Hall-effect sensor signal conditioning circuit with open circuit fault detection function

Abstract

The present invention provides a Hall speed sensor signal conditioning circuit with an open circuit fault detection function, including a level conversion, an electrical isolation circuit and a gate pull-up control circuit, wherein the input end of the level conversion and electrical isolation circuit is connected to the Hall speed sensor signal end, and the output end is connected to the single-chip frequency input module interface; the level conversion and electrical isolation circuits are both connected to the gate pull-up control circuit, and the gate pull-up control circuit is connected to the single-chip switch output module interface. Beneficial effects of the present invention: The Hall speed sensor signal conditioning circuit with an open circuit fault detection function described in the present invention achieves the purpose of time-sharing control of the switch tube gate pull-up function by adding a relay control circuit, thereby being able to distinguish the source of the gate high level signal, and realizing the open circuit fault detection function, and its structure is simple, easy to implement and low in cost.

Description

Technical Field

[0001] The invention belongs to the technical field of engine electronic control system signal processing, and in particular relates to a Hall speed sensor signal conditioning circuit with an open circuit fault detection function, which is suitable for an engine electronic control system with a sensor open circuit fault detection requirement. Background Art

[0002] Hall speed sensors are widely used in engine speed acquisition due to their low cost and high reliability. The signal conditioning circuit in the electronic control system is responsible for electrical isolation and level conversion of the output signal, and transmits it to the frequency acquisition module of the single-chip microcomputer. In recent years, with the increasing application of Hall speed sensors, the demand for their reliability has continued to increase. At the same time, the fault diagnosis function based on them for the engine electronic control system has been put on the agenda. However, the natural property of the Hall speed sensor output signal that changes with the crankshaft position (the output signal high and low levels are randomized and vary due to different cam / crankshaft positions) makes it difficult to distinguish between its open circuit fault characterization and normal operation characterization, which brings difficulties to the engine electronic control system's fault diagnosis. This situation is not conducive to the realization of all-round monitoring of the sensor's operating status, and limits the further improvement of the operating reliability of the entire engine control system. Summary of the invention

[0003] In view of this, the present invention aims to provide a Hall speed sensor signal conditioning circuit with an open circuit fault detection function to solve the problem that the existing Hall speed sensor cannot perform all-round monitoring in the operating state.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A Hall speed sensor signal conditioning circuit with an open circuit fault detection function comprises a level conversion, an electrical isolation circuit and a gate pull-up control circuit, wherein the input end of the level conversion and electrical isolation circuit is connected to the Hall speed sensor signal end, and the output end is connected to the single-chip computer frequency input module interface; the level conversion and electrical isolation circuits are both connected to the gate pull-up control circuit, and the gate pull-up control circuit is connected to the single-chip computer switch output module interface.

[0006] Furthermore, the level conversion and electrical isolation circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a diode D1, a MOSFET switch tube Q1 and a photocoupler U1, the cathode of the resistor R1 and the diode D1 are simultaneously connected to the signal end of the Hall speed sensor; the first end of the resistor R1, the first end of the capacitor C1 and the first end of the resistor R2 are connected; the second end of the resistor R2 is connected to the gate of the MOSFET switch tube Q1; the anode of the diode D1, the second end of the capacitor C1 and the source of the MOSFET switch tube Q1 are all connected To the negative pole GP of the power supply VCC; the drain of the MOSFET switch tube Q1 is connected to the negative pole of the light-emitting diode on the input side of the photocoupler U1; the positive pole of the light-emitting diode on the input side of the photocoupler U1 is connected to one end of the resistor R3; the other end of the resistor R3 is connected to the positive pole VCC of the power supply VCC; the emitter of the photosensitive transistor on the output side of the photocoupler U1 is connected to the negative pole GD of the power supply VDD; the collector of the photosensitive transistor on the output side of the photocoupler U1 is pulled up to the positive pole VDD of the power supply VDD through the resistor R4, and is simultaneously output to the interface of the single-chip microcomputer frequency input module.

