CN117929965A - Open loop detection circuit and vehicle-mounted charger - Google Patents
Open loop detection circuit and vehicle-mounted charger Download PDFInfo
- Publication number
- CN117929965A CN117929965A CN202410089656.9A CN202410089656A CN117929965A CN 117929965 A CN117929965 A CN 117929965A CN 202410089656 A CN202410089656 A CN 202410089656A CN 117929965 A CN117929965 A CN 117929965A
- Authority
- CN
- China
- Prior art keywords
- differential amplifier
- resistor
- voltage signal
- signal
- detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 160
- 238000005070 sampling Methods 0.000 claims abstract description 90
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 claims abstract description 36
- 239000003990 capacitor Substances 0.000 claims description 26
- 230000003321 amplification Effects 0.000 description 15
- 238000003199 nucleic acid amplification method Methods 0.000 description 15
- 238000010586 diagram Methods 0.000 description 6
- 150000003071 polychlorinated biphenyls Chemical class 0.000 description 5
- 230000006870 function Effects 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000002596 correlated effect Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Landscapes
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The embodiment of the application provides an open-loop detection circuit and a vehicle-mounted charger, wherein the open-loop detection circuit comprises a sampling resistor, a differential amplifier, a detection module, a first signal generation module and a second signal generation module, and the sampling resistor is used for sampling the output current of the vehicle-mounted charger OBC; the first end of the sampling resistor is connected with the first input end of the differential amplifier and the output end of the first signal generation module through a first flat cable, the second end of the sampling resistor is connected with the second input end of the differential amplifier and the output end of the second signal generation module through a second flat cable, and the output end of the differential amplifier is connected with the detection port of the detection module; when the OBC is not started and the output end of the first signal generating module or the output end of the second signal generating module outputs a voltage signal, the detecting module determines whether the first flat cable and/or the second flat cable have faults according to the voltage signal detected by the detecting port. The embodiment of the application can accurately detect whether the current feedback loop of the OBC is open or not.
Description
Technical Field
The application relates to the technical field of electronic circuits, in particular to an open-loop detection circuit and a vehicle-mounted charger.
Background
At present, direct current voltage and current output by an on-board charger (OBC) are fed back to a control chip through a voltage sampling loop and a current sampling loop, and the control chip adjusts the magnitude of the OBC output voltage and current according to the current received voltage and current feedback information, so that stable output of the voltage and the current is realized.
Under normal conditions, the connection of the control chip and the current feedback loop is normal. If the current feedback loop is open-loop, the control chip cannot acquire voltage and current signals, the output gain is always improved, and under the condition, the current output by the OBC is increased rapidly, and the OBC is damaged.
Disclosure of Invention
The embodiment of the application provides an open-loop detection circuit and a vehicle-mounted charger, which can accurately detect whether a current feedback loop of an OBC is open-loop or not.
The first aspect of the embodiment of the application provides an open-loop detection circuit, which comprises a sampling resistor, a differential amplifier, a detection module, a first signal generation module and a second signal generation module, wherein the sampling resistor is used for sampling the output current of an OBC (on-board battery) of a vehicle-mounted charger;
The first end of the sampling resistor is connected with the first input end of the differential amplifier and the output end of the first signal generation module through a first flat cable, the second end of the sampling resistor is connected with the second input end of the differential amplifier and the output end of the second signal generation module through a second flat cable, and the output end of the differential amplifier is connected with the detection port of the detection module;
and under the condition that the OBC is not started and the output end of the first signal generation module or the output end of the second signal generation module outputs a voltage signal, the detection module determines whether the first flat cable and/or the second flat cable have faults according to the voltage signal detected by the detection port.
Optionally, in a case that the voltage signal detected by the detection port of the detection module is greater than a first set threshold, it is determined that at least one of the first flat cable and the second flat cable is disconnected.
Optionally, in a case that the voltage signal detected by the detection port of the detection module is smaller than the first set threshold, it is determined that neither the first flat cable nor the second flat cable has a fault.
Optionally, the first end of the sampling resistor and the second end of the sampling resistor are located on a first printed circuit board, the first input end of the differential amplifier and the second input end of the differential amplifier are located on a second printed circuit board, and the output end of the first signal generating module and the output end of the second signal generating module are located on the second printed circuit board.
Optionally, when the OBC is not turned on and the output end of the first signal generating module outputs a first voltage signal and the output end of the second signal generating module outputs a second voltage signal, the detecting module determines whether the differential amplifier fails according to the voltage signal detected by the detecting port; the absolute value of the difference between the first voltage signal and the second voltage signal is larger than a second set threshold.
Optionally, determining that the differential amplifier fails when the voltage signal detected by the detection port of the detection module is not located in the set threshold interval;
And under the condition that the voltage signal detected by the detection port of the detection module is located in the set threshold interval, determining that the differential amplifier does not have faults.
