-stored corresponding relationship table is established by experiment or simulation. In the implementation process, the corresponding relationship table can be stored in the non-volatile memory of the discharge control module, such as EEPROM or Flash. As a preferred embodiment, the corresponding relationship table is stored in the form of a two-dimensional array, where one dimension is the gate voltage value and the other dimension is the corresponding time constant. In the exponential decay stage, the control module calculates the current required time constant by real-time voltage sampling value, queries the table to obtain the matching gate voltage value, and then outputs the PWM signal to drive the gate of the second MOS tube D2. Thus, the discharge current is accurately decayed according to the rules.

[0040] Therefore, in the exponential decay stage, the current dV / dt is calculated, and according to the current discharge condition, the required time constant τ is determined; the mapping table is queried to find the gate voltage that can produce the required τ value, and the gate voltage of the MOS tube is adjusted to control the rate of exponential decay. By establishing the mapping relationship between the gate voltage and the time constant, the problem of difficult accurate control of parameters in the traditional exponential decay mode is improved. Since the time constant directly affects the slope of the discharge curve, accurate control can avoid voltage backflush phenomenon, and compared with the fixed parameter decay mode, the discharge speed can be dynamically optimized according to the actual working condition.

[0041] Embodiment two The embodiment provides a current test discharge system based on active discharge and stage control, please refer to Figure 3 , comprising: An active discharge module for realizing a constant current discharge mode and an exponential decay mode.

[0042] A discharge control module for receiving a discharge instruction, monitoring the voltage of an energy storage capacitor C1 and generating a control signal.

[0043] A current monitoring module for monitoring the discharge current.

[0044] The discharge control module adjusts the gate voltage of the MOS tube in the active discharge module according to the voltage of the energy storage capacitor C1 and the feedback signal of the current monitoring module, so that the discharge process experiences the constant current discharge mode, the exponential decay mode and the off mode in turn.

[0045] Specifically, the active discharge module includes a first MOS tube D1 and a second MOS tube D2 connected in parallel with the energy storage capacitor C1, the first MOS tube D1 is used for constant current discharge mode, and the second MOS tube D2 is used for exponential decay mode. In this embodiment, a first discharge resistor R1 and a second discharge resistor R2 are further connected in series with the first MOS tube D1 and the second MOS tube D2. The discharge resistor is used to limit the size of the discharge current to prevent excessive current from damaging the MOS tube. The discharge control module stores a mapping table of the second MOS tube D2 gate voltage and the time constant for parameter query in the exponential decay mode. In the exponential decay mode, the second MOS tube D2 gate voltage is dynamically adjusted by querying the mapping table, so that the discharge current decays according to the exponential law.

[0046] In this embodiment, a transient voltage suppressor TVS is further connected in parallel across the energy storage capacitor C1, which is used to protect the electronic circuit from voltage transients and surges. As a preferred embodiment, the discharge control module can be implemented by a microcontroller or a programmable logic device, and the discharge process in each stage is controlled by a pre-set program logic. The voltage of the energy storage capacitor C1 can be realized by a high-precision ADC chip to collect the voltage signal in real time. The current monitoring module can be realized by a Hall sensor or a sampling resistor combined with a signal conditioning circuit to monitor the size of the discharge current in real time.

[0047] The segmented control strategy realizes efficient and safe discharge of the energy storage capacitor C1. In the constant current discharge phase, the discharge current is maintained constant through closed-loop control, which improves the discharge speed; in the exponential decay phase, the voltage back-attack phenomenon is avoided by dynamically adjusting the MOS tube gate voltage; in the off phase, the discharge loop is timely cut off to ensure the safety and reliability of the discharge process.

[0048] Further, the active discharge module further includes a discharge resistor connected in series with the second MOS tube D2.

[0049] Specifically, the resistance range of the discharge resistor is usually selected to be 1Ω-10Ω, which can effectively limit the peak value of the discharge current and avoid the second MOS tube D2 from bearing excessive current impact in the conduction moment. As a preferred embodiment, the discharge resistor can be a power metal film resistor, and its rated power should be not less than 5W to meet the long-time working requirement.

