Photoelectric test conversion circuit and photoelectric test conversion method

Abstract

The present invention discloses a photoelectric test conversion circuit and a photoelectric test conversion method. The circuit includes: when a light signal of a light source is detected, a photosensitive unit generates a current under the action of an external power supply, the positive electrode of a first external power supply is connected to the input end of a main control unit, the output end of the main control unit is connected to a first switch unit, one end of a power supply chip is connected to the first switch unit, and the other end of the power supply chip is connected to an optical performance detection unit. The main control unit is used to control the first switch unit to be turned on and send a signal to the power supply chip, and the power supply chip starts the optical performance detection unit to detect the optical performance of the image sensor to be tested. The second external power supply is connected to the second switch unit and the electrical performance detection unit. After the light source is turned off, when the main control unit controls the first switch unit to be turned off, the second switch unit is turned on, and the electrical performance detection unit is started to detect the electrical performance of the image sensor to be tested. The circuit can more conveniently perform photoelectric testing.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit testing, and in particular to a photoelectric testing conversion circuit and a photoelectric testing conversion method. Background Art

[0002] Image sensors are an important electronic device involved in the optoelectronic field and are widely used in many fields such as industrial imaging, machine vision, scientific research and exploration. Therefore, image sensors will undergo many complex tests before leaving the factory, mainly including optical performance tests and electrical performance tests. The current common testing method in the industry is usually to design a test board for optical performance test items and another test board for electrical performance test items. Doing so, on the one hand, makes the test process relatively complicated, and on the other hand, it will also incur high costs due to the production of two test boards. In order to test all indicators of the image sensor, test engineers may need to repeat the test on two test boards many times, and the workload of the operator is also large.

[0003] Therefore, it is urgent to provide a testing solution to improve the above problems. Summary of the invention

[0004] The embodiment of the present invention provides a photoelectric test conversion circuit and a photoelectric test conversion method, which are used to integrate optical test functions and electrical test functions in the circuit of a test board, and realize conversion between test modules with different functions through a switch unit, so that photoelectric testing can be performed more conveniently.

[0005] In a first aspect, the present invention provides a photoelectric test conversion circuit, comprising: an optical test circuit module and an electrical test circuit module, wherein: the optical test circuit module comprises a photosensitizing unit, a first switch unit, a main control unit, a power supply chip and an optical performance detection unit; the electrical test circuit module comprises a second switch unit and an electrical performance detection unit.

[0006] Wherein, the photosensitive unit is connected to the first switch unit, and the photosensitive unit is used to generate a current when a light signal emitted by a light source is detected, and the current flows through the first switch unit to form a voltage difference of the first switch unit; the positive electrode of the first external power supply VCC is connected to the input end of the main control unit, the output end of the main control unit is connected to the first switch unit, one end of the power chip is connected to the first switch unit, and the other end of the power chip is connected to the optical performance detection unit, and the main control unit is used to control whether the first switch unit is turned on. When the first switch unit is turned on, the signal sent by the main control unit is transmitted to the power chip, and the power chip is used to start the optical performance detection unit; the optical performance detection unit is used to detect the optical performance of the image sensor to be tested;

[0007] Among them, the positive pole of the second external power supply VDD is connected to the second switch unit and the electrical performance detection unit, the output end of the optical performance detection unit is connected to the second switch unit and grounded, after the light source is turned off, when the main control unit controls the first switch unit to turn off, the second switch unit is turned on and the electrical performance detection unit is started, and the electrical performance detection unit is used to detect the electrical performance of the image sensor to be tested.

[0008] The beneficial effects of the photoelectric test conversion circuit provided by the present invention are: on the one hand, it is possible to use a test board to realize the test of photoelectric performance, and on the other hand, it is possible to use the photosensitive unit and the switch unit to realize the optical performance test of the image sensor in a bright and dark light field environment, thereby realizing the integrated test of the image sensor in different scenes, and the overall power consumption is low, the operation is convenient, and the service life of the test board is greatly extended.

