WO2017067306A1

WO2017067306A1 - Circuit for detecting abrupt change in voltage, reset circuit and electronic device

Info

Publication number: WO2017067306A1
Application number: PCT/CN2016/095497
Authority: WO
Inventors: 张军永
Original assignee: 深圳拓邦股份有限公司
Priority date: 2015-10-22
Filing date: 2016-08-16
Publication date: 2017-04-27
Also published as: CN107885304B; CN105242766B; CN107885304A; CN105242766A

Abstract

Provided are a circuit for detecting an abrupt change in a voltage, a reset circuit and an electronic device. The circuit for detecting an abrupt change in a voltage comprises: a discharging circuit (1); and a bleeder circuit (2). The bleeder circuit (2) comprises a second capacitor (C2) and a third capacitor (C3) mutually connected in series. A connection point where the second capacitor (C2) and the third capacitor (C3) are connected is an output terminal of the bleeder circuit (2). The other end of the second capacitor (C2) is connected to a controlling power source (VCC). The other end of the third capacitor (C3) is connected to ground. Upon an abrupt change in a voltage of the controlling power source (VCC), the output terminal of the bleeder circuit (2) outputs a first level signal. The discharging circuit (1) comprises a fourth resistor (R4). The fourth resistor (R4) has one end connected with the end of the second capacitor (C2) connected to the power source and the other end connected with the end of the third capacitor (C3) connected to ground and is thus also connected to ground. The circuit for detecting an abrupt change in a voltage, the reset circuit and the electronic device can sensitively detect a fluctuation in a power source and provide a control signal in real time for subsequent processing.

Description

Voltage abrupt detection circuit, reset circuit and electronic device

[0001] The present invention relates to the field of electronic circuits, and more particularly to a voltage abrupt detection circuit, a reset circuit, and an electronic device.

Background technique

[0002] Currently, in a battery-powered system, in order to protect the battery, the battery voltage is generally detected by the MCU, the low-voltage protection point and the protection unlocking point are set, and when the battery voltage is detected to be lower than the low-voltage protection point, the battery enters the low-voltage protection. The system also goes to sleep without powering the system. After entering the sleep state, when the battery voltage is detected to be higher than the protection unlock point, the system resets, exits the sleep state, and returns to the normal state.

[0003] However, when the battery does not supply power to the system, the battery voltage tends to rise. The recovery range is related to the battery capacity and the previous load. When the battery voltage rises to a certain level, if the protection unlock point is set too low, there is The protection unlock point may be exceeded, the system starts to work, the battery starts to supply power again, and there may be frequent protection and unlocking. On the other hand, if the protection unlock point is set too high, then replacing the battery with less power may not work properly. This makes it very difficult to protect the setting of the unlock point.

[0004] In order to avoid these two bad phenomena, there is no need to set the unlocking point. As long as the battery voltage reaches the low voltage protection point, the MCU sleeps directly, and no matter how the battery voltage changes, there will be no malfunction. After replacing the battery, even if It is a battery with low power. As long as the battery voltage is not lower than the low voltage protection point, the system can start normally. It is necessary to design a reset circuit to meet the above requirements.

technical problem

[0005] The technical problem to be solved by the present invention is to provide a reset circuit and an electronic device that do not need to provide an unlocking point, in view of the drawback that the above-described unlocking point is difficult to set.

Problem solution

Technical solution

[0006] The technical solution adopted by the present invention to solve the technical problem thereof is: constructing a voltage abrupt detection circuit, Bit circuit and electronic device.

[0007] In the voltage abrupt detection circuit of the present invention, a discharge circuit and a voltage dividing circuit are included;

[0008] The voltage dividing circuit includes a second capacitor C2 and a third capacitor C3 connected in series with each other, the connection point is an output end of the voltage dividing circuit; and the other end of the second capacitor C2 is connected to a main control power source; The other end of the third capacitor C3 is grounded; after the voltage of the main control power source is suddenly changed, the output end of the voltage dividing circuit outputs a first level signal;

[0009] The discharge circuit includes a fourth resistor R4, one end of the fourth resistor R4 is connected to one end of the second capacitor C2 connected to the power source, and the other end of the fourth resistor R4 is opposite to the third capacitor C3. One end of the ground is connected and grounded.

