Chip aging test system

Abstract

The chip aging test system is characterized in that: the signal isolation circuit is arranged between the control circuit and the heating circuit; the first photoelectric coupler in the signal isolation circuit is used to convert the first control signal output by the control circuit into a first optical signal, and then convert the first optical signal into a second control signal output to the heating circuit, so as to control the on-off of the heating switch to reach a corresponding heating power; the electrical signal isolation between the control circuit and the heating circuit is realized; the control circuit is grounded through the first grounding line, and the heating circuit is grounded through the second grounding line, so that the grounding lines of the heating circuit and the control circuit are independent of each other and do not interfere with each other; in the case that the heating power is high and the current of the heating circuit output signal is large, the noise generated by the heating circuit output signal can reduce the interference on the control circuit, thereby improving the accuracy of the chip aging test.

Description

Technical Field

[0001] This disclosure relates to automated testing techniques, and in particular to a chip aging test system. Background Technology

[0002] Chip aging tests are used to assess chip reliability. They accelerate the aging process of new chips by simulating extreme environments such as high temperature, high pressure, and high current, identifying chips that fail quickly and ensuring the stability and lifespan of chips leaving the factory. The principle behind high-temperature accelerated aging is to increase the chemical reaction rate by raising the temperature, thereby shortening the chip's lifespan. During high-temperature aging tests, a high-power heating system capable of rapidly responding to test signals is required to ensure temperature stability during the aging process.

[0003] The temperature control system for chip aging tests typically consists of a heating circuit (heating rod, heating ceramic plate, etc.), a cooling system (liquid cooling system, air cooling system, etc.), and a temperature sensor. The heating circuit must have sufficient output power and a fast enough response to accurately control the temperature of the chip under test within a specific temperature range.

[0004] In related technologies, the output power of a single heating rod is typically tens of watts, and the power supply voltage and current of a single-channel heating circuit are relatively weak (e.g., voltage is typically less than 24V, and current is typically less than 3A), thus the design requirements for the control circuit are relatively simple. However, in test scenarios where the output power consumption of a single-channel heating circuit is required to reach hundreds of watts, the noise generated by the pulse width modulation (PWM) signal output by the heating circuit can cause strong interference to the control circuit, thereby affecting the temperature stability of the chip under test. Utility Model Content

[0005] This disclosure provides a chip aging test system that can reduce the interference of noise generated by the output signal of the heating circuit on the control circuit and improve the accuracy of chip aging test.

[0006] In one aspect of this disclosure, a chip aging test system is provided, including a control circuit, a signal isolation circuit, and a heating circuit. The output terminal of the control circuit is connected to the input terminal of the signal isolation circuit, and the input terminal of the heating circuit is connected to the output terminal of the signal isolation circuit. The control circuit is grounded through a first grounding line, and the heating circuit is grounded through a second grounding line. The control circuit is used to output a first control signal, wherein the first control signal represents the duty cycle of the output signal of the heating circuit; The signal isolation circuit is provided with a first optocoupler, which is used to convert the received first control signal into a first optical signal through a light-emitting device, and to convert the first optical signal into a second control signal through a photosensitive device. The heating circuit is used to receive the second control signal and control the on / off state of the heating switch based on the second control signal.

[0007] Optionally, in the signal isolation circuit, the output terminal of the first optocoupler is connected to the first output pull-up power supply through a first output pull-up resistor; When the first optocoupler is turned on, the second control signal output by the signal isolation circuit is at a low level; when the first optocoupler is turned off, the second control signal output by the signal isolation circuit through the first output pull-up resistor is at a high level. Wherein, the resistance value of the first output pull-up resistor is less than the preset resistance value, so that when the first optocoupler is turned off, the output current of the signal isolation circuit is greater than the preset current value.

[0008] Optionally, the signal isolation circuit includes a heating feedback signal isolation circuit, the input terminal of which is connected to the output terminal of the heating switch in the heating circuit, and the output terminal of which is connected to the control circuit. The heating feedback signal isolation circuit is provided with a second optocoupler. The second optocoupler is used to convert the received heating output signal into a second light signal through a light-emitting device, and to convert the second light signal into a heating feedback signal through a photosensitive device. The control circuit is used to receive the heating feedback signal and generate a heating circuit monitoring result by comparing the waveform of the heating feedback signal with the waveform of the control signal. The monitoring results of the heating circuit include one of the following: When the duty cycle of the heating feedback signal is the same as the duty cycle of the first control signal, the monitoring result of the heating circuit is that the heating switch is in normal condition. When the duty cycle of the heating feedback signal is different from the duty cycle of the first control signal, the heating circuit monitoring result indicates that the heating switch is in an abnormal state. Specifically, when the heating feedback signal remains at a low level for a duration exceeding a first preset duration, the heating circuit monitoring result indicates that the heating switch is short-circuited. When the heating feedback signal remains at a high level for a duration exceeding a second preset duration, the heating circuit monitoring result indicates that the heating switch is open-circuited.

