Low-side driving circuit and electronic equipment

Abstract

A low-side driving circuit and an electronic device belong to the technical field of driving, are connected with a load, and output a driving signal through the driving circuit. The first switching circuit switches on or switches off the transmission of the power supply direct current according to the driving signal; the temperature difference detection circuit outputs a first trigger signal in response to the condition that the difference between the temperature of the first switching circuit and the temperature of the driving circuit is greater than a preset value; the second switch circuit connects a driving signal to a power ground according to the first trigger signal, so that the first switch circuit stops working; therefore, protection under the working condition of large transient temperature change (such as a load short circuit fault) of the switching tube in the first switching circuit is realized, and the safety and the reliability are improved.

Description

Technical Field

[0001] The present application belongs to the field of drive technology, and in particular relates to a low-side drive circuit and an electronic device. Background Art

[0002] The relevant low-side driving circuit includes a temperature detection circuit, a driving circuit, a first switching circuit and a second switching circuit. The driving circuit outputs a driving signal. The switching circuit transmits a power supply DC to power the load according to the driving signal. When the temperature of the first switching circuit is greater than a preset temperature, the temperature detection circuit outputs a trigger signal to enable the second switching circuit to transmit the driving signal to the power ground, thereby realizing temperature protection for the low-side driving circuit.

[0003] However, when the first switch circuit in the above low-side driving circuit is short-circuited, the temperature of the first switch circuit rises very quickly. Due to the circuit delay, the switch tube in the first switch circuit is not turned off in time, and the switch tube is damaged by breakdown.

[0004] Therefore, the safety and reliability of the related low-side driving circuit are low. Utility Model Content

[0005] In view of the above problems, the present application provides a low-side driving circuit and an electronic device, aiming to solve the problems of low safety and reliability of related low-side driving circuits.

[0006] In a first aspect, the present application provides an embodiment of the present application that provides a low-side driving circuit connected to a load, including:

[0007] A driving circuit, used for outputting a driving signal;

[0008] A first switch circuit, connected to the load and the drive circuit, and configured to turn on or off the transmission of the power supply DC according to the drive signal;

[0009] a temperature difference detection circuit, configured to output a first trigger signal in response to a difference between the temperature of the first switch circuit and the temperature of the drive circuit being greater than a preset value;

[0010] The second switch circuit is connected to the temperature difference detection circuit, the drive circuit and the first switch circuit, and is used to transmit the drive signal to the power ground according to the first trigger signal to stop the first switch circuit from working.

[0011] In the technical solution of the embodiment of the present application, when the difference between the temperature of the first switch circuit and the temperature of the drive circuit is greater than a preset value, the temperature difference detection circuit outputs a first trigger signal to enable the second switch circuit to transmit the drive signal to the power ground according to the first trigger signal, thereby stopping the first switch circuit from working; since the temperature of the first switch circuit rises very quickly when the difference between the temperature of the first switch circuit and the temperature of the drive circuit is greater than the preset value, protection is achieved for the operating conditions where the transient temperature change of the switch tube in the first switch circuit is large (such as a load short circuit fault), reducing the possibility of the switch tube in the first switch circuit not being shut down in time due to circuit delay, reducing the possibility of breakdown damage of the switch tube, and improving the reliability and safety of the low-side drive circuit.

[0012] In some embodiments, it also includes:

[0013] a temperature detection circuit connected to the second switch circuit, and configured to output a second trigger signal in response to the temperature of the first switch circuit being greater than a preset temperature;

[0014] The second switch circuit is specifically configured to transmit the drive signal to a power ground according to the first trigger signal and / or the second trigger signal, so as to stop the first switch circuit from working.

[0015] By adopting the above scheme, when the temperature of the first switch circuit is greater than the preset temperature, the drive signal is transmitted to the power ground, so that the first switch circuit stops working, achieving temperature protection of the low-side drive circuit, and further improving safety and reliability.

[0016] In some embodiments, the first switch circuit has a control end, an input end, and an output end, and is specifically used to receive a drive signal from the control end, receive the power supply DC from the input end, and transmit the power supply DC to the output end according to the drive signal.

[0017] The first switch circuit has a simple structure and low cost.

[0018] In some embodiments, the load is an inductive load; the low-side driving circuit further includes a first clamping circuit and a pull-down circuit;

[0019] The inductive load is used to generate an induced electromotive force when the power supply DC is disconnected, so as to output a first negative voltage to the input end of the first switch circuit;

[0020] The first switch circuit is further configured to output a second negative voltage from the control terminal according to the first negative voltage;

[0021] The first clamping circuit is connected to the inductive load and the first switch circuit, and is used to clamp a first voltage between the first negative electrode voltage and the second negative electrode voltage, and output a conducting current according to the supply DC power;

[0022] The pull-down circuit is connected to the first clamp circuit, the first switch circuit and the drive circuit, and is used to output a switch signal to a control end of the first switch circuit according to the conduction current;

[0023] The first switch circuit is further used to transmit the supply DC power according to the switch signal to eliminate the induced electromotive force.

