CN214177152U - Low-side load driving circuit with open circuit diagnosis function - Google Patents
Low-side load driving circuit with open circuit diagnosis function Download PDFInfo
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- CN214177152U CN214177152U CN202120263120.6U CN202120263120U CN214177152U CN 214177152 U CN214177152 U CN 214177152U CN 202120263120 U CN202120263120 U CN 202120263120U CN 214177152 U CN214177152 U CN 214177152U
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Abstract
The utility model relates to a low-side load driving circuit with open circuit diagnosis function, which comprises a low-side driving chip, a follow current module and an internal power supply, and further comprises a field effect transistor, a current detection resistor, a sensitive load, a feedback resistor, a pull-up resistor and a current detection module; the low-side driving chip is sequentially connected with the field effect transistor, the current detection resistor and one end of the inductive load, the other end of the inductive load is used for being connected with the storage battery power supply, the low-side driving chip is further sequentially connected with the output ends of the feedback resistor and the field effect transistor, a connecting circuit between the field effect transistor and the current detection resistor is further sequentially connected with the follow current module and the internal power supply through a branch, the pull-up resistor is connected with the two ends of the follow current module in parallel, and the current detection resistor is further connected with the current detection module through a branch. Compared with the prior art, the utility model has the advantages of greatly improved load open circuit diagnostic rate of accuracy, made things convenient for the investigation of real vehicle field trouble, walk the line simple, easy to carry out.
Description
Technical Field
The utility model belongs to the technical field of low limit load drive circuit and specifically relates to a low limit load drive circuit with open a way diagnostic function is related to.
Background
At present, inductive loads such as an oil inlet metering valve, an HC nozzle metering valve and the like in an automobile are mostly driven by low sides, and the current passing through the loads needs to be monitored in real time. The special low-side driving chip can not only realize the driving of multiple paths of low sides, but also carry out electrical fault diagnosis, and simultaneously, because the chip integration level is high, the layout space of the PCB is greatly saved, so that the special low-side driving chip is widely applied to automobile electronics. To protect the load and the driving circuit, the low-side driven inductive load is usually reflowed by a freewheeling diode having an anode connected to the low-side and a cathode connected to the internal power supply of the ECU.
Under the condition that the load is normally connected and is not driven, the low-side driving output voltage can be pulled up to the voltage of the battery jar, and when an open-circuit fault occurs, the driving chip can modulate the low-side output voltage to a certain diagnosis threshold voltage (3V) through an output end feedback loop.
The utility model discloses an use solenoid valve low side drive circuit that backs a car in AMT selector shelves as disclosing utility model CN205244354U, low side drive module comprises integrated low drive chip, load diagnosis module includes load anodal signal diagnosis branch road and load negative pole signal diagnosis branch road, MCU electronic control module links to each other with filtering module, filtering module links to each other with low side drive module's enable end, low side drive module's drive end links to each other with solenoid valve negative pole end of backing a car, the solenoid valve positive pole end of backing a car links to each other with power module, low side drive module's drive end is connected with afterflow module one end, load anodal signal diagnosis branch road, load negative pole signal diagnosis branch road one end are connected with the solenoid valve positive pole end of backing a car respectively, its other end is connected with MCU electronic control module, the afterflow module includes afterflow diode D1 and electrolytic capacitor E1, the positive end of the diode D1 is connected with the negative end of the reversing electromagnetic valve, the negative end of the diode D1 is connected with one end of an electrolytic capacitor E1, and the other end of the electrolytic capacitor E1 is grounded.
There are 2 problems with using driver chip internal diagnostic logic: 1) at high temperature, under the condition that a load is really in an open circuit, the voltage value output by the low side is pulled up to be close to the cathode voltage of a fly-wheel diode due to the large leakage current of the fly-wheel diode, and the voltage is far larger than the open circuit diagnosis threshold voltage, so that the drive chip cannot accurately report the open circuit fault; 2) under the condition of not connecting with an external load, the driving circuit cannot output correct PWM waveforms, and further the integrity of components of the driving circuit cannot be preliminarily judged.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a low limit load drive circuit with open circuit diagnostic function for overcoming the defect that the drive chip can not accurately report the open circuit fault when the prior art is at high temperature.