[0009] In a possible implementation, the photosensitive unit includes a photosensitive device U1, the first switch unit includes a thyristor S1, an amplifier Q1 and an N-type MOS tube Q2; the positive electrode of the first external power supply VCC is connected to the collector of the photosensitive device U1, the first external power supply VCC is also connected to the collector of the amplifier Q1, the emitter of the photosensitive device U1 is connected to the base of the amplifier Q1; the control electrode of the thyristor S1 is connected to the emitter of the amplifier Q1, the anode of the thyristor S1 is connected to the output end of the main control unit; the cathode of the thyristor S1 is connected to the input end of the power chip; the power chip is connected to the gate of the N-type MOS tube Q2, and the output end of the optical performance detection unit SC1 is connected to the source of the N-type MOS tube Q2 and grounded. In this embodiment, the N-type MOS tube is used to avoid the disadvantage of the high failure rate of the traditional mechanical switch, and the circuit performance is relatively stable.

[0010] In another possible implementation, the second switch unit includes an N-type MOS tube Q3, the positive electrode of the second external power supply VDD of the electrical performance detection unit SC2 is connected to the drain of the N-type MOS tube Q2, and is also connected to the gate of the N-type MOS tube Q3; the positive electrode of the second external power supply VDD of the electrical performance detection unit SC2 is connected to the input end of the electrical performance detection unit SC2, and the output end of the electrical performance detection unit SC2 is connected to the drain of the N-type MOS tube Q3; the source of the N-type MOS tube Q3 is grounded.

[0011] In other possible implementations, when the light source generates a light signal, the emitter of the photosensor U1 generates a current of (1+β1)Ip, where β1 is the gain of the photosensor U1 and Ip is the emitter current of the photosensor U1.

[0012] In yet another possible implementation, the photoelectric test conversion circuit further includes a voltage-dividing resistor, and the voltage-dividing resistor is used to adjust the output voltage of the first external power supply VCC and the second external power supply VDD.

[0013] In a second aspect, an embodiment of the present invention further provides a photoelectric test conversion method, which is applied to the photoelectric test conversion circuit as described in the first aspect, and the method includes:

[0014] In a light field test environment, the light emitted by the light source is controlled to irradiate the photosensitive unit of the photoelectric test conversion circuit, the main control unit of the photoelectric test conversion circuit controls the first switch unit to be turned on, and a trigger signal is transmitted to the power chip through the first switch unit, and the power chip starts the optical performance detection unit to detect the optical performance of the image sensor to be tested under bright field conditions;

[0015] In a dark field test environment, the light source is turned off, the photosensitive unit does not generate current, and before the voltage difference of the first switch unit is greater than the conduction voltage, the optical performance detection unit continues to detect the optical performance of the image sensor to be tested under the dark field condition, and after the voltage difference of the first switch unit is less than or equal to the conduction voltage, the optical performance detection unit does not work;

[0016] The main control unit turns off the first switch unit to turn on the second switch unit, and starts the electrical performance detection unit to detect the electrical performance of the image sensor to be detected.

[0017] The beneficial effect of the photoelectric test conversion method provided by the present invention is that it can realize the conversion functions of different test circuits simply and reliably, making the test more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a photoelectric test conversion circuit structure provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of another photoelectric test conversion circuit structure provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of a photoelectric test conversion method provided by an embodiment of the present invention;

[0022] Figure 4A local circuit simulation data diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] Figure 1 The photoelectric test conversion circuit provided by the embodiment of the present invention for testing the photoelectric performance of an image sensor includes a light test circuit module and an electric test circuit module.

[0024] The optical test circuit module includes a photosensitive unit, a first switch unit, a main control unit, a power chip and an optical performance detection unit SC1. The electrical test circuit module includes a second switch unit and an electrical performance detection unit SC2.

[0025] Among them, the photosensitive unit is connected to the first switch unit, and the photosensitive unit is used to generate current when a light signal emitted by a light source is detected, and the current flows through the first switch unit to form a voltage difference of the first switch unit; the positive pole of the first external power supply VCC is connected to the input end of the main control unit, and the output end of the main control unit is connected to the first switch unit, one end of the power chip is connected to the first switch unit, and the other end of the power chip is connected to the optical performance detection unit SC1, and the main control unit is used to control whether the first switch unit is turned on. When the first switch unit is turned on, the signal sent by the main control unit is transmitted to the power chip, and the power chip is used to start the optical performance detection unit SC1; the optical performance detection unit SC1 is used to detect the optical performance of the image sensor to be tested.