Optionally, the first signal generating module includes a first signal input source, a first resistor, a second resistor, a first diode and a first capacitor; the first signal input source is connected with the first end of the first resistor, the second end of the first resistor is connected with the first end of the second resistor, the first end of the first capacitor and the positive electrode of the first diode, the second end of the second resistor and the second end of the first capacitor are grounded, and the negative electrode of the first diode is connected with the first input end of the differential amplifier.
Optionally, the second signal generating module includes a second signal input source, a third resistor, a fourth resistor, a second diode, and a second capacitor; the second signal input source is connected with the first end of the third resistor, the second end of the third resistor is connected with the first end of the fourth resistor, the first end of the second capacitor and the positive electrode of the second diode, the second end of the fourth resistor and the second end of the second capacitor are grounded, and the negative electrode of the second diode is connected with the second input end of the differential amplifier.
Optionally, the first signal input source is generated by the detection module.
Optionally, the second signal input source is generated by the detection module.
A second aspect of the embodiment of the present application provides a vehicle-mounted charger, including an open loop detection circuit according to any one of the first aspect of the embodiment of the present application.
The open-loop detection circuit comprises a sampling resistor, a differential amplifier, a detection module, a first signal generation module and a second signal generation module, wherein the sampling resistor is used for sampling the output current of an OBC (on-board battery) of the vehicle-mounted charger; the first end of the sampling resistor is connected with the first input end of the differential amplifier and the output end of the first signal generation module through a first flat cable, the second end of the sampling resistor is connected with the second input end of the differential amplifier and the output end of the second signal generation module through a second flat cable, and the output end of the differential amplifier is connected with the detection port of the detection module; and under the condition that the OBC is not started and the output end of the first signal generation module or the output end of the second signal generation module outputs a voltage signal, the detection module determines whether the first flat cable and/or the second flat cable have faults according to the voltage signal detected by the detection port. In the embodiment of the application, when the OBC is not started and the output end of the first signal generating module or the output end of the second signal generating module outputs the voltage signal, the detecting module determines whether at least one of the first flat cable and the second flat cable has a fault according to the voltage signal detected by the detecting port. Whether the first flat cable and/or the second flat cable have faults or not can be accurately detected, and the first flat cable and the second flat cable are positioned in a current feedback loop of the OBC (the current feedback loop of the OBC comprises a sampling resistor, a differential amplifier and a detection module), so that whether the current feedback loop of the OBC is open-loop or not is accurately detected.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are necessary for the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application and that other drawings may be obtained from them without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of an open loop detection circuit according to an embodiment of the present application;
fig. 2 is a schematic diagram of a specific structure of an open loop detection circuit according to an embodiment of the present application;
fig. 3 is a schematic diagram of a specific structure of another open loop detection circuit according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The terms first, second and the like in the description and in the claims and in the above-described figures are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed but may optionally include additional steps or elements not listed or inherent to such process, article, or apparatus.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the described embodiments of the application may be combined with other embodiments.
Referring to fig. 1, fig. 1 is a schematic diagram of an open loop detection circuit according to an embodiment of the application. As shown in fig. 1, the open loop detection circuit 100 includes a sampling resistor Rs, a differential amplifier U1, a detection module 10, a first signal generation module 20, and a second signal generation module 30, where the sampling resistor Rs is used to sample an output current of the vehicle-mounted charger OBC;
The first end of the sampling resistor is connected with the first input end of the differential amplifier and the output end of the first signal generation module through a first flat cable, the second end of the sampling resistor is connected with the second input end of the differential amplifier and the output end of the second signal generation module through a second flat cable, and the output end of the differential amplifier is connected with the detection port of the detection module;
and under the condition that the OBC is not started and the output end of the first signal generation module or the output end of the second signal generation module outputs a voltage signal, the detection module determines whether the first flat cable and/or the second flat cable have faults according to the voltage signal detected by the detection port.
In the embodiment of the application, the differential amplifier is an electronic amplifier which amplifies the difference between the voltages of two input ends with a fixed gain. The differential amplifier is used for amplifying and outputting the difference value of the voltages of the first input end and the second input end of the differential amplifier. The differential amplifier has strong capability of suppressing common mode interference and noise.
The sampling resistor is used for sampling the output current of the vehicle-mounted charger OBC. When the OBC works, the output current of the OBC flows through the sampling resistor, a differential pressure is formed between the first end and the second end of the sampling resistor, and the differential amplifier can amplify the differential pressure and then output the amplified differential pressure to the detection port of the detection module for detection. The detection module judges the current flowing through the sampling resistor according to the voltage signal detected by the detection module. For example, if the resistance of the sampling resistor is 1 milliohm (mΩ), the current flowing is 10A, the voltage difference between the first input terminal and the second input terminal of the differential amplifier is 0.01V, and if the amplification factor of the differential amplifier is 500, the voltage signal detected by the detection port of the detection module is 5V. The detection module may calculate the current flowing through the sampling resistor according to the following formula:
I＝U/(Rs*A)；
Wherein I is the current flowing through the sampling resistor, U is the voltage signal detected by the detection port of the detection module, rs is the resistance value of the sampling resistor, and A is the amplification factor of the differential amplifier.
