CN217112630U

CN217112630U - Comparator circuit and pulse signal detection device for vehicle generator

Info

Publication number: CN217112630U
Application number: CN202220758802.9U
Authority: CN
Inventors: 张善理; 张红燕; 赵晨远; 梁群
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2022-08-02
Anticipated expiration: 2032-04-01

Abstract

The utility model relates to a comparator circuit and a pulse signal detection device for vehicle generator including this comparator circuit. The comparator circuit includes: inputting a pin; an output pin; a reference power supply; the comparator comprises a first input end, a second input end and an output end, wherein the second input end is connected to an input pin of the comparator circuit; a voltage divider sub-circuit including a first terminal, a second terminal connected to the output terminal of the comparator, a third terminal connected to a reference power supply, and a fourth terminal connected to the first input terminal of the comparator, and configured to provide different reference thresholds for the comparator circuit based on a supply voltage of the reference power supply; and a level shift sub-circuit connected between the first terminal of the voltage division sub-circuit and the output pin of the comparator circuit. According to the utility model discloses a comparator circuit can follow mains voltage and adjust its high, low threshold value automatically in proportion to, can reduce circuit cost to application range is wider.

Description

Comparator circuit and pulse signal detection device for vehicle generator

Technical Field

The utility model relates to a comparator circuit field, more specifically, the utility model relates to a comparator circuit to and including this comparator circuit, be used for vehicle generator's pulse signal detection device.

Background

The vehicle generator is the primary power source for the vehicle and can replace the vehicle battery to power the entire vehicle electrical system after the engine is started. In order to ensure the normal operation of the vehicle electrical system, it is necessary to monitor the pulse signal output by the generator in real time.

Typically, a comparator circuit is employed to detect the pulse signal of the generator. The conventional comparator utilizes a fixed threshold to filter noise in the input signal, however, when the power voltage of the comparator fluctuates greatly, it is not easy to filter noise pulses proportional to the power voltage. Furthermore, a fixed threshold comparator also does not facilitate modular design of the circuit, as such a comparator is difficult to be compatible with both 12V and 24V vehicle electrical systems.

The hysteresis comparator can overcome jitter interference in the input signal, and even if the input signal jitters near a low threshold value, the output voltage can be kept stable and cannot be influenced by the interference signal as long as the high threshold value is not exceeded. The conventional hysteresis comparator is connected in the following manner: the output end of the slave comparator is connected to the non-inverting input end (or the inverting input end) of the comparator through a positive feedback resistor. However, the conventional hysteretic comparator can only output its own power supply voltage at the highest, and the power supply voltage of the comparator is usually a fixed value (e.g. 3.3V or 5V). That is, both the high and low thresholds of the comparator are limited by the supply voltage and cannot follow the supply voltage in a fixed proportion, e.g., the thresholds of the comparator cannot be set to 0.6Vbat and 0.8Vbat, where Vbat is the voltage of any variable vehicle electrical system.

In practice, for a vehicle generator, the amplitude of the noise signal at its output terminal typically varies in proportion to the vehicle supply voltage, in particular, the amplitude of the noise signal is in a direct proportional relationship with the vehicle supply voltage. In the case of fluctuations in the vehicle supply voltage, it is difficult to achieve synchronous adjustment of the comparator threshold with changes in the supply voltage using a hysteresis comparator with a fixed threshold, and thus it is difficult to achieve a good filtering effect.

In addition, in order to expand the range of use of products, more and more automobile manufacturers seek hardware modularization and generalization of the in-vehicle electronic devices. The application to generator pulse signal detection equipment requires that a hysteresis comparator can simultaneously meet the requirements of 12V and 24V vehicle electrical systems, and the traditional hysteresis comparator with a fixed threshold value is obviously difficult to meet the requirements.

