CN104135691B - MCU reset control circuits and television set - Google Patents

Abstract

The invention discloses an MCU reset control circuit. The MCU reset control circuit includes: a monitoring module for receiving the input of a DC power supply voltage, and correspondingly outputting valid monitoring signals/invalid monitoring signals according to whether or not the DC power supply voltage fluctuates; The anti-shake module is used to receive the input of the DC power supply voltage, and output the valid anti-shake signal/invalid anti-shake signal according to whether the DC power supply voltage is within the allowable voltage range; the voltage conversion module is used to receive the DC power supply voltage Input, convert the input voltage into the MCU power supply voltage and output it to the MCU, and disconnect the output of the MCU power supply voltage according to the received valid monitoring signal and invalid anti-shake signal, so that the MCU can be reset. The invention also discloses a TV set. The solution of the invention is simple and easy to implement, low in cost, does not need to occupy the I/O port of the MCU for reset, occupies less resources, and has wider applicability.

Description

MCU reset control circuit and TV

technical field

The invention relates to the technical field of reset, in particular to an MCU reset control circuit and a television.

Background technique

Instantaneous abnormality of the TV's AC power supply (for example, the voltage fluctuation of the AC power grid is too large or the TV's power cord is not in good contact with the AC socket, resulting in an abnormal TV's AC power supply) will cause the DC voltage output of the TV power supply to temporarily drop or disappear. , Returning to normal again is called voltage sag. The voltage sag may cause the TV system to enter an abnormal state and cannot be automatically restored. It needs to be turned on again to return to normal, causing inconvenience to users and affecting the overall performance of the TV.

In order to avoid the voltage sag of TV power output caused by abnormal AC power supply, the following methods are often used at present: 1) Add a special AC voltage detection circuit at the AC end of the power supply, restart the power supply when the AC power supply is abnormal, and control various power supplies at the same time. The timing of the output voltage; this method is complex in design, difficult and expensive. 2) Turn on the watchdog of the TV software, and reset the MCU of the main board of the TV when abnormal; the software design of this method is complicated, and the stability and reliability are poor.

Contents of the invention

The main purpose of the present invention is to solve the technical problems of complex, high cost, poor stability and reliability of the existing MCU reset control scheme.

To achieve the above object, the present invention provides a MCU reset control circuit, the MCU reset control circuit includes:

The monitoring module is used to receive the input of the DC power supply voltage, and output a valid monitoring signal/invalid monitoring signal according to whether the DC power supply voltage fluctuates or not;

The anti-shake module is used to receive the input of the DC power supply voltage, and output a valid anti-shake signal/invalid anti-shake signal according to whether the DC power supply voltage is within the allowable voltage range;

The voltage conversion module is used to receive the input of the DC power supply voltage, convert the input voltage into the MCU power supply voltage and output it to the MCU, and disconnect the output of the MCU power supply voltage according to receiving the effective monitoring signal and the invalid anti-shake signal , so that the MCU is reset;

The MCU reset control circuit also includes a DC power supply terminal, the DC power supply terminal is respectively connected to the input terminal of the monitoring module, the input terminal of the anti-shake module and the input terminal of the voltage conversion module, and the input terminal of the monitoring module The output terminal is connected to the first controlled terminal of the voltage conversion module, the output terminal of the anti-shake module is connected to the second controlled terminal of the voltage conversion module, and the output terminal of the voltage conversion module outputs the MCU power supply voltage.

Preferably, when the voltage conversion module receives the effective monitoring signal and the effective anti-shake signal, it maintains the output of the MCU supply voltage, so as to maintain the normal operation of the MCU.

Preferably, the monitoring module includes a first energy storage unit, a second energy storage unit, a first switch unit and a one-way conduction unit, wherein: the conduction input terminal of the one-way conduction unit is the input of the monitoring module terminal, the conduction output end of the unidirectional conduction unit is connected to the charge and discharge end of the second energy storage unit; the charge and discharge end of the first energy storage unit is connected to the conduction input end of the unidirectional conduction unit, The trigger terminal of the first switch unit is connected to the charge and discharge terminal of the first energy storage unit, the first conducting terminal of the first switch unit is connected to the charge and discharge terminal of the second energy storage unit, and the first switch unit is connected to the charge and discharge terminal of the second energy storage unit. The second conduction end of a switch unit is the output end of the monitoring module;

When the voltage of the DC power supply terminal decreases, the first energy storage unit discharges through the DC power supply terminal; when the voltage of the trigger terminal of the first switch unit is lower than the voltage of the first conduction terminal, the second The conduction end outputs an effective monitoring signal.