[0009] Optionally, the input terminal of the heating feedback signal isolation circuit is provided with a first voltage divider resistor and a second voltage divider resistor; The first voltage divider resistor is connected in series with the second voltage divider resistor, the anode of the light-emitting device in the second optocoupler is connected to the voltage divider point between the first voltage divider resistor and the second voltage divider resistor, and the light-emitting device is connected in parallel with the second voltage divider resistor; Specifically, when the heating output signal causes the voltage across the emitter in the second optocoupler to be higher than the optocoupler conduction voltage parameter, the second optocoupler is turned on; when the heating output signal causes the voltage across the emitter in the second optocoupler to be lower than the optocoupler conduction voltage parameter, the second optocoupler is turned off.

[0010] Optionally, in the heating feedback signal isolation circuit, the output terminal of the second optocoupler is connected to the second output pull-up power supply through a second output pull-up resistor; When the heating output signal is high, the second optocoupler is turned on, and the heating feedback signal output by the heating feedback signal isolation circuit is low. When the heating output signal is low, the second optocoupler is turned off, and the heating feedback signal output by the heating feedback signal isolation circuit is high.

[0011] Optionally, the chip aging test system further includes a power switch and a power monitoring circuit, wherein the two ends of the power switch are respectively connected to the power supply of the heating circuit and the heating circuit; The power monitoring circuit includes at least one monitoring chip and at least two parallel sampling resistors. The two ends of the sampling resistors are respectively connected to the output terminal of the power switch circuit and the input terminal of the heating circuit. The monitoring chip is used to detect the actual operating voltage value of the heating circuit and the actual operating current value of the heating circuit through the sampling resistors. When the actual operating voltage value is in an abnormal voltage range or the actual operating current value is in an abnormal current range, the monitoring chip sends an interrupt signal to the control circuit. The control circuit is used to send a switch-off signal to the power switch when the interrupt signal is received, so as to control the power switch to turn off.

[0012] Optionally, the signal isolation circuit includes a power monitoring signal isolation circuit, wherein the input terminal of the power monitoring signal isolation circuit is connected to the output terminal of the power monitoring circuit, and the output terminal of the power monitoring signal isolation circuit is connected to the control circuit; The power monitoring signal isolation circuit is equipped with an isolation chip, which is used to isolate the clock signal sent by the control circuit to the monitoring chip and the bidirectional digital signal between the control circuit and the monitoring chip. or, The power monitoring signal isolation circuit is provided with at least three third optocouplers, which are used to isolate the clock signal sent by the control circuit to the monitoring chip and the bidirectional digital signal between the control circuit and the monitoring chip.

[0013] Optionally, the heating circuit includes a heating drive circuit and a heating switch circuit; The heating drive circuit includes a push-pull circuit composed of a first transistor and a second transistor. The push-pull circuit is used to amplify the input current and output a heating drive current to the heating switch circuit. The heating switch circuit includes the heating switch, which is used to close when the received second control signal is high level to control the heating rod to be energized and heated, and to close when the received second control signal is low level to control the heating rod to stop heating.

[0014] Optionally, the heating switch is a MOSFET switch, and the heating switch circuit further includes a drive adjustment circuit and an initial state setting circuit; The drive adjustment circuit includes a drive adjustment resistor, which is connected in series between the signal isolation circuit and the gate of the MOS transistor switch. The initial state setting circuit includes an initial state setting resistor, the two ends of which are connected to the gate and source of the MOS transistor switch, respectively, and is used to control the MOS transistor switch to be in the off state when the heating switch circuit is powered on.

[0015] Optionally, the heating switch is a MOSFET switch, and the heating switch circuit further includes a filter circuit and a surge absorption circuit; The filter circuit is equipped with a ceramic energy storage capacitor, which is connected to the input terminal of the heating switch. The ceramic energy storage capacitor is used to provide instantaneous current when the heating switch is closed and to absorb the energy released by parasitic inductance when the heating switch is turned off. The surge absorption circuit includes a surge absorption capacitor and a surge absorption resistor connected in series. The surge absorption circuit is connected in parallel with the MOSFET and is used to absorb the surge impact energy generated by the surge pulse voltage. The surge absorption capacitor is connected to the drain of the MOSFET switch, and the surge absorption resistor is connected to the source of the MOSFET switch.

[0016] Based on the embodiments of this disclosure, by setting a signal isolation circuit between the control circuit and the heating circuit, the first control signal output by the control circuit is converted into a first optical signal by the first optocoupler in the signal isolation circuit, and then the first optical signal is converted into a second control signal and output to the heating circuit to control the heating switch to achieve the corresponding heating power. This achieves electrical signal isolation between the control circuit and the heating circuit. At the same time, the control circuit is grounded through the first grounding line, and the heating circuit is grounded through the second grounding line, so that the grounding lines of the heating circuit and the control circuit are independent of each other and do not interfere with each other. When the heating power is high and the current of the heating circuit output signal is large, the noise generated by the heating circuit output signal can be reduced to interfere with the control circuit, thereby improving the accuracy of chip aging test.

