A multi-channel integrated switch circuit

Abstract

A multi-channel integrated switch circuit comprises a main body, on which a power pin, a ground pin, a plurality of signal input terminals and a plurality of trigger output terminals are provided; at least three switch circuits of the same structure are integrated in the main body, and any of the switch circuits comprises an NMOS power switch tube, a protection diode and an acceleration diode; in any of the switch circuits, the drain of the NMOS power switch tube is connected to the anode of the protection diode, the cathode of the protection diode is connected to the power pin, the cathode of the acceleration diode is connected to the gate of the NMOS power switch tube, and the source of the NMOS power switch tube is connected to the anode and the ground pin of the acceleration diode; any of the signal input terminals is uniquely connected to the gate of an NMOS power switch tube, and the trigger output terminals are uniquely connected to the drain of an NMOS power switch tube. The switch protection function of the present invention is good, the applicable scenes are wide, the integration is high, and it is conducive to miniaturization application.

Description

Technical Field

[0001] The present invention relates to the field of control circuits, and in particular to a multi-channel integrated switch circuit. Background Art

[0002] In the field of control circuits, electronic switches are a type of electronic device that is used more frequently. When controlling inductive loads, the following problems generally occur: 1. The peak voltage generated during the switching process can easily damage the electronic switch; 2. When the switching frequency is high, the electronic switch connected to the inductive load will heat up severely and make the electronic switch easily damaged; 3. When the power device works continuously for a long time and there are problems with the heat dissipation environment, even low-frequency switching may damage the electronic switch; 4. For general loads with high power, separate components are used to implement electronic switches. The connection of separate components is complex, the size of the PCB board cannot be reduced, and the production cost of the product is difficult to reduce. Therefore, in order to solve the above problems, it is necessary to conduct in-depth research. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a multi-channel modular integrated switch circuit with switch protection.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a multi-channel integrated switch circuit, comprising a main body, on which a power pin, a ground pin, a plurality of signal input terminals and a plurality of trigger output terminals are provided; at least three switch circuits of the same structure are integrated in the main body, and any of the switch circuits comprises an NMOS power switch tube, a protection diode and an acceleration diode; in any of the switch circuits, the drain of the NMOS power switch tube is connected to the anode of the protection diode, the cathode of the protection diode is connected to the power pin, the cathode of the acceleration diode is connected to the gate of the NMOS power switch tube, and the source of the NMOS power switch tube is connected to the anode and the ground pin of the acceleration diode; any of the signal input terminals is uniquely connected to the gate of an NMOS power switch tube, and any of the trigger output terminals is uniquely connected to the drain of an NMOS power switch tube.

[0006] Furthermore, an anti-shock capacitor is integrated in the body, and two ends of the anti-shock capacitor are electrically connected to the power pin and the ground pin respectively.

[0007] Furthermore, a gate resistor is integrated in the body; the gate resistor is connected in parallel with the accelerating diode.

[0008] Furthermore, the switch circuit also includes a trigger control protection circuit; the signal input end is connected to the gate of the NMOS power switch tube via the trigger control protection circuit.

[0009] Furthermore, the trigger control protection circuit includes a trigger unit and a proportional integration circuit unit, wherein the input of the trigger unit and the input of the proportional integration circuit unit are both connected to the signal input terminal, the output signal of the proportional integration circuit unit is used to control the operation enable of the trigger unit, and the output of the trigger unit is correspondingly connected to the gate of the NMOS power switch tube; the proportional gain of the proportional integration circuit unit is less than 1.

[0010] Furthermore, in at least one switching circuit, the trigger control protection circuit also includes a resistor R2 and a capacitor C2; one end of the resistor R2 is connected to the signal input end, and the other end of the resistor R2 is connected to the capacitor C2 and the input of the trigger unit; the other end of the capacitor C2 is electrically connected to the ground pin.

[0011] The present invention also provides a motor trigger circuit, comprising a motor and a multi-channel integrated switch circuit as described above; the motor comprises a first trigger winding and a second trigger winding; the first trigger winding and the second trigger winding are both provided with a center tap; the multi-channel integrated switch circuit integrates four switch circuits of the same structure, wherein the trigger output ends of two switch circuits are respectively connected to the two ends of the first trigger winding, and the trigger output ends of the other two switch circuits are respectively connected to the two ends of the second trigger winding; the power pin, the center tap of the first winding, and the center tap of the second winding are all connected to an external power supply.