[0007] Furthermore, the gate pull-up control circuit includes a resistor R5, a resistor R6, a resistor R7, a relay K1, a diode D2, a transistor Q2 and a photocoupler U2; the fixed contact 1 of the relay K1 is connected to the positive electrode VCC of the power supply VCC; the normally closed contact 2 of the relay K1 is connected to the signal end of the Hall speed sensor; the normally open contact 3 of the relay K1 is suspended and not connected to any terminal; one end 5 of the coil of the relay K1 is respectively connected to the negative electrode of the diode D2 and the collector of the transistor Q2; the other end 6 of the coil of the relay K1 is connected to the positive electrode of the diode D2 and the negative electrode of the power supply VCC at the same time. Pole GP; the emitter of transistor Q2 is connected to the positive electrode VCC of power supply VCC, and is connected to one end of resistor R5; the other end of resistor R5 is simultaneously connected to the base of transistor Q2 and one end of resistor R6; the other end of resistor R6 is connected to the collector of the phototransistor on the output side of photocoupler U2; the emitter of the phototransistor on the output side of photocoupler U2 is connected to the negative electrode GP of power supply VCC; the positive electrode of the light-emitting diode on the input side of photocoupler U2 is connected to the positive electrode VDD of power supply VDD; the negative electrode of the light-emitting diode on the input side of photocoupler U2 is connected to the interface of the single-chip microcomputer switch quantity output module through resistor R7.

[0008] Furthermore, the Hall rotation speed sensor signal conditioning circuit with open circuit fault detection function requires that when open circuit fault detection is not performed, the connection end between the control resistor R7 and the single-chip microcomputer switch output module is at a high level.

[0009] Furthermore, the Hall speed sensor signal conditioning circuit with open circuit fault detection function requires that when performing open circuit fault detection, if the microcontroller frequency module detects a high level, there is no need to change the control state of the connection end between the resistor R7 and the microcontroller switch output module.

[0010] Furthermore, the Hall speed sensor signal conditioning circuit with open circuit fault detection function requires that when performing open circuit fault detection, if the single-chip microcomputer frequency module detects a low level, the connection end between the resistor R7 and the single-chip microcomputer switch output module needs to be controlled to be a low level.

[0011] Compared with the prior art, the Hall speed sensor signal conditioning circuit with open circuit fault detection function described in the present invention has the following advantages:

[0012] (1) The Hall-effect sensor signal conditioning circuit with open-circuit fault detection function described in the present invention achieves the purpose of time-sharing control of the gate pull-up function of the switch tube by adding a relay control circuit, thereby being able to distinguish the source of the gate high-level signal and realize the open-circuit fault detection function. The structure is simple, easy to implement and low in cost.

[0013] (2) The Hall-effect sensor signal conditioning circuit with open-circuit fault detection function described in the present invention helps to achieve all-round monitoring of the sensor's operating status, further improving the operating reliability of the engine control system, and has a simple principle and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 The schematic diagram of the Hall-effect sensor signal conditioning circuit with open circuit fault detection function according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0016] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0017] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0018] Hall speed sensor signal conditioning circuit with open circuit fault detection function, such as Figure 1As shown, it includes a level conversion, an electrical isolation circuit and a gate pull-up control circuit, the input end of the level conversion and electrical isolation circuit is connected to the Hall speed sensor signal end, and the output end is connected to the single-chip frequency input module interface; the level conversion and electrical isolation circuits are both connected to the gate pull-up control circuit, and the gate pull-up control circuit is connected to the single-chip switch output module interface. The Hall speed sensor signal conditioning circuit with open circuit fault detection function of the present invention achieves the purpose of time-sharing control of the switch tube gate pull-up function by adding a relay control circuit, and then can distinguish the source of the gate high level signal, and realizes the open circuit fault detection function. It has a simple structure, is easy to implement and has low cost.