SUMMERY OF THE UTILITY MODEL

The utility model provides a comparator circuit, it has positive feedback bleeder circuit, can follow mains voltage and adjust its high, low threshold value automatically proportionally. Particularly, according to the utility model discloses a comparator circuit includes:

an input pin for receiving a pulse signal from a vehicle;

an output pin for outputting a comparison result of the comparator circuit;

a reference power supply;

a comparator comprising a first input, a second input, and an output, wherein the second input of the comparator is connected to the input pin of the comparator circuit;

a voltage divider sub-circuit including a first terminal, a second terminal connected to the output of the comparator, a third terminal connected to the reference power supply, and a fourth terminal connected to the first input of the comparator, and configured to provide different reference thresholds for the comparator circuit based on a supply voltage of the reference power supply; and

a level shifting sub-circuit connected between a first terminal of the voltage divider sub-circuit and an output pin of the comparator circuit.

Optionally, the voltage divider sub-circuit comprises:

a first resistor;

a second resistor, a first end of the second resistor being connected to the reference power supply, a second end of the second resistor being connected to a first end of the first resistor;

a first end of the third resistor is connected to the second end of the second resistor, and a second end of the third resistor is grounded; and

a switch assembly configured to selectively turn on or off a connection between the second end of the first resistance and the first end of the second resistance based on an output result at an output terminal of the comparator.

Optionally, the switching component comprises a first transistor and a second transistor each having a power input terminal, a power output terminal, and a control terminal,

wherein a power input terminal of the first transistor is connected to a first terminal of the second resistor, a power output terminal of the first transistor is connected to a second terminal of the first resistor,

the control end of the second transistor is connected to the output end of the comparator, the power input end of the second transistor is connected to the control end of the first transistor, and the power output end of the second transistor is grounded.

Optionally, the comparator circuit further includes a fourth resistor, a first end of the fourth resistor is connected to the power input end of the first transistor, and a second end of the fourth resistor is connected to the control end of the first transistor.

Optionally, the level shifting sub-circuit comprises:

a power supply is pulled up;

a fifth resistor, a first end of the fifth resistor being connected to the pull-up power supply, a second end of the fifth resistor being connected to an output pin of the comparator circuit; and

and the anode of the diode is connected to the second end of the fifth resistor, and the cathode of the diode is connected to the power input end of the second transistor.

Optionally, the comparator circuit further includes a sixth resistor, a first end of the sixth resistor is connected to the output end of the comparator, and a second end of the sixth resistor is connected to the control end of the second transistor.

Optionally, the comparator circuit further includes a seventh resistor and an eighth resistor, a first end of the seventh resistor is connected to the input pin of the comparator circuit, a second end of the seventh resistor is connected to the first end of the eighth resistor and the second input end of the comparator, and a second end of the eighth resistor is grounded.

Optionally, the comparator circuit further includes a ninth resistor, a first end of the ninth resistor is connected to the control end of the first transistor, and a second end of the ninth resistor is connected to the power input end of the second transistor.

Optionally, the first transistor is a PNP-type triode or a P-channel MOSFET; and/or the second transistor is an NPN type triode.

Another aspect of the present invention provides a pulse signal detection device for a vehicle generator, the pulse signal detection device including the comparator circuit as described above.

According to the utility model discloses an advantage that comparator circuit has for traditional hysteresis comparator circuit includes:

1) the high and low threshold values of the comparator circuit can automatically and proportionally track the power supply voltage, so that the noise signal which changes in proportion to the power supply voltage can be effectively filtered.

2) For the core device comparator U1, the output end thereof is not directly connected to the reference power supply BAT +, but is connected to BAT + through the second transistor Q2, the fourth resistor R4 and the ninth resistor R9, which is equivalent to constructing a high voltage isolation barrier around the comparator; similarly, the non-inverting INPUT terminal of the comparator U1 is not directly connected to the reference power supply BAT +, but is connected to the reference power supply BAT + through the second resistor R2 and the grounded third resistor R3, and the inverting INPUT terminal of the comparator U1 is not directly connected to the INPUT pin INPUT, but is connected to the INPUT pin INPUT through the seventh resistor R7 and the grounded eighth resistor R8, which is equivalent to a high-voltage isolation barrier also constructed at the INPUT terminal of the comparator, so that the selectable model range of the comparator U1 is wide, and for example, a low-cost and general-purpose low-voltage comparator chip or amplifier chip can be used for implementation.

