Driving circuit, controller and current limiting structure control and use method

Abstract

The invention belongs to the technical field of power electronics, and particularly relates to a driving circuit, a controller and a current limiting structure control and use method. The embodiment of the invention discloses a driving circuit (800) formed by a switching device, a triode or an integrated circuit, a resistor and a capacitor. Configuration of the working state can be achieved through the calibration resistor, and then output of power excitation of the second external connection end (892) to the third external connection end (893) is dispatched through a control signal of the first external connection end (891) of the drive circuit (800). Faults such as short circuit to ground can be detected and discriminated by detecting a voltage signal of the fourth external end (894); the working state of the switching device can be adjusted by calibrating the resistance device, the current limiting working condition is dynamically entered, and out-of-control power consumption is avoided; the product and the method can be used for low-current or low-power loads such as light-emitting diode (LED) driving, pulse width modulation (PWM) control and other application scenes, and can be integrated with products such as a system on chip (SoC) and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic circuits, and in particular relates to a driving circuit, a controller, and a current limiting structure control and use method. Background Art

[0002] The drive circuit or drive chip is a component that ensures the stable operation of many types of load devices, such as motors, solenoid valves, light-emitting diodes (LEDs), lamps and other equipment or devices. It is often connected to the power supply of the load in the form of a switch or chip.

[0003] Common drive circuits or drive chips, whose main switching devices are metal oxide semiconductor field effect transistors MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and use such Figure 1 The functional structure shown in the figure; in order to meet the needs of functional safety, fault diagnosis, function recovery and other modules are designed at the same time; however, when a short circuit to ground occurs in the driving circuit, its detection component often misdiagnoses, and the short circuit to ground cannot be checked by diagnosing the output voltage.

[0004] In addition, current limiting resistors or current detection currents are added to the relevant drive circuits to ensure the effectiveness of ground short-circuit fault diagnosis. This will increase the difficulty of circuit integration and cause over-design for small current application scenarios. The output capacity of the drive chip is far greater than the demand, causing unnecessary waste and increasing unnecessary costs.

[0005] It should be pointed out that the relevant scheme cannot realize the diagnosis of short-circuit fault to ground by collecting the output voltage; among them, the above-mentioned scheme of adding current limiting resistor will increase the output voltage drop; and the additional current detection circuit will increase the difficulty and cost of system integration; therefore, it is necessary to provide a concise and efficient technical solution to solve the technical problems faced in the fault diagnosis and function recovery process in the above-mentioned small current drive application. Summary of the invention

[0006] The embodiment of the present invention discloses a driving circuit, which can use discrete components or integrated circuits to realize load driving control; its core unit includes a first switch device, a second switch device, and a third switch device; wherein the first base of the first switch device is connected to the third collector of the third switch device via a sixth resistor, the first emitter of the first switch device is connected to the second emitter of the second switch device via an eighth resistor, the first emitter of the first switch device is also connected to the second base of the second switch device via a seventh resistor, and the first collector of the first switch device is connected to the third external terminal via a first resistor. wherein the third external terminal is also connected to the fourth external terminal via a second resistor, and the fourth external terminal is also connected to the second ground terminal via a third resistor.

[0007] Furthermore, its second emitter is also connected to the second external terminal, and the second collector of the second switching device is connected to the first base; the third base of the third switching device is connected to the first external terminal via the fourth resistor, the third base is connected to the third emitter of the third switching device via the fifth resistor, and the third emitter is connected to the first ground terminal.

[0008] Specifically, the above-mentioned first external terminal can be connected to a control signal, and the control signal can be used to provide a first switching level to the first external terminal. When the first switching level is greater than a preset third switching voltage threshold, the third switching device can operate in a switching state; at this time, the second external terminal is connected to the second power supply, and the voltage of the second power supply must be greater than a preset second operating voltage threshold.