Preferably, the unidirectional conduction unit includes a first diode, the first energy storage unit includes a first capacitor, the second energy storage unit includes a second capacitor, and the first switch unit includes a PNP transistor , the monitoring module also includes a first resistor, a second resistor and a second diode, wherein:

The anode of the first diode is the input terminal of the monitoring module, and the anode of the first diode passes through the cathode of the second diode, the anode of the second diode and the The first capacitor is grounded, the first resistor is connected in parallel with the second diode, and the cathode of the first diode is grounded through the second capacitor;

The base of the PNP transistor is connected to the anode of the second diode, the emitter of the PNP transistor is connected to the cathode of the first diode, and the collector of the PNP transistor is The two resistors are grounded, and the collector of the PNP transistor is the output terminal of the monitoring module.

Preferably, the anti-shake module includes a voltage stabilizing unit and a second switch unit, the input end of the first voltage stabilizing unit is the input end of the anti-shake module, and the output end of the first voltage stabilizing unit is connected to the The trigger end of the second switch unit, the first conduction end of the first switch unit is grounded, and the second conduction end of the first switch unit is the output end of the anti-shake module; the voltage stabilizing unit When the voltage at the DC power supply terminal drops below the allowable voltage range, the voltage stabilizing unit is turned off; when the second switch unit is turned off, the second conduction terminal of the second switch unit Output invalid anti-shake signal.

Preferably, the voltage stabilizing unit includes a voltage stabilizing tube, the second switch unit includes a first NPN triode, the anti-shake module further includes a third resistor, and the cathode of the voltage stabilizing tube is the anti-shake module The anode of the Zener tube is connected to the base of the first NPN transistor through the third resistor, the emitter of the first NPN transistor is grounded, and the collector of the first NPN transistor is the anti-shake output of the module.

Preferably, the voltage conversion module includes an abnormality determination unit, a third switch unit and a voltage conversion unit, the first signal input terminal of the abnormality determination unit is the first controlled terminal of the voltage conversion module, and the abnormality determination The second signal input end of the unit is the second controlled end of the voltage conversion module, the signal output end of the abnormality determination unit is connected to the trigger end of the third switch unit, and the first lead of the third switch unit The conduction end is grounded, the second conduction end of the third switch unit is connected to the enable end of the voltage conversion unit, the power supply end of the voltage conversion unit is the input end of the voltage conversion module, and the output of the voltage conversion unit is The terminal is the output terminal of the voltage conversion module;

The abnormality judging unit outputs an abnormal signal when receiving a valid monitoring signal and an invalid anti-shake signal; the third switch unit is turned on when the abnormality judging unit outputs an abnormal signal, so that its second conducting end is grounded; When the second conducting end of the third switching unit of the voltage conversion unit is grounded, the output terminal of the voltage conversion unit stops outputting.

Preferably, the abnormality determination unit includes a fourth resistor and a third diode, the third switch unit includes a second NPN transistor, and the voltage conversion unit includes a fifth resistor and a voltage conversion chip, and the voltage conversion The chip includes a voltage input terminal, a voltage output terminal and an enable terminal;

One end of the fourth resistor is the first controlled end of the voltage conversion module, the other end of the fourth resistor is the second controlled end of the voltage conversion module, and the other end of the fourth resistor is connected to The anode of the third diode, the cathode of the third diode is the signal output terminal of the abnormality determination unit;

The base of the second NPN transistor is connected to the cathode of the third diode, the emitter of the second NPN transistor is grounded, and the collector of the second NPN transistor is connected to the fifth resistor. One end, the other end of the fifth resistor is connected to the voltage input end of the voltage conversion chip; the voltage input end of the voltage conversion chip is the input end of the voltage conversion module, and the collector of the second NPN transistor Connect the enabling terminal of the voltage conversion chip, the voltage output terminal of the voltage conversion chip is the output terminal of the voltage conversion module.

In addition, in order to achieve the above object, the present invention also provides a TV set, including an MCU, and the TV set also includes the above-mentioned MCU reset control circuit.

The MCU reset control circuit of the present invention controls the output of the MCU power supply voltage through the monitoring module, the anti-shake module and the power conversion module to realize the reset control of the MCU. It can be applied to MCUs without a reset interface, and has wider applicability; specifically, when the DC power supply voltage drops and fluctuates beyond the allowable voltage range, the voltage conversion module disconnects the output of the MCU power supply voltage In order to reset the MCU, when the fluctuation of the DC power supply voltage is small, and the fluctuation does not exceed the allowable voltage range, the reset is not controlled, which avoids the situation that the reset control is too sensitive and causes false reset operations, and is more stable and reliable.

Description of drawings

Fig. 1 is the module schematic diagram of the first embodiment of the MCU reset control circuit of the present invention;

Fig. 2 is the module schematic diagram of the second embodiment of the MCU reset control circuit of the present invention;

FIG. 3 is a circuit schematic diagram of the second embodiment of the MCU reset control circuit of the present invention.