[0012] In the above switch circuit, the signal input terminal is physically isolated from the working power supply. The switch circuit can work normally when the input signal voltage is higher or lower than the working power supply voltage, and has great adaptability. The integrated NMOS power switch tube enables the switch circuit to adapt to high-power load control, and the integrated protection diode can ensure the safety of the NMOS power switch tube when the switch circuit controls the inductive load. Since the equivalent capacitance between the source and the gate of the NMOS power switch tube increases when the power design is large, it will affect the switching speed of the power switch tube. The design of the acceleration diode can provide a channel to consume the charge on the equivalent capacitance more quickly, so that the switch circuit can work in a higher frequency range. Through the integrated design, the user's peripheral circuit and wiring layout are simplified, and it can be used for the switch control of different inductive devices such as stepper motors, solenoid valves or relays, meeting a variety of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0014] Figure 1 FIG. 1 is a schematic diagram of the circuit structure of a single-channel switch circuit in Example 1;

[0015] Figure 2 The figure shows a motor connection schematic diagram of the multi-channel integrated switch circuit in Example 1;

[0016] Figure 3 The figure shows a circuit structure diagram of a single-way switch circuit in Example 2.

[0017] Figure 4 Schematic diagram of the circuit structure of the proportional-integral circuit unit in Example 2.

[0018] Figure 5 Schematic diagram of the circuit structure of the single-way switch circuit in Example 3. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the present invention, the technical solution of the utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0020] Example 1

[0021] This embodiment provides a multi-channel integrated switch circuit, including a body, on which a power pin (VCC), a ground pin (GND), a plurality of signal input terminals and a plurality of trigger output terminals are provided; the body integrates four switch circuits of the same structure, such as Figure 1 As shown, one of the switch circuits includes an NMOS power switch tube Q1, a protection diode D2, an acceleration diode D1 and a gate resistor R1; the drain of the NMOS power switch tube Q1 is connected to the anode of the protection diode D2, the cathode of the protection diode D2 is connected to the power pin VCC, the cathode of the acceleration diode D1 is connected to the gate of the NMOS power switch tube Q1, and the source of the NMOS power switch tube Q1 is connected to the anode of the acceleration diode D1 and the ground pin GND; any of the signal input terminals is uniquely connected to the gate of an NMOS power switch tube, and any of the trigger output terminals is uniquely connected to the drain of an NMOS power switch tube; the gate resistor is connected in parallel with the acceleration diode. Smaller input current helps to reduce power consumption, reduce heat dissipation, and can also ensure the normal triggering of the NMOS power switch tube. In this embodiment, the resistor R1 adopts a 100kΩ pull-down resistor. At the same time, the resistor R1 can also convert the input current into a voltage, so that the switch circuit can be controlled by current triggering and has current drive control capability.

[0022] Obviously, the signal input terminal is physically isolated from the power pin VCC. The switch circuit can work normally when the input signal voltage is higher or lower than the working power voltage. The integrated NMOS power switch tube Q1 enables the switch circuit to adapt to the control of higher power loads. The integrated protection diode D1 can ensure the safety of the NMOS power switch tube when the switch circuit controls the inductive load. When the inductive load is heavy, an external diode can be connected to the power pin and the trigger output terminal in parallel with the protection diode, so that when the switch controls the inductive load, there can be enough channels to conduct and release through the protection diode and the external diode. Since the equivalent capacitance between the source and the gate increases when the power design of the NMOS power switch tube is large, it affects the switching speed of the power switch tube. The design of the acceleration diode can provide a channel to consume the charge on the equivalent capacitance faster, so that the switch circuit can work in a higher frequency range. It is suitable for resistive loads. The multi-way switch circuit can also make the integrated circuit used in occasions where inductive loads and resistive loads are mixed, and the application is more flexible. Through integrated design, the user's peripheral circuit and wiring layout are simplified, and it can be used for the switch control of different inductive devices such as stepper motors, solenoid valves or relays, and can also be applied to the switch control of resistive devices, meeting a variety of application scenarios. As a special embodiment, an anti-shock capacitor is also integrated in the body, and the two ends of the anti-shock capacitor are electrically connected to the power pin and the ground pin respectively, so as to improve the voltage spike generated by the inductive load at the power pin VCC port during the freewheeling phase, which helps to improve the circuit reliability. When the inductive load is heavy, an external capacitor can also be connected in parallel (see Figure 2 ).