[0009] The fourth resistor and the fifth resistor can divide the control signal to obtain a third base voltage. When the third base voltage is greater than the third switch voltage threshold, the third switch device is saturated and turned on and is in a switch state.

[0010] Furthermore, the ratio of the third turn-on voltage of the third emitter to the eighth resistor can be adjusted to be greater than a preset current protection turn-on threshold Ilimit by adjusting device parameters; at this time, the overcurrent protection turn-on threshold of the drive circuit can be changed.

[0011] Specifically, its sixth resistor can also be set to be greater than a preset pull-up resistance threshold, and make the voltage of the first base greater than the first switching voltage threshold, and make the first switching device operate in a switching state; at this time, it can ensure that its third switching device operates in the saturation zone or is in a switching state.

[0012] Among them, the first switch device, the second switch device and the third switch device can adopt a triode structure; specifically, the first switch device and the second switch device can both adopt a PNP structure, and the third switch device can correspondingly adopt an NPN structure.

[0013] Furthermore, in order to improve the electromagnetic compatibility and anti-static capability of the driving circuit, a second capacitor device may be provided between the third external terminal and the first ground terminal and / or a third capacitor device may be provided between the fourth external terminal and the second ground terminal; and the above-mentioned connections or connections are all electrical connections.

[0014] Furthermore, its first external terminal can be electrically connected to a PWM signal and / or a switching timing signal; its second external terminal can be electrically connected to an LED lighting device, and the second operating current of the LED lighting device can be less than a second current threshold and / or the second rated power of the LED lighting device can be less than a second power threshold; at this time, the drive circuit will obtain better current limiting characteristics with pure hardware implementation.

[0015] Specifically, the first switching device, the second switching device and / or the third switching device can be integrated and manufactured on a substrate of a preset chip, which can be a first system on chip SoC and / or a preset second semiconductor circuit, which can be a microprocessor MCU and / or a session border controller SBC and / or a pre-driver chip.

[0016] Correspondingly, an embodiment of the present invention also discloses a controller, whose core hardware is powered by any of the above drive circuits or performs voltage detection; and when the voltage at the fourth external terminal of its drive circuit is less than a preset alarm voltage threshold or is zero, a fault code is reported; if the fault code exists, a preset protection program is started, a preset circuit is started and / or a specified plan is executed.

[0017] Furthermore, an embodiment of the present invention also discloses a current limiting structure control and use method; similarly, its core hardware also adopts the above driving circuit and further includes a first voltage detection step and / or a second voltage detection step; wherein, the first voltage detection step and / or the second voltage detection step can judge the fault state according to the fourth diagnostic voltage of the fourth external terminal and / or adjust the second working state of the second switching device according to the voltage across the eighth resistor device.

[0018] Specifically, if the fourth diagnostic voltage is less than the fourth voltage threshold, it can be considered that the driving circuit or the related circuit is short-circuited to the ground; if the driving circuit has fault information recorded in the preset fault list, the input signal of the first external terminal can be changed to turn off the third switching device until the first switching device and / or the second switching device are turned off, thereby achieving the corresponding protection effect.

[0019] Furthermore, the use of its driving circuit and the driving control method may also be provided with a third fault recovery step and / or a fourth threshold calibration step; the third fault recovery step may switch the working state according to the pre-calibrated action threshold of the first switching device, the second switching device and / or the third switching device; the fourth threshold calibration step may replace the first resistor with a potentiometer or adjust the resistance value of the first resistor according to the load type connected to its third external terminal; the potentiometer can be used to match different load powers connected to its third external terminal; and its second working state includes a switching working state and an amplifying working state.

[0020] In addition, the present invention can also be used in applications such as chips and self-recovering power supplies; the chip also includes any of the above drive circuits and / or a storage medium body for storing computer programs; when the computer program is executed by a microprocessor, the above current limiting structure control and use method can be implemented; similarly, the self-recovering power supply also includes any of the above drive circuits, controllers and / or chips; it can be used to solve the same technical problem pointed out in the technical background, and there is no need to elaborate.