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

detailed description

It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The present invention provides an MCU reset control circuit, which is connected with the MCU (not shown in the figure). Referring to Fig. 1, in the first embodiment, the MCU reset control circuit includes: a monitoring module 10, which is used to receive the input of the DC power supply voltage, and output a valid monitoring signal/invalid monitoring according to whether the DC power supply voltage fluctuates or drops Signal; the anti-shake module 20 is used to receive the input of the DC power supply voltage, and according to whether the DC power supply voltage is/is in the allowable voltage range (the allowable voltage range can be pre-set in the anti-shake module 20 according to the actual situation), and the corresponding output Effective anti-shake signal/invalid anti-shake signal; voltage conversion module 30, used to receive the input of DC power supply voltage, convert the input voltage into MCU power supply voltage and output to MCU (that is, output to the power supply interface of MCU), and according to the received The effective monitoring signal and the invalid anti-shake signal disconnect the output of the MCU power supply voltage, so that the MCU can be reset. The MCU reset control circuit also includes a DC power supply terminal P_VCC, the DC power supply terminal P_VCC is respectively connected to the input terminal of the monitoring module 10, the input terminal of the anti-shake module 20 and the input terminal of the voltage conversion module 30, and the output terminal of the monitoring module 10 is connected to the voltage conversion module. The first controlled terminal S1 of 30, the output terminal of the anti-shake module 20 is connected to the second controlled terminal S2 of the voltage conversion module 30, and the output terminal M_VCC of the voltage conversion module 30 outputs the MCU supply voltage.

In this embodiment, the monitoring module 10 monitors whether the DC power supply voltage fluctuates and decreases (that is, whether it is stable). When the DC power supply voltage fluctuates and decreases, it indicates that the DC power supply voltage is unstable and a sag occurs. At this time, an effective monitoring signal is output to the voltage conversion Module 30; when the DC power supply voltage remains stable without fluctuations, the monitoring module 10 outputs an invalid monitoring signal; when the DC power supply voltage returns to a normal value, the monitoring module 10 outputs an invalid monitoring signal. The anti-shake module 20 detects whether the fluctuation of the DC power supply voltage falls within the allowable voltage range, that is, whether the fluctuation value of the DC power supply voltage is within the allowable fluctuation range, and is still within the allowable voltage range after the fluctuation of the DC power supply voltage drops , at this time, the anti-shake module 20 determines that the fluctuation of the DC power supply voltage is a jitter signal, and the anti-shake module 20 outputs an effective anti-shake signal to control the normal operation output of the voltage conversion module 30, and the voltage conversion module 30 can still output normal MCU Power supply voltage; when the fluctuation of the DC power supply voltage drops greatly, and the fluctuation of the DC power supply voltage falls beyond the allowable voltage range (for example, the DC power supply voltage drops to 0V instantaneously or the range of the instantaneous drop is too large), the DC power supply voltage is determined at this time. The fluctuation is a non-shaking signal, and it is determined that the DC power supply voltage value at this time is an abnormal voltage value, an invalid anti-shaking signal is output, and the normal operation output of the voltage conversion module 30 is no longer controlled. At this time, the effective monitoring signal output by the monitoring module 10 controls the voltage The conversion module 30 disconnects and outputs the MCU power supply voltage; when the DC power supply voltage returns to the allowable voltage range (including the normal value of the DC power supply voltage), the anti-shake module 20 outputs an effective anti-shake signal.

The mode of operation of the MCU reset control circuit of the present embodiment is:

1. When the DC power supply voltage is normal, the monitoring module 10 outputs an invalid monitoring signal, the anti-shake module 20 outputs an effective anti-shake signal, and the voltage conversion module 30 works normally to output the MCU power supply voltage.

2. When the fluctuation of the DC power supply voltage drops, but the fluctuation value is small, and the DC power supply voltage after the fluctuation is within the allowable voltage range, the monitoring module 10 outputs an effective monitoring signal, but the anti-shake module 20 outputs an effective anti-shake signal, and the voltage conversion module 30. After receiving the valid monitoring signal and the valid anti-shake signal, keep the output of the MCU power supply voltage, so as to keep the MCU working normally.

3. When the DC power supply voltage fluctuates and drops, and the fluctuation value is large (for example, the DC power supply voltage drops to 0V instantaneously), and the fluctuated DC power supply voltage exceeds the allowable voltage range, the monitoring module 10 outputs an effective monitoring signal, and the anti-shake module 20 outputs For the invalid anti-shake signal, the voltage conversion module 30 disconnects the output of the MCU power supply voltage after receiving the valid monitoring signal and the invalid anti-shake signal, so as to reset the MCU. For the MCU whose power supply voltage is changed from yes to no, the reset is performed when the output of the MCU power supply voltage is disconnected. value or returns to the allowable voltage range to reset. When the DC power supply voltage fluctuation drops beyond the allowable voltage range and returns to the allowable voltage range (including the normal value of the DC power supply voltage), the anti-shake module 20 outputs an effective anti-shake signal to the voltage conversion module 30, and the voltage conversion module 30 resumes normal operation and output MCU supply voltage.