[0024] By adopting the above scheme, when the power supply DC is disconnected, the first clamping circuit clamps the first voltage between the first negative electrode voltage and the second negative electrode voltage, thereby clamping the drain-gate voltage of the switch tube in the switch circuit and reducing the possibility of the switch tube breakdown; and the first clamping circuit also outputs a conduction current according to the power supply DC to make the pull-down circuit output a switch signal to the control end of the first switch signal, so that the first switch circuit transmits the power supply DC and eliminates the induced electromotive force; thereby further realizing the protection of the drain-gate voltage of the switch tube in the switch circuit; therefore, the possibility of the switch tube breakdown is reduced, and when applied to inductive loads, the reliability and safety of the low-side drive circuit are improved.

[0025] In some embodiments, it also includes:

[0026] a current detection circuit, connected to the drive circuit, the first switch circuit, the first clamp circuit and the inductive load, and configured to detect the current of the DC power supply to output a current detection signal;

[0027] A third switching circuit is connected to the current detection circuit, the drive circuit and the first switching circuit, and is used to connect the control end of the first switching circuit and the output end of the first switching circuit in response to the voltage of the current detection signal being greater than a first preset voltage, so that the first switching circuit stops transmitting the power supply DC.

[0028] By adopting the above solution, when the current of the power supply DC is greater than the first preset current, the first switch circuit stops transmitting the power supply DC, thereby achieving overcurrent protection of the low-side drive circuit.

[0029] In some embodiments, the temperature difference detection circuit includes:

[0030] a first sampling circuit, used for sampling the temperature of the first switch circuit to output a first sampling voltage;

[0031] a second sampling circuit, used for sampling the temperature of the driving circuit to output a second sampling voltage;

[0032] The comparison circuit is connected to the first sampling circuit, the second sampling circuit and the second switch circuit, and is used to output a first trigger signal in response to a difference between the first sampling voltage and the second sampling voltage being greater than a second preset voltage.

[0033] The temperature difference detection circuit has a simple structure and low cost.

[0034] In some embodiments, it also includes:

[0035] A current limiting circuit is connected to the driving circuit and the first switching circuit, and is used to limit the current of the driving signal.

[0036] Through the above technical solution, the current of the driving signal is limited, thereby improving the reliability and safety of the low-side driving circuit.

[0037] In some embodiments, the driving circuit includes:

[0038] An oscillator circuit, used for outputting a first square wave signal;

[0039] a charge pump circuit, connected to the oscillation circuit, and configured to boost the supply voltage based on the first square wave signal to output a second square wave signal;

[0040] A shaping circuit is connected to the charge pump circuit and the first switch circuit, and is used for shaping the second square wave signal to output a driving signal.

[0041] Through the above technical solution, square wave output can be achieved through an oscillation circuit and a charge pump circuit, which simplifies the hardware design and reduces the cost, and improves the stability of the driving signal through the shaping circuit.

[0042] In some embodiments, the first switch circuit includes a field effect transistor;

[0043] The drain of the field effect transistor serves as the input end of the first switch circuit and is connected to the load to receive the DC power supply;

[0044] The source of the field effect tube is connected to the power ground;

[0045] The gate of the field effect transistor serves as a control terminal of the first switch circuit and is connected to the drive circuit to receive a drive signal.

[0046] The first switch circuit has a simple and reliable structure and low cost.

[0047] In a second aspect, an embodiment of the utility model further provides an electronic device, which includes an inductive load and the above-mentioned low-side driving circuit.

[0048] By adopting the above solution, since the electronic device includes the low-side driving circuit of any of the above solutions, the safety and reliability of the low-side driving circuit can be improved, and can be applied to high-power scenarios.

[0049] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0051] Figure 1 A schematic diagram of a low-side drive circuit provided in one embodiment of the present application;

[0052] Figure 2 Another structural schematic diagram of a low-side driving circuit provided in an embodiment of the present application;

[0053] Figure 3 Another structural schematic diagram of a low-side driving circuit provided in an embodiment of the present application;

[0054] Figure 4 Another structural schematic diagram of a low-side driving circuit provided in an embodiment of the present application;

[0055] Figure 5 A schematic diagram of a structure of a temperature difference detection circuit in a low-side drive circuit provided in an embodiment of the present application;

[0056] Figure 6 Another structural schematic diagram of a low-side driving circuit provided in an embodiment of the present application;

[0057] Figure 7 A schematic diagram of a structure of a driving circuit in a low-side driving circuit provided in an embodiment of the present application;

[0058] Figure 8 A partial circuit schematic diagram of a low-side driver circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0059] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0061] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0062] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0063] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0064] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0065] At present, from the perspective of market development, the application of low-side drivers for loads is becoming more and more extensive. Low-side drivers are widely used in transportation tools such as electric bicycles, motorcycles, and automobiles, as well as in military equipment and aerospace and other fields. With the continuous expansion of low-side driver application areas, its market demand is also constantly expanding.

[0066] In order to solve the problem of poor reliability and safety, the applicant has found that the temperature difference detection circuit can be connected to the first switch circuit in design, and the inductive load generates an induced electromotive force to output a first negative voltage to the first switch circuit when the power supply DC is disconnected, so that the first switch circuit outputs a second negative voltage. When the difference between the temperature of the first switch circuit and the temperature of the drive circuit is greater than a preset value, the temperature difference detection circuit outputs a first trigger signal, so that the second switch circuit transmits the drive signal to the power ground to turn off the first switch circuit; thereby improving the safety and reliability of the low-side drive circuit.

