High-voltage VI source module for SOC test

Abstract

The invention relates to the technical field of high-voltage VI modules, and particularly discloses a high-voltage VI source module for SOC testing, which comprises an output stage module, a sampling module and a control and conversion module, the output stage module is constructed by adopting discrete high-voltage power devices, supports four-quadrant operation, and can realize flexible output and absorption of voltage and current; the sampling module is composed of a voltage sampling unit and a current sampling unit which respectively monitor voltage and current signals of the output stage in real time. The control and conversion module comprises a control unit and a digital-to-analog conversion unit; the digital-to-analog conversion unit is responsible for converting a digital control signal into an analog control signal to drive the output stage and converting analog voltage and current signals collected by the sampling module into digital feedback signals; and the control unit receives the digital feedback signals and adjusts the output of the digital-to-analog conversion unit in real time through a closed-loop control algorithm, so that high-precision and high-stability control on the output-stage voltage or current is realized.

Description

Technical Field

[0001] This invention relates to the field of high-voltage VI module technology, and more specifically to a high-voltage VI source module for SOC testing. Background Technology

[0002] In automated test equipment (ATE), the voltage or current source, i.e., the VI source, is a key module for SOC testing. It can switch between voltage source (FV mode) and current source (FI mode) operation, and also has voltage measurement (MV mode) and current measurement (MI mode) functions. It supports four-quadrant operation and can accurately control voltage and current to meet the core requirements of electrical characteristic testing of semiconductor devices.

[0003] In traditional SOC testing scenarios, the output voltage of a VI source is typically below 24V. However, with the expansion of SOC application scenarios and functional upgrades, the demand for high-voltage SOC testing is becoming increasingly urgent, requiring VI sources to provide higher voltage outputs. Existing single-channel VI sources consist of functional units such as a controller, DAC, output stage, voltage sense, current sense, and ADC. The implementation solutions are mainly divided into two categories: one is to integrate all functional units into a single chip; the other is to use discrete components to build each functional unit separately and connect them.

[0004] However, integrated chip solutions have significant drawbacks: limited output voltage and current ranges make them difficult to adapt to diverse application scenarios; limited chip heat dissipation capabilities result in low thermal power, preventing full-range output at maximum current or voltage; functional integration makes performance optimization difficult, and loop bandwidth and output voltage slew rate are relatively low. Furthermore, the zeros and poles introduced by each module in the closed loop can easily disrupt loop stability, leading to high debugging difficulties for discrete device solutions; and the design of high-channel-density boards is challenging, resulting in low integration. In summary, existing solutions cannot simultaneously meet the requirements of high-voltage SOC testing in terms of output range, integration, debugging convenience, and performance, and urgently need improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a high-voltage VI source module for SOC testing, which solves the following technical problems.

[0006] The objective of this invention can be achieved through the following technical solutions: A high-voltage VI source module for SOC testing includes: Output stage module: Based on discrete high-voltage power devices, used for four-quadrant operation; Sampling module: voltage sampling unit and current sampling unit, wherein the voltage sampling unit acquires the voltage signal of the output stage module in real time, and the current sampling unit acquires the current signal of the output stage module in real time; Control and Conversion Module: Includes a control unit and a digital-to-analog converter (DAC). The DAC converts digital control signals into analog control signals. The DAC also converts the voltage signal into a digital voltage feedback signal and the current signal into a digital current feedback signal. The control unit adjusts the output of the digital-to-analog converter in real time based on the digital voltage feedback signal and the digital current feedback signal through a closed-loop control algorithm.

[0007] As a further aspect of the present invention, the control unit is also used to receive a control signal, which is a digital or analog signal used for switching operating states.

[0008] As a further aspect of the present invention: the output stage module further includes a power amplification module unit and a mode switching unit. The output stage module adopts a push-pull high-voltage operational amplifier combined with an N-type and a P-type power MOSFET structure to provide bidirectional positive and negative voltage output capability. The mode switching unit is used to switch the voltage source and current source operating modes according to the control signal.

[0009] As a further aspect of the present invention: the voltage sampling unit includes a high-precision, low-temperature-drift voltage divider resistor network and a voltage follower. The voltage divider resistor network is used to scale the high output voltage, and the voltage follower is used to provide input impedance and low output impedance to achieve signal isolation and impedance matching.

