Reset circuit and electronic equipment

Abstract

The embodiment of the utility model discloses a reset circuit and electronic equipment. The reset circuit is characterized in that a first control end of a first switch element is electrically connected with a micro-control unit; the second control end of the second switch element is electrically connected with the output end of the first switch element, and the output end of the second switch element is electrically connected with the reset pin and the Vbus pin of the micro-control band unit; wherein the reset circuit is configured to enable the first switch element to be switched off and the second switch element to be switched on under the action of a Vbus when the micro-control unit is in an abnormal state, so that the reset pin has a first level for resetting the micro-control unit; when the micro-control unit is in a normal state, the micro-control unit outputs a first voltage to enable the first switch element to be switched on, the second switch element responds to the switch-on of the first switch element to be switched off to enable the reset pin to have a second level, and the second level enables the micro-control unit not to be reset. By means of the mode, it can be avoided that when the MCU works normally, external USB equipment is inserted, and the MCU is reset.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of hardware circuits, and in particular, to a reset circuit and an electronic device having the reset circuit. Background Art

[0002] During normal use, consumer electronic devices may freeze due to abnormal conditions or become stuck due to static electricity. At this time, a reset operation is required to restore the device. However, current consumer electronics rarely have a reset button. Some use the method of inserting a USB device to reset the MCU. However, when the MCU system is normal, inserting a USB device to reset will cause the MCU to reset even in normal state, which will cause the device with LED display light or screen to turn off instantly, or cause the temporary data stored in the MCU to be lost. Utility Model Content

[0003] An embodiment of the present application provides a reset circuit, which is used to reset a micro control unit to avoid resetting the micro control unit due to insertion of an external USB device when the micro control unit is operating normally.

[0004] At least one embodiment of the present application provides a reset circuit for resetting a micro control unit, including:

[0005] A first switch element comprises a first control terminal, wherein the first control terminal is electrically connected to the micro control unit;

[0006] A second switch element, comprising a second control end, the second control end is electrically connected to the output end of the first switch element, the output end of the second switch element is electrically connected to the reset pin of the micro-controller unit, and the second control end is also used to be electrically connected to the Vbus pin;

[0007] The reset circuit is configured to turn off the first switch element when the micro control unit is in an abnormal state, and turn on the second switch element to output a first level under the action of the Vbus to reset the micro control unit;

[0008] When the micro control unit is in a normal state, the micro control unit outputs a first voltage to turn on the first switch element, and the second switch element is turned off in response to the turning on of the first switch element and then outputs a second level so that the micro control unit is not reset.

[0009] In one embodiment, a boost circuit is connected between the first switch element and the micro control unit, and the boost circuit is used to increase the first voltage to a second voltage, and the first switch element is turned on under the action of the second voltage.

[0010] In one embodiment, the voltage boost circuit includes a voltage doubler circuit.

[0011] In one embodiment, the reset circuit further includes a delay circuit, and the delay circuit is used to delay the resetting of the micro control unit.

[0012] In one embodiment, the reset circuit further includes a third switch element, an output end of the third switch element is electrically connected to the second control end, the third switch element is configured to lag behind the conduction of the second switch element, and the second switch element is turned off in response to the conduction of the third switch element.

[0013] In one embodiment, the first switching element includes a first NMOS tube, the second switching element includes a second NMOS tube, the G pole of the first NMOS tube is electrically connected to the micro control unit, the S pole of the first NMOS tube is electrically connected to the reference ground, the D pole of the first NMOS tube is electrically connected to the G pole of the second NMOS tube, the S pole of the second NMOS tube is electrically connected to the reference ground, and the D pole of the second NMOS tube is electrically connected to the reset pin of the micro control unit.

[0014] In one embodiment, the reset circuit also includes a first resistor and a first capacitor, the first end of the first resistor is electrically connected to the Vbus pin, the second end is electrically connected to the G pole of the second NMOS tube, the positive pole of the first capacitor is electrically connected to the second end of the first resistor, and the negative pole of the first capacitor is electrically connected to the reference ground.

