Hardwire control circuit for peripheral device

Abstract

This application provides a hard-wired control circuit for an external device. The hard-wired control circuit connects the external device and a power supply, which supplies power to both the hard-wired control circuit and the external device. The hard-wired control circuit includes a protection circuit and a current detection circuit. The protection circuit is directly connected to the external device. The current detection circuit is connected to the protection circuit, collects current signals, converts the current signals into voltage signals, and outputs them to the controller. The protection circuit controls whether the power supply provides power to the external device by switching it on and off. The voltage signal is used to determine the operating status of the external device. This application solves the technical problem that existing hard-wired circuits are difficult to implement comprehensively for diagnosis and protection in practical applications.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and more specifically, to a hardwired control circuit for an external device. Background Technology

[0002] Hard-wired circuit schemes for transmitting electrical signals generally adopt a simple path mode or a switch control method with an enable signal. However, without diagnostic functions, it is impossible to determine whether the peripheral device is working properly.

[0003] Therefore, at least one of the following problems exists in the related technologies: existing hard-wired circuits are difficult to achieve comprehensive diagnosis and protection in practical applications. Utility Model Content

[0004] This invention solves the technical problem that existing hard-wired circuits are difficult to diagnose and protect comprehensively in practical applications.

[0005] To address the aforementioned problems, this utility model provides a hardwired control circuit for an external device. The hardwired control circuit connects the external device and a power supply, which supplies power to both the hardwired control circuit and the external device. The hardwired control circuit includes: a protection circuit directly connected to the external device; and a current detection circuit connected to the protection circuit. The current detection circuit collects current signals and converts these signals into voltage signals, which are then output to the controller. The protection circuit controls whether the power supply provides power to the external device by switching it on and off. The voltage signal is used to determine the operating status of the external device.

[0006] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: The hard-wired control circuit of this application includes current detection and diagnostic protection functions. The power supply provides power to the external device through the hard-wired control circuit and simultaneously provides power to the hard-wired control circuit without adding an additional power supply. The protection circuit protects the hard wires of both the hard-wired control circuit and the external device. At the same time, the voltage signal identifies the status of the external device, achieving full coverage of diagnostic functions. Problems can be quickly located, realizing comprehensive protection, accurate diagnosis, and flexible control of the external device, while ensuring the reliability and cost-effectiveness of the hard-wired control circuit.

[0007] In one embodiment of this utility model, the current detection circuit includes: an operational amplifier connected to a power supply, the operational amplifier having a non-inverting input terminal, an inverting input terminal, and an output terminal, the non-inverting input terminal being connected to the power supply and the inverting input terminal being connected to a protection circuit; a first transistor having a first base, a first collector, and a first emitter, the first base being connected to the output terminal, the first collector being connected to the non-inverting input terminal, and the first emitter being connected to a controller via a fourth resistor; wherein the first emitter is also grounded via a third resistor.

[0008] Compared with existing technologies, the technical effects achieved by this solution are as follows: The current detection circuit utilizes a negative feedback loop composed of a first transistor and an operational amplifier, enabling both the operational amplifier and the first transistor to operate in the linear region. The current signal is acquired by utilizing the virtual short and virtual open characteristics of the operational amplifier. The current signal passes through the first transistor to the third and fourth resistors to form a voltage signal. The first emitter is connected to the controller through the fourth resistor, enabling the voltage signal to be input to the controller's AD port for diagnosis. The operating status of the external device is identified by the voltage value of the AD port.

[0009] In one embodiment of this invention, the hard-wired control circuit further includes a capacitor pump circuit, which is connected between the operational amplifier and the power supply.

[0010] Compared with existing technologies, the technical effects achieved by this solution are as follows: by using the capacitor pump principle, the operational amplifier can be supplied with a higher operating voltage than the power supply without adding an additional power supply. This not only simplifies circuit design but also improves the system's energy efficiency, as capacitor pumps are generally more efficient than traditional boost circuits.

[0011] In one embodiment of this utility model, the capacitor pump circuit includes: a first Zener diode and a second Zener diode, with the operational amplifier connected to the power supply in sequence through the first Zener diode and the second Zener diode; a second capacitor, one end of which is connected between the first Zener diode and the second Zener diode, and the other end of which is connected to the pulse signal; and a fourth capacitor, one end of which is connected between the operational amplifier and the first Zener diode, and the other end of which is grounded.

[0012] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: the first Zener diode, the second Zener diode, the second capacitor, and the fourth capacitor utilize the principle that the voltage across the capacitor cannot change abruptly to form a capacitor pump effect, thereby raising the power supply voltage to power the operational amplifier.