[0010] As a further aspect of the present invention: the current sampling unit further includes a precision sampling resistor and a differential amplifier circuit. The precision sampling resistor is connected in series in the output current path of the output stage module to sense the load current flowing to the device under test. The differential amplifier circuit detects the voltage difference across the precision sampling resistor and outputs a voltage signal proportional to the load current.

[0011] As a further aspect of the present invention: the digital-to-analog conversion unit adopts a high-precision digital-to-analog converter, the resolution of the high-precision digital-to-analog converter is greater than 16 bits, the output analog voltage range of the high-precision digital-to-analog converter is [-10V, 10V], and the analog voltage range is amplified to [-48V, 48V] by the output stage module.

[0012] As a further aspect of the present invention: the control unit is based on an FPGA or an ARM microcontroller with a floating-point arithmetic unit, and has a built-in digital PID controller to correct the output value of the digital-to-analog converter in real time according to the digital voltage feedback signal and the digital current feedback signal.

[0013] As a further aspect of the present invention: the digital-to-analog conversion unit is based on a sampling analog-to-digital converter, which includes several sampling channels. Each sampling channel simultaneously acquires digital voltage feedback signals and digital current feedback signals, and communicates with the control unit via a digital serial interface.

[0014] The beneficial effects of this invention are: This invention successfully achieves a high voltage output of up to ±48V by using discrete power devices to construct the output stage and combining it with a high-precision sampling and closed-loop control architecture, significantly expanding the voltage range applicable to SOC testing. At the same time, the modular design and integrated digital control enable this solution to overcome the problems of limited output capability, poor heat dissipation, and difficult debugging of traditional integrated chip solutions while ensuring output accuracy and stability. It supports multi-channel high-density integration and effectively meets the core requirements of modern high-voltage, high-precision, and high-efficiency SOC testing. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 This is a flowchart illustrating a high-voltage VI source module for SOC testing according to the present invention. Figure 2 This is a simplified diagram of the VI source structure of a high-voltage VI source module for SOC testing according to the present invention. Detailed Implementation

[0017] 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.