[0015] In one embodiment, the reset circuit also includes a second resistor, a second capacitor and a third NMOS tube, the first end of the second resistor is connected between the Vbus pin and the first end of the first resistor, the second end of the second resistor is electrically connected to the positive electrode of the second capacitor, the negative electrode of the second capacitor is electrically connected to the reference ground, the G electrode of the third NMOS tube is electrically connected to the positive electrode of the second capacitor, the D electrode of the third NMOS tube is electrically connected to the G electrode of the second NMOS tube, the S electrode of the third NMOS tube is electrically connected to the reference ground, and the resistance value of the second resistor is greater than the resistance value of the first resistor.

[0016] In one embodiment, the first control terminal is electrically connected to a PWM output pin of the micro control unit.

[0017] An embodiment of the present application also provides an electronic device, including a micro control unit and a USB interface, and also includes the reset circuit described in the above embodiment.

[0018] In the reset circuit provided in the above embodiment, when the microcontroller unit is abnormal, the first switch element is turned off, and the second switch element is turned on under the action of Vbus so that the reset pin has a first level, and the first level resets the MCU. When the microcontroller unit is normal, the microcontroller unit outputs a first voltage to turn on the first switch element, and the output voltage of the first switch element acts on the second switch element to turn off the second switch element, thereby causing the reset pin to have a second level, and the second level does not reset the MCU. Therefore, in this way, it is possible to avoid the MCU being reset due to the insertion of an external USB device when the MCU is working normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0020] Figure 1 A schematic diagram of the structure of a reset circuit provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the structure of a reset circuit provided in an embodiment of the present application;

[0022] Figure 3 A schematic diagram of the structure of a reset circuit provided in an embodiment of the present application;

[0023] Figure 4 A schematic diagram of the structure of a reset circuit provided in an embodiment of the present application;

[0024] Figure 5 A schematic diagram of the structure of a reset circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" / "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "left", "right", "inside", "outside" and similar expressions used in this specification are for illustrative purposes only.

[0026] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0027] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0028] In the embodiments of the present application, the "installation" includes fixing or restricting a component or device to a specific position or place by welding, screwing, clamping, bonding, etc. The component or device can remain stationary at the specific position or place or move within a limited range. After the component or device is fixed or restricted to a specific position or place, it may or may not be disassembled, and there is no limitation in the embodiments of the present application.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] An embodiment of the present application provides a reset circuit, which is applied to electronic equipment, such as Figure 1 As shown, the reset circuit includes a first switch element 10 and a second switch element 20, the first switch element 10 includes a first control terminal 11 and a first output terminal 12, the second switch element 20 includes a second control terminal 21 and a second output terminal 22, the first control terminal 11 is electrically connected to one of the pins of the MCU (Microcontroller Unit) of the electronic device, the first output terminal 12 is electrically connected to the second control terminal 21 of the second switch element 20, and the second control terminal 21 is also electrically connected to the Vbus pin of the USB interface, and the second output terminal 22 is electrically connected to the reset pin RST of the MCU, and the reset pin RST can reset the MCU by a high level or a low level.

[0031] When the MCU is abnormal, there is no voltage output on the MCU pin electrically connected to the first control terminal 11, so that the first switch element is cut off. At this time, the input voltage of the second control terminal 21 comes from Vbus. When an external USB device is inserted into the USB interface of the electronic device, the MCU recognizes that the USB device is inserted into the USB interface, and then controls the supply of voltage to the Vbus of the USB interface. Since the first switch element is in the cut-off state, the input voltage of the second control terminal 21 of the second switch element 20 comes from the Vbus voltage. Under the action of the Vbus voltage, the second switch element 20 is turned on. When the second switch element 20 is turned on, the reset pin RST has a first level, and the first level is applied to the reset pin RST of the MCU to reset the MCU.