[0067] The low-side drive circuit disclosed in the embodiment of the present application can be used in an electric device. The electric device can be, but is not limited to, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0068] According to some embodiments of the present application, referring to Figure 1 , Figure 1 A schematic diagram of the structure of a low-side driver circuit provided in an embodiment of the present application is shown. For ease of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0069] The low-side driving circuit is connected to a load L, and includes a driving circuit 01 , a first switch circuit 02 , a temperature difference detection circuit 03 and a second switch circuit 04 .

[0070] The driving circuit 01 is used to output a driving signal.

[0071] The first switch circuit 02 is connected to the load L and the drive circuit 01, and is used to turn on or off the transmission of the power supply DC according to the drive signal.

[0072] The temperature difference detection circuit 03 is used to output a first trigger signal in response to the difference between the temperature of the first switch circuit 02 and the temperature of the drive circuit 01 being greater than a preset value.

[0073] The second switch circuit 04 is connected to the temperature difference detection circuit 03, the drive circuit 01 and the first switch circuit 02, and is used to transmit the drive signal to the power ground according to the first trigger signal to stop the first switch circuit 02 from working.

[0074] The temperature difference detection circuit 03 is specifically used to output a first trigger signal in response to the difference between the temperature of the first switch circuit 02 and the temperature of the drive circuit 01 being greater than a preset value. At this time, the second switch circuit is turned on and the first switch circuit is turned off. Among them, the preset value is the critical value of the protection device, that is, the critical value of the temperature difference between the first switch temperature and the second switch temperature, and the preset value is defined according to the actual device's tolerance. In one embodiment, the preset value can be 60K, that is, when the difference between the temperature of the first switch circuit 02 and the temperature of the drive circuit 01 is greater than 60K, the second switch circuit is turned on and the first switch circuit is turned off. The first trigger signal is used to control the state of the second switch circuit, specifically, the first trigger signal is used to control the conduction of the second switch circuit.

[0075] It should be noted that the first switch circuit 02 and the second switch circuit 04 may include a switch tube. The drive circuit 01 may include a square wave generator and a charge pump circuit. The temperature difference detection circuit 03 may include a thermistor and a comparator. The power supply DC is used to drive the switch tube in the first switch circuit 02.

[0076] It is understandable that, when the load L is short-circuited, the transient temperature of the switch tube in the first switch circuit 02 changes rapidly. At this time, if the switch tube is not turned off in time, but the switch tube is turned off after the temperature of the switch tube reaches the preset temperature, the switch tube will not be turned off in time due to circuit delay, and the switch tube will be damaged by breakdown. Therefore, in the embodiment of the present application, when the difference between the temperature of the first switch circuit 02 and the temperature of the drive circuit 01 is greater than the preset value, the temperature difference detection circuit 03 outputs the first trigger signal, and the second switch circuit 04 transmits the drive signal to the power supply ground according to the first trigger signal, so that the first switch circuit 02 stops working and disconnects the transmission of the power supply DC, and the switch tube is turned off in time under the condition that the transient temperature of the switch tube in the first switch circuit 02 changes rapidly.

[0077] In the technical solution of the embodiment of the present application, since the temperature difference between the first switch circuit 02 and the temperature of the drive circuit 01 is greater than the preset value, the temperature rise speed of the first switch circuit 02 is very fast, thereby realizing protection for the working condition of large transient temperature change of the switch tube in the first switch circuit 02 (such as the fault of short circuit of load L), reducing the possibility of the switch tube in the first switch circuit 02 not being shut down in time due to circuit delay, reducing the possibility of breakdown damage of the switch tube, and improving the reliability and safety of the low-side drive circuit.

[0078] According to some embodiments of the present application, optionally, please continue to refer to Figure 2 , Figure 2 A schematic diagram of the structure of a low-side driver circuit provided by another embodiment of the present application is shown. For ease of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0079] The above low-side drive circuit is Figure 1 In addition to all the components and assemblies of the low-side driving circuit shown, the low-side driving circuit also includes a temperature detection circuit 05.

[0080] The temperature detection circuit 05 is connected to the second switch circuit 04 and is used to output a second trigger signal in response to the temperature of the first switch circuit 02 being greater than a preset temperature;

[0081] The second switch circuit 04 is specifically configured to transmit a driving signal to a power ground according to the first trigger signal and / or the second trigger signal, so as to stop the first switch circuit 02 from working.

[0082] In one embodiment, the temperature detection circuit 05 is specifically used to output a second trigger signal according to the first enable signal in response to the temperature of the first switch circuit 02 being greater than a preset temperature, wherein the preset temperature is a critical value of the operating temperature of the switch tube in the first switch circuit 02 .

[0083] It should be noted that the second switching circuit includes a NAND gate and a switch tube. When the first trigger signal and / or the second trigger signal is at a low level, the NAND gate outputs a high level and controls the switch tube to be turned on to transmit the drive signal to the power ground.

[0084] It can be understood that the second switch circuit 04 transmits the drive signal to the power ground according to the first trigger signal and / or the second trigger signal, so that the control end of the first switch circuit 02 is connected to the power ground, and the first switch circuit 02 stops transmitting the power supply DC to the load L.