[0017] The technical solutions of this disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0019] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein: Figure 1 A schematic diagram of the structure of a chip aging test system provided in an exemplary embodiment of this disclosure; Figure 2 A schematic diagram of an FPGA chip in a control circuit provided for an exemplary embodiment of this disclosure; Figure 3 A schematic diagram of a signal isolation circuit provided for an exemplary embodiment of this disclosure; Figure 4 A schematic diagram of the structure of a chip aging test system provided as another exemplary embodiment of this disclosure; Figure 5 A schematic diagram of a heating feedback signal isolation circuit provided for an exemplary embodiment of this disclosure; Figure 6 A schematic diagram of the structure of a chip aging test system provided as another exemplary embodiment of this disclosure; Figure 7 A schematic diagram of a power monitoring circuit provided for an exemplary embodiment of this disclosure; Figure 8 A schematic diagram of a power monitoring signal isolation circuit provided for an exemplary embodiment of this disclosure; Figure 9 A schematic diagram of a push-pull circuit provided for an exemplary embodiment of this disclosure. Figure 10A graph showing the relationship between transistor gain and collector current provided for an exemplary embodiment of this disclosure; Figure 11 This is a schematic diagram of a heating switch circuit provided for an exemplary embodiment of the present disclosure.

[0020] The attached figures are labeled as follows: Control circuit - 101; Signal isolation circuit - 102; Heating circuit - 103; Power switch - 104; Power monitoring circuit - 105; Heating circuit power supply - 106; Push-pull circuit - 901; Heating switch - 1101; Drive adjustment circuit - 1102; Initial state setting circuit - 1103; Filtering circuit - 1104; Surge absorption circuit - 1105; First grounding line - 1011; Control signal isolation circuit - 1021; Heating feedback signal isolation circuit - 1022; Power monitoring signal isolation circuit - 1023; Second grounding line - 1031. Detailed Implementation

[0021] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0022] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of this disclosure are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0023] It should also be understood that in the embodiments disclosed herein, "a plurality of" may refer to two or more, and "at least one" may refer to one, two or more.

[0024] It should also be understood that any component, data or structure mentioned in the embodiments of this disclosure can generally be understood as one or more unless expressly defined or given to the contrary in the context.

[0025] Furthermore, the term "and / or" in this disclosure is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this disclosure generally indicates that the preceding and following related objects have an "or" relationship.

[0026] It should also be understood that the description of the various embodiments in this disclosure emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0027] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0028] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0029] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0031] Figure 1 This is a schematic diagram of a chip aging test system provided in an exemplary embodiment of the present disclosure. The chip aging test system includes a control circuit 101, a signal isolation circuit 102, and a heating circuit 103. The output terminal of the control circuit 101 is connected to the input terminal of the signal isolation circuit 102, and the input terminal of the heating circuit 103 is connected to the output terminal of the signal isolation circuit 102. The control circuit 101 is grounded through a first grounding line 1011, and the heating circuit 103 is grounded through a second grounding line 1031.

[0032] Specifically, control circuit 101 outputs a first control signal, which characterizes the duty cycle of the output signal of the heating circuit. Illustratively, the output signal of heating circuit 103 is a pulse-width modulation (PWM) signal. The duty cycle refers to the ratio of the duration of the high level within one pulse cycle to the total duration of the cycle. By changing the duty cycle of this PWM signal, different heating powers can be output equivalently. Control circuit 101 can be equipped with devices such as Complex Programmable Logic Devices (CPLDs), Field Programmable Gate Arrays (FPGAs), and Microcontroller Units (MCUs) to generate the first control signal based on the chip aging test program. Illustratively... Figure 2 A schematic diagram of an FPGA in a control circuit 101 is shown. The FPGA can be connected to the signal isolation circuit 102 through corresponding pins, output a first control signal, and monitor the heating circuit 103 and the power supply for abnormalities by receiving corresponding feedback signals.

[0033] The signal isolation circuit 102 includes a first optocoupler. This first optocoupler converts the received first control signal into a first optical signal via a light-emitting device, and then converts the first optical signal into a second control signal via a photosensitive device. When the input terminal of the first optocoupler receives an electrical signal (i.e., the first control signal output by the control circuit 101), the light-emitting device (e.g., a light-emitting diode) converts the electrical signal into an optical signal (hereinafter referred to as the first optical signal). The photosensitive device (e.g., a photodiode or phototransistor) receives the first optical signal and generates an electrical signal, thereby outputting the second control signal. This achieves the disconnection of the electrical connection between the control circuit 101 and the heating circuit 103 using the optical signal as a medium, isolating the control circuit 101 and the heating circuit 103 into two independent circuits. Simultaneously, the control circuit 101 is grounded through a first grounding line 1011, and the heating circuit 103 is grounded through a second grounding line 1031, achieving grounding line isolation between the control circuit 101 and the heating circuit 103. This avoids interference from the output signal of the heating circuit 103 to the control circuit 101 when they share a common power supply system.

[0034] The heating circuit 103 is used to receive the second control signal and control the on / off state of the heating switch based on the second control signal.