The purpose of the utility model can be realized through the following technical scheme:
a low-side load driving circuit with an open-circuit diagnosis function comprises a low-side driving chip, a follow current module and an internal power supply, and further comprises a field effect transistor, a current detection resistor, an inductive load, a feedback resistor, a pull-up resistor and a current detection module;
the low-side driving chip is sequentially connected with the field effect transistor, the current detection resistor and one end of an inductive load, the other end of the inductive load is used for being connected with a storage battery power supply, the low-side driving chip is further sequentially connected with the feedback resistor and the output end of the field effect transistor, a connecting circuit between the field effect transistor and the current detection resistor is further sequentially connected with the follow current module and an internal power supply through a branch, the pull-up resistor is connected with two ends of the follow current module in parallel, and the current detection resistor is further connected with the current detection module through a branch;
the low-side driving chip is used for providing driving voltage for the field effect transistor and performing fault diagnosis on the current flowing through the feedback resistor;
the current detection module is used for carrying out fault diagnosis on the current flowing through the current detection resistor.
Furthermore, the current detection module comprises a main control chip, a filtering module and a current detection amplifying module which are connected in sequence, and the current detection amplifying module is connected with the current detection resistor.
Further, the filtering module comprises a filtering capacitor and a filtering resistor, two ends of the filtering resistor are respectively connected with the main control chip and the current detection amplifying module, and the filtering resistor is connected with a connecting line of the main control chip through a branch line and then is grounded behind the filtering capacitor.
Further, the current detection amplifying module is a current detection amplifying chip.
Further, the main control chip is a chip with 12-bit AD sampling precision.
Further, the model of the low-side driving chip is C3 MIO.
Further, the freewheel module is a freewheel diode.
Further, the cathode of the freewheeling diode is connected with the internal power supply, and the anode of the freewheeling diode is connected with a connecting line between the field-effect tube and the current detection resistor.
Further, the internal power supply is an ECU internal power supply.
Further, the low-side load driving circuit is packaged in an ECU.
Compared with the prior art, the utility model has the advantages of it is following:
the utility model discloses a pull-up resistance and the examination resistance of ECU internal power supply cooperate on pulling up, avoided because the drive chip that the leakage current that freewheeling diode exists when the high temperature leads to can't correctly diagnose the emergence of the load condition of opening a way, greatly improved the load and opened a way diagnostic rate of accuracy, also can carry out preliminary diagnosis to drive circuit integrality simultaneously under the condition of not connecing the load, greatly made things convenient for the investigation of real vehicle on-the-spot trouble. Meanwhile, the scheme has simple wiring, no special component and is easy to implement.
Drawings
Fig. 1 is a schematic view of an installation state of the low-side load driving circuit of the present invention;
fig. 2 is a schematic circuit diagram of the low-side load driving circuit of the present invention;
in the figure, 1, a low-side driving chip, 2, a field effect transistor, 3, a current detection resistor, 4, an inductive load, 5, a feedback resistor, 6, a freewheeling diode, 7, a pull-up resistor, 8, a main control chip, 9, a filter capacitor, 10, a filter resistor, 11 and a current detection amplifying chip.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Example 1
The embodiment provides a low-side load driving circuit with an open-circuit diagnosis function, which comprises a low-side driving chip 1, a follow current module and an internal power supply, and is characterized in that the low-side load driving circuit further comprises a field effect transistor 2, a current detection resistor 3, an inductive load 4, a feedback resistor 5, a pull-up resistor 7 and a current detection module;
the low-side driving chip 1 is sequentially connected with a field effect transistor 2, a current detection resistor 3 and one end of an inductive load 4, the other end of the inductive load 4 is used for being connected with a storage battery power supply, the low-side driving chip 1 is further sequentially connected with a feedback resistor 5 and the output end of the field effect transistor 2, a connecting circuit between the field effect transistor 2 and the current detection resistor 3 is further sequentially connected with a follow current module and an internal power supply through a branch, a pull-up resistor 7 is connected to two ends of the follow current module in parallel, and the current detection resistor 3 is further connected with a current detection module through a branch;
the low-side driving chip 1 is used for providing driving voltage for the field effect transistor 2 and performing fault diagnosis on current flowing through the feedback resistor 5;
the current detection module is used for carrying out fault diagnosis on the current flowing through the current detection resistor 3.
As a preferred embodiment, the current detection module includes a main control chip 8, a filtering module and a current detection amplifying module, which are connected in sequence, and the current detection amplifying module is connected with the current detection resistor 3.
As a preferred embodiment, the filter module includes a filter capacitor 9 and a filter resistor 10, two ends of the filter resistor 10 are respectively connected to the main control chip 8 and the current detection amplifying module, and a connection line between the filter resistor 10 and the main control chip 8 is also connected to the filter capacitor 9 through a branch line and then grounded.
As a preferred embodiment, the current detection amplifying module is a current detection amplifying chip 11.