[0032] When the MCU is normal, a first voltage is outputted on the MCU pin electrically connected to the first control terminal 11. Under the action of the first voltage, the first switch element 10 is turned on, so that the voltage outputted from the first output terminal 11 of the first switch element 10 acts on the second control terminal 21 of the second switch element 20. The second switch element 20 is turned off under the action of the voltage outputted from the first output terminal 11. The second switch element 20 is turned off so that the reset pin has a second level. The second level acts on the reset pin of the MCU so that the MCU is not reset.

[0033] Thus, through the reset circuit provided in this embodiment, when the MCU is abnormal and the electronic device is stuck, the second switch element 20 is turned on by inserting an external USB device, and the MCU reset pin RST is reset under the action of the first level. When the MCU is in a normal state, although a voltage is generated on the Vbus pin of the electronic device with the external USB device inserted, since the first switch element 10 is turned on, the voltage output by the first output terminal 12 of the first switch element 10 turns off the second switch element 20, that is, the Vbus voltage has no effect on the second switch element 20, and the reset pin of the MCU is not reset under the action of the second level, thereby preventing the MCU from being reset when the external USB device is inserted when the MCU is in a normal state.

[0034] In some embodiments, Figure 2As shown, the first switch element 10 is a first NMOS tube, the second switch element 20 is a second NMOS tube, the first control terminal 11 of the first switch element 10 is the G pole of the first NMOS tube, the first output terminal 12 is the D pole of the first NMOS tube, the second control terminal 21 of the second switch element 20 is the G pole of the second NMOS tube, and the second output terminal 22 is the D pole of the second NMOS tube. Thus, the G pole of the first NMOS tube is electrically connected to one of the pins of the MCU, the D pole of the first NMOS tube is electrically connected to the G pole of the second NMOS tube, the G pole of the second NMOS tube is also electrically connected to the Vbus pin, and the S pole of the first NMOS tube and the S pole of the second NMOS tube are both electrically connected to the reference ground. The MCU adopts a low-level reset, the reset pin RST is electrically connected to the D pole of the second NMOS tube, and the reset pin RST is also electrically connected to one end of the pull-up resistor R3, and the other end of the pull-up resistor R3 is electrically connected to the power supply VCC.

[0035] When the MCU is abnormal, there is no voltage output on the MCU pin electrically connected to the G pole of the first NMOS tube, that is, the G pole of the first NMOS tube is at a low level, and the low level turns off the first NMOS tube. When an external USB device is inserted into the USB interface, the Vbus pin generates a voltage, which is applied to the G pole of the second NMOS tube. The voltage is greater than the turn-on voltage of the second NMOS tube, thereby turning on the second NMOS tube. Since the S pole of the second NMOS tube is electrically connected to the reference ground, when the second NMOS tube is turned on, the first level output by the D pole of the second NMOS tube is a low level, which is applied to the reset pin RST of the MCU to reset the MCU.

[0036] When the MCU is normal, a high-level first voltage is outputted on the MCU pin electrically connected to the G pole of the first NMOS tube. Under the action of the first voltage, the first NMOS tube is turned on. Since the S pole of the first NMOS is electrically connected to the reference ground, the D of the first NMOS tube will output a low-level voltage. The low voltage is applied to the G pole of the second NMOS tube to put the second NMOS tube in a cut-off state, and then the reset pin RST is in a high-level state under the action of the pull-up resistor R3. The high level is the above-mentioned second level, and the high level prevents the MCU from being reset.

[0037] In some embodiments, the reset circuit further includes a delay circuit 30, which is used to delay resetting the MCU when an external USB device is inserted when the MCU is in an abnormal state, so as to avoid resetting the MCU immediately after the external USB device is inserted.

[0038] Specifically, Figure 2As shown, the delay circuit 30 includes a first resistor R1 and a first capacitor C1, and the first resistor R1 and the first capacitor C1 form an RC delay circuit. The first end of the first resistor R1 is electrically connected to the Vbus pin, and the second end is electrically connected to the G pole of the second NMOS tube. The positive electrode of the first capacitor C1 is electrically connected to the second end of the first resistor R1, and the negative electrode of the first capacitor C1 is electrically connected to the reference ground. When an external USB device is inserted, a voltage is generated on Vbus, and the voltage will charge the first capacitor C1. Since the voltage across the capacitor cannot change suddenly, the voltage across the first capacitor C1 will slowly increase. When it increases to a voltage greater than the turn-on voltage of the second NMOS tube, the second NMOS tube begins to conduct, thereby generating a low level on the reset pin RST to reset the MCU.