[0013] In one embodiment of this utility model, the hard-wired control circuit further includes: a fourth Zener diode, one end of which is connected to the controller and the other end of which is connected to the second power supply; and a fifth Zener diode, one end of which is connected to the controller and the other end of which is grounded.

[0014] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: In order to avoid damage to the controller's ports, a fourth and fifth Zener diode are set at the controller's AD port and connected to a second power supply to stabilize the voltage and provide protection, preventing damage to the controller's pin terminals.

[0015] In one embodiment of this utility model, the protection circuit includes: a second transistor, which has a second base, a second collector, and a second emitter, wherein the second collector is connected to an external device and the second emitter is connected to a power supply through an eighth resistor; and a fourth transistor, which has a fourth base, a fourth collector, and a fourth emitter, wherein the fourth collector is connected to the second base, the fourth emitter is grounded, and the fourth base is connected to the enable signal of the external device.

[0016] Compared with existing technologies, the technical effects achieved by this solution are as follows: The fourth base of the fourth transistor is connected to the EN enable signal of the external device. When the EN enable signal is high, the fourth transistor is turned on, which in turn turns on the second transistor, thereby activating the protection circuit and outputting the power supply to the external device. The current limiting of the external device can be adjusted by adjusting the value of the eighth resistor. Therefore, this application allows for arbitrary setting of the current detection threshold within the operational amplifier's capability range. By allowing arbitrary setting of the current detection threshold within the operational amplifier's capability range, it can adapt to different types of load control circuits without redesigning the entire circuit. This flexibility allows the same hardware to be applied to various different scenarios, thereby reducing development costs and improving product versatility.

[0017] In one embodiment of this utility model, the protection circuit further includes a third transistor, which has a third base, a third collector and a third emitter, with the third collector connected to the second base, the third emitter connected to the power supply and the third base connected to the second emitter.

[0018] Compared with existing technologies, the technical effects achieved by this solution are as follows: the third transistor acts as a current-limiting protection device. When an external device is accidentally grounded, the third transistor is turned on, reducing the voltage of the second base of the second transistor, causing the second transistor to turn off and thus cutting off the protection circuit. This limits the current and protects the hard-wired control circuit. In this application, the second transistor is used as the main control switch, and its conduction state is jointly determined by the fourth transistor (controlled by the EN enable signal) and the third transistor (overcurrent protection). At the same time, the hard-wired control circuit of this application is composed of passive components, which has strong anti-interference ability, high reliability, low cost, and eliminates the dependence on integrated ICs, which is beneficial for the value analysis of the project.

[0019] In one embodiment of this utility model, the protection circuit further includes a third diode, which is connected between the external device and the second collector, with the anode of the third diode connected to the second collector and the cathode of the third diode connected to the external device.

[0020] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: the third diode is a reverse protection diode, and the cathode of the third diode is connected to the external device. When the external device is mistakenly connected to the power supply, the presence of the third diode can protect the hard-wired control circuit and prevent damage to the internal components of the hard-wired control circuit.

[0021] In one embodiment of this utility model, the protection circuit further includes a seventh resistor, one end of which is connected to the second base and the other end of which is connected to the second emitter.

[0022] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: the seventh resistor is a fixed resistor, which prevents malfunctions when there is no control.

[0023] By adopting the technical solution of this utility model, the following technical effects can be achieved:

[0024] (1) The protection circuit realizes the protection of the hard-wired control circuit and the hard wires of the external equipment; at the same time, the voltage signal identifies the status of the external equipment, realizes full coverage of diagnostic functions, and can quickly locate the problem; it realizes comprehensive protection, accurate diagnosis and flexible control of the external equipment, while ensuring the reliability and cost-effectiveness of the hard-wired control circuit.

[0025] (2) By using the capacitor pump principle, the operating voltage of the operational amplifier can be higher than that of the power supply without adding an additional power supply;

[0026] (3) In order to avoid damage to the controller's ports, a fourth Zener diode and a fifth Zener diode are set at the controller's AD port and connected to the second power supply to stabilize the voltage and provide protection, so as to prevent damage to the controller's pin terminals.

[0027] (4) In this application, the second transistor is used as the main control switch, and its conduction state is determined by the fourth transistor and the third transistor. At the same time, the hard-wired control circuit of this application is composed of passive components, which has strong anti-interference ability, high reliability, low cost, and gets rid of dependence on integrated ICs, which is conducive to the value analysis of the project.