[0018] It should be noted that the VI source can be used as a voltage source and a current source, and it can also measure voltage and current. It also supports four-quadrant operation, which means that the VI source can be used as a power source in the first and third quadrants, as a load in the second and fourth quadrants, and can measure voltage and current in all quadrants. VI sources provide precise voltage and current control, which is crucial for testing the electrical characteristics of semiconductor devices. In traditional SOC testing, VI sources in ATE (Automatic Test Equipment) require relatively low voltages, typically less than 24V. However, with the increasing diversity and functionality of SOC applications, higher voltages are needed from VI sources to meet the testing demands of high-voltage SOCs. VI sources generally have several channels, with each channel consisting of functional units such as a controller, DAC, output stage, voltage sense, current sense, and ADC. Figure 1 As shown, there are generally two existing technical solutions: one is to integrate each functional unit onto a single chip, and the other is to use discrete components to build each functional unit and connect them together. Please see Figure 1 As shown, the present invention is a high-voltage VI source module for SOC testing, comprising: Output stage module: Based on discrete high-voltage power devices, used for four-quadrant operation; In a preferred embodiment of the present invention, the output stage module further includes a power amplification module unit and a mode switching unit. The output stage module adopts a push-pull high-voltage operational amplifier combined with an N-type and a P-type power MOSFET structure to provide bidirectional positive and negative voltage output capability. The mode switching unit is used to switch the voltage source and current source operating modes according to the control signal. Specifically, the output stage module, as the core power output unit of the high-voltage VI source module for SOC testing, is based on discrete high-voltage power devices and realizes the four-quadrant operation required for high-voltage SOC testing to cover the power supply and load simulation requirements of SOC under different test scenarios. The power supply and load simulation requirements specifically include: the first quadrant provides forward high voltage power supply to the SOC and tests forward load characteristics; the second quadrant simulates the SOC as a load absorbing reverse current under forward voltage; the third quadrant provides reverse high voltage power supply to the SOC and tests reverse load characteristics; and the fourth quadrant simulates the SOC as a load absorbing forward current under reverse voltage. At the same time, it solves the defects of traditional integrated chip solutions such as narrow output range and limited thermal power, and adapts to the testing requirements of [24V, 30V] high voltage SOCs. The main topology of the output stage module adopts a composite structure of push-pull high-voltage operational amplifier combined with N-type and P-type power MOSFETs to achieve bidirectional voltage output capability. The push-pull high-voltage operational amplifier is selected with a withstand voltage of ≥40V and an output drive capability of ≥1A to ensure that it can provide a stable drive signal for the subsequent power MOSFETs. The N-type power MOSFET is selected with low on-resistance and high avalanche withstand capability to achieve positive high voltage or high current output. The P-type power MOSFET is selected with complementary parameters matching the N-type to achieve reverse high voltage or high current output. The two work together to enable the bidirectional voltage output range of the output stage module to cover [-30V, 30V] and the bidirectional current output range to cover [-5A, 5A], meeting the positive and negative power supply test requirements of different types of high-voltage SOCs. The power amplifier module is electrically connected to the signal output terminal of the gear shifting unit. Its core function is to receive the amplified analog signal from the gear shifting unit and further enhance the signal's driving capability. Internally, it integrates a high-bandwidth power amplifier chip and a current-limiting protection circuit. This allows it to boost the driving capability of the input analog signal to over 5A to handle sudden high loads that may occur during SOC testing, while also limiting the output current to a set threshold through the current-limiting protection circuit to prevent overload damage to the output stage module due to SOC failure. Simultaneously, the power amplifier module is equipped with a customized heat dissipation component. This component includes an aluminum alloy heat sink with flow channels and high thermal conductivity thermally conductive silicone. The thermally conductive silicone is tightly bonded between the power MOSFET and the heat sink, ensuring that the junction temperature of the power devices does not exceed 125°C when the output stage module is operating at full load, thus preventing thermal runaway from affecting test stability. The mode switching unit is electrically connected to the logic control unit and is used to switch the voltage source and current source operating modes of the output stage module according to the control signals sent by the logic control unit: when receiving the FV mode command, the analog switch inside the mode switching unit turns on the voltage feedback loop, transmitting the output voltage sampling signal of the output stage module to the voltage Sense module of the integrated functional chip, and achieving output voltage stabilization through closed-loop control; when receiving the FI mode command, the analog switch switches to the current feedback loop, transmitting the output current sampling signal of the output stage module to the current Sense module of the integrated functional chip, and achieving output current stabilization through closed-loop control; and the response time of the mode switching unit is ≤1μs, ensuring that there is no output overshoot during mode switching during SOC testing, and avoiding damage to the SOC device under test; Sampling module: voltage sampling unit and current sampling unit, wherein the voltage sampling unit acquires the voltage signal of the output stage module in real time, and the current sampling unit acquires the current signal of the output stage module in real time; Specifically, the sampling module, as the core feedback unit for closed-loop control of the high-voltage VI source module in SOC testing, mainly consists of a voltage sampling unit and a current sampling unit. The two work together to achieve real-time, high-precision acquisition of the output voltage and current of the output stage module, thereby ensuring the stability of the output signal and the reliability of the test data during high-voltage SOC testing. Among them, the voltage sampling unit needs to cover the high-voltage output range of [24V, 30V], and the current sampling unit needs to be adapted to the high-current output scenario of [1A, 5A] to meet the testing requirements of high-voltage devices such as power management SOC and motor drive SOC. In a preferred embodiment of the present invention, the voltage sampling unit includes a high-precision, low-temperature-drift voltage