[0039] It should be noted that the delay circuit 30 is not limited to the RC delay circuit in the embodiment. Those skilled in the art may also adopt other well-known delay circuits, such as any one of a voltage comparator delay circuit, a timer delay circuit, a transistor delay circuit or a relay delay circuit.

[0040] In some embodiments, Figure 3 As shown, the reset circuit also includes a second resistor R2, a second capacitor C2 and a third NMOS tube 40, the first end of the second resistor R2 is connected between the Vbus pin and the first end of the first resistor R1, the second end of the second resistor R2 is electrically connected to the positive electrode of the second capacitor C2, the negative electrode of the second capacitor C2 is electrically connected to the reference ground, the G electrode of the third NMOS tube 40 is electrically connected to the positive electrode of the second capacitor C2, the D electrode of the third NMOS tube 40 is electrically connected to the G electrode of the second NMOS tube, the S electrode of the third NMOS tube 40 is electrically connected to the reference ground, and the resistance value of the second resistor R2 is greater than the resistance value of the first resistor R1.

[0041] When the MCU is abnormal, insert an external USB device to reset it, and a voltage is generated on Vbus, which will charge the first capacitor C1 and the second capacitor C2. Since the resistance of the second resistor R2 is greater than the resistance of the first resistor R1, the charging speed of the second capacitor C2 is slower than the charging speed of the first capacitor C1. When the voltage across the first capacitor C1 is greater than the turn-on voltage of the second NMOS tube, the second NMOS tube is turned on and outputs a low level to reset the MCU. After the second NMOS tube is turned on, the voltage across the second capacitor C2 gradually increases. When it increases to a voltage greater than the voltage across the third NMOS tube, the third NMOS tube 40 is turned on, and the S pole of the third NMOS tube 40 is electrically connected to the reference ground, so that the D pole of the third NMOS tube outputs a low level, which is applied to the G pole of the second NMOS tube so that the second NMOS tube is turned off, and the reset pin RST is changed from a low level to a high level under the action of the pull-up resistor R3, thereby releasing the reset of the MCU.

[0042] In some embodiments, Figure 4 As shown, in order to facilitate the conduction of the first NMOS tube, a boost circuit 50 is connected between the G stage of the first NMOS and the pin of the MCU. The boost circuit 50 increases the first voltage output by the MCU pin to a second voltage, and then the larger second voltage drives the first NMOS tube 10 to conduct.

[0043] Specifically, the boost circuit 50 is a voltage doubling circuit, which is formed by a combination of a third capacitor C3, a first diode D1, a second diode D2, a fourth capacitor C4, a fourth resistor R3 and a fifth resistor R5. The voltage across the third capacitor C3 is the output voltage of the voltage doubling circuit, that is, the second voltage after the first voltage is boosted. The G pole of the second NMOS tube is electrically connected to the positive electrode of the third capacitor C3, and then the boosted second voltage is guided to the G pole of the second NMOS tube. It is easy to understand that the boost circuit can also adopt other circuit forms well known to those skilled in the art, and it only needs to boost the first voltage to the second voltage.

[0044] And, in some embodiments, the G stage of the first NMOS tube is electrically connected to the PWM pin of the MCU, and then the first NMOS tube is driven to conduct by the PWM signal to improve the stability of the reset circuit.

[0045] It should be noted that, in some other embodiments, the first switching element 10 and the second switching element 20 can also be any one of a PMOS tube, a transistor, an insulated gate bipolar transistor (IGBT) device, an integrated gate-commutated thyristor (IGCT) device, a gate-turn-off thyristor (GTO) device, a silicon-controlled rectifier (SCR) device, a junction-gate field-effect transistor (JFET) device, a MOS-controlled thyristor (MCT) device, etc.

