CN212572500U - Power-on and power-off reset circuit - Google Patents
Power-on and power-off reset circuit Download PDFInfo
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- CN212572500U CN212572500U CN202021701979.2U CN202021701979U CN212572500U CN 212572500 U CN212572500 U CN 212572500U CN 202021701979 U CN202021701979 U CN 202021701979U CN 212572500 U CN212572500 U CN 212572500U
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Abstract
The utility model relates to the technical field of circuits, in particular to power-on and power-off reset circuit. The utility model discloses a go up electric reset circuit down, including RC series circuit, zener diode Z1, the return circuit discharges, switch tube Q1 and switch tube Q2, the RC series circuit connects between system power and ground, the return circuit that discharges is used for when system power is electrified, discharge RC series circuit's electric capacity, RC series circuit's output termination zener diode Z1's negative terminal, zener diode Z1's positive terminal meets switch tube Q1's control utmost point, switch tube Q1 is set up to when switch tube Q1's control is high-level, switch tube Q1 switches on, and then drive switch tube Q2 breaks off and raises the level of the foot that resets. The utility model discloses can adjust reset time and reset voltage point, adaptability is good, and circuit structure is simple, easily realizes, and is with low costs.
Description
Technical Field
The utility model belongs to the technical field of the circuit, specifically relate to an upper and lower electricity reset circuit.
Background
Most of the existing electronic products are controlled by the MCU processor, and in the power-on and power-off processes, because a system power supply is unstable, the MCU processor is very easy to cause work halt or malfunction during working, and therefore, the MCU processor needs to be reset by the reset circuit. The reset means that a reset pin of the MCU processor is provided with a reset level opposite to a normal working level within a certain time range so as to meet the reset requirement of the MCU processor.
When different modules work, the time sequences required to be started are different, so the time required to be reset is also different; different systems have different voltage ranges of power supplies, such as 3.3V, 5V, 9V, 12V, 15V, 24V, etc., and voltage reset points need to be set differently. However, the reset IC of the existing MCU processor is a fixed voltage point and reset time, so different reset ICs are required, adaptability is poor, and management and use are troublesome.
Disclosure of Invention
An object of the utility model is to provide an go up the electric reset circuit and be used for solving the technical problem that above-mentioned exists.
In order to achieve the above object, the utility model adopts the following technical scheme: a power-on and power-off reset circuit comprises an RC series circuit, a voltage stabilizing diode Z1, a discharge circuit, a switch tube Q1 and a switch tube Q2, wherein the RC series circuit is connected between a system power supply and the ground, the discharge circuit is used for discharging a capacitor of the RC series circuit when the system power supply is powered off, the output end of the RC series circuit is connected with the negative end of the voltage stabilizing diode Z1, the positive end of a voltage stabilizing diode Z1 is connected with the control electrode of a switch tube Q1, and the switch tube Q1 is set to be switched on by a switch tube Q1 when the control electrode of a switch tube Q1 is at a high level, so that a switch tube Q2 is driven to be switched off to raise the level of a reset pin.
Further, the RC series circuit comprises a resistor R2 and a capacitor C1, a first end of the resistor R2 is connected with a system power supply, a second end of the resistor R2 is connected with the capacitor C1 in series and is grounded, and a node between the resistor R2 and the capacitor C1 is connected with a negative end of the zener diode Z1.
Furthermore, the discharge loop comprises a diode D1 and a resistor R1, the positive terminal of the diode D1 is connected with the node between the resistor R2 and the capacitor C1, and the negative terminal of the diode D1 is connected with a resistor R1 in series to be connected with the system power supply.
Further, the switching tube Q1 and the switching tube Q2 are both NPN triodes, the base of the switching tube Q1 is connected to the positive terminal of the zener diode Z1, one path of series resistor R4 of the collector of the switching tube Q1 is connected to the system power supply, the other path is connected to the base of the switching tube Q2, the emitters of the switching tubes Q1 and Q2 are both grounded, the collector of the switching tube Q2 is connected to the series resistor R6 and is connected to the system power supply, and the collector of the switching tube Q2 is used for being connected to the reset pin.
Furthermore, the circuit also comprises a resistor R3, and the resistor R3 is connected in series with the base of the switching tube Q1.
Further, the circuit also comprises a resistor R5, and the resistor R5 is connected in series with the base of the switching tube Q2.
Further, the capacitor C2 is included, and the capacitor C2 is connected between the base of the switching tube Q2 and the ground.