[0035] The heating circuit 103 controls the on / off state of the heating switch based on the second control signal. For example, when the second control signal is high, it controls the heating switch to close so that the heating device is powered on and heated. When the second control signal is low, it controls the heating switch to turn off so that the heating device is powered off.

[0036] Based on the embodiments of this disclosure, by setting a signal isolation circuit between the control circuit and the heating circuit, the first control signal output by the control circuit is converted into a first optical signal by the first optocoupler in the signal isolation circuit, and then the first optical signal is converted into a second control signal and output to the heating circuit to control the heating switch to achieve the corresponding heating power. This achieves electrical signal isolation between the control circuit and the heating circuit. At the same time, the control circuit is grounded through the first grounding line, and the heating circuit is grounded through the second grounding line, so that the grounding lines of the heating circuit and the control circuit are independent of each other and do not interfere with each other. When the heating power is high and the current of the heating circuit output signal is large, the noise generated by the heating circuit output signal can be reduced to interfere with the control circuit, thereby improving the accuracy of chip aging test.

[0037] In one possible implementation, in the signal isolation circuit 102, the output terminal of the first optocoupler is connected to a first output pull-up power supply through a first output pull-up resistor. When the first optocoupler is on, the second control signal output by the signal isolation circuit 102 is at a low level; when the first optocoupler is off, the second control signal output by the signal isolation circuit 102 through the first output pull-up resistor is at a high level. The resistance value of the first output pull-up resistor is less than a preset resistance value, so that the output current of the signal isolation circuit 102 is greater than a preset current value when the first optocoupler is off.

[0038] The first output pull-up power supply is used to power the photosensitive device in the first optocoupler. When the first control signal is high, the light-emitting device in the first optocoupler generates a first optical signal, the first optocoupler conducts and generates current, and the output of the signal isolation circuit 102 is pulled low. When the first control signal is low, the light-emitting device in the first optocoupler does not generate a first optical signal, the first optocoupler is cut off, the first output pull-up power supply pulls the output of the signal isolation circuit 102 high, and the output current of the signal isolation circuit 102 can be controlled by setting a reasonable first output pull-up resistor. For example, since the current output by the signal isolation circuit 102 is ultimately used to drive the heating switch, if the heating switch opens and closes slowly or the on-resistance of the heating switch is too high, it will lead to high losses in the heating switch itself, and may even cause the heating switch to overheat and be damaged. Therefore, setting a small output pull-up resistor to amplify the output current can improve the driving capability of the signal isolation circuit 102, improve the response speed of the heating switch, and thus reduce the losses of the heating switch. At the same time, the resistance of the first output pull-up resistor is greater than the preset minimum resistance to avoid excessive power consumption of the first output pull-up resistor due to excessive output current.

[0039] Indicative Figure 3 A schematic diagram of a signal isolation circuit 102 is shown. As shown, the output of the first optocoupler U27C is connected to a 48V first output pull-up power supply through four first output pull-up resistors R498, R499, R504, and R508. The forward voltage (VF) of the first optocoupler U27C is 1.2V, and the high level of the first control signal FPGA_HEATER_PWM output by the control circuit 101 is 3.3V. When the first optocoupler U27C is turned on, the input current of the signal isolation circuit 102 is (3.3V-1.2V) / 200Ω=10.5mA. The first output pull-up resistors are four 4KΩ resistors in 0805 packages (connected in series and then in parallel as shown in the diagram, with an equivalent resistance of 4.02KΩ). When the first optocoupler is turned off, a 48V pull-up drive capability is achieved, and the output current is approximately 11.94mA.

[0040] In one possible implementation, such as Figure 4 As shown, in the above embodiment, the first optocoupler, the first output pull-up resistor, and the first output pull-up power supply constitute the control signal isolation circuit 1021 in the signal isolation circuit 102. The signal isolation circuit 102 also includes a heating feedback signal isolation circuit 1022. The input terminal of the heating feedback signal isolation circuit 1022 is connected to the output terminal of the heating switch in the heating circuit 103, and the output terminal of the heating feedback signal isolation circuit 1022 is connected to the control circuit 101. If a circuit failure occurs in a high-power circuit, it can easily lead to the burnout of the test board and the chip under test. The heating feedback signal isolation circuit 1022 in this embodiment can feed back the heating output signal output by the heating circuit 103 to the control circuit 101, so that the control circuit 101 can monitor whether the output signal of the heating circuit 103 is normal, and realize the abnormal monitoring of the heating circuit.

[0041] Optionally, the heating feedback signal isolation circuit 1022 includes a second optocoupler. This second optocoupler converts the received heating output signal into a second optical signal via a light-emitting device, and then converts the second optical signal into a heating feedback signal via a photosensitive device. While feeding back the heating output signal to the control circuit 101, the heating feedback signal isolation circuit 1022 uses an optocoupler to isolate the heating output signal, thereby ensuring electrical isolation between the control circuit 101 and the heating circuit 103.

