Reset circuit

Abstract

The invention discloses a reset circuit, which comprises a power supply unit, a switch unit and a control unit, and is characterized in that the power supply unit is connected between a first output pin and a second output pin of a transformer; the switch unit is connected between the power supply unit and the wireless transmission unit, the switch unit comprises an MOS tube, the MOS tube is connected with a second output pin of the transformer and a reference voltage, and the wireless transmission unit is connected with the reference voltage; the control unit is connected among the first output pin of the transformer, the control end of the MOS tube and the second output pin of the transformer; when the first output pin of the transformer stops working, the control unit generates a low level signal to disconnect the power supply unit and the wireless transmission unit; when the first output pin of the transformer works normally, the control unit generates a high level signal to conduct the connection between the power supply unit and the wireless transmission unit. According to the reset circuit, the wireless transmission unit is rapidly reset through the MOS tube, and the reset time is shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated circuits, and in particular relates to a reset circuit. Background Art

[0002] The wireless transmission unit must be consistent with the signal at the front end of the transformer when in use to ensure system compatibility, signal integrity, power matching, data transmission rate, electromagnetic compatibility, and compliance with interface standards, thereby ensuring that the system can work efficiently and stably, avoiding communication errors, system failures or damage, and improving overall stability and reliability. Therefore, when the signal from the transformer changes, the wireless transmission unit needs to be reset quickly.

[0003] In the prior art, because there are capacitors for filtering in the circuit between the transformer and the wireless transmission unit, when the transformer is working normally, these capacitors can ensure that the signal input to the wireless transmission unit is free of noise interference; when the transformer loses power, the voltage across the capacitor cannot change instantly, resulting in a delay in the reset of the wireless transmission unit. The prior art often connects resistors in parallel across the capacitor to consume the voltage generated when the capacitor is discharged, but the resistors cannot achieve instantaneous reset of the wireless transmission unit; and the presence of resistors will increase the power consumption of the entire circuit; the prior art can also achieve rapid reset of the wireless transmission unit by detecting the voltage on the AC side of the transformer, but this method will increase the complexity of the circuit.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a reset circuit, which can solve the technical problem in the prior art that the wireless transmission unit cannot be quickly reset in a short time.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a reset circuit which can solve the technical problems of the existing reset circuit, such as high power consumption, slow reset speed and complex circuit.

[0007] In order to achieve the above object, a specific embodiment of the present invention provides a reset circuit connected between the transformer and the wireless transmission unit, and the reset circuit includes:

[0008] A power supply unit connected between the first output pin and the second output pin of the transformer;

[0009] A switch unit is connected between the power supply unit and the wireless transmission unit, the switch unit comprises a MOS tube, a first end of the MOS tube is connected to the second output pin of the transformer, a second end of the MOS tube is connected to a reference voltage, and the wireless transmission unit is connected to the reference voltage;

[0010] A control unit is connected between the first output pin of the transformer, the control end of the MOS tube and the second output pin of the transformer;

[0011] When the first output pin of the transformer stops working, the control unit generates a low level signal at the control end of the MOS tube to disconnect the connection between the power supply unit and the wireless transmission unit;

[0012] When the first output pin of the transformer works normally, the control unit generates a high level signal at the control end of the MOS tube to conduct the connection between the power supply unit and the wireless transmission unit.

[0013] In one or more embodiments of the present invention, the MOS tube is an NMOS tube, the control end of the MOS tube is a gate, the first end of the MOS tube is a source, and the second end of the MOS tube is a drain, wherein:

[0014] When the control end of the MOS tube is a low level signal, the MOS tube is disconnected;

[0015] When the control end of the MOS tube is a high level signal, the MOS tube is turned on.

[0016] In one or more embodiments of the present invention, the power supply unit includes a first diode and a second capacitor, wherein:

[0017] The first end of the first diode is connected to the first output pin of the transformer;

[0018] The first end of the second capacitor is connected to the second end of the first diode and the input pin of the wireless transmission unit respectively, and the second end of the second capacitor is connected to the second output pin of the transformer.

[0019] In one or more embodiments of the present invention, the control unit includes a first resistor, a first capacitor and a second diode, wherein:

[0020] The first end of the first resistor is connected to the first output pin of the transformer;

[0021] The first end of the second diode is connected to the second end of the first resistor;

[0022] The first end of the first capacitor is connected to the second end of the second diode and the control end of the MOS tube, and the second end of the first capacitor is connected to the second output pin of the transformer.