3) The comparator circuit comprises an independent level conversion sub-circuit, the sub-circuit is suitable for being connected with MCU IO pins required by different levels, for example, a V _ MCU is 3.3V interface, if other level interfaces (for example, 1.8V) are required to be connected, only a pull-up power supply V _ MCU in the level conversion sub-circuit needs to be changed into 1.8V, therefore, the comparator circuit has good modularity, the comparator circuit can be directly used on vehicle electronic equipment with different power supply voltages, and the application range is wide.

4) Because the transistor Q1 in the voltage divider circuit adopts the MOSFET, the internal resistance is low (generally dozens of m omega-hundreds of m omega), compared with the resistance value of the R1 (generally dozens of K omega-hundreds of K omega) connected in series with the MOSFET, the conduction internal resistance of the Q1 can be ignored, and therefore the comparator circuit can still have good linearity when being suitable for large voltage fluctuation of 9-32V. In addition, the MOSFET of the Q1 can be replaced by a PNP type triode, so that the circuit cost is further reduced.

Drawings

Fig. 1 shows a schematic diagram of a comparator circuit according to a first embodiment of the invention.

Fig. 2 shows a schematic diagram of a comparator circuit according to a second embodiment of the invention.

Detailed Description

A comparator circuit according to the present invention will be described below by way of embodiments with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention to those skilled in the art. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. Rather, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement the present invention. Thus, the following aspects, features, embodiments and advantages are merely illustrative and should not be considered elements or limitations of the claims except where explicitly recited in a claim(s).

The applicant researches and discovers that the bus power supply voltage of the whole vehicle electrical system is not constant, for example, in a 24V vehicle electrical system, when a storage battery is used for supplying power independently, the whole vehicle power supply voltage generally fluctuates between 22 and 24VDC, and the specific voltage value depends on the discharge state of the storage battery; after the vehicle engine is started, the vehicle electrical system voltage generally fluctuates between 26 VDC and 28VDC, depending on the load of the vehicle electrical system. That is, for the vehicle electrical system, there is a voltage difference of 28-22 ═ 6V.

In addition, a large number of loads of electrical devices exist on the power line of the entire vehicle, and the switching actions of the operating states of the electrical devices, such as turning on and off, can cause voltage fluctuations on the power line of the entire vehicle, for example, five types of pulse interference on the power line of the ISO7637 standard.

If the high and low thresholds of the hysteretic comparator cannot follow the variations in the supply voltage, a malfunction of the comparator may be caused when the noise voltage exceeds the fixed threshold of the comparator. In addition, the vehicle electrical systems exhibit a modularization trend, and therefore, each electrical module (particularly, the comparator module) is required to be capable of adapting to different vehicle electrical systems, for example, 12V/24V compatible vehicle electrical systems, and thus the comparator is required to be capable of adjusting its own threshold value in proportion to the system power supply voltage within a range of 9-32 VDC.

Therefore, according to the utility model provides a mains voltage follow-up type comparator circuit, its high, low threshold value can follow the noise in the mains voltage automatically and become the proportion undulant to can play the fine effect of removing the noise.

Fig. 1 shows a schematic diagram of a comparator circuit according to a first exemplary embodiment of the present invention. As shown in fig. 1, the comparator circuit includes an INPUT pin INPUT for receiving a pulse signal from a vehicle, an OUTPUT pin OUTPUT for outputting a comparison result of the comparator circuit, and a reference power supply BAT +. The comparator circuit is generally composed of a comparator U1, a voltage divider sub-circuit 10, and a level shifter sub-circuit 20, and the detailed circuit structure and connection relationship among these components will be mainly described with reference to fig. 1.