[0042] The control circuit 101 is used to receive the heating feedback signal and generate a heating circuit monitoring result by comparing the waveform of the heating feedback signal with the waveform of the control signal; the heating circuit monitoring result includes one of the following: When the duty cycle of the heating feedback signal is the same as the duty cycle of the first control signal, the heating circuit monitoring result indicates that the heating switch is in normal condition. When the duty cycle of the heating feedback signal is different from the duty cycle of the first control signal, the heating circuit monitoring result is that the heating switch is in an abnormal state; specifically, when the heating feedback signal is continuously at a low level for a duration exceeding the first preset duration, the heating circuit monitoring result is that the heating switch is short-circuited; when the heating feedback signal is continuously at a high level for a duration exceeding the second preset duration, the heating circuit monitoring result is that the heating switch is open-circuited.

[0043] Since the high and low levels of the first control signal and the second control signal are opposite, i.e., the high and low levels of the first control signal and the heating output signal are opposite, after the heating output signal undergoes photoelectric signal conversion through the second optocoupler, the high and low levels of the heating output signal and the heating feedback signal are again opposite. Therefore, under normal circumstances, the duty cycles of the first control signal and the heating feedback signal should be consistent. When the duty cycle of the heating feedback signal is different from that of the first control signal, the heating circuit monitoring result indicates an abnormal heating switch state. The control circuit 101 can stop outputting the first control signal or directly control the power switch to turn off, and generate an abnormal alarm message.

[0044] In one possible implementation, the input terminal of the heating feedback signal isolation circuit 1022 is provided with a first voltage divider resistor and a second voltage divider resistor; the first voltage divider resistor and the second voltage divider resistor are connected in series, the anode of the light-emitting device in the second optocoupler is connected to the voltage divider point between the first voltage divider resistor and the second voltage divider resistor, and the light-emitting device is connected in parallel with the second voltage divider resistor.

[0045] Specifically, when the heating output signal causes the voltage across the emitter in the second optocoupler to exceed the optocoupler's on-state voltage parameter, the second optocoupler is turned on; when the heating output signal causes the voltage across the emitter to fall below the optocoupler's on-state voltage parameter, the second optocoupler is turned off. By setting a voltage divider resistor, the heating output signal does not need to drop below the optocoupler's on-state voltage parameter to turn off the second optocoupler. This prevents situations where a high-power heating circuit's output signal is too low to trigger the second optocoupler's turn-off, leading to the control circuit 101 failing to detect output shutdown or resulting in incorrect detection results.

[0046] Indicative Figure 5 A schematic diagram of a heating feedback signal isolation circuit 1022 is shown. (As shown) Figure 5 As shown, the optocoupler turn-on voltage parameter VE of the second optocoupler U30A is 1.2V. The heating output signal HEATER_CTRL is divided by a 30KΩ first voltage divider resistor R672 and a 2KΩ second voltage divider resistor R1235. When the voltage across the second optocoupler U30A is higher than the optocoupler turn-on voltage parameter of 1.2V, the heating output signal voltage is 20V. That is, as long as the heating output signal voltage is lower than 20V, the second optocoupler U30A will be turned off, thus adjusting the threshold for judging the high and low levels of the heating output signal. If no voltage divider resistor is set, the heating output signal voltage needs to be lower than 1.2V for the control circuit 101 to detect a low level. However, the low level of the heating output signal from a high-power heating circuit is usually higher, which can easily lead to false detection.

[0047] In one possible implementation, the output of the second optocoupler in the heating feedback signal isolation circuit is connected to a second output pull-up power supply via a second output pull-up resistor. When the heating output signal is high, the second optocoupler is turned on, and the heating feedback signal output by the heating feedback signal isolation circuit is low. When the heating output signal is low, the second optocoupler is turned off, and the heating feedback signal output by the heating feedback signal isolation circuit is high.

[0048] Indicative, such as Figure 5 As shown, the resistance values ​​of the first voltage divider resistor, the second voltage divider resistor, and the second output pull-up resistor need to be matched. Figure 5 The second output pull-up power supply shown is 3.3V. The second output pull-up resistor is composed of a 4.7KΩ resistor R668 and a 100Ω resistor R673 connected in series, with an equivalent resistance of 4.8KΩ. Therefore, the output drive current of the second optocoupler is approximately 0.7mA. The current transfer ratio (CTR) parameter of the second optocoupler is 50%~60%, so the input current of the second optocoupler is approximately 0.11mA~1.4mA. Based on this current range and the voltage value of the output signal of the heating circuit, the appropriate voltage divider resistor value can be calculated.

[0049] Based on the embodiments of this disclosure, by setting a voltage divider resistor at the input terminal of the heating feedback signal isolation circuit 1022, the judgment threshold for high and low levels of the heating output signal is improved, which can improve the accuracy of heating circuit monitoring and avoid false detection caused by low level not being recognized.

[0050] In one possible implementation, such as Figure 6 As shown, the chip aging test system also includes a power switch 104 and a power monitoring circuit 105. The two ends of the power switch 104 are connected to the heating circuit power supply 106 and the heating circuit 103, respectively.