[0085] By adopting the above solution, when the temperature of the first switch circuit 02 is greater than the preset temperature, the drive signal is transmitted to the power ground, so that the first switch circuit 02 stops working, achieving temperature protection of the low-side drive circuit, and further improving safety and reliability.

[0086] According to some embodiments of the present application, optionally, the first switch circuit 02 has a control end, an input end and an output end, and is specifically used to access a drive signal from the control end, access a power supply DC from the input end, and transmit the power supply DC to the output end according to the drive signal.

[0087] It can be understood that the first switch circuit 02 can include a field effect transistor, the gate of the field effect transistor serves as the control end of the first switch circuit 02, the drain of the field effect transistor serves as the input end of the first switch circuit 02, and the source of the field effect transistor serves as the output end of the first switch circuit 02.

[0088] The first switch circuit 02 has a simple structure and low cost.

[0089] According to some embodiments of the present application, optionally, please continue to refer to Figure 3 , Figure 3 A schematic diagram of the structure of a low-side driver circuit provided by another embodiment of the present application is shown. For ease of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0090] The above low-side drive circuit is Figure 1 In addition to all components and assemblies of the low-side driving circuit shown, the load L is an inductive load L; the low-side driving circuit also includes a first clamping circuit 06 and a pull-down circuit 07 .

[0091] The inductive load L is used to generate an induced electromotive force when the DC power supply is disconnected, so as to output a first negative voltage to the input end of the first switch circuit 02.

[0092] The first switch circuit 02 is further configured to output a second negative voltage from the control terminal according to the first negative voltage.

[0093] The first clamping circuit 06 is connected to the inductive load L and the first switch circuit 02, and is used to clamp the first voltage between the first negative voltage and the second negative voltage, and output a conduction current according to the power supply DC. Specifically, the first clamping circuit 06 is connected to the control end of the first switch circuit 02 and the input end of the first switch circuit 02, that is, the first switch circuit 02 includes a switch tube, and the first clamping circuit 06 is connected to the gate of the switch tube and the drain of the switch tube.

[0094] The pull-down circuit 07 is connected to the first clamp circuit 06 , the first switch circuit 02 and the drive circuit 01 , and is used to output a switch signal to the control end of the first switch circuit according to the conduction current.

[0095] The first switch circuit 02 is also used to transmit the power supply direct current according to the switch signal to eliminate the induced electromotive force.

[0096] It can be understood that at this time, the first clamping circuit 06 clamps the first voltage between the first negative voltage and the second negative voltage, that is: the first clamping circuit 06 clamps the first voltage between the input end of the first switch circuit 02 and the control end of the first switch circuit 02, so that the drain-gate voltage of the switch tube in the first switch circuit 02 can be clamped; and the first clamping circuit 06 outputs a conduction current according to the power supply DC to make the first switch circuit 02 transmit the power supply DC to eliminate the induced electromotive force, thereby further realizing the protection of the drain-gate voltage of the switch tube in the switch circuit. It is worth emphasizing that only when the load L is an inductive load L, the low-side drive circuit needs to be configured with the first clamping circuit 06 and the pull-down circuit 07.

[0097] By adopting the above scheme, when the power supply DC is disconnected, the first clamping circuit 06 clamps the first voltage between the first negative electrode voltage and the second negative electrode voltage, thereby clamping the drain-gate voltage of the switch tube in the switch circuit and reducing the possibility of the switch tube breakdown; and the first clamping circuit 06 also outputs a conduction current according to the power supply DC to make the pull-down circuit 07 output a switch signal to the control end of the first switch signal, so that the first switch circuit 02 transmits the power supply DC and eliminates the induced electromotive force; thereby further realizing the protection of the drain-gate voltage of the switch tube in the switch circuit; therefore, the possibility of the switch tube breakdown is reduced, and when applied to the inductive load L, the reliability and safety of the low-side drive circuit are improved.

[0098] According to some embodiments of the present application, optionally, please continue to refer to Figure 4 , Figure 4 A schematic diagram of the structure of a low-side driver circuit provided by another embodiment of the present application is shown. For ease of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0099] The above low-side drive circuit is Figure 1 In addition to all the components and assemblies of the low-side driving circuit shown, the low-side driving circuit also includes a current detection circuit 08 and a third switch circuit 09 .

[0100] The current detection circuit 08 is connected to the driving circuit 01, the first switch circuit 02, the first clamping circuit 06 and the inductive load L, and is used to detect the current of the DC power supply to output a current detection signal;

[0101] The third switch circuit 09 is connected to the current detection circuit 08, the drive circuit 01 and the first switch circuit 02, and is used to connect the control end of the first switch circuit 02 and the output end of the first switch circuit 02 in response to the voltage of the current detection signal being greater than the first preset voltage, so that the first switch circuit 02 stops transmitting the power supply DC.

[0102] It can be understood that by connecting the control end of the first switch circuit 02 and the output end of the first switch circuit 02, the gate-source voltage of the switch tube in the first switch circuit 02 is made 0V, so that the first switch circuit 02 stops transmitting the power supply DC.

[0103] By adopting the above solution, when the current of the power supply DC is greater than the first preset current, the first switch circuit 02 stops transmitting the power supply DC, thereby achieving overcurrent protection of the low-side drive circuit.

[0104] In some embodiments, optionally, please continue to refer to Figure 5 The temperature difference detection circuit 03 includes a first sampling circuit 031 , a second sampling circuit 032 and a comparison circuit 033 .