[0019] The level conversion and electrical isolation circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a diode D1, a MOSFET switch tube Q1 and a photocoupler U1. The cathode of the resistor R1 and the diode D1 are simultaneously connected to the signal end of the Hall speed sensor; the first end of the resistor R1, the first end of the capacitor C1 and the first end of the resistor R2 are connected; the second end of the resistor R2 is connected to the gate of the MOSFET switch tube Q1; the anode of the diode D1, the second end of the capacitor C1 and the source of the MOSFET switch tube Q1 are all connected to the The negative electrode GP of the source VCC; the drain of the MOSFET switch tube Q1 is connected to the negative electrode of the light-emitting diode on the input side of the photocoupler U1; the positive electrode of the light-emitting diode on the input side of the photocoupler U1 is connected to one end of the resistor R3; the other end of the resistor R3 is connected to the positive electrode VCC of the power supply VCC; the emitter of the photosensitive transistor on the output side of the photocoupler U1 is connected to the negative electrode GD of the power supply VDD; the collector of the photosensitive transistor on the output side of the photocoupler U1 is pulled up to the positive electrode VDD of the power supply VDD through the resistor R4, and is simultaneously output to the interface of the single-chip microcomputer frequency input module.

[0020] The gate pull-up control circuit includes a resistor R5, a resistor R6, a resistor R7, a relay K1, a diode D2, a transistor Q2 and a photocoupler U2; the fixed contact 1 of the relay K1 is connected to the positive electrode VCC of the power supply VCC; the normally closed contact 2 of the relay K1 is connected to the signal end of the Hall speed sensor; the normally open contact 3 of the relay K1 is suspended and not connected to any terminal; one end 5 of the coil of the relay K1 is respectively connected to the negative electrode of the diode D2 and the collector of the transistor Q2; the other end 6 of the coil of the relay K1 is connected to the positive electrode of the diode D2 and the negative electrode GP of the power supply VCC at the same time ; The emitter of transistor Q2 is connected to the positive electrode VCC of power supply VCC, and is connected to one end of resistor R5; the other end of resistor R5 is simultaneously connected to the base of transistor Q2 and one end of resistor R6; the other end of resistor R6 is connected to the collector of the phototransistor on the output side of photocoupler U2; the emitter of the phototransistor on the output side of photocoupler U2 is connected to the negative electrode GP of power supply VCC; the positive electrode of the light-emitting diode on the input side of photocoupler U2 is connected to the positive electrode VDD of power supply VDD; the negative electrode of the light-emitting diode on the input side of photocoupler U2 is connected to the interface of the microcontroller switch output module via resistor R7.

[0021] The Hall-effect sensor signal conditioning circuit with open-circuit fault detection function requires that the connection end between the control resistor R7 and the single-chip microcomputer switch output module be at a high level when open-circuit fault detection is not performed.

[0022] The Hall speed sensor signal conditioning circuit with open circuit fault detection function requires that when performing open circuit fault detection, if the single-chip computer frequency module detects a high level, there is no need to change the control state of the connection terminal between the resistor R7 and the single-chip computer switch output module.

[0023] The Hall speed sensor signal conditioning circuit with open circuit fault detection function requires that when performing open circuit fault detection, if the single-chip computer frequency module detects a low level, the connection end between the resistor R7 and the single-chip computer switch output module needs to be controlled to be a low level.

[0024] The working principle of this embodiment is as follows:

[0025] When there is no need to detect the open circuit fault of the Hall speed sensor, the normally closed contact of the relay pulls up the gate of the MOSFET switch tube to prevent the gate from floating and causing the switch tube Q1 to be misconnected; when it is necessary to detect the open circuit fault of the Hall speed sensor, first detect the collector level state of the phototransistor on the output side of the optocoupler U1: if it is high or low, it means that the Hall sensor pulls down the gate of the MOSFET switch tube Q1, and it can be directly determined that there is no open circuit fault; if it is a low level, it is necessary to further control R7 and the connection end of the microcontroller switch quantity module to a low level. If the collector level state of the phototransistor on the output side of the optocoupler U1 does not change, it is determined that there is no open circuit fault. If the collector level state of the phototransistor on the output side of the optocoupler U1 changes, it is determined that an open circuit fault occurs.