[0010] In the reset circuit of the present invention, for initializing the main control chip, the reset circuit includes a driving circuit, an execution circuit, and the above-mentioned voltage abrupt detecting circuit;

[0011] an input end of the driving circuit is connected to an output end of the voltage abrupt detecting circuit, an output end of the driving circuit is connected to an input end of the executing circuit; when an input end of the driving circuit receives the The first level signal 吋, the output end of the driving circuit outputs a second level signal to the execution circuit;

[0012] an input end of the execution circuit is connected to an output end of the driving circuit, an output end of the execution circuit is connected to a reset port of the main control chip; when an input end of the execution circuit receives the The second level signal 吋, the output of the execution circuit outputs a reset signal to the reset port.

[0013] Preferably, the driving circuit includes a transistor Q1, a second resistor R2 and a third resistor R3;

[0014] The base of the transistor Q1 is the input end of the driving circuit, and the collector of the transistor Q1 is the output end of the driving circuit;

[0015] The base of the transistor Q1 is connected to the output end of the voltage dividing circuit via the second resistor R2, the collector of the transistor Q1 is connected to the input end of the execution circuit, and the emission of the transistor Q1 Extremely grounded;

[0016] The base of the transistor Q1 is grounded through the third resistor R3.

[0017] Preferably, the execution circuit includes a first resistor R1 and a first capacitor C1;

[0018] one end of the first resistor R1 is connected to the auxiliary power source, and the other end is grounded through the first capacitor C1;

[0019] a connection point of the first resistor R1 and the first capacitor C1 is connected to a collector of the transistor Q1 as an input end of the execution circuit;

[0020] a connection point of the first resistor R1 and the first capacitor C1 is also connected to a reset port of the main control chip Connected as the output of the execution circuit.

[0021] Preferably, the capacity of the second capacitor C2 and the third capacitor C3 of the voltage dividing circuit are equal.

[0022] Preferably, the transistor Q1 is an NPN type transistor.

[0023] Preferably, the main control power source is a replaceable battery.

[0024] Preferably, the main control chip is one or more of a single chip microcomputer, an ARM, a DSP, a CPU, and an FPGA.

[0025] In the electronic device of the present invention, comprising a reset circuit and a main control chip, the reset circuit is configured to initialize the main chip, and the reset circuit is the reset circuit according to any one of the above .

Preferably, the electronic device comprises a battery powered product.

Advantageous effects of the invention

Beneficial effect

[0027] The voltage abrupt detection circuit, the reset circuit and the electronic device embodying the invention have the following beneficial effects: the power supply fluctuation can be sensitively detected, and the control signal is given for subsequent processing.

[0028] Further, in the battery protection system, the power supply fluctuation can be sensitively detected, and the reset signal of the main control chip is given, the battery protection circuit is simplified, and the cost is saved.

Brief description of the drawing

DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a circuit schematic diagram of a voltage abrupt detecting circuit according to an embodiment of the present invention;

2 is a circuit schematic diagram of a reset circuit according to an embodiment of the present invention;

3 is a measured waveform of a base of a reset circuit VCC\MCUPOWER\RESET\Ql according to an embodiment of the present invention.

Embodiments of the invention

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0034] In order to simplify the battery protection program, the present invention provides a method for resetting without replacing the battery by setting an unlocking point. Reset circuit and electronic device. Accordingly, the present invention also provides a voltage abrupt detecting circuit for use in the reset circuit of the present invention in accordance with the reset circuit. In the meantime, the reset circuit of the present invention can also be used as a normal reset circuit, and the use effect is no different from the conventional reset circuit. The difference between the reset circuit and the traditional reset circuit is that the traditional reset circuit relies on the power-on of the MCU itself to reset, and the reset circuit can be reset not only in this way, but also through other power supplies or a certain range. The fluctuation is reset. The details are described below separately.