[0105] The first sampling circuit 031 is used to sample the temperature of the first switch circuit 02 to output a first sampling voltage;

[0106] The second sampling circuit 032 is used to sample the temperature of the driving circuit 01 to output a second sampling voltage;

[0107] The comparison circuit 033 is connected to the first sampling circuit 031 , the second sampling circuit 032 and the second switch circuit 04 , and is used to output a first trigger signal in response to a difference between the first sampling voltage and the second sampling voltage being greater than a second preset voltage.

[0108] It can be understood that the first sampling voltage is negatively correlated with the temperature of the first switching circuit 02, and the second sampling voltage is negatively correlated with the temperature of the driving circuit 01. The comparison circuit 033 is specifically used to output a first trigger signal in response to the difference between the second sampling voltage and the first sampling voltage being greater than the second preset voltage.

[0109] The temperature difference detection circuit 03 has a simple structure and low cost.

[0110] According to some embodiments of the present application, optionally, please continue to refer to Figure 6 , Figure 6 A schematic diagram of the structure of a low-side driver circuit provided by another embodiment of the present application is shown. For ease of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0111] The above low-side drive circuit is Figure 1 In addition to all components and assemblies of the low-side driver circuit shown, the low-side driver circuit also includes a current limiting circuit 10 .

[0112] The current limiting circuit 10 is connected to the driving circuit 01 and the first switch circuit 02, and is used to limit the current of the driving signal.

[0113] It can be understood that the current limiting circuit 10 may include a current limiting resistor, and by limiting the current of the driving signal, the possibility of damage to the switch tube in the first switch circuit 02 caused by a large current is reduced.

[0114] Through the above technical solution, the current of the driving signal is limited, thereby improving the reliability and safety of the low-side driving circuit.

[0115] In some embodiments, optionally, please continue to refer to Figure 7 The driving circuit 01 includes an oscillation circuit 011, a charge pump circuit 012 and a shaping circuit 013.

[0116] The oscillation circuit 011 is used to output a first square wave signal.

[0117] The charge pump circuit 012 is connected to the oscillation circuit 011 and is used to boost the supply voltage based on the first square wave signal to output a second square wave signal.

[0118] The shaping circuit 013 is connected to the charge pump circuit 012 and the first switch circuit 02, and is used for shaping the second square wave signal to output a driving signal.

[0119] In one embodiment, the oscillation circuit 011 is specifically configured to output a first square wave signal according to the second enable signal. The charge pump circuit 012 may include a multi-stage charge pump boost circuit.

[0120] Through the above technical solution, square wave output can be achieved through the oscillation circuit 011 and the charge pump circuit 012, which simplifies the hardware design and reduces the cost, and improves the stability of the driving signal through the shaping circuit 013.

[0121] In some embodiments, optionally, refer to Figure 8 , the first switch circuit 02 includes a field effect transistor M1.

[0122] The drain of the field effect transistor M1 serves as the input end of the first switch circuit 02 and is connected to the load L to receive the DC power supply; the source of the field effect transistor M1 is connected to the power ground; the gate of the field effect transistor M1 serves as the control end of the first switch circuit 02 and is connected to the drive circuit 01 to receive the drive signal.

[0123] The first switch circuit 02 has a simple and reliable structure and low cost.

[0124] In some embodiments, optionally, please continue to refer to Figure 8 The first clamping circuit 06 includes a first voltage regulator tube Z1.

[0125] The cathode of the first voltage regulator tube Z1 serves as the first end of the first clamping circuit 06, and is connected to the inductive load L and the first switch circuit 02 to access the first cathode voltage and the DC power supply; the anode of the first voltage regulator tube Z1 serves as the second end of the first clamping circuit 06, and is connected to the pull-down circuit 07, the first switch circuit 02 and the drive circuit 01 to access the second cathode voltage and output the conduction current.

[0126] The pull-down circuit 07 includes a first resistor R1.

[0127] The first end of the first resistor R1 serves as the conduction circuit input end of the pull-down circuit 07 and the switch signal output end of the pull-down circuit 07, and is connected to the first clamping circuit 06, the driving circuit 01 and the first switch circuit 02 to connect the conduction current and output the switch signal; the first end of the first resistor R1 is connected to the power ground.

[0128] The temperature detection circuit 05 includes a first voltage source DC1, a first comparator U1, a first inverter U2, a second inverter U3, a first temperature sensitive diode D01 and a second resistor R2.

[0129] The positive electrode of the first voltage source DC1 is connected to the first power supply VDD, the negative electrode of the first voltage source DC1 is connected to the first end of the second resistor R2 and the positive electrode of the first temperature-sensitive diode D01, the negative electrode of the first temperature-sensitive diode D01 is connected to the power ground, the second end of the second resistor R2 is connected to the non-inverting input end of the comparator U1, the output end of the comparator U1 is connected to the input end of the first inverter U2, the output end of the first inverter U2 is connected to the input end of the second inverter U3, the inverting input end of the comparator U1 serves as the reference voltage input end of the temperature detection circuit 05 to access the reference voltage; the output end of the second inverter U3 serves as the second trigger signal output end of the temperature detection circuit 05, and is connected to the second switch circuit 04 to output the second trigger signal.

