Power-on and power-off circuit, chip and electronic device

Abstract

The application discloses a power-on and power-off circuit, which comprises a power input end, a power output end, a pre-power-on circuit, a switch circuit and a feedback circuit, wherein the input end of the pre-power-on circuit is connected with the power input end, the output end of the pre-power-on circuit is connected with the power output end, the input end of the switch circuit is connected with the power input end, the output end of the switch circuit is connected with the power output end, the input end of the feedback circuit is connected with the power output end, and the output end of the feedback circuit is connected with the switch circuit. The power-on and power-off circuit can realize the functions of fast power-on and power-off shutdown of the power output port, and has simple circuit structure and low cost.

Description

Technical Field

[0001] This invention relates to the field of circuits, and more particularly to a power-on and power-off circuit, a chip, and an electronic device. Background Technology

[0002] In some electronic devices, it is necessary to record the number of power-on and power-off cycles during operation. In the background technology, some devices have a large capacitor connected between the power input terminal and ground to ensure that they can continue to operate for a period of time after a power outage, so as to reliably record the system's state during power failure.

[0003] When the input terminal loses power, due to the presence of a large capacitor at the input terminal, the voltage drop rate at the power supply output terminal will be relatively slow. At the critical minimum operating voltage point of the subsequent system, the voltage will fluctuate back and forth, resulting in an unstable state. This makes it impossible for the output terminal to determine the actual state, or even to judge it as repeated power-off and power-on, making it impossible to accurately count the number of power-on and power-off cycles. Summary of the Invention

[0004] To address this, this patent provides a power-on / power-off circuit, chip, and electronic device that enables rapid power-on and power-off shutdown of the power output port. The circuit structure is simple and the cost is low.

[0005] To achieve the objectives of this invention, the following technical solution is adopted:

[0006] On one hand, embodiments of this application disclose a power-on power-off circuit, the circuit comprising:

[0007] Power input terminal;

[0008] Power output terminal;

[0009] A pre-power-on circuit, wherein the input terminal of the pre-power-on circuit is connected to the power input terminal, and the output terminal of the pre-power-on circuit is connected to the power output terminal;

[0010] A switching circuit, wherein the input terminal of the switching circuit is connected to the power input terminal and the output terminal is connected to the power output terminal;

[0011] The feedback circuit has its input terminal connected to the power supply output terminal and its output terminal connected to the switching circuit.

[0012] In this power-on / power-off circuit, the switching circuit is turned on after receiving the first trigger signal output by the feedback circuit, and the pre-power-on circuit is turned off after the switching circuit is turned on.

[0013] In some embodiments, the switching circuit includes a first switching circuit and a second switching circuit;

[0014] Specifically, when the control terminal of the second switching circuit receives the first trigger signal output by the feedback circuit, the second switching circuit is turned on; when the control terminal of the first switching circuit receives the second trigger signal output by the second switching circuit, the first switching circuit is turned on.

[0015] In some embodiments, the first switching circuit includes an input terminal, an output terminal, and a control terminal;

[0016] The input terminal of the first switching circuit is connected to the power input terminal, and the output terminal of the first switching circuit is connected to the power output terminal.

[0017] The second switching circuit includes a control terminal and an output terminal. The output terminal of the feedback circuit is connected to the control terminal of the second switching circuit, and the output terminal of the second switching circuit is connected to the control terminal of the first switching circuit.

[0018] In some embodiments, the power-on power-off circuit further includes a power-off circuit, one end of which is connected to the power output terminal and the other end is grounded.

[0019] In some embodiments, the pre-power-on circuit includes a first transistor, the positive terminal of which is connected to a power input terminal and the negative terminal of which is connected to a power output terminal.

[0020] In some embodiments, the pre-power-on circuit includes N first transistors, wherein the positive terminal of the first of the N first transistors is connected to the power input terminal, and the negative terminal of the Nth of the N first transistors is connected to the power output terminal.

[0021] N is an integer greater than 1.

[0022] In some embodiments, the first switching circuit includes a second transistor and a first resistor, wherein the control terminal of the second transistor is connected to the first terminal of the first resistor, the first electrode of the second transistor is connected to the power input terminal and the second terminal of the first resistor, the second electrode of the second transistor is connected to the power output terminal, and the first terminal of the first resistor is connected to the power input terminal.