As shown in FIG. 1, the voltage abrupt detecting circuit of the embodiment of the present invention includes a discharge circuit 1 and a voltage dividing circuit 2.

among them:

[0036] The voltage dividing circuit 2 includes a second capacitor C2 and a third capacitor C3 connected in series with each other, the connection point is the output end of the voltage dividing circuit 2; the other end of the second capacitor C2 is connected to the main control power source; the third capacitor C3 The other end is grounded; the output of the voltage dividing circuit 2 outputs a first level signal when the voltage of the main control power supply suddenly changes. Specifically, the second capacitor C2 and the third capacitor _{C3 are} used as voltage dividing capacitors, and the withstand voltage value is greater than the maximum voltage of the battery, and the capacity determines the length of the reset signal. Different capacities may also result in different voltage division results. Need to adjust, here select the capacitor of the same capacity, that is, the capacity of the second capacitor C2 and the third capacitor C3 of the voltage dividing circuit 2 are equal.

[0037] The discharge circuit 1 includes a fourth resistor R4. One end of the fourth resistor R4 is connected to one end of the second capacitor C2 connected to the power source, and the other end of the fourth resistor R4 is connected to one end of the third capacitor C3 and grounded.

[0038] The implementation principle of the voltage abrupt detection circuit of the embodiment of the present invention is based on the following principle: Because the capacitor has isolated DC power, through the characteristics of the alternating current, when the main control power supply has a large voltage fluctuation, for the capacitor, similar to AC characteristics, this 吋C2, C3 series voltage division, the voltage of the main control power supply is allocated according to the capacitance capacity. The voltage that is instantaneously divided into voltages on C3 gives the first level signal, which can be used in many ways. The reset circuit here is just one of the applications. For example, the voltage after AC rectification can be detected by the voltage abrupt detection circuit if it exceeds a certain amplitude fluctuation by resistor divider current limiting and capacitor filtering. When the voltage of the main control power supply is stabilized, the voltage directly acts on C2. This 吋 voltage is a DC characteristic and is isolated by C2 and cannot be divided into C3.

[0039] The voltage abrupt detection circuit of the embodiment of the present invention can sensitively detect power supply fluctuations, and give a control signal for subsequent processing.

[0040] As shown in FIG. 2, the reset circuit of the embodiment of the present invention is used for initializing a main control chip, and the reset circuit is The circuit includes a drive circuit 3, an execution circuit 4, and the above-described voltage abrupt detection circuit. among them:

[0041] The input end of the driving circuit 3 is connected to the output end of the voltage dividing circuit 2 of the voltage abrupt detecting circuit, and the output end of the driving circuit 3 is connected to the input end of the executing circuit 4; when the input end of the driving circuit 3 receives the first A level signal 吋, the output of the drive circuit 3 outputs a second level signal to the execution circuit 4. Specifically, in the reset circuit of the embodiment of the present invention, the driving circuit 3 includes a transistor Q1, a second resistor R2, and a third resistor R3; the base of the transistor Q1 is an input terminal of the driving circuit 3, and the collector of the transistor Q1 The output terminal of the driving circuit 3; the base of the transistor Q1 is connected to the output end of the voltage dividing circuit 2 via the second resistor R2, the collector of the transistor Q1 is connected to the input terminal of the execution circuit 4, and the emitter of the transistor Q1 is grounded; the transistor Q1 The base is grounded through a third resistor R3. Transistor Q1 is an NPN type triode. It can be understood that the driving circuit 3 here is not limited to the triode. In theory, other circuits can be used instead, and the triode is changed to other devices, such as an op amp IC, or an R3 shunt regulator directly after the MCU interrupt port. Here, the driving circuit 3 is not required to be high. If the voltage varies greatly, the MOS transistor can be driven after the partial voltage, that is, after the voltage is divided, the voltage of C3 is greater than 2.5V, and the MOS transistor can be changed.