[0021] In summary, the embodiment of the present invention discloses a driving circuit constructed by using a switching device, a transistor or an integrated circuit and a resistor and a capacitor; the configuration of the working state of the switching device can be realized by calibrating the resistor, and then the output of the power excitation of the second external terminal to the third external terminal can be scheduled by the control signal of the first external terminal of the driving circuit; and the detection and identification of the short-circuit fault to the ground can be realized by detecting the voltage signal of the fourth external terminal; the working state of the switching device can also be adjusted by calibrating the resistor device, dynamically entering the current limiting condition and avoiding power consumption out of control; its products and methods can be used for small current or low power loads such as light-emitting diode LED (Light-Emitting Diode) drive, PWM (Pulse Width Modulation) control, session border controller SBC (Session Border Controller), pre-driver chip and other application scenarios, and can be integrated with products such as system on chip SoC (System on Chips).

[0022] It should be noted that the terms "first", "second" and similar terms used in this article are only for describing the various components in the technical solution, and do not constitute a limitation of the technical solution, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; elements with "first", "second" and similar terms indicate that the corresponding technical solution contains at least one of the element. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention and facilitate further understanding of the technical effects, technical features and purposes of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation to the present invention.

[0024] The same reference numerals in the accompanying drawings represent the same components, and the details of each drawing are as follows.

[0025] Figure 1 The figure is a schematic diagram of an application scenario of an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of a driving circuit embodiment of the present invention.

[0027] Figure 3 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 1 .

[0028] Figure 4 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 2 .

[0029] Figure 5 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 3 .

[0030] Figure 6 The figure is a schematic diagram of a flow chart of an embodiment of the method of the present invention.

[0031] The meanings of the various reference numerals / numbers are as follows.

[0032] 100-first voltage detection step; 200-second voltage detection step; 300-third fault recovery step; 400-fourth threshold calibration step; 700-self-recovery power supply; 800- driving circuit; 801-first switching device; 802-second switch device; 803-third switching device; 811-a first resistance device; 812-a second resistance device; 813- a third resistance device; 814- a fourth resistance device; 815-fifth resistance device; 816-sixth resistance device; 817-seventh resistor device; 818-eighth resistance device; 821 - a first capacitor device (not shown in the drawings); 822- a second capacitor device; 823- a third capacitor device; 881-first ground terminal; 882- second ground terminal; 888-eighth ground terminal; 891-first external terminal; 892-second external terminal; 893-third external terminal; 894 - fourth external terminal; 900-Vehicles or other electrical equipment; 901-controller; 903-chip; 909-battery or other power source; 910-first power supply unit; 911 - first battery component; 920- second drive and protection unit; 921 - first integrated charge pump; 922-second overvoltage protection; 923-third battery reverse connection protection; 924-Fourth short circuit protection; 925-Fifth overheat protection; 926-sixth overcurrent protection; 930 - third load unit; 931-first relay load; 932-second controller load; 933- third motor load; 934-fourth preheating load; 935-Fifth lighting load; 936 - Sixth heating load. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described below are only for explaining the technical solutions of the present invention, rather than for limiting the present invention. In addition, the parts described in the embodiments or the accompanying drawings are only examples of the relevant parts of the present invention, rather than the whole of the present invention.

[0034] like Figure 2 The driving circuit 800 shown can be used as follows Figure 1 The application scenario shown is particularly suitable for small current loads. Its core includes a first switch device 801, a second switch device 802, and a third switch device 803.

[0035] Among them, the first base of the first switching device 801 is connected to the third collector of the third switching device 803 via the sixth resistor 816, the first emitter of the first switching device 801 is connected to the second emitter of the second switching device 802 via the eighth resistor 818, the first emitter of the first switching device 801 is also connected to the second base of the second switching device 802 via the seventh resistor 817, and the first collector of the first switching device 801 is connected to the third external terminal 893 via the first resistor 811.