The core element comparator U1 may be implemented by using a low-cost common low-voltage comparator chip or amplifier chip, and includes a first input terminal 1 (e.g., a non-inverting input terminal), a second input terminal 2 (e.g., an inverting input terminal), and an output terminal 5, where the first input terminal 1 of the comparator is used for connecting to a feedback voltage divider sub-circuit, and the second input terminal is used for receiving a pulse signal from a vehicle.

The voltage divider circuit 10 has four connection terminals, wherein a first terminal is connected to the input terminal of the level shifter circuit 20, a second terminal is connected to the output terminal of the comparator U1, a third terminal is connected to the reference power BAT +, and a fourth terminal is connected to the first input terminal of the comparator U1.

Specifically, as shown in fig. 1, the voltage divider sub-circuit 10 includes a first resistor R1, a second resistor R2, a third resistor R3, and a switching element configured by a first transistor Q1 and a second transistor Q2.

A first end of the second resistor R2 is connected to the reference power source BAT +, a second end of the second resistor R2 is connected to a first end of the first resistor R1, a first end of the third resistor R3 is connected to a second end of the second resistor R2, and a second end of the third resistor R3 is grounded. In addition, the connection between the second end of the first resistor R1 and the first end of the second resistor R2 is selectively switched on or off under the control of the switch assembly.

Transistors Q1, Q2 each have a power input, a power output, and a control terminal. In the first embodiment shown in fig. 1, the first transistor Q1 is configured as a P-channel MOSFET, and the second transistor Q2 is configured as an NPN-type transistor.

Thus, under this first embodiment, the power input terminal of the first transistor Q1 is configured as the source of a P-channel MOSFET, the power output terminal of the first transistor Q1 is configured as the drain of a P-channel MOSFET, and the control terminal of the first transistor Q1 is configured as the gate of a P-channel MOSFET. In addition, the power input terminal of the second transistor Q2 is configured as a collector of an NPN transistor, the power output terminal of the second transistor Q2 is configured as an emitter of the NPN transistor, and the control terminal of the second transistor Q2 is configured as a base of the NPN transistor.

The connection relationship of the respective terminals of the transistors Q1, Q2 is also clearly shown in fig. 1, wherein the power input terminal of the first transistor Q1 is connected to the first terminal of the second resistor R2, the power output terminal of the first transistor Q1 is connected to the second terminal of the first resistor R1,

a control end of the second transistor Q2 is connected to the output end 5 of the comparator U1, a power input end of the second transistor Q2 is connected to a control end of the first transistor Q1, and a power output end of the second transistor Q2 is grounded.

In addition, the comparator circuit according to the present invention may further include a fourth resistor R4, wherein a first end of the fourth resistor R4 is connected to the power input terminal of the first transistor Q1, and a second end of the fourth resistor R4 is connected to the control terminal of the first transistor Q1. The comparator circuit may further include a ninth resistor R9, a first end of the ninth resistor R9 is connected to the control end of the first transistor Q1, and a second end of the ninth resistor R9 is connected to the power input end of the second transistor Q2.

Since the non-inverting input end 1 of the comparator U1 is connected with the voltage dividing sub-circuit 10, and the output end thereof is not directly connected with the reference power supply BAT +, but is connected with the BAT + through the second transistor Q2, the fourth resistor R4 and the ninth resistor R9, which is equivalent to that a high-voltage isolation barrier is constructed around the comparator; similarly, the non-inverting INPUT of the comparator U1 is not directly connected to the reference power supply BAT +, but is connected to the reference power supply BAT + through the second resistor R2 and the grounded third resistor R3, and the inverting INPUT of the comparator U1 is not directly connected to the INPUT pin INPUT, but is connected to the INPUT pin INPUT through the seventh resistor R7 and the grounded eighth resistor R8, which is equivalent to a high voltage isolation barrier also being constructed at the INPUT of the comparator. Thus, the comparator U1 may be implemented using a low-voltage comparator chip or amplifier chip of a low-cost, general-purpose type.