[0050] By adding a bleeder resistor, the discharge system has multiple technical advantages: first, the bleeder resistor and the MOS tube jointly constitute a composite discharge path, which can share part of the power consumption and reduce the temperature rise of the MOS tube in the constant current discharge stage; second, in the exponential decay mode, the bleeder resistor and the MOS tube dynamic resistance jointly determine the time constant, making the discharge curve more smooth and controllable; finally, when the system is accidentally powered off, the bleeder resistor can provide a passive discharge channel to ensure that the residual voltage of the energy storage capacitor C1 can be safely discharged.

[0051] Further, the discharge control module stores a mapping table of the second MOS tube D2 gate voltage and the time constant for parameter query in the exponential decay mode.

[0052] Specifically, the mapping table stores the time constant parameters corresponding to different gate voltages in the form of discrete data, which is determined by the product of the dynamic resistance of the second MOS tube D2 and the capacitance value of the load capacitor. As a preferred embodiment, the mapping table can be stored in a two-dimensional array structure, where the first column is the gate voltage value and the second column is the time constant measured by experiment.

[0053] By pre-storing the corresponding relationship between the gate voltage and the time constant, the target gate voltage value can be quickly determined in the exponential decay stage, avoiding the processing delay caused by real-time calculation. Compared with the prior art, this method improves the voltage overshoot problem when switching the single-stage constant current discharge mode, and by accurately controlling the dynamic parameters of the exponential decay process, both the discharge speed and the potential damage of the test equipment caused by overshoot are avoided.

[0054] The following explains with specific embodiments: Implementation scenario: automobile power module test (test current 200A, energy storage capacitor C1 15mF, target discharge time ≤80ms). The system uses Infineon IRFP4668PbF power MOS tube as the discharge switch, and the on-resistance of the device is 1.8mΩ, and the maximum drain current is 290A. The bleeder resistor is selected from WSHP2818R300FEA type 0.3Ω / 50W resistor and TE CFR100 series 100Ω resistor. The energy storage capacitor C1 is composed of three 2200μF high polymer capacitors in parallel, and the equivalent series resistance is 3mΩ. The control system is realized based on Xilinx Artix-7 FPGA, and cooperates with 16-bit ADC for analog-digital conversion, with a sampling rate of 1MSPS. The current detection uses a Hall effect sensor ACS770LCB-200B with a detection accuracy of ±1%.

[0055] The entire discharge process is divided into three stages: The first stage is a constant current discharge stage. When the discharge instruction is sent, the discharge control module immediately starts the closed-loop control system and sends the first control signal to the first MOS tube D1. The current sensor monitors the discharge current in real time and sends the feedback signal to the discharge control module. The PID controller outputs the gate control voltage Vgs according to the current deviation, and accurately maintains the discharge current at 160 A. At the same time, the discharge control module continuously monitors the energy storage capacitor C1 voltage, and automatically switches to the second stage when the voltage drops to 15 V.

[0056] The second stage is an exponential decay stage. The discharge control module stops sending the first control signal and starts sending the second control signal to the second MOS tube D2. The system calculates the expected voltage change rate according to the current capacitor voltage, and then queries the Vgs-τ mapping table pre-stored in the discharge control module to obtain the corresponding gate control voltage. By dynamically adjusting the gate voltage to control the time constant τ, the voltage is smoothly decayed according to the exponential law. When the capacitor voltage drops to 1 V, it enters the third stage.