[0036] Furthermore, the third external terminal 893 is connected to the fourth external terminal 894 via the second resistor 812, and the fourth external terminal 894 is connected to the second ground terminal 882 via the third resistor 813; the second emitter is connected to the second external terminal 892, and the second collector of the second switching device 802 is connected to the first base; the third base of the third switching device 803 is connected to the first external terminal 891 via the fourth resistor 814, the third base is connected to the third emitter of the third switching device 803 via the fifth resistor, and the third emitter is connected to the first ground terminal 881.

[0037] Among them, the first external terminal 891 can be connected to a control signal, which is used to provide a first switching level to the first external terminal 891. When the first switching level is greater than a preset third switching voltage threshold, the third switching device 803 will operate in a switching state; at this time, the second external terminal 892 is connected to the second power supply, and the voltage of the second power supply is greater than the preset second operating voltage threshold.

[0038] Specifically, the fourth resistor 814 and the fifth resistor 815 divide the control signal to obtain a third base voltage. When the third base voltage is greater than the third switch voltage threshold, the third switch device 803 is saturated and turned on and is in a switching state.

[0039] Furthermore, the ratio of the third turn-on voltage of the third emitter to the eighth resistor 818 can be made greater than a preset current protection turn-on threshold value Ilimit.

[0040] In addition, the sixth resistor 816 can be made greater than a preset pull-up resistance threshold, the voltage of the first base can be made greater than the first switch voltage threshold, and the first switch device 801 can operate in the above switch state.

[0041] Specifically, the first switch device 801, the second switch device 802 and the third switch device 803 in the driving circuit 800 can all be transistors; and the first switch device 801 and the second switch device 802 can adopt a PNP structure, and correspondingly, the third switch device 803 adopts an NPN structure.

[0042] Furthermore, a second capacitor 822 may be provided between the third external terminal 893 and the first ground terminal 881 and / or a third capacitor 823 may be provided between the fourth external terminal 894 and the second ground terminal 882; this may be used to improve electromagnetic compatibility (EMC) and / or electrostatic discharge (ESD) protection characteristics.

[0043] Specifically, its first external terminal 891 can be electrically connected to the PWM signal and / or the switch timing signal, and the second external terminal 892 can be electrically connected to the LED lighting device, the second operating current of the LED lighting device is less than the second current threshold and / or the second rated power of the LED lighting device is less than the second power threshold.

[0044] The first switch device 801, the second switch device 802 and / or the third switch device 803 can be integrated and manufactured as follows: Figure 3 , Figure 4 , Figure 5 On the substrate of the chip 903 shown, the chip 903 may be a first system on chip SoC and / or a preset second semiconductor circuit, and the second semiconductor may be provided with a microprocessor MCU, a session border controller SBC and / or a pre-driver chip.

[0045] In addition, if Figure 3 , Figure 4 , Figure 5 The controller 901 shown adopts Figure 2 The driving circuit 800 shown is powered or performs voltage detection; and when the voltage of the fourth external terminal 894 of the driving circuit 800 is less than the preset alarm voltage threshold or is zero, a fault code is reported; if the fault code exists, the preset protection program is started, the preset circuit is started and / or the specified plan is executed.

[0046] Similarly, in Figure 6 In the current limiting structure control and use method shown, the following is adopted Figure 2 The driving circuit 800 shown further includes a first voltage detection step 100 and / or a second voltage detection step 200; wherein the first voltage detection step 100 and / or the second voltage detection step 200 determines the fault state according to the fourth diagnostic voltage of the fourth external terminal 894 and / or adjusts the second working state of the second switching device 802 according to the voltage across the eighth resistor device 818.

[0047] Specifically, if the fourth diagnostic voltage is less than the fourth voltage threshold, it is considered that the drive circuit 800 is short-circuited to the ground; in addition, if the drive circuit 800 has fault information recorded in a preset fault list, the third switch device 803 can be turned off by changing the input signal of the first external terminal 891 until the first switch device 801 and / or the second switch device 802 are turned off.