[0130] The second switch circuit 0405 includes a NAND gate U4, a second field effect transistor M2 and a third resistor R3.

[0131] The first input terminal of the NAND gate U4 is used as the second trigger signal input terminal of the second switch circuit 04, and is connected to the temperature detection circuit 05 to receive the second trigger signal; the second input terminal of the NAND gate U4 is used as the first trigger signal input terminal of the second switch circuit 04, and is connected to the temperature difference detection circuit 03 to receive the first trigger signal; the third input terminal of the NAND gate U4 is used as the first enable signal input terminal of the second switch circuit 04 to receive the first enable signal; the output terminal of the NAND gate U4 is connected to the gate of the second field effect transistor M2;

[0132] The drain of the second field effect transistor M2 serves as the driving signal input terminal of the second switch circuit 04, and is connected to the driving circuit 01 and the first switch circuit 02 to receive the driving signal; the source of the second field effect transistor M2 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 is connected to the power ground.

[0133] The current detection circuit 0806 includes a third field effect transistor M3 and a fourth resistor R4.

[0134] The drain of the third field effect transistor M3 serves as the DC power supply input terminal of the current detection circuit 08, and is connected to the load L, the first switch circuit 02 and the first clamp circuit 06 to access the DC power supply; the source of the third field effect transistor M3 and the first end of the fourth resistor R4 serve together as the current detection signal output terminal of the current detection circuit 08, and are connected to the third switch circuit 09 to output the current detection signal; the second end of the fourth resistor R4 is connected to the power ground.

[0135] The third switch circuit 09 includes a fourth field effect transistor M4.

[0136] The gate of the fourth field effect transistor M4 serves as the control end of the third switch circuit 09 and is connected to the current detection circuit 08 to access the current detection signal; the drain of the fourth field effect transistor M4 serves as the first end of the third switch circuit 09 and is connected to the control end of the drive circuit 01 and the first switch circuit 02; the source of the fourth field effect transistor M4 serves as the second end of the third switch circuit 0907 and is connected to the power ground and the output end of the first switch circuit 02.

[0137] The current limiting circuit 10 includes a fifth resistor R5.

[0138] The first end of the fifth resistor R5 serves as the driving signal input end of the current limiting circuit 10 and is connected to the driving circuit 01 to receive the driving signal; the second end of the fifth resistor R5 serves as the driving signal output end of the current limiting circuit 10 and is connected to the first switching circuit 02 to output the driving signal.

[0139] The oscillation circuit 011 includes a second voltage source DC2, a hysteresis comparator U5, a third inverter U6, a fifth field effect transistor M5, a first capacitor C1 and a sixth resistor R6.

[0140] The positive electrode of the second voltage source DC2 is connected to the first power supply VDD, the negative electrode of the second voltage source DC2 is connected to the input end of the hysteresis comparator U5, the drain of the fifth field effect transistor M5 and the first end of the first capacitor C1, the output end of the hysteresis comparator U5 is connected to the input end of the third inverter U6, the input end of the third inverter U6 and the first end of the first capacitor C1, the source of the fifth field effect transistor M5 is connected to the first end of the sixth resistor R6, and the second end of the sixth resistor R6 is connected to the power ground; the output end of the third inverter U6 and the gate of the fifth field effect transistor M5 are used together as the square wave signal output end of the oscillation circuit 011, and are connected to the charge pump circuit 012012 to output the first square wave signal; the enable end of the hysteresis comparator U5 is used as the enable signal input end of the oscillation circuit 011011 to access the second enable signal EN2.

[0141] The charge pump circuit 012 includes a fourth inverter U7, a fifth inverter U8, a first switch K1, a first diode D1, a second diode D2, a third diode D3, a second capacitor C2 and a third capacitor C3.

[0142] The input end of the fourth inverter U7 is connected to the oscillation circuit 011 as the square wave signal input end of the charge pump circuit 012 to receive the first square wave signal; the output end of the fourth inverter U7 is connected to the first end of the second capacitor C2 and the input end of the fifth inverter U8, the output end of the fifth inverter U8 is connected to the first end of the third capacitor C3, the first end of the first switch K1 is connected to the first power supply VDD, the second end of the first switch K1 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the second end of the second capacitor C2 and the anode of the second diode D2, the cathode of the second diode D2 is connected to the second end of the third capacitor C3 and the anode of the third diode D3; the cathode of the third diode D3 is connected to the shaping circuit 013 as the square wave signal output end of the charge pump circuit 012 to output the second square wave signal; the control end of the first switch K1 is connected to the enable signal input end of the charge pump circuit 012 to receive the third enable signal EN3.

[0143] The shaping circuit 013 includes a sixth field effect transistor M6; the gate of the sixth field effect transistor M6 serves as the second square wave signal input terminal of the shaping circuit 013, and is connected to the charge pump circuit 012 to receive the second square wave signal; the gate of the sixth field effect transistor M6 serves as the drive signal output terminal of the shaping circuit 013, and is connected to the first switch circuit 02 and the second switch circuit 04 to output the drive signal; the drain of the sixth field effect transistor M6 is connected to the first power supply VDD.

