CN211653036U - Bias circuit, power supply circuit and testing device - Google Patents
Bias circuit, power supply circuit and testing device Download PDFInfo
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- CN211653036U CN211653036U CN202020168156.1U CN202020168156U CN211653036U CN 211653036 U CN211653036 U CN 211653036U CN 202020168156 U CN202020168156 U CN 202020168156U CN 211653036 U CN211653036 U CN 211653036U
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Abstract
The application provides a bias circuit, a power supply circuit and a testing device. The bias circuit includes: the device comprises a control module, a voltage conversion module and a first resistor; the control module is connected with one end of the first resistor, and the control end of the voltage conversion module is connected with the other end of the first resistor; the input end of the voltage conversion module is used for connecting an external power supply; and the output end of the voltage conversion module is used for connecting an external module. After the external power supply inputs a voltage signal to the input end of the voltage conversion module, the voltage output by the voltage conversion module to the external module is correspondingly changed by changing the electric signal output by the control module and by shunting the electric signal through the first resistor. Therefore, under the condition that the external input voltage is not changed, the bias circuit can output different bias voltages without modifying the design of a peripheral circuit, so that the voltage bias requirement of an external module is met.
Description
Technical Field
The application relates to the technical field of integrated module testing, in particular to a pull bias circuit, a power supply circuit and a testing device.
Background
With the rapid development of the integrated module, the function of the integrated module is more and more prominent. In the process of testing the integrated module, the stability of the integrated module needs to be tested, and one of the tests is to test the stability of the integrated module when the input voltage of the power supply fluctuates (i.e. a voltage bias test).
In the conventional voltage bias test, there are generally two methods. One is to use external power supplies with different voltage outputs to supply power to the integrated module to carry out voltage bias design. There is a problem in that it is troublesome to design an external power supply of different voltage outputs. The other is that under the condition that the input voltage is not changed, the resistance voltage division is adopted, and the output pull bias voltage is changed in a mode of pulling up and pulling down the resistance. However, in the actual testing process, some peripheral resistors of the integrated module need to be removed sometimes, some peripheral resistors need to be welded sometimes, and the variation range of the obtained pull bias voltage each time is small, so that the operation is inconvenient.
SUMMERY OF THE UTILITY MODEL
An object of the embodiment of the application is to provide a bias circuit, a power supply circuit and a testing device, which are used for outputting different bias voltages without modifying the design of a peripheral circuit under the condition that the external input voltage is not changed, so as to meet the voltage bias requirement of an external module.
In a first aspect, an embodiment of the present application provides a bias circuit, including: the circuit comprises a control module, a voltage conversion module, a first resistor, a second resistor, a third resistor and a fourth resistor;
the control module is connected with one end of the first resistor, and the control end of the voltage conversion module is connected with the other end of the first resistor; the input end of the voltage conversion module is used for connecting an external power supply;
the control module is connected with one end of the second resistor, and the other end of the second resistor is grounded;
one end of the third resistor is connected with the control end of the voltage conversion module, and the other end of the third resistor is grounded;
the control end of the voltage conversion module is connected with one end of a fourth resistor, and the other end of the fourth resistor is used for being connected with an external module and being connected with the output end of the voltage conversion module.
The voltage signal output by the voltage conversion module can be correspondingly changed according to the electric signal output by the control module by changing the electric signal output by the control module and the mode that the electric signal is shunted by the first resistor. Therefore, under the condition that the external input voltage is not changed, the bias circuit can output different bias voltages without modifying the design of a peripheral circuit, so that the voltage bias requirement of an external module is met.
In an alternative embodiment, the control module is a micro control unit.
In an alternative embodiment, the voltage conversion module is a programmable dc converter.
In an optional embodiment, the bias circuit further includes: a digital potentiometer;
the input end of the digital potentiometer is used for being connected with the external power supply, the control end of the digital potentiometer is connected with the control module, and the output end of the digital potentiometer is used for being connected with the external module;
and the input end of the digital potentiometer is used for outputting corresponding bias voltage to the external module according to the instruction sent by the control module after receiving the voltage signal input by the external power supply.
The control module controls the digital potentiometer to output a voltage value, and the digital potentiometer has the advantages of high adjustment precision, low noise, vibration resistance, interference resistance and the like, so that when the external module has higher requirements on the precision of input voltage, the digital potentiometer can be controlled to output an accurate voltage value, and a bias voltage is provided for the external module.
In an alternative embodiment, the micro control unit comprises: an analog-to-digital conversion module;
the analog-to-digital conversion module is connected with the output end of the voltage conversion module and is used for collecting the voltage signal output by the voltage conversion module.