[0026] Among them, the positive pole of the second external power supply VDD is connected to the second switch unit and the electrical performance detection unit SC2, the output end of the optical performance detection unit SC1 is connected to the second switch unit and grounded, after the light source is turned off, when the main control unit controls the first switch unit to turn off, the second switch unit is turned on and the electrical performance detection unit SC2 is started, and the electrical performance detection unit SC2 is used to detect the electrical performance of the image sensor to be tested.

[0027] In a possible embodiment, Figure 2As shown, the photosensitive unit includes a photosensitive device U1, and the first switch unit includes a thyristor S1, an amplifier Q1 and an N-type MOS tube Q2; the positive electrode of the first external power supply VCC is connected to the collector of the photosensitive device U1, and the first external power supply VCC is also connected to the collector of the amplifier Q1, and the emitter of the photosensitive device U1 is connected to the base of the amplifier Q1; the control electrode of the thyristor S1 is connected to the emitter of the amplifier Q1, and the anode of the thyristor S1 is connected to the output end of the main control unit U2; the cathode of the thyristor S1 is connected to the input end of the power chip U3; the power chip U3 is connected to the gate of the N-type MOS tube Q2, and the output end of the optical performance detection unit SC1 is connected to the source of the N-type MOS tube Q2 and grounded. When the light source generates a light signal, the photosensitive device U1 generates a current at the emitter under the action of the first external power supply VCC, and the current is (1+β1)Ip, where β1 is the amplification factor of the photosensitive device U1, and Ip is the emitter current of the photosensitive device U1. Optionally, the photosensitive device U1 is a photosensitive diode.

[0028] In addition, the second switch unit includes an N-type MOS tube Q3, the second external power source VDD is connected to the drain of the N-type MOS tube Q2, and is also connected to the gate of the N-type MOS tube Q3; the positive electrode of the second external power source VDD is connected to the input end of the electrical performance detection unit SC2, and the output end of the electrical performance detection unit SC2 is connected to the drain of the N-type MOS tube Q3; the source of the N-type MOS tube Q3 is grounded. In this embodiment, the typical optical test function and the electrical test function are integrated together, and the conversion between the test circuits is realized through the thyristor and the N-type MOS-FET, which can be tested more conveniently.

[0029] Optionally, the N-type MOS transistor Q2 and the N-type MOS transistor Q3 may both be N-type MOS-FET transistors, which can avoid the disadvantage of high failure rate of traditional mechanical switches.

[0030] Optionally, the photoelectric test conversion circuit further includes a voltage dividing resistor, and the voltage dividing resistor is used to adjust the output voltage of the first external power supply VCC and the second external power supply VDD. For example, Figure 2 As shown, the voltage divider circuit may include a resistor R1 , a resistor R2 , a resistor R3 , a resistor R4 , a resistor R5 and a resistor R6 .

[0031] like Figure 3 As shown, the present invention also provides a photoelectric test conversion method, which can be applied to the above-mentioned photoelectric test conversion circuit and can specifically include the following steps:

[0032] S301, in a light field test environment, controls the light source to emit light to illuminate the photosensitive unit of the photoelectric test conversion circuit, the main control unit of the photoelectric test conversion circuit controls the first switch unit to be turned on, and transmits a trigger signal to the power chip through the first switch unit, and the power chip starts the optical performance detection unit SC1 to detect the optical performance of the image sensor to be tested under bright field conditions.

[0033] S302, in a dark field test environment, turn off the light source, the photosensitive unit does not generate current, and before the voltage difference of the first switch unit is greater than the turn-on voltage, the optical performance detection unit SC1 continues to detect the optical performance of the image sensor to be tested under dark field conditions, and after the voltage difference of the first switch unit is less than or equal to the turn-on voltage, the optical performance detection unit SC1 does not work.