The utility model has the advantages of:
the utility model discloses can adjust reset time and reset voltage point, adaptability is good, can adapt to different system supply voltage and satisfy the reset time demand of different systems, and circuit structure is simple, easily realizes, and is with low costs.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a circuit diagram of an embodiment of the present invention.
Detailed Description
To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.
The present invention will now be further described with reference to the accompanying drawings and detailed description.
As shown in fig. 1, the power-on/power-off reset circuit comprises an RC series circuit, a zener diode Z1, a discharge circuit, a switch tube Q1 and a switch tube Q2, wherein the RC series circuit is connected between a system power supply VCC and a ground GND, the discharge circuit is used for discharging a capacitor of the RC series circuit when the system power supply VCC is powered off, an output end of the RC series circuit is connected with a negative end of the zener diode Z1, a positive end of the zener diode Z1 is connected with a control electrode of a switch tube Q1, and the switch tube Q1 is arranged to be switched on when the control electrode of the switch tube Q1 is at a high level, so as to drive the switch tube Q2 to be switched off to raise the level of a reset pin.
In this embodiment, the RC series circuit includes a resistor R2 and a capacitor C1, a first terminal of the resistor R2 is connected to the system power VCC, a second terminal of the resistor R2 is connected in series with the capacitor C1 and is grounded GND, and a node between the resistor R2 and the capacitor C1 is connected to a negative terminal of the zener diode Z1. The RC series circuit has simple structure, easy realization and low cost, but is not limited to the RC series circuit, and in other embodiments, the RC series circuit can also be realized by adopting other existing RC series circuit structures.
In this embodiment, the discharge loop includes a diode D1 and a resistor R1, the positive terminal of the diode D1 is connected to the node between the resistor R2 and the capacitor C1, and the negative terminal of the diode D1 is connected in series with a resistor R1 to the system power VCC.
The resistance of the resistor R2 is much larger than that of the resistor R1, for example, the resistance of the resistor R2 is several tens times larger than that of the resistor R1.
In this embodiment, the switching tube Q1 and the switching tube Q2 are both NPN triodes, the base of the switching tube Q1 is connected to the positive terminal of the zener diode Z1, one path of series resistor R4 of the collector of the switching tube Q1 is connected to the system power VCC, the other path is connected to the base of the switching tube Q2, the emitters of the switching tubes Q1 and Q2 are both grounded GND, the collector of the switching tube Q2 is connected to the series resistor R6 and is connected to the system power VCC, the collector of the switching tube Q2 is used for being connected to the reset pin RST of the MCU processor, the switching tube Q1 and the switching tube Q2 are NPN triodes, and the structure is simple and low in cost, but not limited thereto, and in other embodiments, the switching tube Q1 and the switching tube Q2 may also be implemented by using other existing switching tubes, such as MOS tubes.
Further, in this embodiment, the protection circuit further includes a resistor R3, the resistor R3 is connected in series to the base of the switching tube Q1, and the resistor R3 limits the current of the switching tube Q1, so as to protect the switching tube Q1 from being burned out.
Further, in this embodiment, the protection circuit further includes a resistor R5, the resistor R5 is connected in series to the base of the switching tube Q2, and the resistor R5 limits the current of the switching tube Q2, so as to protect the switching tube Q2 from being burned out.
Further, in this embodiment, the capacitor C2 is further included, and the capacitor C2 is connected between the base of the switching tube Q2 and the ground GND, so as to improve the stability of the base voltage of the switching tube Q2, thereby improving the reliability.
The working process is as follows:
when a system power supply VCC is electrified, the system power supply VCC charges a capacitor C1 through a resistor R2, when the voltage on the capacitor C1 is not greater than the breakdown voltage of a voltage-stabilizing diode Z1, a switch tube Q1 is cut off, the system power supply VCC can turn on a triode Q2 through resistors R4 and R5, so that a reset pin RST signal is pulled down, and the MCU processor is prevented from working when the system power supply VCC is unstable, and the system works abnormally; when the system power supply VCC is gradually increased, the voltage on the capacitor C1 is also gradually increased, when the breakdown voltage of the Zener diode Z1 is reached, the Zener diode Z1 is conducted, the switch tube Q1 is turned on through the resistor R3, so that the base potential of the switch tube Q2 is pulled to the ground, the switch tube Q2 is turned off, the signal RST of the reset pin is raised, the reset of the MCU processor is completed, and the normal operation is started.