When the external module performs a voltage bias design, a designer needs to accurately know a voltage value at each moment when the external module works. The analog-digital conversion module is connected with the output end of the voltage conversion module, so that the voltage value output by the voltage conversion module to the external module can be accurately obtained in real time.
In an optional embodiment, the bias circuit further includes: a capacitor;
one end of the capacitor is connected with the analog-to-digital conversion module, the other end of the capacitor is grounded, and the capacitor is used for filtering the voltage signal collected by the analog-to-digital conversion module and output by the voltage conversion module.
Because the acquired voltage signal has a noise signal, the interference of the noise signal can be effectively eliminated by adopting a capacitance filtering method, so that the voltage acquired by the analog-to-digital conversion module is more accurate.
In an optional embodiment, the analog-to-digital conversion module is further configured to connect to a display screen; the display screen is used for displaying the voltage signals collected by the analog-to-digital conversion module and output by the voltage conversion module.
The output bias voltage of the voltage conversion module is displayed through the display screen, so that a user can intuitively know the output voltage of the voltage conversion module, and the voltage value of the input external module can be recorded conveniently in real time.
In a second aspect, an embodiment of the present application provides a power supply circuit, including: an external power supply and a pull bias circuit as described in any of the previous embodiments;
the external power supply is connected with the input end of the voltage conversion module;
and the output end of the voltage conversion module is used for being connected with an external module and providing a bias voltage for the external module.
In an alternative embodiment, the external module is an optical module.
Through the control of the voltage conversion module and the control module, when the external power supply voltage is not changed, the output voltage of the voltage conversion module can be changed at will, and the requirement that the input voltage of the optical module is biased at will is effectively met.
In a third aspect, an embodiment of the present application provides a test apparatus, including: a bias circuit and a host computer as described in any one of the previous embodiments;
the output end of the voltage conversion module is used for being connected with an external module, and the upper computer is used for being connected with the external module and the bias circuit;
the bias circuit is used for providing a plurality of bias voltages for the external module, and the upper computer is used for monitoring the working state of the external module under different bias voltages.
The upper computer is connected with the pull bias circuit and obtains the pull bias voltage value output by the pull bias circuit in real time. The host computer obtains various parameters of the external module under different bias voltages through communication with the external module, so that testers can complete voltage bias test more conveniently.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a block diagram of a pull-bias circuit according to an embodiment of the present disclosure;
fig. 2 is a block diagram of another structure of a pull-bias circuit according to an embodiment of the present disclosure;
fig. 3 is a block diagram of a pull-bias circuit according to an embodiment of the present disclosure;
fig. 4 is a block diagram of a power supply circuit according to an embodiment of the present disclosure;
fig. 5 is a block diagram of a test apparatus according to an embodiment of the present disclosure.
Icon: 10-a bias circuit; 101-a control module; 102-a voltage conversion module; 103-a digital potentiometer; 1011-a micro control unit; 1012-analog-to-digital conversion module; 1013-display screen; 20-a power supply circuit; 201-an external power supply; 30-a test device; 301-upper computer.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.
Referring to fig. 1, fig. 1 is a block diagram of a pull-bias circuit according to an embodiment of the present disclosure, in which the pull-bias circuit 10 can implement a voltage pull-bias function.
In this embodiment, the pull-bias circuit 10 includes a control module 101, a voltage conversion module 102, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The control module 101 is connected with one end of the first resistor R1, and the control end of the voltage conversion module 102 is connected with the other end of the first resistor R1; the input end of the voltage conversion module 102 is used for connecting an external power supply; the control module 101 is connected with one end of the second resistor R2, and the other end of the second resistor R2 is grounded; one end of the third resistor R3 is connected to the control end of the voltage conversion module 102, and the other end is grounded; the control terminal of the voltage converting module 102 is connected to one terminal of the fourth resistor R4, and the other terminal of the fourth resistor R4 is used for being connected to an external module and connected to the output terminal of the voltage converting module 102.
The first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all constant value resistors. According to the working principle of the circuit diagram, the calculation formula of the output voltage of the output terminal of the voltage conversion module 102 can be obtained as follows:
wherein VoutOutput voltage, V, at the output of the voltage conversion module 102adjThe output voltage of the control terminal of the voltage converting module 102 is represented by R1, R2, R3, and R4, which are all constant resistors. I isoutIs the current output controlled by the control module 101.
In the bias circuit 10 in the embodiment of the present application, by changing the electric signal output by the control module 101, the electric signal is shunted by the first resistor R1, so that the voltage signal output by the voltage conversion module 102 can be correspondingly changed according to the electric signal output by the control module 101. Therefore, under the condition that the external input voltage is not changed, the bias circuit can output different bias voltages without modifying the design of a peripheral circuit, so that the voltage bias requirement of an external module is met.