[0051] Indicative, such as Figure 7As shown, the power monitoring circuit 105 includes at least one monitoring chip and at least two parallel sampling resistors (R729 and R731). The two ends of the sampling resistors are connected to the output terminal of the power switch circuit and the input terminal of the heating circuit 103, respectively. The monitoring chip is used to detect the actual operating voltage value of the heating circuit 103 and the actual operating current value of the heating circuit 103 through the sampling resistors. For example, it can directly detect the voltage across the heating circuit 103 and calculate the actual operating current value of the heating circuit 103 based on the voltage across the sampling resistors and the resistance value of the sampling resistors. When the actual operating voltage value or the actual operating current value falls within an abnormal voltage range or an abnormal current range, it sends an interrupt signal to the control circuit 101. Upon receiving the interrupt signal, the control circuit 101 sends a switch-off signal to the power switch 104 to control the power switch 104 to turn off. The monitoring chip sends the interrupt signal to the control circuit 101 through the Inter-Integrated Circuit (IIC) bus interface and the IIC bus. Simultaneously, the control circuit 101 can send the upper and lower threshold values ​​corresponding to the abnormal current range to the monitoring chip through the IIC bus.

[0052] Optionally, when there is at least one heating circuit 103, a monitoring chip can be set for each heating circuit 103, or a monitoring chip can be set for each heating circuit 103 corresponding to each chip under test. This embodiment of the present disclosure does not limit the correspondence between the monitoring chip and the heating circuit 103.

[0053] In one possible implementation, such as Figure 6 As shown, the signal isolation circuit 102 also includes a power monitoring signal isolation circuit 1023. The input terminal of the power monitoring signal isolation circuit 1023 is connected to the output terminal of the power monitoring circuit 105, and the output terminal of the power monitoring signal isolation circuit 1023 is connected to the control circuit 101.

[0054] The power monitoring signal isolation circuit 1023 can employ an isolation chip (such as an IIC isolation chip) or an optocoupler for electrical signal isolation. Specifically, the power monitoring signal isolation circuit includes an isolation chip to isolate the clock signal sent from the control circuit 101 to the monitoring chip, as well as the bidirectional digital signals between the control circuit 101 and the monitoring chip; or, the power monitoring signal isolation circuit includes at least three third optocouplers, which are used to isolate the clock signal sent from the control circuit 101 to the monitoring chip, as well as the bidirectional digital signals between the control circuit 101 and the monitoring chip. The bidirectional digital signals include an interrupt signal sent from the monitoring chip to the control circuit 101 and a threshold adjustment signal sent from the control circuit 101 to the monitoring chip (a digital signal used to update the upper and lower threshold values ​​corresponding to the abnormal current value range).

[0055] Indicative Figure 8 A schematic diagram of a power monitoring signal isolation circuit 1023 that uses optocouplers to achieve electrical signal isolation is shown. Figure 8 The three isolation circuits, from top to bottom, are used to isolate the clock signal sent from the control circuit 101 to the monitoring chip, the digital signal sent from the control circuit 101 to the monitoring chip, and the digital signal sent from the monitoring chip to the control circuit 101, respectively.

[0056] Based on the embodiments of this disclosure, by setting up a power monitoring circuit 105, the working voltage and working current of the high-power heating circuit are monitored. When the actual working voltage value is in the abnormal voltage range or the actual working current value is in the abnormal current range, the power switch is controlled to be turned off to avoid damage to the chip under test due to circuit failure. At the same time, a power monitoring signal isolation circuit 1023 is set between the power monitoring circuit 105 and the control circuit 101 to ensure electrical isolation between the control circuit 101, the power monitoring circuit 105, and the heating circuit 103.

[0057] In one possible implementation, the heating circuit 103 includes a heating drive circuit and a heating switch circuit.

[0058] The heating drive circuit includes a push-pull circuit composed of a first transistor and a second transistor. The push-pull circuit amplifies the input current and outputs the heating drive current to the heating switch circuit. (Illustrative example) Figure 9 A schematic diagram of a push-pull circuit is shown. This push-pull circuit 901 includes an NPN transistor T12 and a PNP transistor T15. The relationship between the transistor's gain hFE and the collector current Ic is as follows: Figure 10 As shown, the maximum input current Ib of the push-pull circuit is approximately 2mA, and the maximum output current Ic of the push-pull circuit is approximately 140mA.

[0059] The heating switch circuit includes a heating switch, which is used to close when the received second control signal is high level to control the heating rod to be energized and heated, and to close when the received second control signal is low level to control the heating rod to stop heating.

[0060] Optional, Figure 11A schematic diagram of a heating switch circuit is shown, wherein the heating switch 1101 is a MOS transistor switch. The heating switch circuit also includes a drive adjustment circuit 1102 and an initial state setting circuit 1103. Indicatively, since the heating switch 1101 turns on with a negative voltage Vgs (i.e., the voltage between the gate G and the source S), a PMOS transistor switch is selected as the heating switch 1101. When selecting the heating switch 1101, consideration should be given to choosing a model with low on-resistance, low parasitic capacitance, high withstand voltage (e.g., withstand voltage greater than 48V), and strong drain current Id (e.g., supporting an output current of over 30A). Low on-resistance and low parasitic capacitance can reduce the conduction loss and switching loss of the heating switch 1101.