The MCU reset control circuit of this embodiment controls the output of the MCU power supply voltage through the monitoring module, the anti-shake module 20 and the power conversion module, so as to realize the reset control of the MCU. The I/O port is reset, which occupies less resources of the MCU, and can be applied to MCUs without a reset interface, and has wider applicability; specifically, when the DC power supply voltage drops and fluctuates and exceeds the allowable voltage range, the voltage conversion module 30 is disconnected from the MCU. The output of the power supply voltage enables the MCU to reset. When the DC power supply voltage fluctuates less and does not exceed the allowable voltage range after the fluctuation, the reset is not controlled, which avoids the reset operation caused by too sensitive reset control, and is more stable and reliable. .

Further, referring to FIG. 2, in the second embodiment, the monitoring module 10 includes a first energy storage unit 11, a second energy storage unit 12, a first switch unit 13 and a one-way conduction unit 14, wherein: the one-way conduction unit The conduction input end of 14 is the input end of monitoring module 10, and the conduction output end of unidirectional conduction unit 14 is connected to the charge and discharge end of second energy storage unit 12; The charge and discharge end of first energy storage unit 11 is connected to unidirectional conduction The conduction input terminal of the unit 14, the trigger terminal of the first switch unit 13 is connected to the charge and discharge terminal of the first energy storage unit 11, and the first conduction terminal of the first switch unit 13 is connected to the charge and discharge terminal of the second energy storage unit 12 , the second conduction terminal of the first switch unit 13 is the output terminal of the monitoring module 10; the first energy storage unit 11 discharges through the DC power supply terminal when the voltage of the DC power supply terminal decreases; the voltage of the first switch unit 13 at its trigger terminal When the voltage is lower than the voltage of the first conduction terminal, the second conduction terminal outputs an effective monitoring signal.

The working principle of the monitoring module 10 is: when the DC power supply voltage of the MCU reset control circuit is normal, the output voltage of the DC power supply terminal charges the first energy storage unit 11 and the second energy storage unit 12, then the first energy storage unit 11 and the second energy storage unit The voltages of the charge and discharge terminals of the energy storage unit 12 are equal, the voltages of the trigger terminal of the first switch unit 13 and the first conduction terminal are equal, and the second conduction terminal of the first switch unit 13 outputs an invalid monitoring signal; when the first energy storage unit 11 and the second energy storage unit 12 are fully charged, the output voltage fluctuation of the DC power supply terminal decreases, and the charge and discharge terminal voltage of the first energy storage unit 11 is higher than the voltage of the DC power supply terminal, and the first energy storage unit 11 passes through the DC power supply terminal. discharge until the voltage of the DC power supply terminal is equal to that of the DC power supply terminal, and because there is a unidirectional conduction unit 14 between the second energy storage unit 12 and the DC power supply terminal, the second energy storage unit 12 does not discharge, so when the voltage fluctuation output by the DC power supply terminal drops , the voltage of the charge and discharge terminal of the second energy storage unit 12 is higher than the voltage of the charge and discharge terminal of the first energy storage unit 11, that is, the voltage of the first conduction terminal of the first switch unit 13 is higher than the voltage of its trigger terminal, then the first switch The second conduction terminal of the unit 13 outputs a valid monitoring signal.

In the second embodiment, the anti-shake module 20 includes a voltage stabilizing unit 21 and a second switch unit 22, the input end of the first voltage stabilizing unit 21 is the input end of the anti-shake module 20, and the output end of the first voltage stabilizing unit 21 Connect the trigger terminal of the second switch unit 22, the first conduction terminal of the first switch unit 13 is grounded, and the second conduction terminal of the first switch unit 13 is the output terminal of the anti-shake module 20; the voltage stabilizing unit 21 is powered by DC When the voltage at the terminal drops below the allowable voltage range, the voltage stabilizing unit 21 is turned off; when the second switch unit 22 is turned off, the second conducting terminal of the second switch unit 22 outputs an invalid anti-shake signal.

The working principle of the anti-shake module 20 is: when the DC supply voltage is within the allowable voltage range (the normal voltage is within the allowable voltage range), the voltage at the input terminal of the voltage stabilizing unit 21 is greater than the conduction voltage of the voltage stabilizing unit 21, and the voltage stabilizing unit 21 is turned on, and the output terminal of the voltage stabilizing unit 21 has a voltage, so that the second switch unit 22 is turned on, so that the second conduction terminal of the second switch unit 22 is connected with its first conduction terminal (ground), that is, the second switch The second conducting end of the unit 22 outputs an effective anti-shake signal; when the fluctuation of the DC supply voltage falls beyond the allowable voltage range, the voltage at the input end of the voltage stabilizing unit 21 is less than the conduction voltage of the voltage stabilizing unit 21, and the voltage stabilizing unit 21 When it is turned off, the output end of the voltage stabilizing unit 21 has no voltage, so that the second switch unit 22 is turned off, so that the second conduction end of the second switch unit 22 outputs an invalid anti-shake signal.