In a preferred embodiment, the main control chip 8 is a chip with 12-bit AD sampling precision.
In a preferred embodiment, the low side driver chip 1 has a model number of C3 MIO.
In a preferred embodiment, the freewheel module is a freewheel diode 6.
In a preferred embodiment, the cathode of the freewheeling diode 6 is connected to the internal power supply and the anode is connected to the connection between the field effect transistor 2 and the current sensing resistor 3.
As a preferred embodiment, the internal power supply is an ECU internal power supply.
As a preferred embodiment, the low-side load driving circuit is packaged in the ECU.
The embodiment further provides an optimal implementation manner, which is described in detail as follows:
aiming at the defects that the prior art can not accurately diagnose open circuit faults and can not judge the integrity of components of a driving circuit when the components are not connected with a load, the embodiment provides the low-side load driving circuit with circuit integrity detection and open circuit diagnosis, the accurate open circuit diagnosis and the drive circuit integrity detection are realized mainly by adopting a current detection resistor and a mode of pulling up low-side drive output to an ECU internal power supply, and the technical scheme is as follows:
as shown in fig. 1 and 2, the low-side load driving circuit with circuit integrity detection and open-circuit diagnosis functions includes an inductive load 4, a current detection resistor 3, a current detection amplification chip 11, a filter resistor 10, a filter capacitor 9, a main control chip 8, a freewheeling diode 6, a pull-up resistor 7, a feedback resistor 5, a low-side driving chip 1, and a field effect transistor 2. Wherein the low-side driving chip 1 is a Deerfu special low-side driving chip C3MIO, and the main control chip 8 has 12-bit AD sampling precision.
One end of an inductive load 4 is connected with a battery power supply, the other end of the inductive load carries out current sampling through a current detection resistor 3, the voltage at two ends of the sampling current detection is processed by a current detection amplifying chip 11, and is transmitted to a main control chip 8 after being filtered by a filter circuit consisting of resistors 10 and 9, and the current passing through the load 4 is monitored in real time through the main control chip.
One end of the current detection resistor 3 is connected with the inductive load, the other end of the current detection resistor is connected with the output end of the field effect transistor 2, and the low-side driving chip 1 provides driving voltage of the gate pole of the field effect transistor 2 to realize the output of PWM (pulse width modulation) waves of the field effect transistor 2. Meanwhile, the output end of the field effect transistor 2 is conveyed to the low-side driving chip 1 through the feedback resistor 5, and real-time monitoring and load electrical fault diagnosis of the output end are achieved.
The cathode of the freewheeling diode 6 is connected with the power supply inside the ECU, the anode is connected between the output end of the field effect tube 2 and the current detection resistor 3, so that freewheeling of the inductive load 4 when the field effect tube 2 is switched on and off is realized, and circuit protection and load protection are provided.
One end of the pull-up resistor 7 is connected with an ECU internal power supply, and the other end is connected between the output end of the field effect tube 2 and the current detection resistor 3.
The low-side driving chip 1 enables a gate pole of the field effect tube 2 to output PWM waves. When the inductive load works normally, the Current _ Feedback passing through the inductive load 4 can be monitored by the main control chip 8. Considering the influence of interference and other factors, when the feedback current value is less than 60 pulses, namely the feedback current is infinitely close to 0A, the load is judged to be open-circuited. When the load is in an open circuit, the voltage of the output end of the field effect tube 2 is modulated at a certain fixed threshold (usually 3V) by the driving chip, and the voltage of the output end of the field effect tube 2 is close to the voltage of an ECU (electronic control unit) internal power supply (usually equal to the voltage of a storage battery) of the cathode of the diode due to the large leakage current of the freewheeling diode at high temperature, so that the driving chip cannot make correct diagnosis on the load open circuit fault existing at high temperature. Aiming at the characteristic of the driving chip, the open-circuit diagnosis function of the driving chip is shielded by a pull-up resistor 7 which is pulled up to an internal power supply of the ECU, and the accurate diagnosis of the load open-circuit fault is realized according to a current feedback value detected by a main control chip 8.
As shown in fig. 2, when no load is connected, Gate _ Drive is driven to make the fet 2 Output a PWM wave, and normally, the same PWM waveform as that when an actual load is connected cannot be measured at the Low _ Side _ Drive _ Output terminal, so that the state of the Drive circuit component cannot be accurately determined. A loop is formed by the pull-up resistor 7 and the field effect tube 2 which are pulled up to an internal power supply of the ECU, similar PWM waves can be Output at a Low _ Side _ Drive _ Output end when the load is connected even if the load is open-circuit, and therefore preliminary diagnosis can be conveniently carried out on the integrity of components of a driving circuit. The resistance of the pull-up resistor 7 cannot be too small, otherwise, when the field effect transistor 2 is turned on, the value of the current flowing through the field effect transistor 2 is too large, which not only causes circuit damage, but also causes the drive chip to misreport the load to cause the short-circuit fault of the power supply.