[0023] This embodiment also provides a motor trigger circuit, such as Figure 2 As shown, it includes a motor and the above-mentioned multi-channel integrated switch circuit; the motor includes a first trigger winding and a second trigger winding; the first trigger winding and the second trigger winding are both provided with a center tap; the trigger output ends of two switch circuits in the multi-channel integrated switch circuit are respectively connected to the two ends of the first trigger winding, and the trigger output ends of the other two switch circuits are respectively connected to the two ends of the second trigger winding; the power pin, the center tap of the first winding, and the center tap of the second winding are all connected to an external power supply. In this embodiment, the motor is a hybrid stepping motor, which is composed of Figure 2 It can be seen that when one of the switch circuits is triggered, the coil connected to the trigger output terminal such as OUT1 is turned on accordingly. When different switch circuits are triggered in a certain order, the motor can achieve forward and reverse switching, and multi-winding or multi-phase motor control, the motor has higher precision, and the winding inductance changes less, the control-execution accuracy, stability and flexibility are better, and the overall structure is set around the integrated circuit, the wiring is simple, and the size is smaller.

[0024] Example 2

[0025] like Figure 3 As shown, in this embodiment, the switch circuit further includes a trigger control protection circuit; the signal input end is connected to the gate of the NMOS power switch tube via the trigger control protection circuit. The trigger control protection circuit comprises a trigger unit and a proportional integration circuit unit, wherein the input of the trigger unit and the input of the proportional integration circuit unit are both connected to the signal input terminal, the output signal of the proportional integration circuit unit is used to control the operation enable of the trigger unit, and the output of the trigger unit is correspondingly connected to the gate of the NMOS power switch tube; the proportional gain of the proportional integration circuit unit is less than 1; by designing the gain less than 1, when a high level is continuously input, the time for the proportional integration circuit unit to reach the circuit voltage limit or the power supply limit is longer. In actual operation, a smaller proportional gain can be designed, and the capacitance and resistance parameters can be appropriately increased to extend the time for integration to the upper limit, so that it can correspond to the control time. Whether it is a level input trigger or a pulse input trigger, the proportional integration method can realize the conversion of voltage-trigger time. When the above-mentioned switch circuit works continuously for a long time, the output voltage of the proportional integration circuit unit is higher. By setting the parameters, the preset continuous working time limit can be realized, and the output voltage of the proportional integration circuit unit reaches the control voltage threshold of the trigger unit, and the trigger unit outputs a low level, thereby turning off the control trigger of the NMOS power switch tube. When the control signal of the signal input terminal is cancelled and the voltage of the proportional-integral circuit unit drops below the control voltage threshold due to capacitor discharge, the trigger unit can be triggered by the control signal of the signal input terminal again, and the NMOS power switch tube is turned on. The combination of the proportional-integral circuit unit and the trigger unit avoids overheating and damage to the chip caused by long-term continuous operation of the power load. As a special case, Figure 3 As shown, in at least one switch circuit, the trigger control protection circuit also includes a resistor R2 and a capacitor C2; one end of the resistor R2 is connected to the signal input end, and the other end of the resistor R2 is connected to the capacitor C2 and the input of the trigger unit; the other end of the capacitor C2 is electrically connected to the ground pin. The resistor R2 and the capacitor C2 form a low-pass filter, and the high-frequency control signal transmitted from the signal input end is introduced into the ground pin, so that the input end of the trigger unit is insensitive to the high-frequency signal, thereby avoiding the serious heating of the electronic switch connected to the inductive load when the switching frequency is high, and causing damage to the chip. Among them, the circuit structure diagram of the proportional integral circuit unit is shown in FIG. Figure 4As shown, it is only for illustration, and a proportional amplifier circuit and an integration circuit can also be set in practice. In this embodiment, the trigger unit uses a transmission gated D trigger, which is level triggered. Since the output state of the enable end of the trigger always changes with the input state during the effective level period, the trigger logic is set to be effective at a low level. When the proportional integration circuit unit outputs a low level, the output state of the trigger is the control signal input of the transmission signal input end. When the proportional integration circuit unit outputs a high level, the trigger cannot respond to the control signal of the signal input end to achieve the protection function. As another embodiment, the trigger control protection circuit also includes a logic circuit, and the logic circuit includes an AND logic circuit and a non-logic circuit; one of the inputs of the AND logic circuit is connected to the output of the trigger unit, the output of the proportional integration circuit unit is connected to the other input of the AND logic circuit through the non-logic circuit, and the output of the AND logic circuit is connected to the gate of the NMOS power switch tube. The AND logic circuit has a certain delay and buffer to a certain extent, and can ensure the normal control logic of the NMOS power switch tube, so the protection effect is better and more stable.