[0028] (5) The presence of the third diode can protect the hard-wired control circuit and prevent damage to the internal components of the hard-wired control circuit. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A control block diagram of a hardwired control circuit for an external device provided in Embodiment 1 of this utility model;

[0031] Figure 2 for Figure 1 The detailed circuit diagram of the hard-wired control circuit for the external device.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Power supply; 10. External device; 101. EN enable signal; 100. Protection circuit; 102. Current signal; 200. Current detection circuit; 203. Voltage signal; 300. Controller; 400. Capacitor pump circuit. Detailed Implementation

[0034] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions in the embodiments of this utility model are clearly and completely described. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0035] Example 1

[0036] See Figure 1 This utility model provides a hardwired control circuit for an external device 10. The hardwired control circuit connects the external device 10 and a power supply 1. The power supply 1 supplies power to both the hardwired control circuit and the external device 10. Figure 2 The hard-wired control circuit includes a protection circuit 100 and a current detection circuit 200. The protection circuit 100 is directly connected to the external device 10. The current detection circuit 200 is connected to the protection circuit 100. The current detection circuit collects the current signal 102 and converts the current signal 102 into a voltage signal 203, which is then output to the controller 300. The protection circuit 100 controls whether the power supply 1 supplies power to the external device 10. The voltage signal 203 is used to determine the operating status of the external device 10.

[0037] In one specific embodiment, the external device 10 is a hardwired external device. The hardwired control circuit of this application includes current detection and diagnostic protection functions. The power supply 1 supplies power to the external device 10 through the hardwired control circuit and simultaneously supplies power to the hardwired control circuit without adding an additional power supply. The protection circuit 100 protects the hardwired control circuit and the external device 10. At the same time, the voltage signal 203 identifies the status of the external device 10, achieving full coverage of diagnostic functions. Problems can be quickly located, realizing comprehensive protection, accurate diagnosis, and flexible control of the external device 10, while ensuring the reliability and cost-effectiveness of the hardwired control circuit.

[0038] Furthermore, the current detection circuit 200 includes: an operational amplifier and a first transistor. The operational amplifier is connected to the power supply 1 and has a non-inverting input terminal, an inverting input terminal, and an output terminal. The non-inverting input terminal is connected to the power supply 1, and the inverting input terminal is connected to the protection circuit 100. The first transistor has a first base, a first collector, and a first emitter. The first base is connected to the output terminal, the first collector is connected to the non-inverting input terminal, and the first emitter is connected to the controller 300 through a fourth resistor. The first emitter is also grounded through a third resistor.

[0039] Specifically, POWER is the power supply 1, U1 is the operational amplifier, Q1 is the first transistor, R3 is the third resistor, R4 is the fourth resistor, DET is the voltage signal 203 of the external device 10, and MCU is the controller 300. The current detection circuit 200 uses the negative feedback loop composed of Q1 and U1 to make U1 and Q1 work in the linear region. It uses the virtual short and virtual open characteristics of the operational amplifier to collect the current signal 102. The current signal 102 passes through Q1 to R3 and R4 to form the voltage signal 203. The first emitter is connected to the controller 300 through the fourth resistor, which can input the voltage signal 203 to the AD port of the controller 300 for diagnosis. The working status of the external device 10 is identified by the voltage value of the AD port.

[0040] Preferably, a fifth resistor R5 is connected in series between the output terminal of U1 and the first base of Q1. R5 is used to prevent the output of U1 from short-circuiting and failing. When the voltage value of the AD port is 0-0.4V, it is determined that the external device 10 is shorted to the power supply; when the voltage value of the AD port is 0.4-3.2V, it is determined that the external device 10 is working normally; when the voltage value of the AD port is 3.3-3.7V, it is determined that the external device 10 is shorted to ground.

[0041] Furthermore, the hard-wired control circuit also includes a capacitor pump circuit 400, which is connected between the operational amplifier and the power supply 1.

[0042] Specifically, since the operational amplifier's supply voltage must be greater than the voltage to be compared, a capacitor pump circuit 400 is set between U1 and POWER to ensure that the operational amplifier has a sufficient operating voltage range. The capacitor pump charges and raises the voltage to provide U1 with a supply voltage greater than POWER, and a simple boost device supplies power to the operational amplifier. By using the capacitor pump principle, this application can provide the operational amplifier with an operating voltage higher than the supply voltage 1 without adding an additional power supply. This not only simplifies the circuit design but also improves the system's energy efficiency, because capacitor pumps are generally more efficient than traditional boost circuits.

[0043] Furthermore, the capacitor pump circuit 400 includes: a first Zener diode and a second Zener diode, with the operational amplifier connected to the power supply 1 in sequence through the first Zener diode and the second Zener diode; a second capacitor, one end of which is connected between the first Zener diode and the second Zener diode, and the other end of which is connected to the pulse signal; and a fourth capacitor, one end of which is connected between the operational amplifier and the first Zener diode, and the other end of which is grounded.