[0023] In some embodiments, the second switching circuit includes a third transistor, the second terminal of which is connected to the control terminal of the second transistor, the first terminal of which is grounded, and the control terminal of which is connected to the feedback circuit.

[0024] In some embodiments, the second switching circuit further includes a third resistor and a fifth resistor, the second terminal of the third transistor is connected to the first terminal of the third resistor, the second terminal of the third resistor is connected to the control terminal of the second transistor, and the two terminals of the fifth resistor are connected to the control terminal and the first terminal of the third transistor, respectively.

[0025] In some embodiments, the feedback circuit includes a sixth resistor, the first end of which is connected to the power output terminal, and the second end of which is connected to the control electrode of the third transistor.

[0026] In some embodiments, the feedback circuit directly or via a resistor supplies the controllable voltage feedback signal to the control electrode of the third transistor.

[0027] In some embodiments, the feedback circuit further includes a fourth resistor, the first end of which is connected to the second end of a sixth resistor, the second end of which is grounded; and a fourth transistor, the positive terminal of which is connected to the second end of the sixth resistor, and the negative terminal of which is connected to the control electrode of a third transistor.

[0028] The fourth resistor is an adjustable resistor.

[0029] The power-on / power-off circuit, wherein the first transistor includes a diode.

[0030] The power-on and power-off circuit includes a second transistor comprising a PNP transistor or a PMOS transistor. In the PNP transistor, the first terminal is the emitter, the second terminal is the collector, and the control terminal is the base. In the PMOS transistor, the first terminal is the source, the second terminal is the drain, and the control terminal is the gate.

[0031] In this power-on / power-off circuit, the third transistor includes an NPN transistor or an NMOS transistor. In the NPN transistor, the first terminal is the emitter, the second terminal is the collector, and the control terminal is the base. In the NMOS transistor, the first terminal is the source, the second terminal is the drain, and the control terminal is the gate.

[0032] The power-on / power-off circuit includes a fourth transistor comprising a diode.

[0033] The power-on power-off circuit also includes a power-off circuit, which includes a second resistor, wherein the first end of the second resistor is connected to the power output terminal and the second end of the second resistor is grounded.

[0034] The power-on and power-off circuit includes a capacitor, the first end of which is connected to the power output terminal, and the second end of which is grounded.

[0035] On the other hand, this disclosure provides an embodiment of a chip that includes the power-on and power-off circuit described above.

[0036] In another aspect, this disclosure provides an electronic device including the aforementioned chip.

[0037] According to this patent, when the power input voltage is turned on, the pre-power-on circuit is turned on, and the power output voltage is generated. The voltage generated at the power output causes the output of the feedback circuit to generate a trigger voltage. The switching circuit is turned on under the action of the trigger voltage, making the current flowing through the pre-power-on circuit extremely small, or even close to zero, causing the pre-power-on circuit to turn off and stop working. At this time, the power output voltage and the input voltage are extremely close and can be regarded as the same. The detection chip connected to the power output adds one power-on count.

[0038] At the instant the power input voltage is turned off, the large capacitor connected between the power input and ground continues to supply power to the power output. Due to the limited capacitance, the voltage generated at the power output drops. When the voltage drops to the power-down voltage count threshold of the back-end chip, the back-end chip increments the power-down count. The power output voltage continues to drop, causing the trigger voltage generated at the output of the feedback circuit to fall below the trigger threshold. At this time, the switching circuit quickly turns off, and the pre-power-on circuit turns on, resulting in a significant voltage drop between the power input and power output, which is lower than the operating voltage of the detection chip, causing the detection chip connected to the power output to stop working.