The level shift circuit 20 is disposed between the first terminal of the voltage division sub-circuit 10 and the OUTPUT pin OUTPUT of the comparator circuit, and is configured to perform a level shift operation on the OUTPUT result of the comparator U1. Specifically, the level shift circuit 20 includes a pull-up power source V _ MCU, a pull-up resistor (also referred to as a fifth resistor) R5, and a diode D1.

A first end of the fifth resistor R5 is connected to the pull-up power supply V _ MCU, and a second end of the fifth resistor R5 is connected to an OUTPUT pin OUTPUT of the comparator circuit; the anode of the diode D1 is connected to the second terminal of the five-resistor R5, and the cathode of the diode D1 is connected to the first terminal of the voltage divider circuit 10, i.e., the power input terminal of the second transistor Q2.

In addition, the output terminal of the comparator U1 and the control terminal of the second transistor Q2 may not be in a direct connection relationship, and an additional sixth resistor R6 may be disposed therebetween.

In addition, another voltage dividing sub-circuit 30 may be further disposed between the inverting INPUT terminal of the comparator U1 and the INPUT pin INPUT of the comparator circuit, the another voltage dividing sub-circuit 30 includes a seventh resistor R7 and an eighth resistor R8, wherein a first end of the seventh resistor R7 is connected to the INPUT pin INPUT of the comparator circuit, a second end of the seventh resistor R7 is connected to a first end of the eighth resistor R8 and the inverting INPUT terminal of the comparator, and a second end of the eighth resistor R8 is grounded.

Fig. 2 shows a schematic diagram of a comparator circuit according to a second exemplary embodiment of the present invention. This second embodiment is different from the first embodiment shown in fig. 1 in that the MOSFET of the first transistor Q1 is replaced with a PNP type transistor, whereby the circuit cost can be further reduced in the place where the demand is not high. However, due to the saturation voltage drop between the collector and emitter of the transistor, the linearity of the circuit following the power supply voltage variation curve is lost to some extent.

Therefore, in this second embodiment, the power input terminal of the first transistor Q1 is configured as the emitter of a PNP transistor, the power output terminal of the first transistor Q1 is configured as the collector of the PNP transistor, and the control terminal of the first transistor Q1 is configured as the base of the PNP transistor.

The voltage divider sub-circuit 10 may provide different reference thresholds for the comparator circuit based on the supply voltage Vbat of the reference power supply BAT +. That is, due to the special configuration of the comparator circuit, in particular of its voltage divider sub-circuit 10, the high threshold Vthh and the low threshold Vthl of the comparator circuit according to the invention may follow the variations of the supply voltage.

The following describes a method for selecting parameters of each component of the comparator circuit and a method for calculating high and low thresholds Vthh and Vthl thereof according to the present invention.

The working principle of the comparator circuit is as follows:

assume that Q1 can select a MOSFET with a low on-resistance, i.e., negligible on-resistance.

When the output terminal 5 of the comparator U1 outputs a low level, Q2 is turned off, the gate voltage and the source voltage of Q1 are equal, and Q1 is turned off. In this case, the threshold of the comparator circuit is determined by a voltage divider circuit composed of R2 and R3.

When the output terminal 5 of the comparator U1 outputs a high level, Q2 is turned on, the gate voltage of Q1 is less than the source voltage thereof, and Q1 is turned on. At this time, the threshold of the comparator circuit is determined by a voltage divider circuit composed of R1, R2, and R3.

Based on the above logic, the calculation formula of the high and low thresholds Vthh and Vthl of the comparator circuit is:

high threshold value:

low threshold value:

when the pulse signal voltage received at the INPUT pin INPUT of the comparator circuit is greater than Vthh, the comparator U1 OUTPUTs a low level, Q2 is turned off, D1 is turned off, and the OUTPUT pin OUTPUT of the comparator circuit is pulled up to a high level by the resistor R5.