For example, if u=5v, rs=1mΩ, a=500, i=10a can be calculated.
The detection module may be a control chip. For example, the control module may be a micro control unit (microcontroller unit, MCU). The detection port of the control module may be an analog-to-digital conversion (ADC) sampling port of the MCU.
The first signal generating module may be a module generating a direct current voltage signal, and the second signal generating module may be a module generating a direct current voltage signal.
If the first and second wirings are not faulty, a voltage at the first terminal of the sampling resistor may be input to the first input terminal of the differential amplifier, and a voltage at the second terminal of the sampling resistor may be input to the second input terminal of the differential amplifier. If the first flat cable fails (e.g., the first flat cable is disconnected), the voltage at the first end of the sampling resistor cannot be input to the first input terminal of the differential amplifier; if the second bus line fails (e.g., the second bus line is disconnected), the voltage at the second terminal of the sampling resistor cannot be input to the second input terminal of the differential amplifier.
When the OBC is not powered on, the sampling resistor does not have a current passing through it, and if the output end of the first signal generating module outputs a voltage signal or the output end of the first signal generating module outputs a voltage signal, and under the condition that the first flat cable and the second flat cable do not have faults, the voltage signal makes the current flowing through the sampling resistor very small at milliohm level, and at milliamp level, the voltage difference between the first input end of the differential amplifier and the second input end of the differential amplifier can be considered to be very small (for example, at microvolt level), the voltage difference between the first input end of the differential amplifier and the second input end of the differential amplifier can be defaulted to be 0, and the voltage signal can be simultaneously input into the first input end of the differential amplifier and the second input end of the differential amplifier, and at this time, the detection port of the detection module cannot detect the voltage signal, and cannot detect the current flowing through the sampling resistor.
When the OBC is not started, no current passes through the sampling resistor, the first end and the second end of the sampling resistor do not have voltage signals, if the output end of the first signal generating module outputs the voltage signals or the output end of the first signal generating module outputs the voltage signals, under the condition that at least one of the first flat cable and the second flat cable is faulty, a large voltage difference is generated between the first input end of the differential amplifier and the second input end of the differential amplifier, and the detection port of the detection module can detect the large voltage signals, so that the current flowing through the sampling resistor is detected. Obviously, when the OBC is not started, no current passes through the sampling resistor, and if the detection port of the detection module detects a larger voltage signal, at least one of the first flat cable and the second flat cable is considered to be faulty.
Specifically, when the OBC is not powered on, no current passes through the sampling resistor, no voltage signal is generated at the first end and the second end of the sampling resistor, if the output end of the first signal generating module outputs the voltage signal (at this time, the output end of the second signal generating module does not output the voltage signal), under the condition that at least one of the first flat cable and the second flat cable is faulty, the first input end of the differential amplifier generates the voltage signal, and the second input end of the differential amplifier does not generate the voltage signal, so that a large voltage difference is generated between the first input end of the differential amplifier and the second input end of the differential amplifier, and the detection port of the detection module can detect the large voltage signal, thereby detecting the current flowing through the sampling resistor. Obviously, when the OBC is not started, no current passes through the sampling resistor, and if the detection port of the detection module detects a larger voltage signal, at least one of the first flat cable and the second flat cable is considered to be faulty.
When the OBC is not started, no current passes through the sampling resistor, no voltage signal is generated at the first end and the second end of the sampling resistor, if the output end of the second signal generating module outputs the voltage signal (at the moment, the output end of the first signal generating module does not output the voltage signal), under the condition that at least one of the first flat cable and the second flat cable is faulty, the second input end of the differential amplifier generates the voltage signal, the first input end of the differential amplifier does not have the voltage signal, the first input end of the differential amplifier and the second input end of the differential amplifier generate a larger voltage difference, and the detection port of the detection module can detect the larger voltage signal, so that the current flowing through the sampling resistor is detected. Obviously, when the OBC is not started, no current passes through the sampling resistor, and if the detection port of the detection module detects a larger voltage signal, at least one of the first flat cable and the second flat cable is considered to be faulty.
In the embodiment of the application, when the OBC is not started and the output end of the first signal generating module or the output end of the second signal generating module outputs the voltage signal, the detecting module determines whether at least one of the first flat cable and the second flat cable has a fault according to the voltage signal detected by the detecting port. Whether the first flat cable and/or the second flat cable have faults or not can be accurately detected, and the first flat cable and the second flat cable are positioned in a current feedback loop of the OBC (the current feedback loop of the OBC comprises a sampling resistor, a differential amplifier and a detection module), so that whether the current feedback loop of the OBC is open-loop or not is accurately detected.