Referring to fig. 2, fig. 2 is a block diagram of another pull-bias circuit according to an embodiment of the present disclosure.
In the embodiment of the present application, the control module 101 is a micro control Unit 1011 (MCU). Optionally, the micro control unit 1011 includes an analog to digital conversion module 1012. The analog-to-digital conversion module is connected to the output end of the voltage conversion module 102, and the analog-to-digital conversion module 1012 is configured to collect a voltage signal output by the voltage conversion module 102.
When the external module is designed for voltage bias, taking the external module as an optical module as an example, a user needs to accurately obtain a voltage value of the optical module at each moment when the optical module works, because technical parameters of the optical module under each bias voltage need to be recorded when the optical module performs a voltage bias test. In this embodiment, by connecting the output of the voltage conversion module 102 to the analog-to-digital conversion module 1012, the voltage value output by the pull-bias circuit to the external module can be accurately obtained in real time, which is convenient for monitoring the working state of the external module.
In the embodiment of the present application, the pull bias circuit 10 further includes a capacitor C1. The capacitor C1 has one end connected to the analog-to-digital conversion module 1012 and the other end connected to ground. The capacitor is used for filtering the voltage signal output by the voltage conversion module 102 collected by the analog-to-digital conversion module 1012. Because the acquired voltage signal has a noise signal, the interference of the noise signal can be effectively eliminated by adopting a capacitive filtering method, so that the voltage acquired by the analog-to-digital conversion module 1012 is more accurate.
In this embodiment, the analog-to-digital conversion module is further configured to connect to the display screen 1013. The display screen 1013 is configured to display the voltage signal collected by the analog-to-digital conversion module 1012 and output by the voltage conversion module. Alternatively, the display screen 1013 may be an Organic Light-Emitting display (OLED), a liquid crystal display, or the like. It is understood that, in other embodiments, the display 1013 may be other display screens, and the application is not limited thereto. The display screen 1013 is arranged to display the output bias voltage of the voltage conversion module 102, so that a user can intuitively know the output voltage of the voltage conversion module 102, and the voltage value input into an external module can be recorded in real time.
Optionally, in this embodiment of the application, the voltage conversion module 102 is a programmable dc converter. The input end of the programmable direct current converter is used for being connected with the external power supply, the control end of the programmable direct current converter is connected with the other end of the first resistor, and the output end of the programmable direct current converter is used for being connected with an external module and a fourth resistor. Alternatively, the programmable dc converter may be, for example, a low dropout linear regulator chip NCP 5663.
When the programmable dc converter is a low dropout regulator chip NCP5663, the third resistor R3 and the fourth resistor R4 may form a peripheral circuit of the NCP5663, wherein the third resistor R3 functions as a pull-down resistor, so the resistance of the third resistor R3 is higher than 1K Ω, for example, optionally, the resistance of the third resistor R3 may be 3K Ω. The resistance value of the fourth resistor R4 is determined according to the formula in the NCP5663 chip handbook, which is:
wherein, VoutValue of voltage, V, output for NCP5663refThe reference voltage of the NCP5663 chip is 0.9V, R3 is the resistance of the third resistor, and R4 is the resistance of the fourth resistor. Illustratively, the third resistor R3 has a resistance of 3K Ω, Vref0.9V, 3.3V, and the resistance of the fourth resistor R4 is 8.2K Ω according to the above formula.
How the pull-bias circuit achieves voltage pull-bias is described below by way of an example.
According to the working principle of the circuit diagram, the calculation formula of the voltage of the output end of the NCP5663 chip can be obtained as follows:
wherein VoutIs the output voltage, V, of the output terminal of the NCP5663 chiprefThe voltage value is 0.9V, R1 is a first resistor, R2 is a second resistor, R3 is a third resistor, and R4 is a fourth resistor, which are all constant value resistors, which are the reference voltage of the NCP5663 chip. I isoutIs the current output controlled by the micro control unit 1011.