[0046] An embodiment of the present application also provides an electronic device, the electronic device includes an MCU, and the MCU is used to control the electronic device to perform various functions. For example, the electronic device can be an aerosol generating device, and the MCU can control the heating element in the aerosol generating device to heat the aerosol generating product to generate an aerosol that can be inhaled by the user, thereby replacing traditional cigarettes. The electronic device also includes a USB interface, and the USB interface can be any one of Micro USB, Type-C or Lightning. The electronic device also includes the reset circuit in the above embodiment. When the MCU in the electronic device generates an abnormality, the user can reset the MCU by inserting an external USB device into the USB interface and then resetting the MCU through the reset circuit.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A reset circuit for resetting a micro control unit, characterized in that: include: A first switch element comprises a first control terminal, wherein the first control terminal is electrically connected to the micro control unit; A second switch element, comprising a second control end, the second control end is electrically connected to the output end of the first switch element, the output end of the second switch element is electrically connected to the reset pin of the micro-controller unit, and the second control end is also used to be electrically connected to the Vbus pin; The reset circuit is configured to turn off the first switch element when the micro control unit is in an abnormal state, and turn on the second switch element under the action of the Vbus to make the reset pin have a first level, and the first level resets the micro control unit; When the microcontroller unit is in a normal state, the microcontroller unit outputs a first voltage to turn on the first switch element, and the second switch element is turned off in response to the turning on of the first switch element so that the reset pin has a second level, and the second level prevents the microcontroller unit from resetting.

2. The reset circuit according to claim 1, characterized in that: A boost circuit is connected between the first switch element and the micro control unit. The boost circuit is used to increase the first voltage to a second voltage. The first switch element is turned on under the action of the second voltage.

3. The reset circuit according to claim 2, characterized in that: The voltage boost circuit includes a voltage doubler circuit.

4. The reset circuit according to claim 1, characterized in that: The reset circuit also includes a delay circuit, and the delay circuit is used to delay the resetting of the micro control unit.

5. The reset circuit according to claim 1, characterized in that: The reset circuit further includes a third switch element, an output terminal of the third switch element is electrically connected to the second control terminal, the third switch element is configured to be turned on later than the second switch element, and the second switch element is turned off in response to the turning on of the third switch element.

6. The reset circuit according to claim 1, characterized in that: The first switching element includes a first NMOS tube, and the second switching element includes a second NMOS tube. The G pole of the first NMOS tube is electrically connected to the micro control unit, the S pole of the first NMOS tube is electrically connected to the reference ground, the D pole of the first NMOS tube is electrically connected to the G pole of the second NMOS tube, the S pole of the second NMOS tube is electrically connected to the reference ground, and the D pole of the second NMOS tube is electrically connected to the reset pin of the micro control unit.

7. The reset circuit according to claim 6, characterized in that: The reset circuit also includes a first resistor and a first capacitor, the first end of the first resistor is electrically connected to the Vbus pin, the second end is electrically connected to the G pole of the second NMOS tube, the positive pole of the first capacitor is electrically connected to the second end of the first resistor, and the negative pole of the first capacitor is electrically connected to the reference ground.

8. The reset circuit according to claim 7, characterized in that: The reset circuit also includes a second resistor, a second capacitor and a third NMOS tube, wherein the first end of the second resistor is connected between the Vbus pin and the first end of the first resistor, the second end of the second resistor is electrically connected to the positive electrode of the second capacitor, the negative electrode of the second capacitor is electrically connected to the reference ground, the G electrode of the third NMOS tube is electrically connected to the positive electrode of the second capacitor, the D electrode of the third NMOS tube is electrically connected to the G electrode of the second NMOS tube, the S electrode of the third NMOS tube is electrically connected to the reference ground, and the resistance value of the second resistor is greater than the resistance value of the first resistor.

9. The reset circuit according to claim 1, characterized in that: The first control terminal is electrically connected to a PWM output pin of the micro control unit.

10. An electronic device, comprising a microcontroller unit and a USB interface, characterized in that: It also includes the reset circuit described in any one of claims 1-9.

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