Optionally, in a case that the voltage signal detected by the detection port of the detection module is greater than a first set threshold, it is determined that at least one of the first flat cable and the second flat cable is disconnected.
Optionally, in a case that the voltage signal detected by the detection port of the detection module is smaller than the first set threshold, it is determined that neither the first flat cable nor the second flat cable has a fault.
In the embodiment of the present application, the first set threshold may be preset, and the first set threshold is a value greater than 0. The first set threshold may be determined based on the resistance of the sampling resistor and the amplification factor of the differential amplifier. The first set threshold may be positively correlated with the resistance of the sampling resistor, and the first set threshold may be positively correlated with the amplification factor of the differential amplifier. In general, the larger the resistance value of the sampling resistor, the larger the first set threshold value may be set, and the larger the amplification factor of the differential amplifier, the larger the first set threshold value may be set. The first set threshold may be stored in a memory of the detection module.
The first set threshold may be a minimum value of a voltage signal that can be detected by a detection port of the detection module. When the voltage signal detected by the detection port of the detection module is greater than a first set threshold, the voltage difference between the first input end and the second input end of the differential amplifier is indicated so that the detection port of the detection module can detect the voltage signal of the output of the differential amplifier.
When the OBC is not started, no current passes through the sampling resistor, no voltage signal is generated at the first end and the second end of the sampling resistor, if the voltage signal is output at the output end of the first signal generating module or the voltage signal is output at the output end of the first signal generating module, under the condition that the first flat cable and the second flat cable are not faulty, the voltage signal makes the current flowing through the sampling resistor very small at milliohm level, and at milliamp level, the voltage difference between the first input end of the differential amplifier and the second input end of the differential amplifier can be considered to be very small (for example, at microvolt level), at this time, the voltage difference between the first input end and the second input end of the differential amplifier makes the voltage signal output by the differential amplifier which cannot be detected by the detection port of the detection module, namely, the voltage signal output by the differential amplifier is 0, and the voltage signal detected by the detection port of the detection module is 0 and is smaller than the first set threshold. Obviously, when the OBC is not started, the detection port of the detection module cannot detect the voltage signal, and if the detection port of the detection module does not detect the voltage signal, the first flat cable and the second flat cable are considered to be free from faults.
When the OBC is not started, no current passes through the sampling resistor, no voltage signal is generated at the first end and the second end of the sampling resistor, if the voltage signal is output by the output end of the first signal generating module or the voltage signal is output by the output end of the first signal generating module, under the condition that at least one of the first flat cable and the second flat cable is faulty, a large voltage difference is generated between the first input end of the differential amplifier and the second input end of the differential amplifier, and the detection port of the detection module can detect the large voltage signal which is larger than a first set threshold value. Obviously, when the OBC is not started, the detection port of the detection module cannot detect the voltage signal, and if the detection port of the detection module detects a larger voltage signal, at least one of the first flat cable and the second flat cable is considered to be faulty.
Optionally, the first end of the sampling resistor and the second end of the sampling resistor are located on a first printed circuit board, the first input end of the differential amplifier and the second input end of the differential amplifier are located on a second printed circuit board, and the output end of the first signal generating module and the output end of the second signal generating module are located on the second printed circuit board.
In the embodiment of the application, the printed circuit boards (printed circuit board, PCB) are connected by a flat cable or pin header. If the first end of the sampling resistor and the second end of the sampling resistor are located on the first printed circuit board, the first input end of the differential amplifier and the second input end of the differential amplifier are located on the second printed circuit board, and the output end of the first signal generating module and the output end of the second signal generating module are located on the second printed circuit board, the first flat cable is used for connecting the first end of the sampling resistor on the first printed circuit board and the first input end of the differential amplifier and the output end of the first signal generating module on the second printed circuit board. The second flat cable is used for connecting the second end of the sampling resistor on the first printed circuit board with the second input end of the differential amplifier on the second printed circuit board and the output end of the first signal generating module.
The first and second wirings between the first and second printed circuit boards are easily damaged. After at least one of the first flat cable and the second flat cable is damaged, the detection module can not acquire a voltage signal when the OBC works, so that the output gain of the OBC can be always improved, under the condition, the current output by the OBC can be increased rapidly, and the OBC can be damaged.
The embodiment of the application can be applied to the situation that the differential amplifier and the sampling resistor are positioned on different PCBs, when the differential amplifier and the sampling resistor are respectively positioned on two different PCBs, the voltage signal can be output through the output end of the first signal generating module or the voltage signal can be output through the output end of the first signal generating module when the OBC is not started, whether the first flat cable and the second flat cable are in failure or not is judged according to whether the voltage signal detected by the detection port of the detection module is larger than a first set threshold value, and accordingly whether at least one of the first flat cable and the second flat cable is in failure or not is detected rapidly and accurately.