[0144] The first sampling circuit 031 includes a second temperature-sensitive diode D02 and a third voltage source DC3; the positive electrode of the third voltage source DC3 is connected to the first power supply VDD; the negative electrode of the third voltage source DC3 and the positive electrode of the second temperature-sensitive diode D02 serve together as the first sampling signal output terminal of the first sampling circuit 031, and are connected to the comparison circuit 033 to output the first sampling signal; the negative electrode of the third voltage source DC3 is connected to the power ground.

[0145] The second sampling circuit 032 includes a third temperature-sensitive diode D03 and a fourth voltage source DC4; the positive electrode of the fourth voltage source DC4 is connected to the first power supply VDD; the negative electrode of the fourth voltage source DC4 and the positive electrode of the third temperature-sensitive diode D03 serve together as the second sampling signal output terminal of the second sampling circuit 032, and are connected to the comparison circuit 033 to output the second sampling signal; the negative electrode of the fourth voltage source DC4 is connected to the power ground.

[0146] The comparison circuit 033 includes a second comparator U9; the non-inverting input terminal of the second comparator U9 serves as the second sampling voltage input terminal of the comparison circuit 033, and is connected to the second sampling circuit 032 to access the second sampling voltage; the inverting input terminal of the second comparator U9 serves as the first sampling voltage input terminal of the comparison circuit 033, and is connected to the first sampling circuit 031 to access the first sampling voltage; the output terminal of the second comparator U9 serves as the first trigger signal output terminal of the comparison circuit 033, and is connected to the second switch circuit 04 to output the first trigger signal.

[0147] Combine the following Figure 8 The circuit principle is explained as follows:

[0148] When the second enable signal EN2 is connected, the hysteresis comparator U5 starts to work and charges the first capacitor C1. When the voltage at the input end of the hysteresis comparator U5 is greater than the comparator threshold, the output signal of the hysteresis comparator U5 is inverted to a first low-level signal, and then inverted and output to a first high-level signal through the third inverter U6. The first high-level signal controls the fifth field effect transistor M5 to turn on, so that the voltage of the input signal of the hysteresis comparator U5 is pulled down, and the first capacitor C1 is discharged. When the voltage of the input signal of the hysteresis comparator U5 is less than the comparator threshold, the output signal of the hysteresis comparator U5 is inverted to a second high-level signal, and then inverted and output to a first high-level signal through the third inverter U6. The fifth field effect transistor M5 is turned on, so that the voltage of the input signal of the hysteresis comparator U5 is pulled down, and the first capacitor C1 is discharged. When the voltage of the input signal of the hysteresis comparator U5 is less than the comparator threshold, the output signal of the hysteresis comparator U5 is inverted to a second high-level signal, and then inverted and output to a first high-level signal through the third inverter U6. The third inverter U6 inverts and outputs a second low-level signal, which controls the fifth field effect tube M5 to be turned off, thereby continuing to charge the first capacitor C1, and repeating this process to generate a first square wave signal; the first square wave signal is connected to the fourth inverter U7 and the fifth inverter U8 in order to generate a complementary square wave to power the charge pump, and after being boosted by the charge pump (including capacitors and diodes), a second square wave signal is output, and the second square wave signal is shaped by the sixth field effect tube M6 to output a drive signal, and the voltage of the drive signal is greater than the turn-on voltage Vth of the field effect tube M1, so that the field effect tube is turned on to drive the load L.

[0149] When the load L is short-circuited, the forward voltage of the second temperature-sensitive diode D02 drops rapidly as the temperature of the first switch circuit 02 rises, the temperature change of the drive circuit 01 is small, and thus the forward voltage drop of the third temperature-sensitive diode D03 changes little. When the difference between the voltage of the anode of the third temperature-sensitive diode D03 and the voltage of the anode of the second temperature-sensitive diode D02 reaches the second preset voltage, the second comparator U9 outputs the first trigger signal (jumps from a high level to a low level), and outputs a high level after passing through the NAND gate U4. At this time, the second field effect transistor M2 is turned on, and the gate of the field effect transistor M1 is pulled down and turned off, thereby protecting the entire circuit.

[0150] When the driving signal stops and the load L is an inductive load L, the field effect tube M1 disconnects the output of the power supply DC; the inductive load L generates an induced electromotive force based on the disconnection of the power supply DC to output a first negative voltage to the drain of the field effect tube M1; the field effect tube M1 outputs a second negative voltage from the gate of the field effect tube M1 according to the first negative voltage; at this time, the first voltage regulator tube Z1 breaks down, clamps the first voltage between the first negative voltage and the second negative voltage, and conducts current to the first end of the first resistor R1 according to the power supply DC output to generate a switching signal at the first end of the first resistor R1 and output it to the gate of the field effect tube M1; the switching signal raises the gate-source voltage of the field effect tube M1, and when the gate-source voltage of the field effect tube M1 is greater than the turn-on voltage, the field effect tube M1 is turned on and transmits the power supply DC to eliminate the induced electromotive force.

[0151] When the temperature rises, the forward voltage of the first temperature-sensitive diode D01 decreases as the temperature rises, and the voltage at the non-inverting input terminal of the first comparator U1 decreases. When it drops to the reference voltage, the output signal of the comparator U1 is reversed from a high level to a low level, and after two reversals, a low level is output; when the first enable signal EN1 is connected, a high level is output after passing through the NAND gate U4, at which time the second field effect transistor M2 is turned on, and the gate of the field effect transistor M1 is pulled down and turned off, thereby protecting the entire circuit.