[0061] The drive regulation circuit 1102 includes a drive regulation resistor connected in series between the signal isolation circuit 102 and the gate of the MOSFET switch to reduce gate oscillations generated by the gate of the MOSFET switch. Since the parasitic inductance of the MOSFET switch and the common-gate amplifier may generate LC oscillations, increasing the drive regulation resistor (e.g., a 33Ω resistor) can provide damping for the heating circuit 103 and reduce Vgs oscillations.

[0062] The initial state setting circuit 1103 includes an initial state setting resistor, whose two ends are connected to the gate and source of the MOSFET switch, respectively. This resistor is used to control the MOSFET switch to be in the off state when the heating switch circuit is powered on. By setting an initial state setting resistor (e.g., an 11KΩ resistor) between the gate and source of the MOSFET switch, a default state can be set when the circuit is uncontrollable during power-on. This pulls the gate (G) of the MOSFET switch up to the source (S) through the initial state setting resistor, ensuring that the voltage between the gate and source is consistent during power-on and power-off processes. This keeps the MOSFET switch in the off state during power-on and prevents abnormal power output from the MOSFET switch.

[0063] In addition, the heating switch circuit also includes a filter circuit 1104 and a surge absorption circuit 1105. The filter circuit 1104 contains a ceramic energy storage capacitor connected to the input terminal of the heating switch 1101. This capacitor provides instantaneous current when the heating switch 1101 is closed and absorbs energy released by parasitic inductance when the heating switch 1101 is turned off. During high-speed switching, the MOSFET switch has high requirements for the instantaneous current changes of the input power supply. Therefore, a sufficiently large ceramic energy storage capacitor needs to be installed at the input terminal of the MOSFET switch to meet the high current demand of the heating rod at the moment the MOSFET switch is turned on, and to absorb the surge energy caused by parasitic inductance at the moment the MOSFET switch is turned off.

[0064] The surge absorption circuit 1105 includes a surge absorption capacitor and a surge absorption resistor connected in series. The circuit is connected in parallel with the MOSFET switch to absorb the surge energy generated by surge pulse voltages. The surge absorption capacitor is connected to the drain of the MOSFET switch, and the surge absorption resistor is connected to the source of the MOSFET switch. Parasitic inductance exists in the drain or source circuit of the MOSFET switch. A surge pulse voltage may appear at the drain and source terminals when the MOSFET switch is turned off. If this surge pulse voltage exceeds the maximum allowable voltage of the MOSFET switch, it will damage the MOSFET switch. Therefore, a μF capacitor and a KΩ resistor are added between the drain and source terminals to absorb the surge energy. The capacitance value of the surge absorption capacitor and the resistance value of the surge absorption resistor can be adjusted according to actual testing requirements.

[0065] Based on the embodiments of this disclosure, by setting a drive adjustment circuit 1102, an initial state setting circuit 1103, a filter circuit 1104, and a surge absorption circuit 1105 in the heating circuit 103, the losses of the MOSFET switch can be reduced, the MOSFET switch can be ensured to be in the off state during power-on to avoid abnormal power output, the impact energy caused by parasitic inductance at the moment of MOSFET switch turn-off can be absorbed, and the surge impact energy can be absorbed. This can reduce the probability of abnormalities in the heating circuit, thereby improving the safety and efficiency of chip aging tests.

Claims

1. A chip aging test system, characterized in that, It includes a control circuit, a signal isolation circuit, and a heating circuit. The output terminal of the control circuit is connected to the input terminal of the signal isolation circuit, and the input terminal of the heating circuit is connected to the output terminal of the signal isolation circuit. The control circuit is grounded through a first grounding line, and the heating circuit is grounded through a second grounding line. The control circuit is used to output a first control signal, wherein the first control signal represents the duty cycle of the output signal of the heating circuit; The signal isolation circuit is provided with a first optocoupler, which is used to convert the received first control signal into a first optical signal through a light-emitting device, and to convert the first optical signal into a second control signal through a photosensitive device. The heating circuit is used to receive the second control signal and control the on / off state of the heating switch based on the second control signal.

2. The system according to claim 1, characterized in that, In the signal isolation circuit, the output terminal of the first optocoupler is connected to the first output pull-up power supply through the first output pull-up resistor. When the first optocoupler is turned on, the second control signal output by the signal isolation circuit is at a low level; when the first optocoupler is turned off, the second control signal output by the signal isolation circuit through the first output pull-up resistor is at a high level. Wherein, the resistance value of the first output pull-up resistor is less than the preset resistance value, and the output current of the signal isolation circuit is greater than the preset current value when the first optocoupler is turned off.