[0023] In one or more embodiments of the present invention, the reset circuit further includes a first zener diode, a first end of the first zener diode is connected to a second end of the first capacitor, and a second end of the first zener diode is connected to a first end of the first capacitor.

[0024] In one or more embodiments of the present invention, the reset circuit further includes a third resistor, a first end of the third resistor is connected to the second end of the first voltage regulator diode, and a second end of the third resistor is connected to the control end of the MOS tube.

[0025] In one or more embodiments of the present invention, the reset circuit further includes a noise reduction unit, and the noise reduction unit includes a second resistor and a third capacitor, wherein:

[0026] The first end of the second resistor is connected to the first end of the MOS tube;

[0027] The first end of the third capacitor is connected to the second end of the second resistor, and the second end of the third capacitor is connected to the second end of the MOS tube.

[0028] In one or more embodiments of the present invention, the wireless transmission unit includes an LDO and a wireless module, wherein:

[0029] The input pin of the LDO is connected to the first end of the second capacitor, the output pin of the LDO is connected to the input pin of the wireless module, and the LDO and the wireless module are also connected to a reference voltage.

[0030] In one or more embodiments of the present invention, the wireless transmission unit further includes an input capacitor, an output capacitor and a feedback circuit, wherein:

[0031] The input capacitor is connected between the input pin of the LDO and the reference voltage;

[0032] The output capacitor is connected between the output pin of the LDO and the reference voltage;

[0033] The feedback circuit is connected between the output pin of the LDO, the feedback pin and the reference voltage.

[0034] In one or more embodiments of the present invention, the feedback circuit includes a fourth resistor and a fifth resistor, wherein:

[0035] The fourth resistor is connected between the output pin of the LDO and the feedback pin of the LDO;

[0036] The fifth resistor is connected between the feedback pin of the LDO and the reference voltage.

[0037] Compared with the prior art, the reset circuit in the present invention can detect the voltage signal of the first output pin of the transformer through the control unit. When the first output pin of the transformer works normally, it means that the AC voltage is connected, and the control unit turns on the MOS tube, thereby turning on the connection between the power supply unit and the wireless transmission unit, so that the wireless transmission unit works normally; when the first output pin of the transformer stops working, it means that the input AC voltage is cut off. At this time, the transformer stops working, and the control unit instantly disconnects the MOS tube and disconnects the connection between the power supply unit and the wireless transmission unit, so that the wireless transmission unit can be quickly reset, shortening the reset time of the wireless transmission unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 is a circuit diagram of a reset circuit in one embodiment of the present invention;

[0040] Figure 2 FIG. 4 is a circuit diagram of an LDO according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] "Coupled" or "connected" or "connected" in the specification includes both direct connection and indirect connection. Indirect connection is a connection through an intermediate medium, such as a connection through an electrically conductive medium, which may have parasitic inductance or parasitic capacitance; indirect connection may also include connection through other active or passive devices on the basis of achieving the same or similar functional purposes, such as connection through circuits or components such as switches and follower circuits. In addition, in the invention, words such as "first" and "second" are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply that there is a certain actual relationship, quantity or order between these technical features.

[0043] In the detailed description of the specification, reference is made to the accompanying drawings forming a part thereof, wherein like reference numerals refer to like parts throughout, and wherein are shown by way of exemplary embodiments that may be implemented. It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description should not be considered in a limiting sense.

[0044] The various operations in the specification may be described in turn as multiple discrete actions or operations in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be interpreted as implying that these operations must be order-dependent. Specifically, these operations may not be performed in the order presented. The described operations may be performed in an order different from the described embodiments. Various additional operations may be performed and / or the described operations may be omitted in additional embodiments.

[0045] For purposes of this disclosure, the phrase "A and / or B" means (A), (B), or (A and B). For purposes of this disclosure, the phrase "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0046] Various components and devices may be referred to or shown herein in the singular, but this is only for ease of discussion, and any element referred to in the singular may include a plurality of such elements in accordance with the teachings herein.

[0047] The specification describes the use of the phrases "in one embodiment" or "in other embodiments" or "in some embodiments", which may each refer to one or more of the same or different embodiments. In addition, the terms "including", "comprising", "having", etc. used in relation to the embodiments of the present disclosure are synonymous.