In the second embodiment, the voltage conversion module 30 includes an abnormality determination unit 31, a third switch unit 32 and a voltage conversion unit 33, the first signal input terminal of the abnormality determination unit 31 is the first controlled terminal of the voltage conversion module 30, The second signal input terminal of the abnormality determination unit 31 is the second controlled terminal of the voltage conversion module 30, the signal output terminal of the abnormality determination unit 31 is connected to the trigger terminal of the third switch unit 32, and the first conduction terminal of the third switch unit 32 is terminal grounded, the second conduction end of the third switch unit 32 is connected to the enable terminal of the voltage conversion unit 33, the power supply terminal of the voltage conversion unit 33 is the input terminal of the voltage conversion module 30, and the output terminal of the voltage conversion unit 33 is a voltage conversion The output terminal M_VCC of module 30; Abnormal judging unit 31 outputs abnormal signal when receiving valid monitoring signal and invalid anti-shake signal; The third switch unit 32 is turned on when abnormal judging unit 31 outputs abnormal signal, makes its second conduction The conducting end of the voltage conversion unit 33 is grounded; when the second conducting end of the third switch unit 32 is grounded, the output terminal of the voltage conversion unit 33 stops outputting.

The working principle of the voltage conversion module 30 is: when the abnormal detection unit receives an effective anti-shake signal, the output terminal of the abnormal detection unit outputs a low level, the third switch unit 32 is cut off, and the voltage conversion unit 33 works normally to output the MCU supply voltage; When the detection unit receives the invalid anti-shake signal and the effective monitoring signal, the output terminal of the abnormality detection unit is at a high level, the third switch unit 32 is turned on, the enabling terminal of the voltage conversion unit 33 is grounded, the voltage conversion unit 33 stops working, and the Open and output the MCU power supply voltage to reset the MCU.

Further, referring to FIG. 3 , in the MCU reset control circuit of this embodiment, the unidirectional conduction unit 14 includes a first diode D1, the first energy storage unit 11 includes a first capacitor C1, and the second energy storage unit 12 includes a second Capacitor C2, the first switch unit 13 includes a PNP transistor Q1, and the monitoring module further includes a first resistor R1, a second resistor R2 and a second diode D2, wherein:

The anode of the first diode D1 is the input terminal of the monitoring module 10, and the anode of the first diode D1 is grounded through the cathode of the second diode D2, the anode of the second diode D2 and the first capacitor C1 in turn. , the first resistor R1 is connected in parallel with the second diode D2, the cathode of the first diode D1 is grounded through the second capacitor C2; the base of the first PNP transistor Q1 is connected to the anode of the second diode D2, and the first The emitter of the PNP transistor Q1 is connected to the cathode of the first diode D1 , the collector of the first PNP transistor Q1 is grounded through the second resistor R2 , and the collector of the first PNP transistor Q1 is the output terminal of the monitoring module 10 . In order to make the circuit of the monitoring module 10 more stable and reliable, in this embodiment, the first diode D1 is connected to the second capacitor C2 through the resistor R6, and a resistor R7 is connected in series with the base of the first PNP transistor Q1. In this embodiment, the first switch unit is preferably a PNP transistor Q1; of course, the first switch unit 13 can also be other types of switch transistors that realize the same function, or other circuits or devices that realize the same function.

The MCU reset control circuit of this embodiment, the voltage stabilizing unit 21 includes a voltage stabilizing tube ZD, the second switch unit 22 includes a first NPN transistor Q2, the anti-shake module also includes a third resistor R3, and the cathode of the voltage stabilizing tube ZD is an anti-shake The input terminal of the module 20, the anode of the voltage regulator tube ZD is connected to the base of the first NPN transistor Q2 through the third resistor R3, the emitter of the first NPN transistor Q2 is grounded, and the collector of the first NPN transistor Q2 is for preventing The output terminal of the shaking module 20. In this embodiment, the second switching unit is preferably the first NPN transistor Q2; of course, the second switching unit 22 can also be other types of switching transistors that realize the same function, or other circuits or devices that realize the same function.

In the MCU reset control circuit of this embodiment, the abnormality determination unit 31 includes a fourth resistor R4 and a third diode D3, the third switch unit 32 includes a second NPN transistor Q3, and the voltage conversion unit 33 includes a fifth resistor R5 and a voltage conversion Chip U1, the voltage conversion chip U1 includes a voltage input terminal Vi, a voltage output terminal Vo and an enable terminal EN; one end of the fourth resistor R4 is the first controlled terminal S1 of the voltage conversion module 30, and the other end of the fourth resistor R4 is The second controlled end S2 of the voltage conversion module 30, the other end of the fourth resistor R4 is also connected to the anode of the third diode D3, and the cathode of the third diode D3 is the signal output end of the abnormality determination unit 31; The base of the NPN transistor Q3 is connected to the cathode of the third diode D3, the emitter of the second NPN transistor Q3 is grounded, the collector of the second NPN transistor Q3 is connected to one end of the fifth resistor R5, and the fifth resistor R5 The other end is connected to the voltage input terminal Vi of the voltage conversion chip U1; the voltage input terminal Vi of the voltage conversion chip U1 is the input terminal of the voltage conversion module 30; the collector of the second NPN transistor Q3 is connected to the enabling terminal EN of the voltage conversion chip U1 , the voltage output terminal Vo of the voltage conversion chip U1 is the output terminal M_VCC of the voltage conversion module 30 . In this embodiment, it is preferred that the third switch unit 32 is the second PNP transistor Q3; the third switch unit 32 may also be other types of switch transistors that realize the same function, or other circuits or devices that realize the same function.