[0039] This invention enables rapid power-on and power-off of the power supply circuit. During power-off, it is less affected by the large capacitor at the input end, effectively preventing false counting during power-off. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of a power-on and power-off circuit provided in an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of the overall structure of a power-on and power-off circuit provided in an embodiment of this application;

[0042] Figure 3 A schematic diagram of a power-on / power-off circuit structure provided in an embodiment of this application;

[0043] Figure 4 A schematic diagram of a power-on / power-off circuit structure provided in an embodiment of this application;

[0044] Figure 5 A schematic diagram of a power-on / power-off circuit structure provided in an embodiment of this application;

[0045] Figure 6 This is a schematic diagram of a power-on and power-off circuit structure provided in an embodiment of this application. Detailed Implementation

[0046] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0047] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0048] In the embodiments of this application, "at least one" refers to one or more; "multiple" refers to two or more. In the description of this application, the terms "first," "second," "third," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor should they be construed as indicating or implying order.

[0049] References such as “one embodiment” or “some embodiments” described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the terms “comprising,” “including,” “having,” and variations thereof, in this specification, mean “including but not limited to,” unless otherwise specifically emphasized.

[0050] The following is in conjunction with the appendix Figure 1-6 The specific embodiments of the present invention will be described in detail below.

[0051] like Figure 1 As shown, the power-on / power-off circuit of the present invention includes a power input terminal 101, a power output terminal 102, a pre-power-on circuit 103, a feedback circuit 104, a switching circuit 105, and a power-off circuit 106. The input terminal of the pre-power-on circuit 103 is connected to the power input terminal 101, and the output terminal of the pre-power-on circuit 103 is connected to the power output terminal 102. The input terminal of the switching circuit 105 is connected to the power input terminal 101, and the output terminal is connected to the power output terminal 102. The input terminal of the feedback circuit 104 is connected to the power output terminal 102, and the output terminal of the feedback circuit 104 is connected to the switching circuit 105. One end of the power-off circuit 106 is connected to the power output terminal 102, and the other end is grounded.

[0052] The operation of the power-on / power-off circuit of the present invention is as follows: After the voltage at the power input terminal 101 is turned on, the pre-power-on circuit 103 is turned on, and the power output terminal 102 generates a voltage. The magnitude of this voltage is equal to the voltage at the power input terminal 101 minus the voltage drop across the pre-power-on circuit 103. The voltage generated at the power output terminal 102 causes the output terminal of the feedback circuit 104 to generate a trigger voltage. The switching circuit 105 is turned on under the action of the trigger voltage. Since the resistance of the switching circuit 105 is much smaller than the resistance of the pre-power-on circuit 103 (or in other words, the voltage drop across the switching circuit 105 after it is turned on is extremely small, close to...), the power-on / power-off circuit of the present invention operates as follows: After the voltage at the power input terminal 101 is turned on, the pre-power-on circuit 103 is turned on, and the pre-power-on circuit 103 is turned on, and the pre-power-off circuit 105 is turned on, the pre-power-on circuit 103 is turned on, and the pre-power-off ... The voltage drop across the pre-power-on circuit 103 is between a few millivolts and 100 millivolts. After the pre-power-on circuit 103 is turned on, the voltage drop across it is at least 1-2V. Therefore, it can be considered that the pre-power-on circuit 103 is short-circuited after the switch circuit 105 is turned on. As a result, the current flowing through the pre-power-on circuit 103 is extremely small, even close to zero, causing the pre-power-on circuit 103 to turn off and stop working. At this time, the voltage at the power output terminal 102 is very close to the voltage at the power input terminal 101, and can be considered to be the same. Thus, the detection chip (not shown in the figure, which can also be called the back-end chip) connected to the power output terminal 102 adds one power-on count.

[0053] At the instant the voltage at power input terminal 101 is turned off, the large capacitor (not shown in the figure) connected between power input terminal 101 and ground continues to supply power to power output terminal 102. Due to the limited capacitance, the voltage generated at power output terminal 102 drops. When the voltage drops to the power-down voltage count threshold of the back-end chip, the back-end chip increments the power-down count. The voltage at power output terminal 102 continues to drop, causing the trigger voltage generated at the output of feedback circuit 104 to fall below the trigger threshold. At this time, switching circuit 105 quickly turns off, and pre-power-on circuit 103 turns on, resulting in a significant voltage drop between power input terminal 101 and power output terminal 102, for example, 1-2V, which is lower than the operating voltage of the detection chip, causing the detection chip connected to power output terminal 102 to stop working. Power-down circuit 106 is used to discharge the residual charge at power output terminal 102 when the voltage at power input terminal 101 is turned off, causing the voltage at power output terminal 102 to drop rapidly.