The value of pull-up resistor 7 is chosen depending on the threshold of the channel for a power short fault.
In fig. 2, Current _ Feedback is Current Feedback, and Drian _ Feedback is drain Feedback.
The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.
Claims (10)
1. A low-side load driving circuit with an open-circuit diagnosis function comprises a low-side driving chip (1), a follow current module and an internal power supply, and is characterized by further comprising a field effect transistor (2), a current detection resistor (3), an inductive load (4), a feedback resistor (5), a pull-up resistor (7) and a current detection module;
the low-side driving chip (1) is sequentially connected with the field effect transistor (2), the current detection resistor (3) and one end of an inductive load (4), the other end of the inductive load (4) is used for being connected with a storage battery power supply, the low-side driving chip (1) is further sequentially connected with the feedback resistor (5) and the output end of the field effect transistor (2), a connecting circuit between the output end of the field effect transistor (2) and the current detection resistor (3) is further sequentially connected with the follow current module and an internal power supply through a branch circuit, the pull-up resistor (7) is connected to two ends of the follow current module in parallel, and the current detection resistor (3) is further connected with the current detection module through a branch circuit;
the low-side driving chip (1) is used for providing driving voltage for the field effect transistor (2) and performing fault diagnosis on current flowing through the feedback resistor (5);
the current detection module is used for carrying out fault diagnosis on the current flowing through the current detection resistor (3).
2. The low-side load driving circuit with the open circuit diagnosis function according to claim 1, wherein the current detection module comprises a main control chip (8), a filtering module and a current detection amplifying module, which are connected in sequence, and the current detection amplifying module is connected with the current detection resistor (3).
3. The low-side load driving circuit with the open circuit diagnosis function according to claim 2, wherein the filtering module comprises a filtering capacitor (9) and a filtering resistor (10), two ends of the filtering resistor (10) are respectively connected to the main control chip (8) and the current detection amplifying module, and a connection line between the filtering resistor (10) and the main control chip (8) is further connected to the filtering capacitor (9) through a branch line and then grounded.
4. The low-side load driving circuit with the open circuit diagnosis function according to claim 2, wherein the current detection amplifying module comprises a current detection amplifying chip (11).
5. The low-side load driving circuit with the open circuit diagnosis function according to claim 2, wherein the main control chip (8) is a chip with 12-bit AD sampling precision.
6. The low-side load driving circuit with the open circuit diagnosis function according to claim 1, wherein the model of the low-side driving chip (1) is C3 MIO.
7. A low-side load driving circuit with an open-circuit diagnosis function according to claim 1, wherein the freewheel module is a freewheel diode (6).
8. The low-side load driving circuit with the open circuit diagnosis function according to claim 7, wherein a cathode of the freewheel diode (6) is connected to the internal power supply, and an anode thereof is connected to a connection line between the output terminal of the field-effect transistor (2) and the current detection resistor (3).
9. The low-side load drive circuit with an open circuit diagnosis function according to claim 1, wherein the internal power supply is an ECU internal power supply.
10. The low-side load driving circuit with an open circuit diagnosis function according to claim 1, wherein the low-side load driving circuit is packaged in an ECU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120263120.6U CN214177152U (en) | 2021-01-30 | 2021-01-30 | Low-side load driving circuit with open circuit diagnosis function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120263120.6U CN214177152U (en) | 2021-01-30 | 2021-01-30 | Low-side load driving circuit with open circuit diagnosis function |
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| Publication Number | Publication Date |
|---|---|
| CN214177152U true CN214177152U (en) | 2021-09-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202120263120.6U Active CN214177152U (en) | 2021-01-30 | 2021-01-30 | Low-side load driving circuit with open circuit diagnosis function |
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- 2021-01-30 CN CN202120263120.6U patent/CN214177152U/en active Active
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Address after: 215000 No.99 tangjiabang Road, Suzhou Industrial Park, Suzhou City, Jiangsu Province Patentee after: Borg Warner drive system (Suzhou) Co.,Ltd. Address before: 215000 No.99 tangjiabang Road, Suzhou Industrial Park, Suzhou City, Jiangsu Province Patentee before: Delphi Technology (Suzhou) Co.,Ltd. |