If the input voltage is 5V, the rated operating voltage of the external module is 3.3V. From the above formula in the NCP5663 chip handbook, it can be concluded that the ratio of R4 to R3 is 8: 3. Since the second resistor R2 and the third resistor R3 are pull-down resistors, optionally, the resistance values of R2 and R3 are 3K Ω. Considering the patch resistor which is relatively easily available on the market, the resistance of the fourth resistor R4 may be selected to be 8.2K Ω. Since the first resistor R1 is connected in parallel with R2 to shunt the current flowing through R1, the resistance of R3 should be close to that of R1, and the resistance of R3 can be selected to be 8.2K Ω. The process of the bias circuit for realizing voltage bias can comprise the following steps:
in the first step, an external power supply inputs a 5V voltage to the input end of the NCP5663 chip, and the micro control unit 1011 outputs the corresponding I according to the above formulaoutSo that V isoutThe output of (2) is 3.3V, so that the normal work of the external module is ensured.
Second, when the external module requires a bias voltage of 2.7V-5V, the MCU 1011 changes IoutSo that V isoutGradually changes from 2.7V to 5V.
Referring to fig. 3, fig. 3 is a block diagram of a pull-bias circuit according to an embodiment of the present disclosure.
In the embodiment of the present application, the pull-bias circuit 10 includes a digital potentiometer 103. The input end of the digital potentiometer 103 is used for connecting an external power supply, the control end of the digital potentiometer 103 is connected with the control module 101, and the output end of the digital potentiometer 103 is used for connecting an external module. The input end of the digital potentiometer 103 is configured to output a corresponding bias voltage to the external module according to an instruction sent by the control module 101 after receiving a voltage signal input by the external power supply.
Specifically, the Digital Potentiometer 103 (also called a Digital control programmable resistor) is a new type of integrated circuit for CMOS Digital/analog mixed signal processing that replaces the conventional mechanical Potentiometer (analog Potentiometer). The digital potentiometer 103 is controlled by a digital input and produces an analog output. The digital potentiometer 103 adopts a numerical control mode to adjust the resistance value, and has the remarkable advantages of flexible use, high adjustment precision, no contact, low noise, difficult contamination, vibration resistance, interference resistance, small volume, long service life and the like.
In this embodiment, after receiving the input voltage of the external power supply, the digital potentiometer 103 receives the instruction sent by the control module 101 through an I2C (Inter-Integrated Circuit) protocol. When a user wants to obtain an output voltage different from an input voltage of an external power supply, the control module 101 may send the instruction to the digital potentiometer 103 according to a user requirement, so that a resistance value inside the digital potentiometer 103 is changed to achieve an effect of dividing the input voltage, and then the digital potentiometer 103 outputs the divided voltage value. Alternatively, the digital potentiometer 103 may be a TPL0401A chip. It is understood that in other embodiments, the digital potentiometer 103 may be another chip, and the application is not limited thereto.
The control module 101 controls the digital potentiometer 103 to output a voltage value, and since the digital potentiometer 103 has advantages of high adjustment precision, low noise, vibration resistance, interference resistance, and the like, when the external module has a high requirement on the precision of the input voltage, the digital potentiometer 103 can be used to output a precise voltage value to provide a bias voltage for the external module.
Referring to fig. 4, based on the same inventive concept, an embodiment of the present application further provides a power supply circuit 20 based on the above-mentioned pull-bias circuit. In this embodiment, the power supply circuit 20 includes an external power supply 201 and the bias circuit 10. The external power supply 201 is connected with the input end of the voltage conversion module; the output end of the voltage conversion module is used for being connected with an external module and providing a bias voltage for the external module.
Optionally, the external module is an optical module. In optical module bias, the bias voltage range of the optical module is 3.0V-3.5V generally, the voltage range of some optical modules is required to be wider, bias is generally performed by changing external power supply voltage, timeliness is low, and operation is inconvenient. Even if the external power supply is provided with a display screen, the output voltage of the power supply can only be displayed generally, but voltage drop exists among the modules, so that the output voltage of the external power supply is different from the working voltage received by the optical module, the working voltage of the optical module cannot be known specifically, and the technical parameters of the optical module at each voltage point are not recorded well.
The existing bias method generally adopts a resistor voltage division mode and solves the problem through a pull-up resistor and a pull-down resistor. In practical use, some resistors need to be removed and sometimes some resistors need to be welded, and the change range of the bias voltage obtained each time is very small, so that the operation is inconvenient. The bias circuit in this application combines control module control through voltage conversion module, when external power supply voltage is unchangeable, can change voltage conversion module's output voltage at will, has effectively solved the demand that optical module input voltage draws partially at will.
By arranging the bias circuit 10 between the external power supply and the optical module, the voltage bias test of the optical module can be effectively completed on the premise that the external power supply voltage is unchanged, and the working voltage value of the optical module can be accurately obtained in real time. Meanwhile, the bias circuit 10 can meet the requirement of certain optical modules on bias of working voltage, and brings convenience to the bias test of other modules. The circuit has the advantages of convenient voltage bias control, high timeliness, high voltage control precision, wide voltage bias range (2-5V) and the like, and can meet the voltage bias requirements of most optical modules at the present stage.