[0054] In one embodiment of the present invention, the switching circuit 105 includes a first switching circuit 1051 and a second switching circuit 1052, such as Figure 2As shown, the power-on and power-off circuit includes a power input terminal 101, a first switching circuit 1051, a power output terminal 102, a second switching circuit 1052, a feedback circuit 104, a pre-power-on circuit 103, and a power-off circuit 106. The power input terminal 101 is connected to the input terminal of the pre-power-on circuit 103, and the output terminal of the pre-power-on circuit 103 is connected to the power output terminal 102. The power input terminal 101 is connected to the input terminal of the first switching circuit 1051, and the output terminal of the first switching circuit 1051 is connected to the power output terminal 102. When the first switching circuit 1051 is turned on, it can short-circuit the two ends of the pre-power-on circuit 103, thereby turning off the pre-power-on circuit 103. The power output terminal 102 is connected to the input terminal of the feedback circuit. The output terminal of the feedback circuit 104 is connected to the trigger terminal of the second switching circuit 1052. After the trigger terminal receives the trigger signal output by the feedback circuit 104, the second switching circuit 1052 is turned on. The output terminal of the second switching circuit 1052 is connected to the trigger terminal of the first switching circuit 1051. After the trigger terminal receives the trigger signal output by the second switching circuit 1052, the first switching circuit 1051 is turned on. One end of the power-off circuit 106 is connected to the power output terminal 102, and the other end is grounded.

[0055] The operation of the power-on / power-off circuit of the present invention is as follows: After the voltage at the power input terminal 101 is turned on, the pre-power-on circuit 103 is turned on, and the power output terminal 102 generates a voltage. The magnitude of this voltage is equal to the voltage at the power input terminal 101 minus the voltage drop across the pre-power-on circuit 103. The voltage generated at the power output terminal 102 causes the output terminal of the feedback circuit 104 to generate a trigger voltage. The second switching circuit 1052 is turned on under the action of the trigger voltage, and the output terminal of the second switching circuit 1052 generates a trigger signal. The first switching circuit 1051 is quickly turned on under the trigger signal. Since the resistance of the first switching circuit 1051 is much smaller than that of the pre-power-on circuit 103... The resistance (or the voltage drop across the first switching circuit 1051 after it is turned on is extremely small, close to a few millivolts to 100 millivolts, while the voltage drop across the pre-power-on circuit 103 after it is turned on is at least 1-2V, so it can be considered that the first switching circuit 1051 after it is turned on short-circuits the two ends of the pre-power-on circuit 103) makes the current flowing through the pre-power-on circuit extremely small, even close to zero, causing the pre-power-on circuit 103 to turn off and stop working. At this time, the voltage at the power output terminal 102 is extremely close to the voltage at the input terminal, and can be considered to be the same. Thus, the detection chip (not shown in the figure, which can also be called the back-end chip) connected to the power output terminal 102 adds one power-on count.

[0056] At the instant the voltage at the power input terminal 101 is turned off, the large capacitor connected between the power input terminal 101 and ground continues to supply power to the power output terminal 102. Due to the limited capacity of the capacitor, the voltage generated at the power output terminal 102 drops. When the voltage drops to the power-down voltage count threshold of the back-end chip, the back-end chip increments the power-down count. The voltage at the power output terminal 102 continues to drop, causing the trigger voltage generated at the output of the feedback circuit 104 to fall below the trigger threshold. At this time, the second switching circuit 1052 is turned off, and its output no longer outputs a signal, causing the first switching circuit 1051 to turn off quickly. At this time, the pre-power-on circuit 103 is turned on, causing a significant voltage drop, such as 1-2V, between the power input terminal 101 and the power output terminal 102, which is lower than the operating voltage of the detection chip, causing the detection chip connected to the power output terminal 102 to stop working.