[0044] Specifically, D1 is the first Zener diode, D2 is the second Zener diode, C2 is the second capacitor, and C4 is the fourth capacitor. D1, D2, C2, and C4 utilize the principle that the voltage across a capacitor cannot change abruptly, creating a capacitor pump effect to raise the POWER voltage to 3.3+POWER to power operational amplifier U1. SW_3V3 is a pulse signal. This application uses a 3.3V PWM signal to drive a capacitor pump circuit 400, which may include a capacitor and several diodes. When the PWM signal switches, the capacitor is charged and discharged. Through appropriate circuit design, the 3.3V input voltage can be raised to, for example, 5V or higher to ensure that operational amplifier U1 has a sufficient operating voltage range.

[0045] Preferably, the capacitor pump circuit 400 also includes a third capacitor C3, which is used for filtering.

[0046] Furthermore, the hard-wired control circuit also includes a fourth Zener diode and a fifth Zener diode. One end of the fourth Zener diode is connected to the controller 300, and the other end of the fourth Zener diode is connected to the second power supply. One end of the fifth Zener diode is connected to the controller 300, and the other end of the fifth Zener diode is grounded.

[0047] Specifically, D4 is the fourth Zener diode, D5 is the fifth Zener diode, and 3V3 is the second voltage, which can be 3.3V. To prevent damage to the controller 300's ports, D4 and D5 are connected to a second power supply at the controller 300's AD port to provide voltage regulation and protection, preventing damage to the controller 300's pin terminals. Specifically, a reverse-biased diode D5 is connected between the MCU's AD port and ground, and another forward-biased diode D4 is connected between the AD port and the power supply. This way, when the AD port voltage is lower than ground, D5 will conduct, preventing further voltage drop; when the AD port voltage is higher than the second power supply voltage, D4 ​​will conduct, limiting voltage rise. This configuration effectively protects the MCU's AD port from overvoltage and reverse voltage damage.

[0048] Furthermore, the protection circuit 100 includes a second transistor and a fourth transistor. The second transistor has a second base, a second collector, and a second emitter. The second collector is connected to the external device 10, and the second emitter is connected to the power supply 1 through an eighth resistor. The fourth transistor has a fourth base, a fourth collector, and a fourth emitter. The fourth collector is connected to the second base, the fourth emitter is grounded, and the fourth base is connected to the enable signal of the external device 10.

[0049] Specifically, Q2 is the second transistor, Q4 is the fourth transistor, and R8 is the eighth resistor. The fourth base of Q4 is connected to the EN enable signal 101 of the external device 10. When the EN enable signal 101 is high, Q4 is turned on, which in turn turns on Q2, thereby turning on the protection circuit 100 and outputting the power supply 1 to the external device 10. The current limiting of the external device 10 can be adjusted by adjusting the value of R8. Therefore, this application can arbitrarily set the current detection threshold value within the operational amplifier's capability range. By allowing the current detection threshold value to be arbitrarily set within the operational amplifier's capability range, it can adapt to different types of load control circuits without redesigning the entire circuit. This flexibility allows the same hardware to be applied to a variety of different scenarios, thereby reducing development costs and improving product versatility.

[0050] Specifically, different current detection thresholds can be set by adjusting the resistance value of R8. For example, if a smaller current needs to be detected, the resistance value of R8 can be increased; if a larger current needs to be detected, the resistance value of R8 can be decreased. In this way, the same circuit can adapt to different load requirements, such as detecting the operating current of LED lights or detecting the operating current of small motors.

[0051] Preferably, a second resistor R2 is connected between the non-inverting input terminal of U1 and POWER, and R2 limits the current of Q4 to control the base current of Q2.

[0052] Furthermore, the protection circuit 100 also includes a third transistor, which has a third base, a third collector and a third emitter, with the third collector connected to the second base, the third emitter connected to the power supply 1, and the third base connected to the second emitter.

[0053] Specifically, Q3 is the third transistor, which plays a current limiting protection role. When the external device 10 is accidentally grounded, Q3 is turned on, reducing the voltage of the second base of Q2, so that Q2 is turned off, which can cut off the protection circuit 100, thereby limiting the current and protecting the hard-wired control circuit. In this application, Q2 is used as the main control switch, and its conduction state is jointly determined by Q4 (controlled by the EN enable signal 101) and Q3 (overcurrent protection).