With reference to Fig. 2, the operating principle of the MCU reset control circuit of the present embodiment is:

1. When the DC power supply voltage output by the DC power supply terminal P_VCC is a normal value (taking 12V as an example, the normal value of the DC power supply voltage in the following description is 12V), the input terminal of the monitoring module 10 receives 12V input, and the 12V DC voltage is passed through The first diode D1 and the resistor R6 charge the second capacitor C2, and the 12V DC voltage also charges the first capacitor C1 through the first resistor R1. After the first capacitor C1 and the second capacitor C2 are charged, the first capacitor C1 The voltage at the terminal is equal to the voltage at both ends of the second capacitor C2, so the base voltage of the first PNP transistor Q1 is equal to the emitter voltage, the first PNP transistor Q1 is cut off, and the collector of the first PNP transistor Q1 (that is, the monitoring module 10 output) output invalid monitoring signal (low level). At the same time, the input end of the anti-shake module 20 (the cathode of the voltage regulator ZD) receives a 12V DC voltage input, and the voltage regulator ZD is turned on (the conduction voltage of the voltage regulator ZD is less than 12V, such as the conduction voltage of the voltage regulator ZD is 9V, the allowable voltage range is 9V～12V), the base voltage of the first NPN transistor Q2 is high level, the first NPN transistor Q2 is turned on, and the collector of the first NPN transistor Q2 (that is, the anti-shake module 20) to output an effective anti-shake signal (low level). One end (the first controlled terminal S1 of the voltage conversion module 30) and the other end (the second controlled terminal S2 of the voltage conversion module 30) of the fourth resistor R4 of the voltage conversion module 30 are both low level, so that the second NPN The base of the NPN transistor Q3 is at a low level, the second NPN transistor Q3 is cut off, the enable terminal EN of the voltage conversion chip U1 is at a high level, the voltage conversion chip U1 works and outputs the MCU power supply voltage to supply power to the MCU, and the MCU works normally.

2. When the DC power supply voltage output by the DC power supply terminal P_VCC fluctuates and drops, but the DC power supply voltage after the fluctuation drops is within the allowable voltage range, the allowable voltage range is 9V~12V as an example, assuming that the DC power supply voltage after the fluctuation drops is 10V; The input terminal of the monitoring module 10 receives a 10V DC voltage input, the voltage across the first capacitor C1 and the second capacitor C2 is 12V, greater than 10V, the first capacitor C1 is quickly discharged to 10V through the second diode D2, but the second The second capacitor C2 is non-conductive because the second diode D2 is reversed, so the second capacitor C2 does not discharge, and it is still 12V. The emitter voltage of the first PNP transistor Q1 is 12V greater than its base voltage 10V, and the first PNP transistor Q1 The PNP transistor Q1 is turned on, and the collector of the first PNP transistor Q1 outputs an effective monitoring signal (high level). The input end of the anti-shake module 20 receives a 10V DC voltage input, the 10V DC voltage is greater than the conduction voltage 9V of the Zener transistor ZD, the Zener transistor ZD is turned on, the base of the first NPN transistor Q2 is at a high level, and the first NPN NPN transistor Q2 is turned on, and the collector of the first NPN transistor Q2 outputs an effective anti-shake signal (low level). The first controlled terminal S1 of the voltage conversion module 30 is at a high level, the second controlled terminal S2 is at a low level, the base of the second NPN transistor Q3 is at a low level, the second NPN transistor Q3 is cut off, and the voltage conversion The enable terminal EN of the chip U1 is at a high level, the voltage conversion chip U1 works normally and outputs the MCU power supply voltage to supply power to the MCU, and the MCU works normally.