When the pulse signal voltage received at the INPUT pin INPUT of the comparator circuit is less than Vthl, the comparator U1 OUTPUTs a high level, Q2 is turned on, D1 is turned on, and the OUTPUT pin OUTPUT of the comparator circuit is pulled low.

According to the above-mentioned operating principle of the comparator circuit, the following set of circuit equations can be listed:

low threshold equation:

high threshold equation:

where Vbat can be reduced from both sides of the equation, then the above equation set can be reduced to the following equation set relating only to the power supply voltage follower factor (where α is the low threshold scaling factor and β is the high threshold scaling factor) and the resistance value:

low threshold equation:

high threshold equation:

when the initial resistance value of the partial resistance and the power supply voltage following coefficients alpha and beta are given, the resistance values of the rest resistors which meet the requirements can be obtained by using the equation set.

For example, when it is required to set a power supply voltage follower type comparator circuit having a low threshold Vthl of 0.5Vbat and a high threshold Vthh of 0.8Vbat, where the power supply voltage Vbat varies from 9 to 32VDC, α may be set to 0.5 and β may be set to 0.8.

Assuming that R1 is 100K, R8 is 20K, and R7 is 180K, based on the simplified equation set, R2 is 65.217K and R3 is 3.43K, and then a similar standard resistance resistor is selected according to the standard resistance table. Similarly, the resistance value satisfying the scaling factor threshold of other power supplies can be solved.

According to the utility model discloses a comparator circuit can use in the pulse signal detection device of vehicle generator for real-time supervision wheel generator's pulse signal.

As described above, according to the present invention, the comparator circuit has a positive feedback voltage-dividing sub-circuit, which can automatically adjust its high and low thresholds in proportion to the power supply voltage, and the advantages of the comparator circuit compared to the conventional hysteresis comparator circuit include:

2) For the core device comparator U1, the output end of the core device comparator U1 is not directly connected with the reference power supply BAT +, but is connected with the BAT + through the second transistor Q2, the fourth resistor R4 and the ninth resistor R9, which is equivalent to constructing a high-voltage isolation barrier around the comparator; similarly, the non-inverting INPUT terminal of the comparator U1 is not directly connected to the reference power supply BAT +, but is connected to the reference power supply BAT + through the second resistor R2 and the grounded third resistor R3, and the inverting INPUT terminal of the comparator U1 is not directly connected to the INPUT pin INPUT, but is connected to the INPUT pin INPUT through the seventh resistor R7 and the grounded eighth resistor R8, which is equivalent to constructing an isolation barrier for high voltage at the INPUT terminal of the comparator, therefore, the selectable model range of the comparator U1 is wide, and for example, the comparator can be implemented by using a low-voltage comparator chip or an amplifier chip with low cost and general purpose.

3) The comparator circuit has an independent level conversion sub-circuit 20, and the sub-circuit is suitable for connecting MCU IO pins with different level requirements, for example, V _ MCU is a 3.3V interface, and if other level interfaces (for example, 1.8V) need to be connected, only the pull-up power supply V _ MCU in the level conversion sub-circuit 20 needs to be changed into 1.8V, so that the comparator circuit has good modularity, can be directly used in vehicle electronic devices with different power supply voltages, and has a wide application range.

4) Because the first transistor Q1 in the voltage-dividing sub-circuit 30 is a MOSFET, its internal resistance is low (generally tens of m Ω to hundreds of m Ω), compared with the resistance value of R1 connected in series with it (generally tens of K Ω to hundreds of K Ω), the on-resistance of Q1 can be ignored, so that the comparator circuit can still have good linearity when adapting to large voltage fluctuation of 9-32V. In addition, the MOSFET of the Q1 can be replaced by a PNP type triode, so that the circuit cost is further reduced.

While certain aspects of the present invention have been shown and discussed, those skilled in the art will appreciate that: changes may be made in the above aspects without departing from the principles and spirit of the invention, the scope of which is, therefore, defined in the appended claims and their equivalents. Furthermore, terms such as "first", "second", "third", and "fourth" do not denote an order of elements or values in time, space, size, or the like, but are used merely to distinguish one element or value from another.