[0057] In the power-on and power-off circuit of this application, the pre-power-on circuit 103, the first switching circuit 1051 and the second switching circuit 1052 all include transistors, and the feedback circuit 104 may also include transistors or may directly output feedback signals from the feedback signal output terminal of an external chip. Optionally, the pre-power-on circuit 103 includes at least one first transistor, and when it includes multiple first transistors, the multiple first transistors are connected in series. The first end of the pre-power-on circuit 103 is the positive terminal, connected to the power input terminal 101, and the last end is the negative terminal, connected to the power output terminal 102. The first switching circuit 1051 includes a second transistor and a first resistor R1, wherein the power input terminal 101 is connected to the first terminal of the first resistor R1 and the first terminal of the second transistor, the second terminal of the second transistor is connected to the power output terminal 102, and the second terminal of the first resistor R1 is connected to the control terminal of the second transistor. The second switching circuit 1052 includes a third transistor, a third resistor R3, and a fifth resistor R5. The second terminal of the third transistor is connected to the first terminal of the third resistor R3, the second terminal of the third resistor R3 is connected to the control terminal of the first transistor, the two ends of the fifth resistor R5 are connected to the control terminal and the first terminal of the third transistor, respectively, and the first terminal of the third transistor is grounded. In another optional embodiment, the second switching circuit 1052 includes a third transistor, the second terminal of the third transistor is connected to the control terminal of the second transistor, the first terminal of the third transistor is grounded, and the control terminal of the third transistor is connected to the feedback circuit 104.

[0058] Optionally, in the above circuit, the first transistor can be a diode, the second transistor can be a PNP transistor or a PMOS transistor, the third transistor can be an NPN transistor or an NMOS transistor, and the fourth transistor can be a diode.

[0059] like Figure 3 As shown, the circuit structure of Implementation 1 of the power-on and power-off circuit is as follows.

[0060] The power input terminal VDD_IN and the output terminal VDD_OUT are connected through at least one diode, meaning the pre-power-on circuit includes at least one diode. Figure 3 The pre-power-on circuit includes a first diode D1 and a second diode D2, which are connected in series. The first diode D1 and the second diode D2 are connected in series. The first end of the first diode is the positive terminal connected to VDD_IN, and the last end is the negative terminal connected to VDD_OUT.

[0061] In some embodiments, such as Figure 3 As shown, the first switching circuit includes a PNP transistor Q1 and a resistor R1, wherein VDD_IN is connected to the first terminal of R1 and the emitter of Q1, the collector of Q1 is connected to VDD_OUT, and the second terminal of R1 is connected to the base of Q1.

[0062] In some embodiments, such as Figure 3 As shown, the second switching circuit includes an NPN transistor Q2, a third resistor R3 and a fifth resistor R5, wherein the collector of Q2 is connected to the first end of R3, the second end of R3 is connected to the base of Q1, the two ends of R5 are connected to the base and emitter of Q2 respectively, and the emitter of Q2 is grounded.

[0063] In some embodiments, such as Figure 3 As shown, the feedback circuit includes a sixth resistor R6, an adjustable resistor (fourth resistor) R4, and a diode D3. The first end of the sixth resistor R6 is connected to VDD_OUT, the second end is connected to the positive terminal of D3, the negative terminal of D3 is connected to the base of Q2, the second end of R6 is connected to the first end of the adjustable resistor R4, and the second end of R4 is grounded.

[0064] In some embodiments, such as Figure 3 As shown, the power-down circuit includes a second resistor R2 and a capacitor C3. The first end of the second resistor R2 and the capacitor C3 is connected to VDD_OUT, and the second end of the second resistor R2 and the capacitor C3 is grounded. C3 acts as a decoupling capacitor.

[0065] When VDD_IN is powered on, its voltage can quickly reach the VDD_OUT output terminal through the first diode D1 and the second diode D2 (one or more diodes can be used depending on actual needs), achieving rapid power-on. At this time, the base of transistor Q2 is at a high level, and transistor Q2 is turned on. The base voltage of transistor Q1 is lower than the emitter voltage, and transistor Q1 is turned on, making the VDD_OUT voltage basically the same as the VDD_IN voltage, and VDD_OUT completes the power-on process. Since the emitter and collector of transistor Q1 are in saturation conduction when transistor Q1 is turned on, the voltage drop will be as small as less than 0.1V, which is far lower than the conduction voltage of the diode. Therefore, the pre-power-on circuit composed of diodes no longer works.