Optionally, when the OBC is not turned on and the output end of the first signal generating module outputs a first voltage signal and the output end of the second signal generating module outputs a second voltage signal, the detecting module determines whether the differential amplifier fails according to the voltage signal detected by the detecting port; the absolute value of the difference between the first voltage signal and the second voltage signal is larger than a second set threshold.
In the embodiment of the present application, the second set threshold may be preset, and the second set threshold is a value greater than 0. The second set threshold may be determined based on the amplification factor of the differential amplifier. The second set threshold may be inversely related to the amplification of the differential amplifier. In general, the larger the amplification factor of the differential amplifier, the smaller the second set threshold value may be set. The second set threshold may be stored in a memory of the detection module.
When the absolute value of the difference value between the first voltage signal and the second voltage signal is larger than a second set threshold value, the detection port of the detection module can detect the voltage signal. When the absolute value of the difference value between the first voltage signal and the second voltage signal is larger than a second set threshold value, the detection port of the detection module can detect the output voltage signal of the differential amplifier.
Optionally, determining that the differential amplifier fails when the voltage signal detected by the detection port of the detection module is not located in the set threshold interval;
And under the condition that the voltage signal detected by the detection port of the detection module is located in the set threshold interval, determining that the differential amplifier does not have faults.
In the embodiment of the application, the set threshold interval may be determined based on the amplification factor of the differential amplifier and the difference between the first voltage signal and the second voltage signal. The threshold section may be set in advance. The interval median value of the set threshold interval may be determined according to the following formula:
Um＝△U*A；
wherein Um is the median value of the set threshold interval, deltaU is the difference between the first voltage signal and the second voltage signal, and A is the amplification factor of the differential amplifier.
The set threshold interval may be (Um-U1, um+u1), where U1 is a floating amount obtained in consideration of an error of the differential amplifier. When the difference between the first voltage signal and the second voltage signal is DeltaU and the amplification factor of the differential amplifier is A, the corresponding set threshold interval is (Um-U1, um+U1).
If the voltage signal detected by the detection port of the detection module is not located in the set threshold value interval, determining that the differential amplifier fails; and if the voltage signal detected by the detection port of the detection module is in the set threshold value interval, determining that the differential amplifier does not fail. According to the embodiment of the application, after the difference value between the first voltage signal and the second voltage signal and the amplification factor of the differential amplifier are determined, whether the differential amplifier fails or not is judged through the voltage signal detected by the detection port of the detection module, and because the amplification factor of the differential amplifier is an inherent parameter of the differential amplifier, the first voltage signal and the second voltage signal can be preset, and whether the differential amplifier fails or not can be accurately judged through the voltage signal detected by the detection port of the detection module.
In the embodiment of the application, when the OBC is not started and the output end of the first signal generating module outputs the first voltage signal and the output end of the second signal generating module outputs the second voltage signal, the detecting module can determine whether the differential amplifier fails according to the voltage signal detected by the detecting port. When the OBC is not started and the output end of the first signal generating module or the output end of the second signal generating module outputs a voltage signal, the detecting module may determine whether at least one of the first flat cable and the second flat cable fails according to the voltage signal detected by the detecting port. Through the newly added first signal generating module and second signal generating module, not only can detect whether at least one of the first flat cable and the second flat cable fails, but also can detect whether the differential amplifier fails, thereby realizing the self-checking function of the detection circuit.
Referring to fig. 2, fig. 2 is a schematic diagram of a specific structure of an open loop detection circuit according to an embodiment of the application. FIG. 2 is a further view of FIG. 1, as shown in FIG. 2, wherein the first signal generating module includes a first signal input source, a first resistor, a second resistor, a first diode, and a first capacitor, as shown in FIG. 1; the first signal input source is connected with the first end of the first resistor, the second end of the first resistor is connected with the first end of the second resistor, the first end of the first capacitor and the positive electrode of the first diode, the second end of the second resistor and the second end of the first capacitor are grounded, and the negative electrode of the first diode is connected with the first input end of the differential amplifier.
In the embodiment of the application, the first resistor can be a current limiting resistor, and the resistance value of the first resistor can be set larger, so that the current flowing through the first resistor is smaller. The current flowing through the first resistor is smaller, so that when the OBC is not started, the first flat cable and the second flat cable are not in failure, the current flowing through the sampling resistor is smaller when the first signal generating module generates a first voltage signal, the differential pressure between the first input end and the second input end of the differential amplifier is small, the differential amplifier cannot detect the differential pressure, the default is that the differential pressure between the first input end of the differential amplifier and the second input end of the differential amplifier is 0, and the detection module cannot misjudge that the current passes through the sampling resistor.