[0034] S303: The main control unit turns off the first switch unit to turn on the second switch unit, and starts the electrical performance detection unit SC2 to detect the electrical performance of the image sensor to be detected.

[0035] Combination Figure 2 Specifically, in the light field test environment: the main control unit U2 and the amplifier tube Q1 turn on the thyristor S1, and the signal is transmitted to the power chip, and then the optical performance detection unit SC1 is started; since the N-type MOS tube Q2 is turned on at this time, the second external power supply VDD connected to the drain of Q2, although it is also connected to the gate of the N-type MOS tube Q3, but VDD has been discharged to the ground through the drain-source end of the N-type MOS tube Q2, so it will not trigger the N-type MOS tube Q3. In addition, in the dark field test environment: the light source is turned off, at this time, although the emitter current of the amplifier tube Q1 disappears, resulting in no signal at the control electrode of the thyristor S1, as long as the voltage between the cathode and anode of the thyristor S1 is greater than its conduction voltage, the thyristor will always be in working state; since the N-type MOS tube Q2 is turned on at this time, the VDD connected to the drain of Q2 will also not trigger the N-type MOS tube Q3.

[0036] When in the electrical test environment: the main control unit U2 sends a signal to reduce the anode voltage of the thyristor S1, and the thyristor is not turned on. The power chip cannot provide energy to the optical performance detection unit SC1, and the N-type MOS tube Q2 is turned off. The VDD connected to the drain of Q2 provides the gate-source voltage to the N-type MOS tube Q3, so that the N-type MOS tube Q3 is turned on; then the electrical performance detection unit SC2 is in working state.

[0037] At this point, the optical and electrical tests of the image sensor in different scenarios have been completed.

[0038] Figure 3The figure is a local circuit simulation data diagram provided by the present invention. According to the simulation data, in order to make different test circuits work normally, the VCC voltage can be 24V DC, and the VDD voltage can be 12V or 24V DC. When testing the optical test circuit, the potential difference between the control electrode and the cathode of the thyristor S1 is 15V, and the potential difference between the anode and the cathode of the thyristor is about 0.7V, so the thyristor S1 can be turned on; according to the simulation data, the potential difference between the two ends of SC1 is 8.5V, the current is 1.5A, and the overall power consumption is 12.75W. When testing the electrical test circuit, according to the simulation data, the SC2 voltage will have a spike of about 16.7V during switching, and then stabilize at 14.2V; at this time, the potential difference between the two ends of SC2 is 14V, the current is 0.97A, and the overall power consumption is 13.58W. The overall power consumption level is low.

[0039] It can be seen that in the light field test environment, when light shines on the test board, the main control unit of the test board sends a signal to the power chip, and the optical test circuit part starts to work; in the dark field test environment, the external light disappears, and the optical test circuit part is still working; the electrical test circuit module is in a non-working state; when the optical parameter test is completed, the main control unit sends a signal to the power chip, and the optical test circuit module stops working, and the electrical test part starts working. On the one hand, a test board can be used to test the photoelectric performance, and on the other hand, the optical performance test of the image sensor in the light and dark light field environment can be realized with the help of the photosensitive unit and the switch unit, realizing the integrated test of the image sensor in different scenes, and the overall power consumption is low, the operation is convenient, and the service life of the test board is greatly extended.

[0040] The above-described embodiments are only preferred embodiments of the present invention, and the embodiments are not intended to limit the patent protection scope of the present invention. Therefore, any equivalent structural changes made using the description and drawings of the present invention should also be included in the protection scope of the present invention.

[0041] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.