[0066] When the input terminal VDD_IN loses power, the voltage of capacitor C3 connected to the output terminal VDD_OUT is discharged to ground through R2, increasing the discharge rate of capacitor C3. At the moment of power loss, the input terminal VDD_IN is affected by the large capacitor at the input terminal, so the voltage of VDD_IN does not return to zero in time. At this time, VDD_OUT still has an output, and the output voltage gradually decreases. When the voltage drops to the power-down voltage count threshold of the back-end chip, the back-end chip adds one power-down count. The voltage continues to drop, causing the trigger voltage generated at the output terminal of the feedback circuit to be lower than the trigger threshold. At this time, the B terminal of Q2 is at a low level, Q2 is in an off state, causing Q1 to turn off. At this time, the pre-power-on circuit is turned on, causing a significant voltage drop between VDD_IN and VDD_OUT, such as 1-2V. At this time, the detection chip connected to the power output terminal can reliably turn off because the operating voltage suddenly drops below the critical minimum operating voltage by a certain margin voltage, without the chip repeatedly powering on and off due to the voltage at the power output terminal fluctuating around the critical minimum operating voltage of the detection chip. In the circuit described above, the voltage threshold for turning on / off transistor Q2 can be adjusted by changing the value of resistor R4 in the positive feedback circuit, according to actual needs. D3, on the other hand, can increase the voltage threshold for turning on / off transistor Q2.

[0067] The feedback circuit in the above circuit can also be implemented by directly leading the corresponding voltage feedback signal from the GPIO port of the back-end chip to the base of Q2 via the sixth resistor R6, such as... Figure 4 As shown, the fourth resistor R4 and diode D3 can be omitted at this time, and the magnitude of the voltage feedback signal is controllable.

[0068] like Figure 5 As shown, the circuit structure of Implementation Method 2 of the power-on and power-off circuit is as follows.

[0069] The power input terminal VDD_IN and the power output terminal VDD_OUT are connected through at least one diode, meaning the pre-power-on circuit includes at least one diode. Figure 5 The pre-power-on circuit includes a first diode D1 and a second diode D2, which are connected in series. The first diode D1 and the second diode D2 are connected in series. The first end of the first diode is the positive terminal connected to VDD_IN, and the last end is the negative terminal connected to VDD_OUT.

[0070] In some embodiments, such as Figure 5 As shown, the first switching circuit includes a PMOS transistor Q10 and a first resistor R1, wherein VDD_IN is connected to the first terminal of R1 and the source of Q10, the drain of Q10 is connected to VDD_OUT, and the second terminal of R1 is connected to the gate of Q10; the second switching circuit includes an NMOS transistor Q2, wherein the drain of Q20 is connected to the gate of Q10, the source of Q20 is grounded, and the gate of Q20 is connected to the feedback circuit.

[0071] In some embodiments, such as Figure 5 As shown, the feedback circuit includes a sixth resistor R6 and an adjustable resistor R4. The first end of the sixth resistor R6 is connected to VDD_OUT, the second end is connected to the first end of the adjustable resistor R4 and the gate of Q20, and the second end of R4 is grounded.

[0072] In some embodiments, such as Figure 5 As shown, the power-down circuit includes a second resistor R2 and a capacitor C3. The first end of the second resistor R2 and the capacitor C3 is connected to VDD_OUT, and the second end of the second resistor R2 and the capacitor C3 is grounded. C3 acts as a decoupling capacitor.

[0073] When VDD_IN is powered on, its voltage can quickly reach the VDD_OUT output terminal through the first diode D1 and the second diode D2 (one or more diodes can be used depending on actual needs), realizing rapid power-on. At this time, the gate of NMOS transistor Q2 is at a high level, NMOS transistor Q20 is turned on, and the gate voltage of PMOS transistor Q10 is lower than the source voltage, so PMOS transistor Q10 is turned on, making the VDD_OUT voltage basically the same as the VDD_IN voltage, and VDD_OUT completes the power-on process. Similar to the transistor in the above embodiment 1, since the resistance of PMOS transistor is close to 0 ohms after it is turned on, the voltage drop on it will also be close to 0V, which is much lower than the conduction voltage of the diode and is close to a short circuit. Therefore, the pre-power-on circuit composed of diodes no longer works.