The second resistor and the first capacitor can be filter modules and can be used for stabilizing the voltage signal generated by the first signal input source, so that the first signal generating module can generate a stable first voltage signal.
The first diode can prevent the voltage of the first end of the sampling resistor from flowing backwards into the first signal generating module, so that the detection module is protected.
The principle of the first signal generating module generating the first voltage signal is as follows: the voltage signal generated by the first signal input source is subjected to current limiting through a first resistor, is filtered through a second resistor and a first capacitor, and is output through a first diode.
Wherein the first signal input source may be generated by the detection module. The first signal input source does not need to be arranged separately, so that the cost can be saved. For example, when the detection module is an MCU, the first signal input source may be an input/output (I/O) port of the MCU. The I/O port of the MCU may output a voltage signal.
In fig. 2, the sampling resistor, the first end of the sampling resistor, and the second end of the sampling resistor are located on the first printed circuit board. The differential issue amplifier, the first input end of the differential amplifier, the second input end of the differential amplifier, the first signal generating module, the output end of the first signal generating module, the second signal generating module, the output end of the second signal generating module, the detection module and the detection port of the detection module in fig. 2 are all located on the second printed circuit board.
Optionally, the second signal generating module of fig. 2 includes a second signal input source, a third resistor, a fourth resistor, a second diode, and a second capacitor; the second signal input source is connected with the first end of the third resistor, the second end of the third resistor is connected with the first end of the fourth resistor, the first end of the second capacitor and the positive electrode of the second diode, the second end of the fourth resistor and the second end of the second capacitor are grounded, and the negative electrode of the second diode is connected with the second input end of the differential amplifier.
In the embodiment of the application, the third resistor may be a current limiting resistor, and the resistance value of the third resistor may be set to be larger, so that the current flowing through the third resistor is smaller. The current flowing through the third resistor is smaller, so that when the OBC is not started, the first flat cable and the second flat cable are not in failure, the current flowing through the sampling resistor is smaller when the second signal generating module generates the second voltage signal, the differential pressure between the first input end and the second input end of the differential amplifier is small, the differential amplifier cannot detect the differential pressure, the default is that the differential pressure between the first input end of the differential amplifier and the second input end of the differential amplifier is 0, and the detection module cannot misjudge that the current passes through the sampling resistor.
The fourth resistor and the second capacitor may be a filtering module, and may be used to stabilize the voltage signal generated by the second signal input source, so that the second signal generating module generates a stabilized second voltage signal.
The second diode can prevent the voltage of the second end of the sampling resistor from flowing backwards into the second signal generating module, so that the detection module is protected.
The principle of the second signal generating module generating the second voltage signal is as follows: the voltage signal generated by the second signal input source is subjected to current limiting through a third resistor, filtering through a fourth resistor and a second capacitor, and outputting a second voltage signal through a second diode.
Wherein the second signal input source is generated by the detection module. The second signal input source is not required to be arranged separately, so that the cost can be saved. For example, when the detection module is an MCU, the second signal input source may be an input/output (I/O) port of the MCU. The I/O port of the MCU may output a voltage signal.
Along with the power density of OBC is higher and higher, the product volume is smaller and smaller, the inside mode that can use polylith printed circuit board (printed circuit board, PCB) stromatolite to place of OBC, need use winding displacement or row needle to connect between the different PCBs, if detection module and current detection circuit divide to arrange on two different PCBs, and winding displacement or row needle between these two PCBs do not insert or damage, the current feedback loop will not establish, after the start command is received to the OBC and the start, can lead to the feedback loop open-loop, detection module can not adopt voltage and current signal, then promote output gain always, can lead to the electric current surge of OBC output under this kind of circumstances, can lead to the damage of OBC.
Referring to fig. 3, fig. 3 is a schematic diagram of a specific structure of another open loop detection circuit according to an embodiment of the application. FIG. 3 is a graph of FIG. 2, as shown in FIG. 3, where FIG. 3 further includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a third capacitor, based on FIG. 2; the first end of the sampling resistor is connected with the first end of the fifth resistor through a first flat cable, the second end of the fifth resistor is connected with the first input end of the differential amplifier and the output end of the first signal generating module, the second end of the sampling resistor is connected with the first end of the sixth resistor through a second flat cable, and the second end of the sixth resistor is connected with the second input end of the differential amplifier and the output end of the second signal generating module. The power supply end of the differential amplifier is connected with a power supply Vcc, the reference end of the differential amplifier is connected with the first end of the third capacitor, the first end of the seventh resistor and the first end of the eighth resistor, the second end of the seventh resistor is connected with a reference voltage, and the second end of the third capacitor and the second end of the eighth resistor are grounded.