3. When the DC power supply voltage output by the DC power supply terminal P_VCC fluctuates and drops, but the DC power supply voltage after the fluctuation drops exceeds the allowable voltage range, the allowable voltage range is 9V~12V as an example, assuming that the DC power supply voltage after the fluctuation drops is 8V; monitor The input terminal of the module 10 receives 8V DC voltage input, the voltage across the first capacitor C1 and the second capacitor C2 is 12V, greater than 8V, the first capacitor C1 is quickly discharged to 8V through the second diode D2, but the second Capacitor C2 is non-conductive due to the reverse of the second diode D2, so the second capacitor C2 does not discharge and is still 12V. The emitter voltage of the first PNP transistor Q1 is 12V greater than its base voltage 8V. The first PNP transistor Q1 The transistor Q1 is turned on, and the collector of the first PNP transistor Q1 outputs a valid monitoring signal (high level). The input terminal of the anti-shake module 20 receives 8V DC voltage input, the 8V DC voltage is less than the conduction voltage 9V of the voltage regulator ZD, the voltage regulator ZD is not conducting, the base of the first NPN transistor Q2 is at a low level, and the first The NPN transistor Q2 is cut off, and the collector of the first NPN transistor Q2 outputs an invalid anti-shake signal (high impedance state). The first controlled terminal S1 of the voltage conversion module 30 is at a high level, and the second controlled terminal S2 is at a high impedance state, so that the base of the second NPN transistor Q3 is at a high level, and the second NPN transistor Q3 is turned on. The enable terminal EN of the voltage conversion chip U1 is at low level, the voltage conversion chip U1 does not work, and there is no MCU power supply voltage output to supply power to the MCU. For the MCU that is triggered by the MCU power supply voltage from yes to no, reset at this time .

4. When the fluctuation of the DC power supply voltage output by the DC power supply terminal P_VCC drops beyond the allowable voltage range of 9V-12V and returns to the allowable voltage range of 9V-12V (for example, 11V), the input terminal of the anti-shake module 20 receives an input of 11V DC voltage , 11V is greater than the conduction voltage 9V of the Zener transistor ZD, the Zener transistor ZD is turned on, the base of the first NPN transistor Q2 is at a high level, the first NPN transistor Q2 is turned on, and the collector of the first NPN transistor Q2 The electrode outputs an effective anti-shake signal (low level). If the DC power supply voltage returns to 12V, the output terminal of the monitoring module 10 (the collector of the first PNP transistor Q1) outputs an invalid monitoring signal (low level) after the first capacitor C1 is fully charged to 12V. to less than 12V (such as 11V), the monitoring module 10 outputs a valid monitoring signal (high level). The second controlled terminal S2 of the voltage conversion module 30 receives an effective anti-shake signal (low level), the base of the second NPN transistor Q3 is at a low level, the second NPN transistor Q3 is cut off, and the voltage conversion chip U1 is enabled Terminal EN is high level, the voltage conversion chip U1 resumes normal operation, outputs the MCU power supply voltage to the MCU, and the MCU resumes normal operation. For the MCU whose power supply voltage is controlled from none to sometimes triggering reset, reset is performed at this time.

The invention also provides a TV set, which includes an MCU and an MCU reset control circuit. The reset control circuit may include the technical solutions in any of the above-mentioned embodiments, and its detailed circuit structure may refer to FIG. 1 and FIG. 3 , which will not be repeated here.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technical fields , are all included in the scope of patent protection of the present invention in the same way.

Claims (9)