divider resistor network and a voltage follower. The voltage divider resistor network is used to scale the high output voltage, and the voltage follower is used to provide input impedance and low output impedance to achieve signal isolation and impedance matching. Specifically, the voltage divider resistor network consists of two high-voltage precision resistors connected in series. The first resistor is a metal film resistor with a withstand voltage ≥50V, accuracy ≤0.1%, and temperature coefficient ≤25ppm / ℃. The second resistor is a low-resistance resistor with the same accuracy and temperature coefficient. The voltage division ratio is set to 10:1-20:1, which can scale the [24V, 30V] high-voltage signal output from the output stage module to [1.2V, 3V], which perfectly matches the [0V, 3V] input range of the ADC in the integrated function chip. At the same time, the voltage divider resistor network is also connected in parallel with a 1000pF high-frequency compensation capacitor to suppress high-frequency noise in the high-voltage signal and ensure that the ripple of the sampling voltage is ≤5mVrms. The voltage follower uses an operational amplifier with high input impedance and low output impedance. Its input terminal is electrically connected to the midpoint of the voltage divider network, and its output terminal is electrically connected to the input terminal of the voltage Sense module of the integrated function chip. On the one hand, the high input impedance of the voltage follower avoids the destruction of the voltage division ratio of the voltage divider network. On the other hand, the low output impedance achieves matching with the input impedance of the integrated function chip, reducing attenuation and interference during signal transmission. At the same time, it also plays a role in signal isolation, preventing the high voltage signal of the output stage module from impacting the integrated function chip. In a preferred embodiment of the present invention, the current sampling unit further includes a precision sampling resistor and a differential amplifier circuit. The precision sampling resistor is connected in series in the output current path of the output stage module to sense the load current flowing to the device under test. The differential amplifier circuit detects the voltage difference across the precision sampling resistor and outputs a voltage signal proportional to the load current. Specifically, the precision sampling resistor is an alloy resistor with no inductance, high precision, and high power rating. It is connected in series in the output current path of the output stage module. When the load current flows through the resistor, a small voltage difference proportional to the current will be generated across the resistor. The temperature coefficient of the resistor is ≤10ppm / ℃, which can effectively avoid sampling errors caused by temperature changes. The differential amplifier circuit employs an instrumentation amplifier with high common-mode rejection ratio and low input offset voltage. Its two input terminals are electrically connected to the two ends of a precision sampling resistor, and its output terminal is electrically connected to the input terminal of the current Sense module of the integrated functional chip. This circuit can accurately detect the small voltage difference across the sampling resistor and amplify it to the standard range of [0V, 3V]. At the same time, it suppresses the interference of the high voltage signal from the output stage module on the sampling signal, ensuring that the current sampling accuracy is ≤0.1%, providing accurate data support for the current characteristic analysis in SOC testing. Control and Conversion Module: Includes a control unit and a digital-to-analog converter (DAC). The DAC converts digital control signals into analog control signals. The DAC also converts the voltage signal into a digital voltage feedback signal and the current signal into a digital current feedback signal. The control unit adjusts the output of the digital-to-analog converter in real time through a closed-loop control algorithm based on the digital voltage feedback signal and the digital current feedback signal. Specifically, the control and conversion module is the central scheduling part of the SOC test high-voltage VI source module. It is used to receive feedback signals, execute closed-loop control algorithms, and output precise control commands to achieve real-time regulation of the voltage or current of the output stage module. At the same time, it connects the external test system and the internal functional unit to ensure that the entire VI source module operates stably according to the test requirements. This module includes a control unit and a digital-to-analog conversion unit, and works in conjunction with the analog-to-digital conversion unit in the integrated functional chip. The digital-to-analog conversion unit is responsible for converting the digital commands of the control unit into analog control signals, while the ADC of the integrated chip converts the analog voltage or current signals output by the sampling module into digital feedback signals. The control unit, as the core decision-making unit, receives digital voltage feedback signals and digital current feedback signals transmitted by the integrated chip ADC through a digital interface on one end, and sends digital control commands to the digital-to-analog converter unit through a similar interface on the other end. After receiving the commands, the digital-to-analog converter unit converts them into corresponding analog control signals and transmits them to the gear shifting unit. After amplification, the signal drives the output stage module to output the target high voltage or high current. The control unit uses a built-in closed-loop control algorithm to compare the deviation between the target output parameters and the digital feedback parameters in real time, and dynamically adjusts the output commands of the digital-to-analog converter unit until the deviation is controlled within the required test accuracy range. In a preferred embodiment of the present invention, the control unit is further configured to receive a control signal, which is a digital or analog signal used for switching operating states. In a preferred embodiment of the present invention, the digital-to-analog conversion unit adopts a high-precision digital-to-analog converter with a resolution greater than 16 bits, and the output analog voltage range of the high-precision digital-to-analog converter is [-10V, 10V]. After being amplified by the output stage module, the analog voltage range is [-48V, 48V]. In a preferred embodiment of the present invention, the control unit is based on an FPGA or an ARM microcontroller with a floating-point arithmetic unit, and has a built-in digital PID controller to correct the output value of the digital-to-analog converter in real time according to the digital voltage feedback signal and the digital current feedback signal. In a preferred embodiment of the present invention, the digital-to-analog conversion unit is based on a sampling analog-to-digital converter, which includes several sampling channels. Each sampling channel simultaneously acquires digital voltage feedback signals and digital current feedback signals, and communicates with the control unit via a digital serial interface.