[0054] Therefore, the protection circuit 100 in this application uses a combination of the third diode D3, the third transistor Q3 and the fourth transistor Q4 to protect the hardwire of the external device 10 from reverse and overcurrent. At the same time, the hardwire control circuit of this application is composed of passive components, which has strong anti-interference ability, high reliability, low cost, and eliminates the dependence on integrated ICs, which is conducive to the value analysis of the project.

[0055] Furthermore, the protection circuit 100 also includes a third diode, which is connected between the external device 10 and the second collector, with the anode of the third diode connected to the second collector and the cathode of the third diode connected to the external device 10.

[0056] Specifically, D3 is the third diode, D3 is a reverse protection diode, and the cathode of D3 is connected to the external device 10. When the external device is mistakenly connected to the power supply, the presence of D3 can protect the hard-wired control circuit and prevent damage to the internal components of the hard-wired control circuit.

[0057] Furthermore, the protection circuit 100 also includes a seventh resistor, one end of which is connected to the second base and the other end of which is connected to the second emitter.

[0058] Specifically, R7 is the seventh resistor, a fixed resistor, to prevent malfunctions when there is no control.

[0059] Preferably, the protection circuit 100 further includes: a first capacitor C1, a sixth resistor R6 and a tenth resistor R10. One end of C1 is connected to the external device 10 and the other end is grounded. C1 is used for filtering. R6 is connected between the second base of Q2 and the fourth collector of Q4. One end of R10 is connected between the fourth base and the enable signal and the other end is grounded. R10 and R7 have the same function: to prevent malfunctions when there is no control.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A hardwired control circuit for an external device (10), the hardwired control circuit connecting the external device (10) and a power supply (1), the power supply (1) supplying power to the hardwired control circuit and the external device (10), characterized in that, The hardwire control circuit includes: A protection circuit (100) is directly connected to the external device (10); A current detection circuit (200) is connected to the protection circuit (100). The current detection circuit collects a current signal (102) and converts the current signal (102) into a voltage signal (203) and outputs it to the controller (300). The power supply (1) is controlled by switching the protection circuit (100) on and off to supply power to the external device (10); the working status of the external device (10) is determined by the voltage signal (203).

2. The hard-wired control circuit according to claim 1, characterized in that, The current detection circuit (200) includes: An operational amplifier is connected to the power supply (1), and the operational amplifier has a non-inverting input terminal, an inverting input terminal and an output terminal. The non-inverting input terminal is connected to the power supply (1), and the inverting input terminal is connected to the protection circuit (100). The first transistor has a first base, a first collector and a first emitter, with the first base connected to the output terminal, the first collector connected to the non-inverting input terminal, and the first emitter connected to the controller (300) through a fourth resistor. The first emitter is also grounded through a third resistor.

3. The hard-wired control circuit according to claim 2, characterized in that, The hardwire control circuit also includes: A capacitor pump circuit (400) is connected between the operational amplifier and the power supply (1).

4. The hard-wired control circuit according to claim 3, characterized in that, The capacitor pump circuit (400) includes: The first Zener diode and the second Zener diode are connected in sequence to the power supply (1) through the first Zener diode and the second Zener diode; The second capacitor has one end connected between the first Zener diode and the second Zener diode, and the other end connected to the pulse signal. A fourth capacitor, one end of which is connected between the operational amplifier and the first Zener diode, and the other end is grounded.

5. The hard-wired control circuit according to any one of claims 2-4, characterized in that, The hardwire control circuit also includes: A fourth Zener diode, one end of which is connected to the controller (300), and the other end of which is connected to a second power supply; The fifth Zener diode has one end connected to the controller (300) and the other end grounded.

6. The hard-wired control circuit according to claim 1, characterized in that, The protection circuit (100) includes: The second transistor has a second base, a second collector, and a second emitter. The second collector is connected to the external device (10), and the second emitter is connected to the power supply (1) through an eighth resistor. The fourth transistor has a fourth base, a fourth collector and a fourth emitter, and the fourth collector is connected to the second base, the fourth emitter is grounded, and the fourth base is connected to the enable signal of the external device (10).

7. The hard-wired control circuit according to claim 6, characterized in that, The protection circuit (100) also includes: The third transistor has a third base, a third collector and a third emitter, and the third collector is connected to the second base, the third emitter is connected to the power supply (1), and the third base is connected to the second emitter.

8. The hard-wired control circuit according to any one of claims 6-7, characterized in that, The protection circuit (100) also includes: A third diode is connected between the external device (10) and the second collector, with the anode of the third diode connected to the second collector and the cathode of the third diode connected to the external device (10).

9. The hard-wired control circuit according to any one of claims 6-7, characterized in that, The protection circuit (100) also includes: A seventh resistor, one end of which is connected to the second base, and the other end of which is connected to the second emitter.

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