[0152] When a short circuit occurs in the driving circuit 01, the current at both ends of the source and drain of the field effect tube M1 suddenly increases. Since the field effect tube M1 and the third field effect tube M3 are connected in parallel, the current at both ends of the drain and source of the third field effect tube M3 will increase. At this time, a current detection signal is output through the first end of the fourth resistor R4. When the voltage of the current detection signal rises to the first preset voltage, the fourth field effect tube M4 connects the gate of the field effect tube M1 and the source of the field effect tube M1, so that the gate-source voltage of the field effect tube M1 is less than the turn-on voltage, thereby limiting the current of the DC power supply to protect the circuit from being burned.

[0153] According to some embodiments of the present application, the present application also provides an electronic device, including a capacitive load and a low-side driving circuit of any of the above schemes.

[0154] Since the electronic device includes the low-side driving circuit of any of the above solutions, the safety and reliability of the low-side driving circuit can be improved, and can be applied to high-power scenarios.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A low-side driving circuit, characterized in that: Connect to the load, including: A driving circuit, used for outputting a driving signal; A first switch circuit, connected to the load and the drive circuit, and configured to turn on or off the transmission of the power supply DC according to the drive signal; a temperature difference detection circuit, configured to output a first trigger signal in response to a difference between the temperature of the first switch circuit and the temperature of the drive circuit being greater than a preset value; The second switch circuit is connected to the temperature difference detection circuit, the drive circuit and the first switch circuit, and is used to transmit the drive signal to the power ground according to the first trigger signal to stop the first switch circuit from working.

2. The low-side driving circuit according to claim 1, characterized in that: Also includes: a temperature detection circuit connected to the second switch circuit, and configured to output a second trigger signal in response to the temperature of the first switch circuit being greater than a preset temperature; The second switch circuit is specifically configured to transmit the drive signal to a power ground according to the first trigger signal and / or the second trigger signal, so as to stop the first switch circuit from working.

3. The low-side driving circuit according to claim 1, characterized in that: The first switch circuit has a control end, an input end and an output end, and is specifically used to receive a driving signal from the control end, receive the power supply DC from the input end, and transmit the power supply DC to the output end according to the driving signal.

4. The low-side driving circuit according to claim 3, characterized in that: The load is an inductive load; the low-side driving circuit further includes a first clamping circuit and a pull-down circuit; The inductive load is used to generate an induced electromotive force when the power supply DC is disconnected, so as to output a first negative voltage to the input end of the first switch circuit; The first switch circuit is further configured to output a second negative voltage from the control terminal according to the first negative voltage; The first clamping circuit is connected to the inductive load and the first switch circuit, and is used to clamp a first voltage between the first negative electrode voltage and the second negative electrode voltage, and output a conducting current according to the power supply DC power; The pull-down circuit is connected to the first clamp circuit, the first switch circuit and the drive circuit, and is used to output a switch signal to a control end of the first switch circuit according to the conduction current; The first switch circuit is further used to transmit the supply DC power according to the switch signal to eliminate the induced electromotive force.

5. The low-side driving circuit according to claim 4, characterized in that: Also includes: a current detection circuit, connected to the drive circuit, the first switch circuit, the first clamp circuit and the inductive load, and configured to detect the current of the DC power supply to output a current detection signal; A third switching circuit is connected to the current detection circuit, the drive circuit and the first switching circuit, and is used to connect the control end of the first switching circuit and the output end of the first switching circuit in response to the voltage of the current detection signal being greater than a first preset voltage, so that the first switching circuit stops transmitting the power supply DC.

6. The low-side driving circuit according to claim 1, characterized in that: The temperature difference detection circuit comprises: a first sampling circuit, used for sampling the temperature of the first switch circuit to output a first sampling voltage; a second sampling circuit, used for sampling the temperature of the driving circuit to output a second sampling voltage; The comparison circuit is connected to the first sampling circuit, the second sampling circuit and the second switch circuit, and is used to output a first trigger signal in response to a difference between the first sampling voltage and the second sampling voltage being greater than a second preset voltage.

7. The low-side driving circuit according to any one of claims 1 to 6, characterized in that: Also includes: A current limiting circuit is connected to the driving circuit and the first switching circuit, and is used to limit the current of the driving signal.

8. The low-side driving circuit according to any one of claims 1 to 6, characterized in that: The driving circuit comprises: An oscillator circuit, used for outputting a first square wave signal; a charge pump circuit, connected to the oscillation circuit, and configured to boost the supply voltage based on the first square wave signal to output a second square wave signal; A shaping circuit is connected to the charge pump circuit and the first switch circuit, and is used for shaping the second square wave signal to output a driving signal.

9. The low-side driving circuit according to any one of claims 1 to 3, characterized in that: The first switch circuit includes a field effect transistor; The drain of the field effect transistor serves as the input end of the first switch circuit and is connected to the load to receive the DC power supply; The source of the field effect tube is connected to the power ground; The gate of the field effect transistor serves as a control terminal of the first switch circuit and is connected to the drive circuit to receive a drive signal.

10. An electronic device, characterized in that: The electronic device comprises an inductive load and a low-side driving circuit as claimed in any one of claims 1 to 9.

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