[0019] The purpose of this invention is to provide a high-voltage VI source module for SOC testing, which consists of an integrated control module, a range switching circuit and an output stage. It has the advantages of wide output range, easy heat dissipation, flexible design improvement, low debugging difficulty and high integration.

[0020] This invention can achieve a high-bandwidth high-voltage output and improve the output slew rate.

[0021] In practical applications, most design requirements involve improving and upgrading the output voltage and current, which translates to improving and upgrading the output stage. If low-power functional units such as the DAC, voltage sense, current sense, and ADC can be integrated together, while using discrete components to build the output stage, the advantages of both existing solutions can be combined, avoiding their disadvantages. However, the output range of integrated functional unit chips is often small, while the output stage built with discrete components has a large output range. Therefore, a range selection module is needed to amplify the signal from the integrated chip to the output stage and attenuate the output signal to the integrated chip. To improve the output slew rate, this invention uses a multiplier for the DAC, and current-mode operational amplifiers are used in both the voltage sense and current sense.

[0022] The VI source of this invention consists of functional units such as controller, DAC, output stage, range selector, voltage sense, current sense and ADC.

[0023] Controller: The logic control unit of the board, used to send control commands to the integrated chip and gear selection.

[0024] Integrated chip: It integrates functional units such as DAC, voltage sense, current sense and ADC to complete loop control and digital-to-analog and analog-to-digital conversion.

[0025] Gear selection: The circuit is built using op-amps, analog switches and multiplexers. Gear selection 2 is used to amplify the signal from the integrated chip to the output stage, while gear selections 1 and 3 are used to attenuate the output signal to the operating voltage range of the integrated chip.

[0026] By leveraging the fast response characteristics of the multiplication DAC and current operational amplifier, the loop bandwidth is increased and the output slew rate is improved, achieving a large loop bandwidth regardless of the voltage level.

[0027] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the invention.

Claims

1. A high-voltage VI source module for SOC testing, characterized in that, include: Output stage module: Based on discrete high-voltage power devices, used for four-quadrant operation; Sampling module: voltage sampling unit and current sampling unit, wherein the voltage sampling unit acquires the voltage signal of the output stage module in real time, and the current sampling unit acquires the current signal of the output stage module in real time; Control and Conversion Module: Includes a control unit and a digital-to-analog converter (DAC). The DAC converts digital control signals into analog control signals. The DAC also converts the voltage signal into a digital voltage feedback signal and the current signal into a digital current feedback signal. The control unit adjusts the output of the digital-to-analog converter in real time based on the digital voltage feedback signal and the digital current feedback signal through a closed-loop control algorithm.

2. The high-voltage VI source module for SOC testing according to claim 1, characterized in that, The control unit is also used to receive control signals, which are digital or analog signals used for switching operating states.

3. The high-voltage VI source module for SOC testing according to claim 1, characterized in that, The output stage module also includes a power amplifier module and a mode switching unit. The output stage module adopts a push-pull high-voltage operational amplifier combined with N-type and P-type power MOSFET structures to provide bidirectional voltage output capability. The mode switching unit is used to switch the voltage source and current source operating modes according to the control signal.

4. The high-voltage VI source module for SOC testing according to claim 1, characterized in that, The voltage sampling unit includes a high-precision, low-temperature-drift voltage divider resistor network and a voltage follower. The voltage divider resistor network is used to scale the high output voltage, and the voltage follower is used to provide input impedance and low output impedance to achieve signal isolation and impedance matching.

5. The high-voltage VI source module for SOC testing according to claim 1, characterized in that, The current sampling unit further includes a precision sampling resistor and a differential amplifier circuit. The precision sampling resistor is connected in series in the output current path of the output stage module to sense the load current flowing to the device under test. The differential amplifier circuit detects the voltage difference across the precision sampling resistor and outputs a voltage signal proportional to the load current.

6. The high-voltage VI source module for SOC testing according to claim 1, characterized in that, The digital-to-analog converter unit uses a high-precision digital-to-analog converter with a resolution greater than 16 bits. The output analog voltage range of the high-precision digital-to-analog converter is [-10V, 10V], and the analog voltage range is amplified to [-48V, 48V] by the output stage module.

7. The high-voltage VI source module for SOC testing according to claim 1, characterized in that, The control unit is based on an FPGA or an ARM microcontroller with a floating-point arithmetic unit, and has a built-in digital PID controller. It corrects the output value of the digital-to-analog converter in real time based on the digital voltage feedback signal and the digital current feedback signal.

8. A high-voltage VI source module for SOC testing according to claim 1, characterized in that, The digital-to-analog conversion unit is based on a sampling analog-to-digital converter, which includes several sampling channels. Each sampling channel simultaneously acquires digital voltage feedback signals and digital current feedback signals, and communicates with the control unit via a digital serial interface.

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