[0026] Example 3

[0027] like Figure 5 As shown, the trigger control protection circuit includes a resistor R2, a capacitor C2, a resistor R3, and a diode D1, wherein the resistor R2 and the capacitor C2 form a low-pass filter, and the resistor R2 prevents the capacitor from being equivalently shorted to form a large current that damages the capacitor C2 when the transient signal is loaded to the signal input terminal, and the resistor R3 and the resistor R1 further reduce the discharge current of the capacitor C2, which helps to further limit the high-frequency control signal transmitted by the signal input terminal, thereby realizing the protection of the NMOS power switch tube Q1 in the working scenario of a large inductive load. Compared with Example 2, this embodiment is simpler and more energy-efficient.

[0028] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be considered exemplary only, and the true scope and spirit of the present invention is indicated by the claims.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-channel integrated switch circuit, comprising a body, on which a power pin, a ground pin, a plurality of signal input terminals and a plurality of trigger output terminals are provided; characterized in that: At least three switch circuits with the same structure are integrated in the body, and any of the switch circuits includes an NMOS power switch tube, a protection diode and an acceleration diode; in any of the switch circuits, the drain of the NMOS power switch tube is connected to the anode of the protection diode, the cathode of the protection diode is connected to the power pin, the cathode of the acceleration diode is connected to the gate of the NMOS power switch tube, and the source of the NMOS power switch tube is connected to the anode and the ground pin of the acceleration diode; any of the signal input terminals is uniquely connected to the gate of an NMOS power switch tube, and any of the trigger output terminals is uniquely connected to the drain of an NMOS power switch tube; The switch circuit further comprises a trigger control protection circuit; the signal input end is connected to the gate of the NMOS power switch tube via the trigger control protection circuit; The trigger control protection circuit comprises a trigger unit and a proportional integral circuit unit, wherein the input of the trigger unit and the input of the proportional integral circuit unit are both connected to the signal input terminal, the output signal of the proportional integral circuit unit is used to control the operation enable of the trigger unit, and the output of the trigger unit is correspondingly connected to the gate of the NMOS power switch tube; the proportional gain of the proportional integral circuit unit is less than 1; In at least one switch circuit, the trigger control protection circuit further includes a resistor R2 and a capacitor C2; one end of the resistor R2 is connected to the signal input end, and the other end of the resistor R2 is connected to the capacitor C2 and the input of the trigger unit; the other end of the capacitor C2 is electrically connected to the ground pin; An anti-shock capacitor is also integrated in the body, and two ends of the anti-shock capacitor are electrically connected to the power pin and the ground pin respectively.

2. The multi-channel integrated switch circuit according to claim 1, characterized in that: A gate resistor is also integrated in the body; the gate resistor is connected in parallel with the accelerating diode.

3. The multi-channel integrated switch circuit according to claim 1, characterized in that: The trigger is a transmission gated D trigger.

4. A motor trigger circuit, comprising a motor, characterized in that: It also includes a multi-channel integrated switch circuit as described in claim 1; the motor includes a first trigger winding and a second trigger winding; the first trigger winding and the second trigger winding are both provided with a center tap; the multi-channel integrated switch circuit integrates four switch circuits with the same structure, wherein the trigger output ends of two switch circuits are respectively connected to the two ends of the first trigger winding, and the trigger output ends of the other two switch circuits are respectively connected to the two ends of the second trigger winding; the power pin, the center tap of the first winding, and the center tap of the second winding are all connected to an external power supply.

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