[0048] As described in the background technology, three technical solutions are generally used in the prior art to achieve rapid reset of the wireless transmission unit. One is to connect a resistor in parallel at both ends of the capacitor, so that the voltage on the capacitor is consumed by the resistor to shorten the reset time of the wireless transmission unit. However, the consumption of the resistor is not complete, and the delay during reset still exists, and the resistor increases the power consumption of the entire circuit during normal operation; the second is to extract the voltage signal at the front stage of the transformer, and control the reset of the wireless transmission unit according to the voltage signal, but the voltage at the front stage of the transformer is relatively high, and a better level conversion circuit is required to convert the signal into a voltage signal suitable for the wireless transmission unit, which increases the design cost; the third is to achieve rapid reset of the wireless transmission unit by detecting the voltage on the AC side of the transformer, but this method will increase the complexity of the circuit.

[0049] In response to the above problems, Figure 1As shown, the present invention provides a reset circuit connected between the transformer T1 and the wireless transmission unit 40 , and the reset circuit includes: a switch unit 10 , a control unit 20 and a power supply unit 30 .

[0050] The power supply unit 30 is connected between the first output pin A and the second output pin B of the transformer T1 .

[0051] The switch unit 10 includes a MOS tube M1, a first end of the MOS tube M1 is connected to the second output pin B of the transformer T1, a second end of the MOS tube M1 is connected to a reference voltage SGND, and the wireless transmission unit 40 is connected to the reference voltage SGND; in one embodiment, the reference voltage SGND is a signal ground voltage.

[0052] The control unit 20 is connected between the first output pin A of the transformer T1 , the control end of the MOS transistor M1 , and the second output pin B of the transformer T1 .

[0053] When the first output pin A of the transformer T1 stops working, the control unit 20 generates a low level signal at the control end of the MOS tube M1 to disconnect the power supply unit 30 from the wireless transmission unit 40 .

[0054] When the first output pin A of the transformer T1 works normally, the control unit 20 generates a high level signal at the control end of the MOS tube M1 to conduct the connection between the power supply unit 30 and the wireless transmission unit 40 .

[0055] By setting a switch unit 10 and a control unit 20 between the power supply unit 30 and the wireless transmission unit 40, the switch unit 10 is a MOS tube M1. When the voltage signal at the first output pin A of the transformer T1 changes, the control unit 20 instantly changes the voltage at the control end of the MOS tube M1 to achieve a rapid reset of the wireless transmission unit 40. Compared with using a resistor to discharge or detecting a signal from the AC side, using the MOS tube M1 as the switch unit, when the control unit 20 turns it on, the on-impedance of the MOS tube M1 is very low, which can reduce the power loss when the reset circuit is turned on and improve efficiency; when the control unit 20 turns it off, the input impedance of the MOS tube M1 is very high, and the current flowing through the MOS tube M1 is negligible, thereby disconnecting the connection between the power supply unit 30 and the wireless transmission unit 40; wherein, when the first output pin A of the transformer T1 stops working, it means that the input AC voltage is cut off, and at this time the transformer T1 stops working. There is a certain delay time from cutting off the input AC voltage to the transformer T1 stopping working, and this delay time is 10 to 20 ms.

[0056] like Figure 1As shown, the power supply unit 30 includes a first diode D1 and a second capacitor C2, wherein the first end of the first diode D1 is connected to the first output pin A of the transformer T1; the first end of the second capacitor C2 is connected to the second end of the first diode D1 and the input pin Vin of the wireless transmission unit 40, and the second end of the second capacitor C2 is connected to the second output pin B of the transformer T1. In one embodiment, the first end of the first diode D1 is an anode, and the second end of the first diode D1 is a cathode.

[0057] Among them, the first diode D1 is used for rectification, which is turned on in the positive half cycle of the pulse waveform output by the transformer T1 and turned off in its negative half cycle; the second capacitor C2 is used to ensure the stability of the voltage delivered to the wireless transmission unit 40, and reduce the ripple of the pulse waveform output by the transformer T1, thereby further reducing noise.

[0058] In a further embodiment, the MOS tube M1 is an NMOS tube, the control end of the MOS tube M1 is a gate, the first end of the MOS tube M1 is a source, and the second end of the MOS tube M1 is a drain, wherein when the control end of the MOS tube M1 is a low level signal, the MOS tube M1 is disconnected; when the control end of the MOS tube M1 is a high level signal, the MOS tube M1 is turned on.