Referring to fig. 5, based on the same inventive concept, an embodiment of the present application further provides a testing apparatus 30 based on the pull bias circuit. In this embodiment, the testing device 30 includes the bias circuit 10 and the upper computer 301. The output end of the voltage conversion module is used for being connected with an external module, and the upper computer is used for being connected with the external module and the bias circuit; the bias circuit is used for providing a plurality of bias voltages for the external module, and the upper computer is used for monitoring the working state of the external module under different bias voltages.
The bias circuit 10 is used for providing a plurality of bias voltages for the external module, and then the upper computer 301 is used for monitoring the working state of the external module under different bias voltages. Alternatively, the external module may be an optical module. All existing optical modules have a Digital Diagnostic Monitoring (DDM) function. The DDM is mainly used for monitoring real-time parameters of the optical module. The parameters comprise working temperature, working voltage, working current, transmitting and receiving optical power and the like, and can also display factory information of the module and prompt alarm/warning. In this embodiment, the upper computer 301 is connected to the pull bias circuit 10, and obtains the pull bias voltage value output by the pull bias circuit 10 in real time. Then the upper computer communicates with the optical module through an I2C protocol, and real-time parameters of the optical module at each voltage point are obtained through the DDM function of the optical module: operating temperature, operating voltage, operating current, transmitted and received optical power, and the like.
In the description of the present application, it should be noted that the terms "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the application usually place when using, and are only used for convenience in describing the present application and simplifying the description, but do not indicate or imply that the devices or elements that are referred to must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.
It should also be noted that, unless expressly stated or limited otherwise, the terms "disposed" and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. A pull bias circuit, comprising: the circuit comprises a control module, a voltage conversion module, a first resistor, a second resistor, a third resistor and a fourth resistor;
the control module is connected with one end of the first resistor, and the control end of the voltage conversion module is connected with the other end of the first resistor; the input end of the voltage conversion module is used for connecting an external power supply;
the control module is connected with one end of the second resistor, and the other end of the second resistor is grounded;
one end of the third resistor is connected with the control end of the voltage conversion module, and the other end of the third resistor is grounded;
the control end of the voltage conversion module is connected with one end of a fourth resistor, and the other end of the fourth resistor is used for being connected with an external module and being connected with the output end of the voltage conversion module.
2. The pull-bias circuit according to claim 1, wherein the control module is a micro-control unit.
3. The pull-bias circuit of claim 1, wherein the voltage conversion module is a programmable dc converter.
4. The pull-bias circuit of claim 1, further comprising: a digital potentiometer;
the input end of the digital potentiometer is used for being connected with the external power supply, the control end of the digital potentiometer is connected with the control module, and the output end of the digital potentiometer is used for being connected with the external module;
and the input end of the digital potentiometer is used for outputting corresponding bias voltage to the external module according to the instruction sent by the control module after receiving the voltage signal input by the external power supply.
5. The pull-bias circuit according to claim 2, wherein the micro-control unit comprises: an analog-to-digital conversion module;
the analog-to-digital conversion module is connected with the output end of the voltage conversion module and is used for collecting the voltage signal output by the voltage conversion module.
6. The pull-bias circuit of claim 5, further comprising: a capacitor;
one end of the capacitor is connected with the analog-to-digital conversion module, the other end of the capacitor is grounded, and the capacitor is used for filtering the voltage signal collected by the analog-to-digital conversion module and output by the voltage conversion module.
7. The bias circuit according to claim 6, wherein the analog-to-digital conversion module is further configured to connect to a display screen; the display screen is used for displaying the voltage signals collected by the analog-to-digital conversion module and output by the voltage conversion module.
8. A power supply circuit, comprising: an external power supply and a pull bias circuit as claimed in any one of claims 1-7;
the external power supply is connected with the input end of the voltage conversion module;
and the output end of the voltage conversion module is used for being connected with an external module and providing a bias voltage for the external module.
9. The power supply circuit of claim 8, wherein the external module is a light module.
10. A test apparatus, comprising: the biasing circuit of any one of claims 1-7 and an upper computer;
the output end of the voltage conversion module is used for being connected with an external module, and the upper computer is used for being connected with the external module and the bias circuit;
the bias circuit is used for providing a plurality of bias voltages for the external module, and the upper computer is used for monitoring the working state of the external module under different bias voltages.
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| CN202020168156.1U CN211653036U (en) | 2020-02-13 | 2020-02-13 | Bias circuit, power supply circuit and testing device |
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