[0042] Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photoelectric test conversion circuit, characterized in that: include: An optical test circuit module and an electrical test circuit module, wherein: The optical test circuit module includes a photosensitive unit, a first switch unit, a main control unit, a power chip and an optical performance detection unit; The electrical test circuit module includes a second switch unit and an electrical performance detection unit; Wherein, the photosensitive unit is connected to the first switch unit, and the photosensitive unit is used to generate a current when a light signal emitted by a light source is detected, and the current flows through the first switch unit to form a voltage difference of the first switch unit; the first external power supply VCC is connected to the input end of the main control unit, the output end of the main control unit is connected to the first switch unit, one end of the power chip is connected to the first switch unit, and the other end of the power chip is connected to the optical performance detection unit, and the main control unit is used to control whether the first switch unit is turned on. When the first switch unit is turned on, the signal sent by the main control unit is transmitted to the power chip, and the power chip is used to start the optical performance detection unit; the optical performance detection unit is used to detect the optical performance of the image sensor to be tested; Among them, the second external power supply VDD is connected to the second switch unit and the electrical performance detection unit, the output end of the optical performance detection unit is connected to the second switch unit and grounded, after the light source is turned off, when the main control unit controls the first switch unit to turn off, the second switch unit is turned on and the electrical performance detection unit is started, and the electrical performance detection unit is used to detect the electrical performance of the image sensor to be tested.

2. The circuit according to claim 1, characterized in that The photosensitive unit includes a photosensitive device U1 and an amplifier tube Q1, and the first switch unit includes a thyristor S1 and an N-type MOS tube Q2; the first external power supply VCC is connected to the collector of the photosensitive device U1, and the first external power supply VCC is also connected to the collector of the amplifier tube Q1, and the emitter of the photosensitive device U1 is connected to the base of the amplifier tube Q1; The control electrode of the thyristor S1 is connected to the emitter of the amplifier tube Q1, the anode of the thyristor S1 is connected to the output end of the main control unit; the cathode of the thyristor S1 is connected to the input end of the power chip; The power chip is connected to the gate of the N-type MOS transistor Q2, and the output end of the optical performance detection unit SC1 is connected to the source of the N-type MOS transistor Q2 and is grounded.

3. The circuit according to claim 2, characterized in that The second switch unit includes an N-type MOS tube Q3, the second external power supply VDD is connected to the drain of the N-type MOS tube Q2, and is also connected to the gate of the N-type MOS tube Q3; the second external power supply VDD is connected to the input end of the electrical performance detection unit SC2, and the output end of the electrical performance detection unit SC2 is connected to the drain of the N-type MOS tube Q3; the source of the N-type MOS tube Q3 is grounded.

4. The circuit according to claim 2, characterized in that When the external light source emits a light signal, the emitter of the photosensitive device U1 generates a current of (1+β1)Ip, where β1 is the amplification factor of the photosensitive device U1 and Ip is the emitter current of the photosensitive device U1.

5. The circuit according to claim 1, characterized in that The photoelectric test conversion circuit further includes a voltage-dividing resistor, and the voltage-dividing resistor is used to adjust the output voltage of the first external power source VCC and the second external power source VDD.

6. A photoelectric test conversion method, applied to the photoelectric test conversion circuit according to any one of claims 1 to 5, the method comprising: In a light field test environment, the light emitted by the light source is controlled to irradiate the photosensitive unit of the photoelectric test conversion circuit, the main control unit of the photoelectric test conversion circuit controls the first switch unit to be turned on, and a trigger signal is transmitted to the power chip through the first switch unit, and the power chip starts the optical performance detection unit to detect the optical performance of the image sensor to be tested under bright field conditions; In a dark field test environment, the light source is turned off, the photosensitive unit does not generate current, and before the voltage difference of the first switch unit is greater than the conduction voltage, the optical performance detection unit continues to detect the optical performance of the image sensor to be tested under the dark field condition, and after the voltage difference of the first switch unit is less than or equal to the conduction voltage, the optical performance detection unit does not work; The main control unit turns off the first switch unit to turn on the second switch unit, and starts the electrical performance detection unit to detect the electrical performance of the image sensor to be detected.

7. The method according to claim 6, characterized in that The main control unit turns off the first switch unit to turn on the second switch unit, including: When the first switch unit is turned off, the optical performance detection unit does not work. When the N-type MOS tube Q2 of the first switch unit is turned off, the second external power supply VDD connected to the drain of the N-type MOS tube Q2 is triggered to provide a gate-source voltage for the N-type MOS tube Q3, so that the N-type MOS tube Q3 is turned on.

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