[0042] The input end of the execution circuit 4 is connected to the output end of the drive circuit 3, the output end of the execution circuit 4 is connected to the reset port of the main control chip; when the input end of the execution circuit 4 receives the second level signal 吋, The output of the execution circuit 4 outputs a reset signal to the reset port. Specifically, in the reset circuit of the embodiment of the present invention, the execution circuit 4 includes a first resistor R1 and a first capacitor C1; one end of the first resistor R1 is connected to the auxiliary power source, and the other end is grounded through the first capacitor C1; The connection point of the first resistor R1 and the first capacitor C1 is connected to the collector of the transistor Q1 as an input terminal of the execution circuit 4; the connection point of the first resistor R1 and the first capacitor C1 is also connected to the reset port of the main control chip. As the output of the execution circuit 4.

[0043] The implementation principle of the reset circuit of the embodiment of the present invention is based on the following principle: Because the capacitor has DC isolation, through the characteristics of the alternating current, for the moment of inserting the battery, the direct current of the battery itself is equivalent to a very short one for the capacitor. The abrupt voltage is similar to the alternating current characteristic, and the second capacitor C2 and the third capacitor C3 are divided in series, and the battery voltage is distributed according to the capacitance. When the battery is plugged in, the battery voltage directly acts on the second capacitor C2, which is a DC characteristic, is isolated by the second capacitor C2, and cannot be divided to the third capacitor C3. Before the battery is inserted, the voltage on the third capacitor C3 is instantaneously driven to drive the latter circuit, and a reset signal is given until the power consumption of the third capacitor C3 is completed. If the voltage changes slowly, even if C3 is divided into voltage, C3's electricity will be discharged through R2 and R3, which is not enough to turn on the triode, the same as R2. R3 also has a certain role in preventing malfunctions.

[0044] The voltage divided by the third capacitor C3 is divided by the second resistor R2 and the third resistor R3 to drive the transistor Q1. After the transistor Q1 is turned on, the voltage on the first capacitor C1 is pulled low to generate a reset signal. Because of the isolated DC action of the capacitor, the second capacitor C2 isolates the input voltage and continues to charge the third capacitor C3. When the third capacitor C3 is discharged through the second resistor R2 and the third resistor R3, the transistor Q1 is turned off. A capacitor C1 is charged by the MCU power supply through the first resistor R1, and the reset ends. The fourth resistor R4 is the same as the battery replacement, and discharges the electricity on the second capacitor C2. If there is no bleed, the voltage on the battery voltage and the second capacitor C2 will be canceled, so that the third capacitor C3 cannot be divided. The partial voltage is insufficient to drive the transistor.

[0045] Further, the main control power source is a replaceable battery. Further, the main control chip is one or more of a single chip microcomputer, an AR M, a DSP, a CPU, and an FPGA.

[0046] FIG. 3 shows the actual waveform of the base of the VC C, MCUPOWER, and RESET transistor Q1 reset by replacing the battery MCU after the battery low voltage protection and the battery voltage recovery is completed. Channel 1 represents the VCC waveform, channel 2 represents the MCUPOWER waveform, channel 3 represents the RESET waveform, and channel 4 represents the transistor Q1 base waveform.

[0047] As shown in FIG. 3, channel 1 represents the VCC voltage, and the actual use of 吋 represents the battery voltage. As can be seen from the waveform diagram, the VCC voltage drops from 12V to about 8V in 650ms. Thereafter, the MCU represented by channel 2 The voltage is 5V, and there is no change. If the traditional reset circuit is used, the battery replacement is completed without reset. With the present invention, VCC rises to 12V due to battery replacement. Channel 3 represents the reset pin RESET waveform. Channel 4 represents the base voltage of the transistor and is also approximately equal to the voltage across the third capacitor C3. At the same time that the VCC voltage rises, the third capacitor C3 is divided into voltages, and the transistor Q1 is driven. The waveform of the channel 4 can be obtained. The voltage of C 3 is about 0.8V, and the transistor is driven for about 20ms, and then a reset level is generated. Maintain about 10ms. That is, the battery is replaced at a very fast speed, about 650ms in the daytime, the voltage fluctuation of the power supply terminal is about 5V due to the presence of the capacitor, and the voltage of the MCU power supply terminal does not change due to the action of the capacitor, and the ordinary reset circuit cannot function, and the present invention is The MCU can be quickly reset to simplify the battery protection program and protect the battery. The same circuit structure is simple, low cost and reliable.