[0048] Furthermore, the use of the drive circuit and the drive control method may also be provided with a third fault recovery step 300 and / or a fourth threshold calibration step 400; the third fault recovery step 300 can switch the working state according to the pre-calibrated action threshold of the first switch device 801, the second switch device 802 and / or the third switch device 803; the fourth threshold calibration step 400 replaces the first resistor 811 with a potentiometer or adjusts the resistance value of the first resistor 811 according to the load connected to the third external terminal 893 to achieve matching calibration; the potentiometer is used to match different load powers connected to the third external terminal 893; its second working state includes a switching working state and an amplifying working state.

[0049] Similarly, if Figure 3 , Figure 4 , Figure 5 The chip 903 shown also includes Figure 2 The driving circuit 800 shown in the figure and / or the storage medium body for storing the computer program; when the computer program is executed by the microprocessor, the above current limiting structure control and use method can be implemented; accordingly, Figure 4 The self-restoring power supply 700 shown includes Figure 2 The driving circuit 800 shown and / or Figure 3 , Figure 4 , Figure 5 The controller 901 and / or chip 903 are shown.

[0050] In practical applications, such as Figure 1 In the scenario shown, the driving circuit 800 can be used as a driving mode of a high-side driver, for connecting a switch or a driving chip to the power supply side of the third load unit 930 .

[0051] Specifically, the above structure can be applied to driving applications of motors, solenoid valves, LED lighting equipment, etc.; its high-side driver chip and / or high-side driver circuit can use a switching device with a MOSFET structure.

[0052] Among them, considering the common functional safety requirements, such as Figure 1The second drive and protection unit 920 shown needs to be provided with fault diagnosis and function recovery components; and when a short-to-ground fault occurs in the output voltage of the high-side drive circuit mainly based on MOSFET, since the equivalent resistance Rdson of MOSFET itself is small, when the short-circuit resistance is too large, its output voltage is difficult to present a low level.

[0053] Based on the above findings, the inventor introduced a circuit structure related to an embodiment of the present invention to overcome the technical problem that a short circuit fault to ground cannot be diagnosed through the output voltage; at the same time, in order to avoid using a current limiting resistor or an additional current detection circuit, a driving circuit based on three switching devices was introduced.

[0054] It should be noted that the embodiments of the present invention are particularly suitable for applications with relatively small current requirements; Figure 2 As shown, the high-side driving PNP transistor T1 is the first switch device 801 , the current clamping PNP transistor T2 is the second switch device 802 , the switch control NPN transistor T3 is the third switch device 803 , and the current limiting resistor R8 is the eighth resistor device 818 .

[0055] In addition, the driving circuit 800 is also provided with transistor base series resistors R4, R6, R7, namely the fourth resistor device 814, the sixth resistor device 816, and the seventh resistor device 817; it is also provided with an output series resistor R1, namely the first resistor device 811; and analog digital (AD) sampling voltage-dividing resistors R2, R3 and the second resistor device 812, the third resistor device 813; and it is also provided with a transistor base pull-down voltage-dividing resistor R5, namely the fifth resistor device 815.

[0056] In order to improve the electrostatic protection capability of the output terminal, namely the third external terminal 893 , an ESD capacitor C2 , namely the second capacitor device 822 , may be provided; in order to improve electromagnetic compatibility, an RC filter capacitor C3 , namely the third capacitor device 823 , may be provided.

[0057] Specifically, its innovation lies in the use of transistor T1 to replace the MOSFET drive circuit, which can greatly simplify the semiconductor processing technology, save costs and improve output efficiency; at the same time, the use of current limiting clamping transistor T2 in conjunction with current limiting resistor R8 can protect the output current; in addition, the software / control strategy can also be combined to realize the diagnosis of ground short-circuit faults.

[0058] Among them, the embodiment of the present invention can avoid the accompanying hazards of excessive power consumption when the high-side driving transistor is short-circuited to ground, thereby avoiding the risk of thermal failure; due to the existence of the clamping transistor, its current limiting resistor can be configured to a smaller resistance value, and when the driving circuit 800 works normally, it will not introduce excessive voltage drop or energy consumption.

[0059] Furthermore, in Figure 2 During the driving process of the driving circuit 800 , i.e. the high-side circuit, if the high-side output needs to be turned on, the driving circuit use and driving control method disclosed in the present invention can be adopted accordingly: a high level is output at the first external terminal 891 .

[0060] At this time, the emitter junction of T3, i.e. the third emitter, will be Figure 3 , Figure 4 , Figure 5 The high level output by the controller 903 or other control unit such as MCU (MicroController Unit) is pushed after voltage division by R4 and R5; after the T3 tube is turned on, the base voltage of the T1 tube begins to decrease, so that the emitter junction of the PNP structure T1 tube, that is, the first emitter, is applied with a voltage difference sufficient to turn on; at this time, the T1 tube begins to turn on and enters the saturation region under the normal resistance value configuration, that is, it works in the switching state.

[0061] Correspondingly, when the high side is turned off, the first external terminal 891 is pulled low, and its switch controls the transistor T3 to be turned off; at this time, the emitter junction voltage drop of the high side driving transistor T1 disappears, thereby causing the high side driving transistor to be turned off, achieving the effect of turning off the high side output.

[0062] In addition, when a short circuit to ground occurs, the current passing through the current limiting resistor R8 increases, which will cause the voltage drop across it to increase; when the current reaches a certain value, the voltage drop across the resistor R8 is sufficient to push the emitter junction of T2 open, that is, T2 works in a switching state; at this time, T2 begins to conduct, causing the base voltage of T3 to begin to decrease.

[0063] According to the input characteristics of the transistor, when the base-emitter voltage VBE begins to increase, the base current increases. When the base current increases to a certain extent, the transistor T1 will enter the amplification region from the saturation region. At this time, the collector-emitter voltage VCE drop increases, making the high-side output current stable, thereby avoiding excessive power consumption of T1.

[0064] Among them, the fourth external terminal 894 can be used for fault diagnosis. When the fourth external terminal 894 samples a low level that is significantly lower than the normal value, it can be used for diagnosing a short-circuit fault to ground by calibrating an appropriate action threshold. At the same time, the output can be shut down by a control signal to protect the transistor T1 or related circuits.

[0065] Specifically, the overcurrent protection start-up threshold, i.e., the action threshold, can be set by the following method; the current limiting clamp transistor and the current limiting resistor can be selected and calibrated to achieve the configuration of the output current protection, i.e., the start-up threshold Ilimit.

[0066] Among them, the opening threshold Ilimit can be set to the product of the emitter junction opening voltage of the clamping transistor T3 and the resistance value of the current limiting resistor R8; for the fourth resistor device and the fifth resistor device, the voltage division at a high level should be able to open the emitter junction of the switch control transistor T3.

[0067] In addition, the resistance value of the sixth resistor device R6 needs to be large enough to enable the switch control transistor T3 to operate in the saturation region, that is, in the switching state, thereby ensuring that the high-side drive transistor T1 can be turned on; at the same time, the resistance value of its first resistor device 811, that is, the output series resistor R1, needs to be determined based on the resistance and voltage requirements of the load, which will not be repeated.

[0068] By adopting the driving circuit 800 in the embodiment of the present invention, the following beneficial effects are achieved in improving the low current high side design.

[0069] First, triodes with mature and simple structures and processes can be used to replace MOSFET devices. At the same time, they can be used in conjunction with chip capacitors and resistors to effectively improve system integration or packaging efficiency. At the same time, product cost control is also utilized. Relevant test data show that its cost can be more than 30% lower than that of the solution with high-side chips and PMOS alone.

[0070] Secondly, if the switching device used has better switching performance, the dynamic performance or response speed of the circuit can be further improved; for example, the triode solution used in the embodiment of the present invention has a significant advantage in switching speed over the high-side chip integrated with MOS devices or the PMOS single high-side drive circuit, and is therefore more suitable for application in PWM drive scenarios.

[0071] Thirdly, the embodiment of the driving circuit 800 of the present invention can bring lower maximum transient power consumption: by adding a current limiting transistor, the transistor current used for high-side driving can be clamped to the design value in a very short time after an overcurrent occurs, so that the time that the transistor used for high-side driving works in a high-power state is shortened to a negligible level.

[0072] Fourthly, the embodiment of the present invention can use a pure hardware solution to implement current clamping, which can avoid the time lag problem when controlled by MCU software; at the same time, its reliability is higher than that of the software solution.

[0073] Fifth, the driving scheme of the embodiment of the present invention can be applied to a variety of application scenarios, especially suitable for small current high-side driving; it can be applied not only to LED lighting switch control, but also to small current PWM signal output and other switch signal output control.

[0074] Compared with the related art, the embodiment of the present invention can realize the diagnosis and recovery of the short-circuit to ground fault under low-cost conditions; and overcomes the defects of the related art in small current applications through a hardware solution.

[0075] On the one hand, the over-design problem of the MOSFET driving scheme in the small current application scenario is overcome, and the waste and additional cost caused by the current capacity far exceeding the demand are avoided; on the other hand, the embodiment of the present invention overcomes the defect that the MOSFET high-side driving scheme cannot directly perform short-circuit diagnosis to ground by collecting the output terminal voltage; in addition, there is no need to adopt the current limiting resistor added in the related scheme, and there is no need to add a separate current detection circuit.

[0076] Among them, the added current limiting resistor will increase the high-side output voltage drop, affecting power consumption and output quality; and the added current detection circuit will increase the difficulty of system integration and manufacturing process.

[0077] As mentioned above, the product of the embodiment of the present invention can be used for high-side driver control of LED lighting solutions, but it is also suitable for Figure 1 Other loads shown; the hardware architecture of the drive circuit 800 based on traditional discrete devices (transistors) can also be expanded to system-on-chip, such as SoC, that is, an integrated hardware solution of MCU+SBC+pre-driver chip structure; its load can be expanded to other drive applications, and is not limited to PWM signal output, switch signal output and other scenarios.

[0078] It should be noted that the above embodiments are only for more clearly illustrating the technical solutions of the present invention. Those skilled in the art will understand that the implementation methods of the present invention are not limited to the above contents, and obvious changes, replacements or substitutions based on the above contents do not exceed the scope of the technical solutions of the present invention; other implementation methods will also fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A driving circuit (800), comprising a first switching device (801), a second switching device (802), and a third switching device (803); wherein: The first base of the first switching device (801) is connected to the third collector of the third switching device (803) via the sixth resistor (816), the first emitter of the first switching device (801) is connected to the second emitter of the second switching device (802) via the eighth resistor (818), the first emitter of the first switching device (801) is also connected to the second base of the second switching device (802) via the seventh resistor (817), the first collector of the first switching device (801) is connected to the third external terminal (893) via the first resistor (811); the third external terminal (893) The fourth external terminal (894) is connected via the second resistor (812), and the fourth external terminal (894) is connected via the third resistor (813) to the second ground terminal (882); the second emitter is connected to the second external terminal (892), and the second collector of the second switch device (802) is connected to the first base; the third base of the third switch device (803) is connected to the first external terminal (891) via the fourth resistor (814), the third base is connected to the third emitter of the third switch device (803) via the fifth resistor, and the third emitter is connected to the first ground terminal (881).

2. The driving circuit (800) according to claim 1, wherein: The first external terminal (891) is connected to a control signal, and the control signal is used to provide a first switching level to the first external terminal (891). When the first switching level is greater than a preset third switching voltage threshold, the third switching device (803) operates in a switching state; the second external terminal (892) is connected to a second power supply, and the voltage of the second power supply is greater than a preset second operating voltage threshold.

3. The driving circuit (800) according to claim 2, wherein: The fourth resistor (814) and the fifth resistor (815) divide the control signal to obtain a third base voltage. When the third base voltage is greater than the third switch voltage threshold, the third switch device (803) is saturated and turned on and is in the switch state.

4. The driving circuit (800) according to claim 1, 2 or 3, wherein: The ratio of the third turn-on voltage of the third emitter to the eighth resistor (818) is greater than a preset current protection turn-on threshold value Ilimit.

5. The driving circuit (800) according to claim 4, wherein: The sixth resistor (816) is greater than a preset pull-up resistance threshold, and causes the voltage of the first base to be greater than a first switch voltage threshold, and causes the first switch device (801) to operate in the switch state.

6. The driving circuit (800) according to any one of claims 1, 2, 3 or 5, wherein: The first switch device (801), the second switch device (802) and the third switch device (803) are triodes.

7. The driving circuit (800) according to claim 6, wherein: The first switch device (801) and the second switch device (802) are both of PNP structure, and the third switch device (803) is of NPN structure.

8. The driving circuit (800) according to any one of claims 1, 2, 3, 5 or 7, wherein: The third external terminal (893) is connected to the first ground terminal (881) via the second capacitor device (822) and / or the fourth external terminal (894) is connected to the second ground terminal (882) via the third capacitor device (823); the connections are electrical connections.

9. The driving circuit (800) according to claim 8, wherein: The first external terminal (891) is electrically connected to a PWM signal and / or a switch timing signal, the second external terminal (892) is electrically connected to an LED lighting device, the second operating current of the LED lighting device is less than a second current threshold and / or the second rated power of the LED lighting device is less than a second power threshold.

10. The driving circuit (800) according to any one of claims 1, 2, 3, 5, 7 or 9, wherein: The first switch device (801), the second switch device (802) and / or the third switch device (803) are integrated and manufactured on a substrate of a preset chip (903), wherein the chip (903) includes a first system on chip SoC and / or a preset second semiconductor circuit, and the second semiconductor circuit includes a microprocessor MCU and / or a session border controller SBC and / or a pre-driver chip.

11. A controller (901), comprising a drive circuit (800) as described in any one of claims 1 to 10 for power supply or voltage detection; and reporting a fault code when the voltage of the fourth external terminal (894) of the drive circuit (800) is less than a preset alarm voltage threshold or is zero; if the fault code exists, starting a preset protection program, starting a preset circuit and / or executing a specified plan.

12. A method for controlling and using a current limiting structure, characterized in that A drive circuit (800) as described in any one of claims 1 to 10 is used, and further includes a first voltage detection step (100) and / or a second voltage detection step (200); wherein the first voltage detection step (100) and / or the second voltage detection step (200) determines the fault state according to the fourth diagnostic voltage of the fourth external terminal (894) and / or adjusts the second working state of the second switch device (802) according to the voltage across the eighth resistor device (818); if the fourth diagnostic voltage is less than a fourth voltage threshold, it is considered that the drive circuit (800) is short-circuited to ground; if the drive circuit (800) has fault information recorded in a preset fault list, the input signal of the first external terminal (891) is changed to turn off the third switch device (803) until the first switch device (801) and / or the second switch device (802) are turned off.

13. The method for controlling and using a current limiting structure according to claim 12, further comprising a third fault recovery step (300) and / or a fourth threshold calibration step (400); the third fault recovery step (300) switches the working state according to the action threshold pre-calibrated by the first switch device (801), the second switch device (802) and / or the third switch device (803); the fourth threshold calibration step (400) replaces the first resistor (811) with a potentiometer or adjusts the resistance value of the first resistor (811) according to the load connected to the third external terminal (893); the potentiometer is used to match different load powers connected to the third external terminal (893); the second working state includes a switch working state and an amplification working state.

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