[0059] like Figure 1 As shown, the control unit 20 includes a first resistor R1, a first capacitor C1 and a second diode D2, wherein the first end of the first resistor R1 is connected to the first output pin A of the transformer T1; the first end of the second diode D2 is connected to the second end of the first resistor R1; the first end of the first capacitor C1 is connected to the second end of the second diode D2 and the control end of the MOS tube M1, and the second end of the first capacitor C1 is connected to the second output pin B of the transformer T1. In one embodiment, the first end of the second diode D2 is an anode, and the second end of the second diode D2 is a cathode.

[0060] In this embodiment, when the control end of the MOS tube M1 is a low-level signal, the control unit 20 generally generates a voltage of 0V at the control end of the MOS tube M1 to disconnect the MOS tube M1; when the control end of the MOS tube M1 is a high-level signal, the control unit 20 generally generates a voltage of about 10V at the control end of the MOS tube M1 to turn on the MOS tube M1. When the first output pin A of the transformer T1 works normally, the first capacitor C1 is charged through the first resistor R1 and the second diode D2, so that the voltage obtained by the first capacitor C1 can be applied to the subsequent circuit, thereby eliminating the influence of the negative voltage. The rectified voltage may have certain fluctuations, and the first capacitor C1 performs filtering to make the output voltage more stable.

[0061] like Figure 1As shown, in a further embodiment, the reset circuit further includes a first zener diode D3, a first end of the first zener diode D3 is connected to the second end of the first capacitor C1, and a second end of the first zener diode D3 is connected to the first end of the first capacitor C1. In one embodiment, the first end of the first zener diode D3 is an anode, and the second end of the first zener diode D3 is a cathode.

[0062] In a further embodiment, the reset circuit further includes a third resistor R3, a first end of the third resistor R3 is connected to the second end of the first voltage stabilizing diode D3, and a second end of the third resistor R3 is connected to the control end of the MOS tube M1.

[0063] Among them, by arranging the first voltage stabilizing diode D3 at both ends of the first capacitor C1, the voltage at the first end of the first capacitor C1 is further stabilized by the first voltage stabilizing diode D3. When the first output pin A of the transformer T1 works normally, the first voltage stabilizing diode D3 clamps the voltage at the control end of the MOS tube M1 to about 10V, so as to ensure that even if the voltage on the first capacitor C1 fluctuates, the MOS tube M1 can be normally turned on.

[0064] like Figure 1 As shown, the reset circuit also includes a noise reduction unit 50, which includes a second resistor R2 and a third capacitor C3, wherein a first end of the second resistor R2 is connected to a first end of the MOS tube M1; a first end of the third capacitor C3 is connected to a second end of the second resistor R2, and a second end of the third capacitor C3 is connected to a second end of the MOS tube M1.

[0065] The noise reduction unit 50 suppresses the electromagnetic interference noise generated by the MOS tube M1 during the switching process; the second resistor R2 and the third capacitor C3 are connected in series and then connected in parallel between the first end and the second end of the MOS tube M1 to suppress the oscillation caused by the parasitic inductance and parasitic capacitance of the MOS tube M1, which may affect the stability of the MOS tube M1.

[0066] like Figure 1 As shown, the wireless transmission unit 40 includes an LDO401 (low voltage difference linear regulator) and a wireless module 402, wherein the input pin Vin of the LDO401 is connected to the first end of the second capacitor C2, the output pin Vout of the LDO401 is connected to the input pin of the wireless module 402, and the LDO401 and the wireless module 402 are also connected to the reference voltage SGND.

[0067] LDO 401 is used to reduce the voltage to supply power to the wireless module 402 to ensure the working stability of the wireless module 402. In one embodiment, the model of LDO 401 may be LM1117-XX.

[0068] like Figure 2As shown, the wireless transmission unit 40 also includes an input capacitor Cin, an output capacitor Cout and a feedback circuit 4011, wherein the input capacitor Cin is connected between the input pin Vin of the LDO401 and the reference voltage SGND; the output capacitor Cout is connected between the output pin Vout of the LDO401 and the reference voltage SGND; the feedback circuit 4011 is connected between the output pin Vin of the LDO401, the feedback pin FB and the reference voltage SGND.

[0069] The feedback circuit 4011 includes a fourth resistor R4 and a fifth resistor R5, wherein the fourth resistor R4 is connected between the output pin Vout of the LDO401 and the feedback pin FB of the LDO401; the fifth resistor R5 is connected between the feedback pin FB of the LDO401 and the reference voltage SGND.