The present invention further provides an electronic device including a reset circuit and a main control chip, wherein the reset circuit is used to initialize the main chip, and the reset circuit is the reset circuit according to any one of the above. Preferably, the electronic device comprises a battery powered product. It is to be understood that the above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and are not to be construed as limiting the scope of the invention; The above technical features may be freely combined, and various modifications and improvements may be made without departing from the spirit and scope of the invention. Equivalent transformations and modifications are intended to be included within the scope of the appended claims.

Claims

Claim

[Claim 1] A voltage abrupt detecting circuit, wherein the voltage abrupt detecting circuit includes a discharging circuit and a voltage dividing circuit;

The voltage dividing circuit includes a second capacitor C2 and a third capacitor C3 connected in series with each other, the connection point is an output end of the voltage dividing circuit; the other end of the second capacitor C2 is connected to a main control power source; The other end of the capacitor C3 is grounded; after the voltage of the main control power source is suddenly changed, the output end of the voltage dividing circuit outputs a first level signal;

The discharge circuit includes a fourth resistor R4, one end of the fourth resistor R4 is connected to one end of the second capacitor C2 connected to the power source, and the other end of the fourth resistor R4 is connected to the ground end of the third capacitor C3. Connect and ground.

[Claim 2] The voltage abrupt detecting circuit according to claim 1, wherein the capacity of the second capacitor C2 and the third capacitor C3 of the divided piezoelectric circuit are equal.

[Claim 3] The voltage abrupt detecting circuit according to claim 1, wherein the main control power source is a replaceable battery.

[Claim 4] A reset circuit for initializing a main control chip, wherein the reset circuit includes a driving circuit, an execution circuit, and the voltage abrupt detecting circuit according to any one of claims 1 to 3. ;

An input end of the driving circuit is connected to an output end of the voltage abrupt detecting circuit, an output end of the driving circuit is connected to an input end of the executing circuit; and an input end of the driving circuit receives the first end a level signal 吋, an output end of the driving circuit outputs a second level signal to the execution circuit;

An input end of the execution circuit is connected to an output end of the driving circuit, an output end of the execution circuit is connected to a reset port of the main control chip; and an input end of the execution circuit receives the second electric The signal is output, and the output of the execution circuit outputs a reset signal to the reset port.

[Claim 5] The reset circuit according to claim 4, wherein the driving circuit includes a transistor Q1, a second resistor R2, and a third resistor R3;

The base of the transistor Q1 is the input end of the driving circuit, and the set of the transistor Q1 An electrode is an output end of the driving circuit;

a base of the transistor Q1 is connected to an output end of the voltage dividing circuit via the second resistor R2, a collector of the transistor Q1 is connected to an input end of the execution circuit, and an emitter of the transistor Q1 is grounded ;

The base of the transistor Q1 is grounded through the third resistor R3.

The reset circuit according to claim 4, wherein the execution circuit comprises a first resistor R1 and a first capacitor C1;

One end of the first resistor R1 is connected to the auxiliary power source, and the other end is grounded through the first capacitor C 1 ;

a connection point of the first resistor R1 and the first capacitor C1 is connected to a collector of the transistor Q1 as an input end of the execution circuit;

A connection point of the first resistor R1 and the first capacitor C1 is also connected to a reset port of the main control chip as an output end of the execution circuit.

The reset circuit according to claim 5, wherein said transistor Q1 is an NPN type transistor.

The reset circuit according to claim 4, wherein the main control chip is one or more of a single chip machine, an ARM, a DSP, a CPU, and an FPGA.

An electronic device comprising a reset circuit and a main control chip, wherein the reset circuit is configured to initialize the main chip, wherein the reset circuit is the reset according to any one of claims 4-8 Circuit.

The electronic device of claim 9, wherein the electronic device comprises a battery powered product.