1. A kind of MCU reset control circuit, it is characterized in that, described MCU reset control circuit comprises: The monitoring module is used to receive the input of the DC power supply voltage, and output a valid monitoring signal/invalid monitoring signal according to whether the DC power supply voltage fluctuates or not; The anti-shake module is used to receive the input of the DC power supply voltage, and output a valid anti-shake signal/invalid anti-shake signal according to whether the DC power supply voltage is within the allowable voltage range; The voltage conversion module is used to receive the input of the DC power supply voltage, convert the input voltage into the MCU power supply voltage and output it to the MCU, and disconnect the output of the MCU power supply voltage according to receiving the effective monitoring signal and the invalid anti-shake signal , so that the MCU is reset; The MCU reset control circuit also includes a DC power supply terminal, the DC power supply terminal is respectively connected to the input terminal of the monitoring module, the input terminal of the anti-shake module and the input terminal of the voltage conversion module, and the input terminal of the monitoring module The output terminal is connected to the first controlled terminal of the voltage conversion module, the output terminal of the anti-shake module is connected to the second controlled terminal of the voltage conversion module, and the output terminal of the voltage conversion module outputs the MCU power supply voltage. 2. MCU reset control circuit as claimed in claim 1, is characterized in that, when described voltage conversion module receives described effective monitor signal and described effective anti-shake signal, keeps the output of MCU power supply voltage, so that all The above MCU keeps working normally. 3. The MCU reset control circuit according to claim 1 or 2, wherein the monitoring module includes a first energy storage unit, a second energy storage unit, a first switch unit and a one-way conduction unit, wherein: the The conduction input end of the one-way conduction unit is the input end of the monitoring module, and the conduction output end of the one-way conduction unit is connected to the charging and discharging end of the second energy storage unit; the first energy storage unit The charge and discharge end of the first switch unit is connected to the conduction input end of the unidirectional conduction unit, the trigger end of the first switch unit is connected to the charge and discharge end of the first energy storage unit, and the first conduction of the first switch unit terminal is connected to the charge and discharge terminal of the second energy storage unit, and the second conduction terminal of the first switch unit is the output terminal of the monitoring module; When the voltage of the DC power supply terminal decreases, the first energy storage unit discharges through the DC power supply terminal; when the voltage of the trigger terminal of the first switch unit is lower than the voltage of the first conduction terminal, the second The conduction end outputs an effective monitoring signal. 4. MCU reset control circuit as claimed in claim 3, is characterized in that, described unidirectional conduction unit comprises first diode, and described first energy storage unit comprises first electric capacity, and described second energy storage unit Including a second capacitor, the first switch unit includes a PNP transistor, and the monitoring module further includes a first resistor, a second resistor and a second diode, wherein: The anode of the first diode is the input terminal of the monitoring module, and the anode of the first diode passes through the cathode of the second diode, the anode of the second diode and the The first capacitor is grounded, the first resistor is connected in parallel with the second diode, and the cathode of the first diode is grounded through the second capacitor; The base of the PNP transistor is connected to the anode of the second diode, the emitter of the PNP transistor is connected to the cathode of the first diode, and the collector of the PNP transistor is The two resistors are grounded, and the collector of the PNP transistor is the output terminal of the monitoring module. 5. MCU reset control circuit as claimed in claim 1 or 2, is characterized in that, described anti-shake module comprises voltage stabilizing unit and the second switch unit, and the input end of described voltage stabilizing unit is described anti-shake module The input terminal, the output terminal of the voltage stabilizing unit is connected to the trigger terminal of the second switch unit, the first conduction terminal of the second switch unit is grounded, and the second conduction terminal of the second switch unit is the trigger terminal of the second switch unit. The output terminal of the anti-shake module; the voltage stabilizing unit is cut off when the voltage of the DC power supply terminal drops below the allowable voltage range; the second switch unit is turned off when the voltage stabilizing unit is turned off , the second conduction terminal of the second switch unit outputs an invalid anti-shake signal. 6. The MCU reset control circuit according to claim 5, wherein the voltage stabilizing unit includes a voltage stabilizing tube, the second switching unit includes a first NPN triode, and the anti-shake module further includes a third resistor, the cathode of the voltage regulator tube is the input terminal of the anti-shake module, the anode of the voltage regulator tube is connected to the base of the first NPN transistor through the third resistor, and the emitter of the first NPN transistor grounded, and the collector of the first NPN transistor is the output terminal of the anti-shake module. 7. MCU reset control circuit as claimed in claim 1 or 2, is characterized in that, described voltage conversion module comprises abnormal judging unit, the 3rd switch unit and voltage converting unit, the first signal input terminal of described abnormal judging unit is the first controlled terminal of the voltage conversion module, the second signal input terminal of the abnormality determination unit is the second controlled terminal of the voltage conversion module, and the signal output terminal of the abnormality determination unit is connected to the first The trigger terminals of the three switch units, the first conduction terminal of the third switch unit is grounded, the second conduction terminal of the third switch unit is connected to the enable terminal of the voltage conversion unit, and the voltage conversion unit’s The power supply terminal is the input terminal of the voltage conversion module, and the output terminal of the voltage conversion unit is the output terminal of the voltage conversion module; The abnormality judging unit outputs an abnormal signal when receiving a valid monitoring signal and an invalid anti-shake signal; the third switch unit is turned on when the abnormality judging unit outputs an abnormal signal, so that its second conducting end is grounded; When the second conducting end of the third switching unit of the voltage conversion unit is grounded, the output terminal of the voltage conversion unit stops outputting. 8. MCU reset control circuit as claimed in claim 7, is characterized in that, described abnormality determination unit comprises the 4th resistor and the 3rd diode, and described 3rd switch unit comprises the 2nd NPN type triode and described voltage The conversion unit includes a fifth resistor and a voltage conversion chip, and the voltage conversion chip includes a voltage input terminal, a voltage output terminal and an enabling terminal; One end of the fourth resistor is the first controlled end of the voltage conversion module, the other end of the fourth resistor is the second controlled end of the voltage conversion module, and the other end of the fourth resistor is connected to The anode of the third diode, the cathode of the third diode is the signal output terminal of the abnormality determination unit; The base of the second NPN transistor is connected to the cathode of the third diode, the emitter of the second NPN transistor is grounded, and the collector of the second NPN transistor is connected to the fifth resistor. One end, the other end of the fifth resistor is connected to the voltage input end of the voltage conversion chip; the voltage input end of the voltage conversion chip is the input end of the voltage conversion module, and the collector of the second NPN transistor Connect the enabling terminal of the voltage conversion chip, the voltage output terminal of the voltage conversion chip is the output terminal of the voltage conversion module. 9. A television, comprising an MCU, characterized in that the television further comprises the MCU reset control circuit according to any one of claims 1-8.