When the system power supply VCC is powered off, the reset pin RST is still at VCC voltage, in the power-off process of the system power supply VCC, the voltage on the capacitor C1 discharges to the system power supply VCC through the diode D1 and the resistor R1, when the voltage is lower than the breakdown voltage of the zener diode Z1, the switch tube Q1 is turned off, the system power supply VCC can turn on the triode Q2 through the resistors R4 and R5, so that the signal of the reset pin RST is pulled down, and the system is normally turned off.
The breakdown voltage value of the Zener diode Z1 can be adjusted to adapt to different system power supply voltages; different reset time can be set through setting the resistance value of the resistor R1 and the capacitance value of the capacitor C1, for example, within 10ms-1S, and the reset time requirements of all systems can be basically met.
The utility model discloses can adjust reset time and reset voltage point, adaptability is good, can adapt to different system supply voltage and satisfy the reset time demand of different systems, and circuit structure is simple, easily realizes, and is with low costs.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (7)
1. A power-on and power-off reset circuit is characterized in that: the power supply control circuit comprises an RC series circuit, a voltage stabilizing diode Z1, a discharging loop, a switch tube Q1 and a switch tube Q2, wherein the RC series circuit is connected between a system power supply and the ground, the discharging loop is used for discharging the capacitor of the RC series circuit when the system power supply is powered down, the output end of the RC series circuit is connected with the negative end of the voltage stabilizing diode Z1, the positive end of the voltage stabilizing diode Z1 is connected with the control electrode of the switch tube Q1, the switch tube Q1 is set to be connected with the switch tube Q1 when the control electrode of the switch tube Q1 is at a high level, and then the switch tube Q2 is driven to be disconnected to raise the level of a reset pin.
2. The power-up and power-down reset circuit of claim 1, wherein: the RC series circuit comprises a resistor R2 and a capacitor C1, the first end of the resistor R2 is connected with a system power supply, the second end of the resistor R2 is connected with the ground of the capacitor C1 in series, and the node between the resistor R2 and the capacitor C1 is connected with the negative end of a voltage stabilizing diode Z1.
3. The power-up and power-down reset circuit of claim 2, wherein: the discharging loop comprises a diode D1 and a resistor R1, the positive end of a diode D1 is connected with a node between the resistor R2 and a capacitor C1, and the negative end of a diode D1 is connected with a resistor R1 in series and connected with a system power supply.
4. The power-up and power-down reset circuit of claim 1, wherein: the switch tube Q1 and the switch tube Q2 are both NPN triodes, the base of the switch tube Q1 is connected with the positive end of a voltage-stabilizing diode Z1, one path of series resistor R4 of the collector of the switch tube Q1 is connected with a system power supply, the other path of series resistor R3683 is connected with the base of the switch tube Q2, the emitters of the switch tube Q1 and the switch tube Q2 are both grounded, the collector of the switch tube Q2 is connected with the series resistor R6 and is connected with the system power supply, and the collector of the switch tube Q2 is used for being connected with.
5. The power-up and power-down reset circuit of claim 4, wherein: the circuit also comprises a resistor R3, and the resistor R3 is connected in series with the base electrode of the switching tube Q1.
6. The power-up and power-down reset circuit of claim 4, wherein: the circuit also comprises a resistor R5, and the resistor R5 is connected in series with the base electrode of the switching tube Q2.
7. The power-up and power-down reset circuit of claim 4, wherein: the switch tube Q2 also comprises a capacitor C2, and the capacitor C2 is connected between the base of the switch tube Q2 and the ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021701979.2U CN212572500U (en) | 2020-08-14 | 2020-08-14 | Power-on and power-off reset circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021701979.2U CN212572500U (en) | 2020-08-14 | 2020-08-14 | Power-on and power-off reset circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212572500U true CN212572500U (en) | 2021-02-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021701979.2U Active CN212572500U (en) | 2020-08-14 | 2020-08-14 | Power-on and power-off reset circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212572500U (en) |
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2020
- 2020-08-14 CN CN202021701979.2U patent/CN212572500U/en active Active
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Denomination of utility model: A power on and power off reset circuit Effective date of registration: 20210908 Granted publication date: 20210219 Pledgee: Bank of China Limited by Share Ltd. Xiamen branch Pledgor: Xiamen haisuo Technology Co., Ltd Registration number: Y2021980009066 |