Claims

1. A Hall speed sensor signal conditioning circuit with open circuit fault detection function, characterized in that: It includes a level conversion, electrical isolation circuit and a gate pull-up control circuit, wherein the input end of the level conversion and electrical isolation circuit is connected to the signal end of the Hall speed sensor, and the output end is connected to the frequency input module interface of the single-chip microcomputer; the level conversion and electrical isolation circuit are both connected to the gate pull-up control circuit, and the gate pull-up control circuit is connected to the switch output module interface of the single-chip microcomputer; the level conversion and electrical isolation circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a diode D1, a MOSFET switch tube Q1 and a photocoupler U1, and the negative electrodes of the resistor R1 and the diode D1 are simultaneously connected to the signal end of the Hall speed sensor; the first end of the resistor R1 , the first end of the capacitor C1 and the first end of the resistor R2 are connected; the second end of the resistor R2 is connected to the gate of the MOSFET switch tube Q1; the anode of the diode D1, the second end of the capacitor C1 and the source of the MOSFET switch tube Q1 are all connected to the negative electrode GP of the power supply VCC; the drain of the MOSFET switch tube Q1 is connected to the negative electrode of the light-emitting diode on the input side of the photocoupler U1; the anode of the light-emitting diode on the input side of the photocoupler U1 is connected to one end of the resistor R3; the other end of the resistor R3 is connected to the positive electrode VCC of the power supply VCC; the emitter of the photosensitive transistor on the output side of the photocoupler U1 is connected to the negative electrode GD of the power supply VDD; the phototransistor on the output side of the photocoupler U1 The collector of the sensitive transistor is pulled up to the positive electrode VDD of the power supply VDD through the resistor R4, and is output to the interface of the frequency input module of the single-chip microcomputer at the same time; the gate pull-up control circuit includes resistors R5, R6, R7, relay K1, diode D2, transistor Q2 and photoelectric coupler U2; the fixed contact 1 of the relay K1 is connected to the positive electrode VCC of the power supply VCC; the normally closed contact 2 of the relay K1 is connected to the signal end of the Hall speed sensor; the normally open contact 3 of the relay K1 is suspended and is not connected to any terminal; one end 5 of the coil of the relay K1 is respectively connected to the negative electrode of the diode D2 and the collector of the transistor Q2; the other end 6 of the coil of the relay K1 is connected to The positive electrode of diode D2 is also connected to the negative electrode GP of power supply VCC; the emitter of transistor Q2 is connected to the positive electrode VCC of power supply VCC and is connected to one end of resistor R5; the other end of resistor R5 is also connected to the base of transistor Q2 and one end of resistor R6; the other end of resistor R6 is connected to the collector of the phototransistor on the output side of photocoupler U2; the emitter of the phototransistor on the output side of photocoupler U2 is connected to the negative electrode GP of power supply VCC; the positive electrode of the light-emitting diode on the input side of photocoupler U2 is connected to the positive electrode VDD of power supply VDD; the negative electrode of the light-emitting diode on the input side of photocoupler U2 is connected to the interface of the microcontroller switch output module via resistor R7.

2. The Hall speed sensor signal conditioning circuit with open circuit fault detection function according to claim 1, characterized in that: The Hall rotation speed sensor signal conditioning circuit with open circuit fault detection function requires that when open circuit fault detection is not performed, the connection end between the control resistor R7 and the single-chip microcomputer switch output module is at a high level.

3. The Hall speed sensor signal conditioning circuit with open circuit fault detection function according to claim 2, characterized in that: The Hall speed sensor signal conditioning circuit with open circuit fault detection function requires that when performing open circuit fault detection, if the single-chip computer frequency module detects a high level, there is no need to change the control state of the connection terminal between the resistor R7 and the single-chip computer switch output module.

4. The Hall speed sensor signal conditioning circuit with open circuit fault detection function according to claim 2, characterized in that: The Hall speed sensor signal conditioning circuit with open circuit fault detection function requires that when performing open circuit fault detection, if the single-chip computer frequency module detects a low level, the connection end between the resistor R7 and the single-chip computer switch output module needs to be controlled to be a low level.

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