[0074] When the input terminal VDD_IN is powered off, the voltage across capacitor C3 connected to the output terminal VDD_OUT is discharged to ground through R2, increasing the discharge rate of capacitor C3 and achieving rapid discharge. At the moment of power failure, the input VDD_IN is affected by the large capacitor at the input terminal, causing the voltage of VDD_IN to fail to return to zero in time. At this time, VDD_OUT still has an output, and the output voltage gradually decreases. When the voltage drops to the power failure voltage count threshold of the back-end chip, the back-end chip increments the power failure count by one. The voltage continues to decrease, causing the trigger voltage generated at the output terminal of the feedback circuit to fall below the trigger threshold. At this time, the gate of Q20 is at a low level, and Q20 is in an off state, causing Q10 to turn off. At this time, the pre-power-on circuit is turned on, resulting in a significant voltage drop between VDD_IN and VDD_OUT, for example, 1-2V. The detection chip connected to the power output terminal is reliably turned off because its operating voltage is suddenly lower than the critical minimum operating voltage by a certain margin, preventing the chip from repeatedly powering on and off due to the voltage at the power output terminal fluctuating around the critical minimum operating voltage of the detection chip. In the above circuit, the voltage threshold used to turn on / off the NMOS transistor Q20 can be adjusted by adjusting the value of R4 in the positive feedback circuit according to actual needs.

[0075] The feedback circuit in the above circuit can also be implemented by directly outputting the corresponding voltage feedback signal from the GPIO port of the back-end chip to the gate of Q20, such as... Figure 6 As shown, the sixth resistors R6 and R4 can be omitted at this time. The gate of Q20 is connected to ground through the fifth resistor R5. The fifth resistor R5 is used to discharge the charge stored on the gate of Q20, so that Q20 can be reliably turned off. The magnitude of this voltage feedback signal is controllable.

[0076] Of course, in this invention, all the above embodiments can also be modified in a certain way. For example, the PNP transistor Q1 in embodiment 1 can be replaced by the PMOS transistor Q10 in embodiment 2, and the NMOS transistor Q20 in embodiment 2 can also be replaced by the NPN transistor Q2 in embodiment 1.

[0077] This application also provides a chip that includes the aforementioned power-on and power-off circuit. The chip (Integrated Circuit, IC) can be, but is not limited to, a System-on-Chip (SoC) chip or a System-in-Package (SIP) chip. This chip, through the aforementioned power-on and power-off circuit, can solve the technical problem of rapid power-on and rapid power-off in power supply circuits.

[0078] This application also provides an electronic device, which includes a device body and the chip described above disposed within the device body. The electronic device may be, but is not limited to, a power bank, wireless charger, fast charger, car charger, car infotainment screen, car, mobile terminal, smart home device, etc. Mobile terminals include, but are not limited to, smartphones, laptops, tablets, etc. Smart home devices include, but are not limited to, smart sockets, smart rice cookers, smart robot vacuums, smart lights, etc. This electronic device, through a power-on and power-off circuit, can solve the technical problem of rapid power-on and rapid power-off in power circuits.

[0079] This invention enables rapid power-on and power-off of the power supply circuit. During power-off, it is less affected by the large capacitor at the input end, effectively preventing false counting during power-off.

[0080] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A power-on reset circuit, comprising: The circuit comprises: a power input end; a power output end; a pre-power-on circuit, an input end of the pre-power-on circuit being connected with the power input end, an output end of the pre-power-on circuit being connected with the power output end, and the pre-power-on circuit being turned on after the voltage of the power input end is turned on; a switch circuit, an input end of the switch circuit being connected with the power input end, and an output end of the switch circuit being connected with the power output end; wherein the switch circuit is turned on after receiving a first trigger signal output by a feedback circuit, the switch circuit is turned off after receiving a second trigger signal output by the feedback circuit, the switch circuit is turned off after the switch circuit is turned on, and the resistance of the switch circuit is smaller than the resistance of the pre-power-on circuit; the feedback circuit, an input end of the feedback circuit being connected with the power output end, and an output end of the feedback circuit being connected with the switch circuit; a power-off circuit, the power-off circuit comprising a second resistor and a capacitor, a first end of the second resistor and a first end of the capacitor being connected with the power output end, and a second end of the second resistor and a second end of the capacitor being grounded.