The first signal input source may be one I/O port of the MCU, and the second signal input source may be another I/O port of the MCU. For example, the first signal input source may be a first I/O port (MCU-I/O-1) of the MCU and the second signal input source may be a second I/O port (MCU-I/O-2) of the MCU.
The eighth resistor and the third capacitor may be filter modules that may be used to stabilize the reference voltage signal input to the reference terminal of the differential amplifier. The seventh resistor is a current limiting resistor for limiting the current of the reference terminal of the differential amplifier, thereby preventing the current flowing through the reference terminal of the differential amplifier from being excessively large and thus protecting the differential amplifier.
The ninth resistor is a current limiting resistor and is used for protecting the detection module and preventing the current flowing through the detection module from being excessive.
In the embodiment of the application, a first voltage signal generated by the first signal generating module is sent to a first input end of the differential amplifier, when a flat cable (a first flat cable) where a fifth resistor is positioned is disconnected, a second input end of the differential amplifier is suspended and has no voltage, the first voltage signal can enable the voltage of the first input end of the differential amplifier to be higher than the voltage of the second input end of the differential amplifier, a voltage difference value between the first input end of the differential amplifier and the second input end of the differential amplifier is amplified by the differential amplifier according to a certain amplification ratio and then is output to a detection module (such as an MCU), and before an OBC does not receive a starting instruction, the detection module acquires the voltage signal and converts the voltage signal into a current value. According to the setting, no current should exist when the OBC is not started, otherwise, the OBC is judged to be abnormal in state; if a starting command is received at the moment, the OBC does not execute the starting command and reports a fault at the same time, so that the functions of identifying a current feedback loop (the current feedback loop of the OBC comprises a sampling resistor, a differential amplifier and a detection module) through a first voltage signal generated by a first signal generation module, opening the loop and protecting the OBC are realized.
The second voltage signal generated by the second signal generating module is sent to the second input end of the differential amplifier, when the connection of the flat cable (second flat cable) where the sixth resistor is located is disconnected, the first input end of the differential amplifier is suspended and has no voltage, the second voltage signal can enable the voltage of the second input end of the differential amplifier to be higher than the voltage of the first input end of the differential amplifier, the voltage difference value between the first input end of the differential amplifier and the second input end of the differential amplifier is amplified by the differential amplifier according to a certain amplification ratio, then the voltage signal is output to the detecting module (for example, MCU), and before the OBC does not receive a starting instruction, if the detecting module acquires the voltage signal, the voltage signal is converted into a current value. According to the setting, no current should exist when the OBC is not started, otherwise, the OBC is judged to be abnormal in state; if the start-up instruction is received at the moment, the OBC does not execute the start-up instruction and reports the fault at the same time, so that the functions of identifying a current feedback loop (the current feedback loop of the OBC comprises a sampling resistor, a differential amplifier and a detection module) through a second voltage signal generated by the second signal generation module, opening the loop and protecting the OBC are realized.
When the first voltage signal is generated by the first signal generating module and the second voltage signal is generated by the second signal generating module, the change of the voltage between the first input end and the second input end of the differential amplifier can be realized by changing the magnitudes of the first voltage signal and the second voltage signal, the voltage is amplified by the differential amplifier in a differential mode and then is output to the detecting module (such as an MCU), and the detecting module can identify whether the working state of the detecting circuit of the differential amplifier is normal or not according to the comparison of the magnitudes of the changed first voltage signal and the second voltage signal and the signal amplified by the differential amplifier in a differential mode.
The embodiment of the application also provides a vehicle-mounted charger, which can comprise an open-loop detection circuit as shown in any one of figures 1 to 3.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.
In several embodiments provided herein, it should be understood that the disclosed open loop detection circuit may be implemented in other ways. For example, the embodiments of open loop detection circuitry described above are merely illustrative, e.g., the division of the elements is merely a logical functional division, and there may be additional divisions in actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed.
Claims (10)
1. The open-loop detection circuit is characterized by comprising a sampling resistor, a differential amplifier, a detection module, a first signal generation module and a second signal generation module, wherein the sampling resistor is used for sampling the output current of an on-board charger (OBC);
The first end of the sampling resistor is connected with the first input end of the differential amplifier and the output end of the first signal generation module through a first flat cable, the second end of the sampling resistor is connected with the second input end of the differential amplifier and the output end of the second signal generation module through a second flat cable, and the output end of the differential amplifier is connected with the detection port of the detection module;
and under the condition that the OBC is not started and the output end of the first signal generation module or the output end of the second signal generation module outputs a voltage signal, the detection module determines whether the first flat cable and/or the second flat cable have faults according to the voltage signal detected by the detection port.
2. The circuit of claim 1, wherein at least one of the first and second flex circuits is determined to be disconnected if the voltage signal detected by the detection port of the detection module is greater than a first set threshold.