3. The system according to claim 1, characterized in that, The signal isolation circuit includes a heating feedback signal isolation circuit. The input terminal of the heating feedback signal isolation circuit is connected to the output terminal of the heating switch in the heating circuit, and the output terminal of the heating feedback signal isolation circuit is connected to the control circuit. The heating feedback signal isolation circuit is provided with a second optocoupler. The second optocoupler is used to convert the received heating output signal into a second light signal through a light-emitting device, and to convert the second light signal into a heating feedback signal through a photosensitive device. The control circuit is used to receive the heating feedback signal and generate a heating circuit monitoring result by comparing the waveform of the heating feedback signal with the waveform of the control signal. The monitoring results of the heating circuit include one of the following: When the duty cycle of the heating feedback signal is the same as the duty cycle of the control signal, the monitoring result of the heating circuit is that the heating switch is in normal condition. When the duty cycle of the heating feedback signal is different from the duty cycle of the control signal, the heating circuit monitoring result indicates that the heating switch is in an abnormal state. Specifically, when the heating feedback signal remains at a low level for a duration exceeding a first preset duration, the heating circuit monitoring result indicates that the heating switch is short-circuited. When the heating feedback signal remains at a high level for a duration exceeding a second preset duration, the heating circuit monitoring result indicates that the heating switch is open-circuited.

4. The system according to claim 3, characterized in that, The input terminal of the heating feedback signal isolation circuit is provided with a first voltage divider resistor and a second voltage divider resistor. The first voltage divider resistor is connected in series with the second voltage divider resistor, the anode of the light-emitting device in the second optocoupler is connected to the voltage divider point between the first voltage divider resistor and the second voltage divider resistor, and the light-emitting device is connected in parallel with the second voltage divider resistor; Specifically, when the heating output signal causes the voltage across the emitter in the second optocoupler to be higher than the optocoupler conduction voltage parameter, the second optocoupler is turned on; when the heating output signal causes the voltage across the emitter in the second optocoupler to be lower than the optocoupler conduction voltage parameter, the second optocoupler is turned off.

5. The system according to claim 3, characterized in that, In the heating feedback signal isolation circuit, the output terminal of the second optocoupler is connected to the second output pull-up power supply through the second output pull-up resistor. When the heating output signal is high, the second optocoupler is turned on, and the heating feedback signal output by the heating feedback signal isolation circuit is low. When the heating output signal is low, the second optocoupler is turned off, and the heating feedback signal output by the heating feedback signal isolation circuit is high.

6. The system according to claim 1, characterized in that, The chip aging test system also includes a power switch and a power monitoring circuit, with the two ends of the power switch connected to the power supply of the heating circuit and the heating circuit, respectively. The power monitoring circuit includes at least one monitoring chip and at least two parallel sampling resistors. The two ends of the sampling resistors are respectively connected to the output terminal of the power switch circuit and the input terminal of the heating circuit. The monitoring chip is used to detect the actual operating voltage value of the heating circuit and the actual operating current value of the heating circuit through the sampling resistors. When the actual operating voltage value is in an abnormal voltage range or the actual operating current value is in an abnormal current range, the monitoring chip sends an interrupt signal to the control circuit. The control circuit is used to send a switch-off signal to the power switch when the interrupt signal is received, so as to control the power switch to turn off.

7. The system according to claim 6, characterized in that, The signal isolation circuit includes a power monitoring signal isolation circuit, the input terminal of which is connected to the output terminal of the monitoring chip, and the output terminal of which is connected to the control circuit. The power monitoring signal isolation circuit is equipped with an isolation chip, which is used to isolate the clock signal sent by the control circuit to the monitoring chip and the bidirectional digital signal between the control circuit and the monitoring chip. or, The power monitoring signal isolation circuit is provided with at least three third optocouplers, which are used to isolate the clock signal sent by the control circuit to the monitoring chip and the bidirectional digital signal between the control circuit and the monitoring chip.

8. The system according to any one of claims 1 to 7, characterized in that, The heating circuit includes a heating drive circuit, a heating switch circuit, and at least one heating rod; The heating drive circuit includes a push-pull circuit composed of a first transistor and a second transistor. The push-pull circuit is used to amplify the input current and output a heating drive current to the heating switch circuit. The heating switch circuit includes the heating switch, which is used to close when the received second control signal is high level to control the heating rod to be energized and heated, and to close when the received second control signal is low level to control the heating rod to stop heating.

9. The system according to claim 8, characterized in that, The heating switch is a MOSFET switch, and the heating switch circuit also includes a drive adjustment circuit and an initial state setting circuit. The drive adjustment circuit includes a drive adjustment resistor, which is connected in series between the signal isolation circuit and the gate of the MOS transistor switch. The initial state setting circuit includes an initial state setting resistor, the two ends of which are connected to the gate and source of the MOS transistor switch, respectively, and is used to control the MOS transistor switch to be in the off state when the heating switch circuit is powered on.

10. The system according to claim 8, characterized in that, The heating switch is a MOSFET switch, and the heating switch circuit also includes a filter circuit and a surge absorption circuit. The filter circuit is equipped with a ceramic energy storage capacitor, which is connected to the input terminal of the heating switch. The surge absorption circuit includes a surge absorption capacitor and a surge absorption resistor connected in series. The surge absorption circuit is connected in parallel with the MOSFET. The surge absorption capacitor is connected to the drain of the MOSFET switch, and the surge absorption resistor is connected to the source of the MOSFET switch.

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