2. The power-on / off circuit according to claim 1, wherein The switch circuit comprises a first switch circuit and a second switch circuit. When the control end of the second switch circuit receives the first trigger signal output by the feedback circuit, the second switch circuit is turned on. When the control end of the first switch circuit receives the second trigger signal output by the second switch circuit, the first switch circuit is turned on. The first switch circuit comprises an input end, an output end and a control end, the input end of the first switch circuit being connected with the power input end, and the output end of the first switch circuit being connected with the power output end.

3. The power-on / off circuit according to claim 2, wherein The second switch circuit comprises an input end, a control end and an output end, the output end of the feedback circuit being connected with the control end of the second switch circuit, the output end of the second switch circuit being connected with the control end of the first switch circuit, and the input end of the second switch circuit being grounded.

4. The power-on and power-off circuit according to claim 1, wherein the pre-power-on circuit comprises a first transistor; the anode end of the first transistor is connected with the power input end, and the cathode end of the first transistor is connected with the power output end.

5. The power-on and power-off circuit according to claim 1, wherein the pre-power-on circuit comprises N first transistors connected in series; the anode end of the first transistor in the N first transistors is connected with the power input end, and the cathode end of the Nth transistor in the N first transistors is connected with the power output end; N is an integer greater than 1. The first switch circuit comprises: a second transistor and a first resistor; 6. The power-on power-off circuit of claim 1, wherein, wherein the control end of the second transistor and the first end of the first resistor are connected, the first pole of the second transistor and the power input end and the first end of the first resistor are connected, the second pole of the second transistor is connected with the power output end, and the second end of the first resistor is connected with the control pole of the second transistor. The second switch circuit comprises: ​ 7. The power-on / off circuit according to claim 6, wherein ​ a third transistor, a second electrode of the third transistor is connected with a first end of a third resistor, a second end of the third resistor is connected with a control electrode of the second transistor, a first electrode of the third transistor is grounded, and the control electrode of the third transistor is connected with the feedback circuit.

8. The power-on / off circuit according to claim 7, wherein The second switch circuit further comprises: a third resistor and a fifth resistor; a second electrode of the third transistor is connected with a first end of the third resistor, a second end of the third resistor is connected with the control electrode of the second transistor, and two ends of the fifth resistor are respectively connected with the control electrode and the first electrode of the third transistor.

9. The power-on / off circuit according to claim 7 or 8, characterized by, The feedback circuit comprises: a sixth resistor, a first end of the sixth resistor is connected with an output end of a power supply, and a second end of the sixth resistor is connected with the control electrode of the third transistor.

10. The power-on / off circuit according to claim 7 or 8, wherein The feedback circuit directly or via a resistor feeds a controllable voltage feedback signal to the control electrode of the third transistor.

11. The power-on / off circuit of claim 9, wherein, The feedback circuit further comprises: a fourth resistor, a first end of the fourth resistor is connected with the second end of the sixth resistor, and a second end of the fourth resistor is grounded; and a fourth transistor, a positive electrode end of the fourth transistor is connected with the second end of the sixth resistor, and a negative electrode end of the fourth transistor is connected with the control electrode of the third transistor; wherein the fourth resistor is an adjustable resistor.

12. The power-on power-off circuit of claim 1 or 4, wherein, The first transistor comprises a diode.

13. The power-on power-off circuit of claim 5, wherein, The second transistor comprises a PNP transistor or a PMOS transistor.

14. The power-on power-off circuit of claim 6, wherein, The third transistor comprises an NPN transistor or an NMOS transistor.

15. The power-on power-off circuit of claim 9, wherein, The fourth transistor comprises a diode.

16. A chip, characterized by The power-on / off circuit comprises any one of claims 1-15.

17. An electronic device, comprising: The chip comprises claim 16.

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