3. The circuit of claim 1, wherein it is determined that neither the first bus line nor the second bus line is faulty if the voltage signal detected by the detection port of the detection module is less than the first set threshold.
4. The circuit of claim 1, wherein the first end of the sampling resistor and the second end of the sampling resistor are located on a first printed circuit board, the first input of the differential amplifier and the second input of the differential amplifier are located on a second printed circuit board, and the output of the first signal generation module and the output of the second signal generation module are located on the second printed circuit board.
5. The circuit of claim 1, wherein the detection module determines whether the differential amplifier is malfunctioning based on the voltage signal detected by the detection port when the OBC is not on and the output of the first signal generation module outputs a first voltage signal and the output of the second signal generation module outputs a second voltage signal; the absolute value of the difference between the first voltage signal and the second voltage signal is larger than a second set threshold.
6. The circuit of claim 5, wherein the differential amplifier is determined to be malfunctioning if the voltage signal detected by the detection port of the detection module is not within a set threshold interval;
And under the condition that the voltage signal detected by the detection port of the detection module is located in the set threshold interval, determining that the differential amplifier does not have faults.
7. The circuit of any one of claims 1-6, wherein the first signal generation module comprises a first signal input source, a first resistor, a second resistor, a first diode, and a first capacitor; the first signal input source is connected with the first end of the first resistor, the second end of the first resistor is connected with the first end of the second resistor, the first end of the first capacitor and the positive electrode of the first diode, the second end of the second resistor and the second end of the first capacitor are grounded, and the negative electrode of the first diode is connected with the first input end of the differential amplifier.
8. The circuit of claim 7, wherein the second signal generation module comprises a second signal input source, a third resistor, a fourth resistor, a second diode, and a second capacitor; the second signal input source is connected with the first end of the third resistor, the second end of the third resistor is connected with the first end of the fourth resistor, the first end of the second capacitor and the positive electrode of the second diode, the second end of the fourth resistor and the second end of the second capacitor are grounded, and the negative electrode of the second diode is connected with the second input end of the differential amplifier.
9. The circuit of claim 8, wherein the first signal input source is generated by the detection module and the second signal input source is generated by the detection module.
10. A vehicle-mounted charger comprising an open loop detection circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410089656.9A CN117929965A (en) | 2024-01-22 | 2024-01-22 | Open loop detection circuit and vehicle-mounted charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410089656.9A CN117929965A (en) | 2024-01-22 | 2024-01-22 | Open loop detection circuit and vehicle-mounted charger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117929965A true CN117929965A (en) | 2024-04-26 |
Family
ID=90753351
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410089656.9A Pending CN117929965A (en) | 2024-01-22 | 2024-01-22 | Open loop detection circuit and vehicle-mounted charger |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117929965A (en) |
-
2024
- 2024-01-22 CN CN202410089656.9A patent/CN117929965A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11095119B2 (en) | Corrosion mitigation for an external connector of an electronic device | |
| JP4296811B2 (en) | Physical quantity sensor device | |
| US10794947B2 (en) | Ground loss detection circuit | |
| JP4103280B2 (en) | Mechanical quantity sensor device | |
| US9991845B2 (en) | Ground fault detection device | |
| CN101325407A (en) | Amplifier | |
| US20140320155A1 (en) | Critical capacitor built in test | |
| CN117929965A (en) | Open loop detection circuit and vehicle-mounted charger | |
| WO2017070902A1 (en) | Method for detecting btb fastening reliability, terminal and detection apparatus | |
| US7443075B2 (en) | Entrapment detecting system | |
| CN209757022U (en) | Vehicle-mounted power supply stabilizing device and system | |
| CN111474503B (en) | High-voltage interlocking system, fault positioning method thereof and high-voltage connector | |
| US7514911B2 (en) | Voltage regulator feedback protection method and apparatus | |
| CN215180528U (en) | Dust collector and filter screen separation and water tank full water detection circuit thereof | |
| JPWO2010100754A1 (en) | Detection system and electrical system | |
| CN215009573U (en) | Power supply overvoltage protection circuit | |
| US20210288486A1 (en) | Power supply system, power supply system control method, and circuit board | |
| CN213934120U (en) | Relay detection circuit and detection device based on differential sampling | |
| CN213122226U (en) | Detection circuit of wireless earphone charging box, charging box and wireless earphone | |
| US9013200B2 (en) | Circuitry for hot-swappable circuit boards | |
| KR20100094206A (en) | Oxygen sensor interface circuitry and method for oxygen sensor monitoring using thereof | |
| JP2009053133A (en) | Earth fault detection circuit for vehicle | |
| CN209764945U (en) | Acquisition circuit based on shunt | |
| CN214310819U (en) | Power supply abnormity detection circuit and PCB | |
| CN216926996U (en) | Power supply protection device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |