A multi-polar input switch control circuit, device and system

Abstract

This application discloses a multipolar input switch control circuit, device, and system, relating to the field of electronic circuit technology. The circuit includes a switch module connected between an input power supply and a load, used to control the on / off state of power supply from the input power supply to the load; a first input terminal for receiving a first control signal; a second input terminal for receiving a second control signal; and a logic control module connected to the first input terminal, the second input terminal, and the control terminal of the switch module. When the first input terminal receives a valid low-level signal and / or the second input terminal receives a valid high-level signal, the logic control module controls the switch module to turn on; when neither the first nor the second input terminal receives a valid level signal, the logic control module controls the switch module to turn off. This application, through a pure hardware logic circuit design, can simultaneously accommodate input signals of two different polarities, namely, active low-level and active high-level, offering wide applicability and high reliability.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a multipolar input switch control circuit, device and system. Background Technology

[0002] In fields such as automotive electronics and industrial control, it is often necessary to control the power supply to the load based on external trigger signals. For example, in a car's backup battery power supply system, when the main battery fails, a fault trigger signal is generated. This signal is used to activate the backup battery switch to connect the backup battery to supply power to the load (such as safety systems or control systems).

[0003] However, the polarity of the trigger signals generated by different devices or sensors may differ. Some sensors output a low-level active signal (i.e., triggering action when the signal transitions from high to low), while others output a high-level active signal (triggering action when the signal transitions from low to high). A traditional solution is to use a microcontroller unit (MCU) in conjunction with a level shifting circuit for detection and control, such as... Figure 6 As shown in the diagram, this solution requires first converting input signals of different polarities into a unified level that the MCU can recognize through a level conversion circuit. Then, the MCU runs a software program to perform logical judgments and finally outputs a control signal to drive the switching transistor to conduct. While this approach is feasible, it increases the complexity of the circuit design, requiring additional software intervention. This not only increases hardware costs (MCU and its peripheral circuits) but also increases the design difficulty and potential instability of the system. For applications requiring only simple logic control, it appears overly cumbersome and inefficient. Summary of the Invention

[0004] The purpose of this application is to provide a multipolar input switch control circuit, device, and system. Through pure hardware logic circuit design, it can simultaneously accommodate input signals of two different polarities: active low and active high. This enables flexible control of a single load switch and has a wide range of applications. The logic control module consists only of basic discrete components such as resistors, diodes, and MOSFETs, eliminating the need for complex programmable devices like MCUs and software development, thus significantly reducing cost and design complexity. It can be effectively applied to cost-sensitive and reliability-critical applications such as automotive electronics and industrial automation control.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a multipolar input switch control circuit, comprising: A switching module is connected between the input power supply and the load, and is used to control the on / off state of the power supply from the input power supply to the load; The first input terminal is used to receive the first control signal; The second input terminal is used to receive the second control signal; The logic control module is connected to the first input terminal, the second input terminal, and the control terminal of the switch module, respectively. Wherein, the first control signal is a low-level active signal, and the second control signal is a high-level active signal; when the first input terminal receives a valid low-level signal and / or the second input terminal receives a valid high-level signal, the logic control module controls the switch module to turn on; when neither the first input terminal nor the second input terminal receives a valid level signal, the logic control module controls the switch module to turn off.

[0006] Optionally, the switching module includes a first MOSFET, the source of which is connected to the input power supply, the drain of which is connected to the load, and the gate of which serves as the control terminal of the switching module and is connected to the logic control module.

[0007] Optionally, the first MOSFET is a P-type MOSFET.

[0008] Optionally, the logic control module includes a first logic control unit and a second logic control unit; The first logic control unit includes: A first pull-up resistor, one end of which is connected to the input power supply, and the other end of which is connected to the first input terminal; A unidirectional conducting device, wherein the anode of the unidirectional conducting device is connected to the control terminal of the switching module, and the cathode of the unidirectional conducting device is connected to the first input terminal; A second pull-up resistor, one end of which is connected to the input power supply, and the other end of which is connected to the control terminal of the switching module; The second logic control unit includes: The second MOSFET has its drain connected to the control terminal of the switching module, its source grounded, and its gate connected to the second input terminal via a voltage divider circuit.

[0009] Optionally, the unidirectional conducting device is a diode.

[0010] Optionally, the second MOSFET is an N-type MOSFET.

[0011] Optionally, the voltage divider circuit includes: A first voltage divider resistor, one end of which is connected to the second input terminal, and the other end of which is connected to the gate of the second MOS transistor; The second voltage divider resistor has one end grounded and the other end connected to the gate of the second MOS transistor.

[0012] Optionally, the logic control module is composed of discrete components and does not include a microcontroller unit.

[0013] In a second aspect, this application provides an electronic device, including: a load and an input power supply, and a multipolar input switch control circuit as described in the first aspect, the multipolar input switch control circuit being connected between the input power supply and the load, for controlling the input power supply to supply power to the load according to an external first control signal and a second control signal.

[0014] Thirdly, this application provides a backup power management system, including: a main power supply, a backup power supply and a load, and a multi-polar input switch control circuit as described in the first aspect, wherein the first control signal and the second control signal are respectively from different fault detection units, and are used to trigger the multi-polar input switch control circuit to conduct when the main power supply fails, so that the backup power supply supplies power to the load.

[0015] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a multipolar input switch control circuit, device, and system. Through pure hardware logic circuit design, it can simultaneously accommodate input signals of two different polarities, active low and active high, enabling flexible control of a single load switch and has a wide range of applications. The logic control module in this application consists only of basic discrete components such as resistors, diodes, and MOSFETs, eliminating the need for complex programmable devices such as MCUs and software development, thus greatly reducing costs and design complexity. This application can be effectively applied to cost-sensitive and reliability-critical applications, such as automotive electronics and industrial automation control. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of a multipolar input switch control circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of the circuit state when both the first control signal and the second control signal are invalid in one embodiment of this application. Figure 3 This is a schematic diagram of the circuit state when the first control signal is valid in one embodiment of this application; Figure 4 This is a schematic diagram of the circuit state when the second control signal is valid in one embodiment of this application; Figure 5 This is a schematic diagram of the circuit state when both the first control signal and the second control signal are valid in one embodiment of this application. Figure 6 This is a schematic diagram of a control scheme using an MCU in the existing technology. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] In one exemplary embodiment, such as Figure 1 As shown, a multipolar input switch control circuit is provided, including: a switch module Q1, a first input terminal KEY1, a second input terminal KEY2, and a logic control module.

[0021] Switching module Q1 is connected between the input power supply VBAT and the load Rload, and is used to control the on / off switching of power supply from the input power supply VBAT to the load Rload. In this embodiment, Q1 is a P-type MOSFET (PMOS), with its source (S) connected to the input power supply VBAT (e.g., 12V), its drain (D) connected to the load Rload, and its gate (G) serving as its control terminal, receiving control signals from the logic control module. When the gate voltage is lower than the source voltage by a certain value (i.e., Vgs is negative), the PMOS transistor is turned on; conversely, when the gate voltage is close to the source voltage, the PMOS transistor is turned off.

[0022] The first input terminal KEY1 is used to receive the first control signal. In this embodiment, the first control signal is active low, that is, it is considered active when the first input terminal KEY1 is pulled down to ground (0V); it is considered inactive when the first input terminal KEY1 is floating or connected to a high level. The first input terminal KEY1 is connected to the logic control module.

[0023] The second input terminal KEY2 is used to receive the second control signal. In this embodiment, the second control signal is active high. That is, when the second input terminal KEY2 is pulled up to a high level (e.g., 12V), it is considered active; when the second input terminal KEY2 is left floating or grounded, it is considered inactive. The second input terminal KEY2 is connected to the logic control module.

[0024] The logic control module is used to control the gate voltage of PMOS transistor Q1 according to the state of the first input terminal KEY1 and the second input terminal KEY2, thereby controlling the on and off state of PMOS transistor Q1. The logic control module includes a first logic control unit and a second logic control unit.

[0025] The first logic control unit is specifically configured as follows: The first pull-up resistor R1 has one end connected to the input power supply VBAT and the other end connected to the first input terminal KEY1. In this embodiment, a diode D1 is used as a unidirectional conduction device. Its anode is connected to the control terminal of the switching module, i.e., the gate of the PMOS transistor Q1, and its cathode is connected to the first input terminal KEY1. The second pull-up resistor R2 has one end connected to the input power supply VBAT and the other end connected to the gate of the PMOS transistor Q1. The second logic control unit is specifically configured as follows: In this embodiment, the second MOSFET Q2 is an N-type MOSFET (NMOS). Its drain is connected to the gate of the PMOS MOSFET Q1, its source is grounded, and its gate is connected to the second input terminal KEY2 through a voltage divider circuit. In this embodiment, the voltage divider circuit consists of a first voltage divider resistor R3 and a second voltage divider resistor R4 connected in series between the second input terminal KEY2 and ground. The common connection point of the first voltage divider resistor R3 and the second voltage divider resistor R4 serves as the voltage divider output terminal of the voltage divider circuit, connected to the gate of the NMOS MOSFET Q2, used to adjust the voltage of the second control signal to the driving voltage range of the NMOS MOSFET Q2.

[0026] This application, through a pure hardware logic circuit design, can simultaneously accommodate input signals of two different polarities: active low and active high, enabling flexible control of a single load switch and having a wide range of applications. The logic control module in this application consists only of basic discrete components such as resistors, diodes, and MOSFETs, eliminating the need for complex programmable devices such as MCUs and software development, thus greatly reducing costs and design complexity. This application can be effectively applied to cost-sensitive and reliability-critical application scenarios.

[0027] The following is combined with Figures 2 to 5 This paper elaborates on the working principle of this multipolar input switch control circuit.

[0028] Circuit state 1: Both the first input terminal KEY1 and the second input terminal KEY2 are invalid.

[0029] like Figure 2 As shown, this is the initial or standby state of the multi-polar input switch control circuit, which requires ensuring that the load is reliably disconnected. At this time, both the first input terminal KEY1 and the second input terminal KEY2 are in an invalid state, that is, both the first input terminal KEY1 (S1 in the figure) and the second input terminal KEY2 (S2 in the figure) are floating. The circuit state analysis at this time is as follows: The first input terminal KEY1 is left floating, and its potential is pulled up to near VBAT voltage (e.g., 12V) through the first pull-up resistor R1. The second input terminal KEY2 is left floating, and its potential is pulled down to ground potential (0V) through the second voltage divider resistor R4. Therefore, the gate of NMOS transistor Q2 is at a low level, and NMOS transistor Q2 is in the off state. The anode and cathode voltages of diode D1 are approximately equal, and diode D1 is subjected to zero bias or a weak reverse bias, therefore diode D1 is in the cutoff state.

[0030] The gate potential of PMOS transistor Q1 is maintained at a high level (12V) through the second pull-up resistor R2, and the source voltage of PMOS transistor Q1 is also 12V. Therefore, the gate-source voltage Vgs≈0V. Since a negative gate-source voltage (Vgs is negative) is required for PMOS transistor Q1 to conduct, the conduction condition is not met at this time. Therefore, PMOS transistor Q1 is in a reliable off state, and the load Rload is completely disconnected from the input power supply VBAT. Experimental data shows that the output voltage is in the microvolt (μV) range at this time, and it is almost in a non-conducting state.

[0031] Circuit state 2: First input terminal KEY1 is valid (low level), and second input terminal KEY2 is invalid.

[0032] like Figure 3As shown, when the first input terminal KEY1 is pulled down to ground (0V), the cathode potential of diode D1 is forcibly pulled down to near 0V. At this time, because the second pull-up resistor R2 pulls up the anode potential of diode D1 to VBAT (e.g., 12V), diode D1 is forward biased (anode 12V, cathode 0V) and conducts. After diode D1 conducts, the anode voltage of diode D1 is clamped near the forward conduction voltage drop Vf (approximately 0.7V). Therefore, the gate voltage of PMOS transistor Q1 is 0.7V, the source voltage of PMOS transistor Q1 is 12V, and the gate-source voltage Vgs≈0.7V-12V=-11.3V, which is much lower than the turn-on threshold voltage of PMOS transistor (e.g., -2V). Therefore, PMOS transistor Q1 is saturated and conducts, and the input power supply VBAT supplies power to the load Rload normally through PMOS transistor Q1. Experimental data shows that the output voltage is 11.997V at this time, the PMOS transistor Q1 is in the conducting state, the second input terminal KEY2 is invalid (floating or grounded), the NMOS transistor Q2 is in the off state, and it does not affect the operation of the circuit.

[0033] Circuit state 3: Second input terminal KEY2 is valid (high level), first input terminal KEY1 is invalid.

[0034] like Figure 4 As shown, when a high level (e.g., 12V) is applied to the second input terminal KEY2, this high level is divided by the first voltage divider resistor R3 and the second voltage divider resistor R4, generating a voltage at the gate of the NMOS transistor Q2. By adjusting the resistance values ​​of the first voltage divider resistor R3 and the second voltage divider resistor R4, it can be ensured that this voltage is above the turn-on threshold of the NMOS transistor Q2, while not exceeding its gate-source withstand voltage limit. For example, when R3=R4, the gate voltage of the NMOS transistor Q2 is approximately 6V, which turns on the NMOS transistor Q2, and the drain of the NMOS transistor Q2 is pulled down to near ground potential (approximately 0V). At this time, the gate voltage of the PMOS transistor Q1 is 0V, and the source voltage of the PMOS transistor Q1 is 12V, Vgs≈0V-12V=-12V. The PMOS transistor Q1 is also saturated and turned on, supplying power to the load Rload. Experimental data shows that the output voltage is 11.997V at this time, and the PMOS transistor Q1 is in the turned-on state. In this state, the first input terminal KEY1 is invalid (floating or connected to a high level). Diode D1 is in a reverse bias state because the anode (0V) voltage is lower than the cathode (high level), and does not participate in the operation, so it does not affect the operation of the circuit.

[0035] Circuit state four: First input terminal KEY1 is valid (low level) and second input terminal KEY2 is valid (high level).

[0036] like Figure 5As shown, when two trigger signals are present simultaneously, it is necessary to ensure that the circuit can still conduct stably without causing logical conflicts. The circuit state analysis at this time is as follows: When the first input terminal KEY1 is active, the cathode potential of diode D1 is forcibly pulled down to near 0V, and the anode of diode D1 is pulled up to VBAT (e.g., 12V) under the action of the second pull-up resistor R2. After diode D1 is forward-biased, the anode voltage of diode D1 is clamped at 0.7V.

[0037] When the second input terminal KEY2 is active, the high level is divided by the first voltage divider resistor R3 and the second voltage divider resistor R4, generating a voltage of about 6V at the gate of NMOS transistor Q2, which turns on NMOS transistor Q2 and pulls down the anode voltage of diode D1 to close to 0V.

[0038] Because the on-resistance of NMOS transistor Q2 is very small, the anode voltage of diode D1 is mainly determined by NMOS transistor Q2 and is pulled down to near 0V (e.g., below 0.1V), lower than the clamping voltage of diode D1 (0.7V). At this time, diode D1 is still forward biased (anode 0.1V, cathode 0V), but the current is very small; the gate-source voltage Vgs of PMOS transistor Q1 is approximately 0V - 12V = -12V, far below the turn-on threshold, therefore PMOS transistor Q1 is saturated and conducting. Experimental data shows that the output voltage is 11.997V at this time, and PMOS transistor Q1 is in the conducting state.

[0039] When both the first input terminal KEY1 and the second input terminal KEY2 are active, the two control paths operate in parallel and are mutually redundant, further ensuring the reliability of PMOS transistor Q1 conduction. Even if one path fails (e.g., diode D1 is open or NMOS transistor Q2 is damaged), the other path can still keep PMOS transistor Q1 conducting, improving the circuit's fault tolerance.

[0040] In one exemplary embodiment, an electronic device is also provided, comprising a load Rload, an input power supply VBAT, and a multipolar input switch control circuit as described above. The multipolar input switch control circuit is connected between the input power supply VBAT and the load Rload, and is used to automatically and reliably control the input power supply to supply power to the load based on a first control signal and a second control signal provided by an external device. Because it employs a purely hardware control circuit, this electronic device can achieve compatibility with different polarity trigger signals at extremely low cost, making it particularly suitable for cost-sensitive and high-reliability applications.

[0041] In one exemplary embodiment, a backup power management system is also provided, particularly suitable for automotive electronics. The system includes a main battery, a backup battery, a load (such as an airbag controller, a brake system electronic control unit, etc.), and a multi-polar input switch control circuit as described above. The input power supply VBAT is the backup battery. A first input terminal KEY1 and a second input terminal KEY2 are respectively connected to different fault detection sensors or controllers. For example, one sensor outputs a low-level active fault signal, and the other outputs a high-level active fault signal. When the main battery fails, either sensor emits a valid trigger signal, and the multi-polar input switch control circuit responds immediately, establishing a connection between the backup battery and the load, ensuring the load still receives power in emergencies. When the main battery failure is resolved or the system is operating normally, neither sensor outputs a valid signal, and the multi-polar input switch control circuit automatically shuts off, cutting off the power supply to the backup battery and preventing energy waste. This design significantly improves vehicle safety and reliability.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multi-polar input switch control circuit, characterized in that, The multipolar input switch control circuit includes: A switching module is connected between the input power supply and the load, and is used to control the on / off state of the power supply from the input power supply to the load; The first input terminal is used to receive the first control signal; The second input terminal is used to receive the second control signal; The logic control module is connected to the first input terminal, the second input terminal, and the control terminal of the switch module, respectively. Wherein, the first control signal is a low-level active signal, and the second control signal is a high-level active signal; when the first input terminal receives a valid low-level signal and / or the second input terminal receives a valid high-level signal, the logic control module controls the switch module to turn on; when neither the first input terminal nor the second input terminal receives a valid level signal, the logic control module controls the switch module to turn off.

2. The multi-polar input switch control circuit according to claim 1, characterized in that, The switching module includes a first MOSFET, the source of which is connected to the input power supply, the drain of which is connected to the load, and the gate of which serves as the control terminal of the switching module and is connected to the logic control module.

3. The multi-polar input switch control circuit according to claim 2, characterized in that, The first MOSFET is a P-type MOSFET.

4. The multipolar input switch control circuit according to claim 1, characterized in that, The logic control module includes a first logic control unit and a second logic control unit; The first logic control unit includes: A first pull-up resistor, one end of which is connected to the input power supply, and the other end of which is connected to the first input terminal; A unidirectional conducting device, wherein the anode of the unidirectional conducting device is connected to the control terminal of the switching module, and the cathode of the unidirectional conducting device is connected to the first input terminal; A second pull-up resistor, one end of which is connected to the input power supply, and the other end of which is connected to the control terminal of the switching module; The second logic control unit includes: The second MOSFET has its drain connected to the control terminal of the switching module, its source grounded, and its gate connected to the second input terminal via a voltage divider circuit.

5. The multi-polar input switch control circuit according to claim 4, characterized in that, The unidirectional conducting device is a diode.

6. The multipolar input switch control circuit according to claim 4, characterized in that, The second MOSFET is an N-type MOSFET.

7. The multipolar input switch control circuit according to claim 4, characterized in that, The voltage divider circuit includes: A first voltage divider resistor, one end of which is connected to the second input terminal, and the other end of which is connected to the gate of the second MOS transistor; The second voltage divider resistor has one end grounded and the other end connected to the gate of the second MOS transistor.

8. The multipolar input switch control circuit according to claim 1, characterized in that, The logic control module is composed of discrete components and does not include a microcontroller unit.

9. An electronic device, characterized in that, include: The load and the input power supply, and the multipolar input switch control circuit as described in any one of claims 1-8, the multipolar input switch control circuit being connected between the input power supply and the load, for controlling the input power supply to supply power to the load according to an external first control signal and a second control signal.

10. A backup power management system, characterized in that, include: The system includes a main power supply, a backup power supply, and a load, as well as a multi-polar input switch control circuit as described in any one of claims 1-8, wherein the first control signal and the second control signal are respectively from different fault detection units, and are used to trigger the multi-polar input switch control circuit to conduct when the main power supply fails, so that the backup power supply can supply power to the load.

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