Claims

1. A comparator circuit, the comparator circuit comprising:

an INPUT pin (INPUT) for receiving a pulse signal from a vehicle;

an OUTPUT pin (OUTPUT) for outputting a comparison result of the comparator circuit;

a reference power supply (BAT +);

a comparator (U1) comprising a first input (1), a second input (2) and an output (5), wherein the second input of the comparator is connected to an input pin of the comparator circuit;

a voltage divider sub-circuit (10) comprising a first terminal, a second terminal connected to the output (5) of the comparator, a third terminal connected to the reference supply and a fourth terminal connected to the first input of the comparator, and configured to provide different reference thresholds for the comparator circuit based on the supply voltage of the reference supply; and

a level shifting sub-circuit (20) connected between the first terminal of the voltage divider sub-circuit (10) and the OUTPUT pin (OUTPUT) of the comparator circuit.

2. Comparator circuit according to claim 1, characterized in that the voltage divider sub-circuit (10) comprises:

a first resistance (R1);

a second resistor (R2), a first terminal of the second resistor being connected to the reference power supply (BAT +), a second terminal of the second resistor being connected to a first terminal of the first resistor;

a third resistor (R3), a first end of the third resistor being connected to a second end of the second resistor, a second end of the third resistor being connected to ground; and

3. The comparator circuit of claim 2, wherein the switching component comprises a first transistor (Q1) and a second transistor (Q2) each having a power input, a power output, and a control terminal,

wherein a power input terminal of the first transistor (Q1) is connected to a first terminal of the second resistor, a power output terminal of the first transistor (Q1) is connected to a second terminal of the first resistor,

wherein a control terminal of the second transistor (Q2) is connected to the output terminal of the comparator, a power input terminal of the second transistor (Q2) is connected to the control terminal of the first transistor (Q1), and a power output terminal of the second transistor (Q2) is grounded.

4. The comparator circuit according to claim 3, characterized in that it further comprises a fourth resistor (R4), a first terminal of said fourth resistor being connected to the power input terminal of said first transistor (Q1), a second terminal of said fourth resistor being connected to the control terminal of said first transistor (Q1).

5. Comparator circuit according to claim 3 or 4, characterized in that the level shifting sub-circuit (20) comprises:

a pull-up power supply (V _ MCU);

a fifth resistor (R5), a first end of the fifth resistor (R5) being connected to the pull-up power supply (V _ MCU), a second end of the fifth resistor (R5) being connected to an OUTPUT pin (OUTPUT) of the comparator circuit; and

a diode (D1), an anode of the diode (D1) being connected to the second terminal of the fifth resistor (R5), a cathode of the diode being connected to the power input terminal of the second transistor.

6. The comparator circuit according to claim 3 or 4, further comprising a sixth resistor (R6), a first terminal of the sixth resistor being connected to the output terminal of the comparator, a second terminal of the sixth resistor being connected to the control terminal of the second transistor (Q2).

7. The comparator circuit according to claim 3 or 4, further comprising a seventh resistor (R7) and an eighth resistor (R8), wherein a first terminal of the seventh resistor is connected to the input pin of the comparator circuit, a second terminal of the seventh resistor is connected to a first terminal of the eighth resistor and a second input terminal of the comparator circuit, and a second terminal of the eighth resistor is connected to ground.

8. The comparator circuit according to claim 3 or 4, further comprising a ninth resistor (R9), a first terminal of the ninth resistor being connected to the control terminal of the first transistor, a second terminal of the ninth resistor being connected to the power input terminal of the second transistor.

9. The comparator circuit according to claim 3 or 4, characterized in that the first transistor (Q1) is a PNP transistor or a P-channel MOSFET; and/or the second transistor (Q2) is an NPN transistor.

10. A pulse signal detection device for a vehicle generator, characterized by comprising a comparator circuit according to any one of claims 1 to 9.