[0057] The third stage is a safe shutdown stage. The discharge control module sets the gate voltage of all MOS tubes to zero, completely shutting down the discharge channel, and ensuring system safety. Table 1 below is the parameter data of this embodiment. The discharge time is reduced from 520 ms to 72 ms, an increase of 86%; the peak energy consumption is reduced from 18.5 J to 7.2 J, a decrease of 61%; and the voltage backflush amplitude is greatly reduced from ±7 V to ±0.8 V, a decrease of 89%. These data show that the current test discharge method based on active discharge and segmented control used in this embodiment improves the discharge efficiency, reduces the energy consumption, and improves the voltage stability, effectively solving the problems existing in the traditional discharge scheme.

[0058] Table 1 Parameter Conventional approach This embodiment Amplitude Discharge time 520 ms 72 ms 86%↓ Peak energy consumption 18.5J 7.2J 61%↓ Voltage overshoot amplitude ±7V ±0.8V 89%↓ The above application of specific examples to illustrate the present invention, is only used to help understand the present invention, and does not limit the present invention. For those skilled in the art to which the present invention belongs, according to the idea of the present invention, a number of simple deductions, deformations or substitutions can be made.

Claims

1. A current test discharge method based on active bleed and segment control, characterized in that, The application relates to a chip current test method and device. After the chip current test is completed, the voltage of an energy storage capacitor is monitored; When the voltage is greater than a first threshold value, a constant current discharge mode is entered, in which the MOS tube gate voltage is adjusted according to the voltage value to maintain the discharge current constant at a set value; The voltage of the energy storage capacitor is continuously monitored, and when the voltage is less than the first threshold value and greater than a second threshold value, an exponential decay mode is switched to, in which the MOS tube gate voltage is continuously adjusted; When the voltage is less than the second threshold value, the MOS tube is turned off, and the discharge process is completed.

2. The active bleed and segment control based current test discharge method of claim 1, wherein, The set value is 60%-90% of the test current.

3. The active bleed and segment control based current test discharge method of claim 1, wherein, The MOS tube comprises a first MOS tube and a second MOS tube. In the constant current discharge mode, the first MOS tube is used for discharging and adjusting the gate voltage thereof. When the exponential decay mode is switched to, the first MOS tube is turned off and the second MOS tube is turned on, and the exponential decay discharge is realized by adjusting the gate voltage of the second MOS tube.

4. The active bleed and segment control based current test discharge method of claim 3, wherein, In the constant current discharge mode, the discharge current is monitored in real time through a current sensor, and the gate voltage of the first MOS tube is adjusted according to the monitoring result to form a closed loop control.

5. The active bleed and segment control based current test discharge method as claimed in claim 3, wherein, In the exponential decay mode the bleed current I(t) = I0x , Wherein I0 is the current value when the exponential decay mode is switched to, tau is a time constant, and t is the time elapsed since the exponential decay stage is started.

6. The active bleed and segment control based current test discharge method of claim 5, wherein, The voltage change rate of the energy storage capacitor is calculated in real time, and the required time constant tau is determined according to the voltage change rate.

7. The active bleed and segment control based current test discharge method as claimed in claim 6, wherein, The corresponding relationship table of the gate voltage of the second MOS tube and the time constant is queried in advance, and the gate voltage of the second MOS tube is dynamically adjusted.

8. A current test discharge system based on active bleed and phase control, characterized by, The application relates to a chip current test method and device. An active discharge module is used for realizing a constant current discharge mode and an exponential decay mode; A discharge control module is used for receiving a discharge instruction, monitoring the voltage of an energy storage capacitor and generating a control signal; A current monitoring module is used for monitoring a discharge current; The discharge control module adjusts the gate voltage of the MOS tube in the active discharge module according to the voltage of the energy storage capacitor and the feedback signal of the current monitoring module, so that the discharge process experiences the constant current discharge mode, the exponential decay mode and the off mode in sequence.

9. The active bleed and phased control based current test discharge system as claimed in claim 8, wherein, The active discharge module further comprises a discharge resistor connected in series with the MOS tube.

10. The active bleed and phased control based current test discharge system as claimed in claim 8, wherein, The discharge control module stores a mapping table of the MOS tube gate voltage and the time constant, which is used for parameter query in the exponential decay mode.

Images