[0070] The reset circuit in this embodiment can detect the voltage signal of the first output pin A of the transformer T1 through the control unit 20. When the first output pin A of the transformer T1 works normally, the control unit 20 turns on the MOS tube M1, and then turns on the connection between the power supply unit 30 and the wireless transmission unit 40, so that the wireless transmission unit 40 works normally; when the first output pin A of the transformer T1 stops working, the control unit 20 instantly disconnects the MOS tube M1, so that the wireless transmission unit 40 can be quickly reset, thereby reducing the reset time of the wireless transmission unit 40.

[0071] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0072] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A reset circuit connected between a transformer and a wireless transmission unit, characterized in that: The reset circuit comprises: A power supply unit connected between the first output pin and the second output pin of the transformer; A switch unit is connected between the power supply unit and the wireless transmission unit, the switch unit comprises a MOS tube, a first end of the MOS tube is connected to the second output pin of the transformer, a second end of the MOS tube is connected to a reference voltage, and the wireless transmission unit is connected to the reference voltage; A control unit is connected between the first output pin of the transformer, the control end of the MOS tube and the second output pin of the transformer; When the first output pin of the transformer stops working, the control unit generates a low level signal at the control end of the MOS tube to disconnect the connection between the power supply unit and the wireless transmission unit; When the first output pin of the transformer works normally, the control unit generates a high level signal at the control end of the MOS tube to conduct the connection between the power supply unit and the wireless transmission unit.

2. The reset circuit according to claim 1, characterized in that: The MOS tube is an NMOS tube, the control end of the MOS tube is a gate, the first end of the MOS tube is a source, and the second end of the MOS tube is a drain, wherein: When the control end of the MOS tube is a low level signal, the MOS tube is disconnected; When the control end of the MOS tube is a high level signal, the MOS tube is turned on.

3. The reset circuit according to claim 1, characterized in that: The power supply unit includes a first diode and a second capacitor, wherein: The first end of the first diode is connected to the first output pin of the transformer; The first end of the second capacitor is connected to the second end of the first diode and the input pin of the wireless transmission unit respectively, and the second end of the second capacitor is connected to the second output pin of the transformer.

4. The reset circuit according to claim 1, characterized in that: The control unit includes a first resistor, a first capacitor and a second diode, wherein: The first end of the first resistor is connected to the first output pin of the transformer; The first end of the second diode is connected to the second end of the first resistor; The first end of the first capacitor is connected to the second end of the second diode and the control end of the MOS tube, and the second end of the first capacitor is connected to the second output pin of the transformer.

5. The reset circuit according to claim 4, characterized in that: The reset circuit further includes a first zener diode, a first end of the first zener diode is connected to the second end of the first capacitor, and the second end of the first zener diode is connected to the first end of the first capacitor.

6. The reset circuit according to claim 5, characterized in that: The reset circuit further includes a third resistor, a first end of the third resistor is connected to the second end of the first voltage stabilizing diode, and a second end of the third resistor is connected to the control end of the MOS tube.

7. The reset circuit according to claim 1, characterized in that: The reset circuit further includes a noise reduction unit, and the noise reduction unit includes a second resistor and a third capacitor, wherein: The first end of the second resistor is connected to the first end of the MOS tube; The first end of the third capacitor is connected to the second end of the second resistor, and the second end of the third capacitor is connected to the second end of the MOS tube.

8. The reset circuit according to claim 3, characterized in that: The wireless transmission unit includes an LDO and a wireless module, wherein: The input pin of the LDO is connected to the first end of the second capacitor, the output pin of the LDO is connected to the input pin of the wireless module, and the LDO and the wireless module are also connected to a reference voltage.

9. The reset circuit according to claim 8, characterized in that: The wireless transmission unit further includes an input capacitor, an output capacitor and a feedback circuit, wherein: The input capacitor is connected between the input pin of the LDO and the reference voltage; The output capacitor is connected between the output pin of the LDO and the reference voltage; The feedback circuit is connected between the output pin of the LDO, the feedback pin and the reference voltage.

10. The reset circuit according to claim 9, characterized in that: The feedback circuit includes a fourth resistor and a fifth resistor, wherein: The fourth resistor is connected between the output pin of the LDO and the feedback pin of the LDO; The fifth resistor is connected between the feedback pin of the LDO and the reference voltage.

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