TWI505074B - Micro-controller reset system and reset method thereof - Google Patents

Description

Microcontroller reset system and its reset method

The present invention relates to a reset system, and more particularly to a reset system for a microcontroller and a reset method thereof.

In today's electronic devices, in order to ensure that the system program can be executed normally when the computer is turned on again, it is necessary to set a reset system for performing resetting on the electronic device. For example, when power is supplied to an electronic device, the microcontroller of the electronic device is maintained in the reset state for a period of time by resetting the output of the system to perform a reset operation. Traditionally, the reset system does this through a built-in timer that keeps the microprocessor in reset for the time set in this section. After the time set by this paragraph, let the microcontroller leave the reset state to start the operation.

However, the traditional reset system is executed before booting. However, some microcontrollers must also perform a reset procedure before shutting down. Otherwise, the system program will not be executed normally after being turned on again. Therefore, for a microcontroller that allows the electronic device to automatically perform a reset procedure before shutting down There are certain requirements for resetting the system.

It is an object of the present invention to provide a reset system and method thereof for automatically causing a microcontroller of an electronic system to automatically perform a reset procedure while in shutdown.

One aspect of the present invention is to provide a reset system for a microcontroller. The reset system includes a uniformity circuit, a buck converter, and a reset circuit. The enabling circuit is electrically connected to a system power supply. When the voltage of the system power supply rises above a first voltage, the enabling circuit outputs a steeply consistent signal of a rising edge. The buck converter, according to the enable signal, steps down the system power supply to output a microcontroller power supply to the microcontroller. The reset circuit electrically connects the system power supply and the microcontroller power supply. When the voltage of the system power supply drops to less than a second voltage, the reset circuit outputs a reset signal to reset the microcontroller. Wherein, the first voltage is less than the second voltage, when the reset system enters the power-down state, the voltage of the system power supply begins to decrease, and then the voltage of the power supply of the microcontroller begins to decrease, when the voltage of the system power supply drops to less than the second When the voltage is greater than the first voltage, the reset circuit outputs a reset signal and the enable circuit still maintains the output enable signal, because the enable signal controls the buck converter to output the power supply of the microcontroller to power the microcontroller, so that The controller is still in operation, and the microcontroller receives the reset signal for resetting, thereby resetting the microcontroller before powering down.

In an embodiment, the reset circuit includes: a first transistor and A voltage comparator. The first transistor is electrically connected to the microcontroller. a voltage comparator electrically connected to the first transistor. When the voltage of the power supply of the system drops to be lower than the second voltage, the voltage comparator outputs a positive voltage signal to turn on the first transistor, when the first transistor When the crystal is turned on, the first transistor outputs a reset signal to reset the microcontroller.

In one embodiment, one of the voltage comparators is electrically connected to the voltage division of the microcontroller power supply, and one of the voltage comparators is electrically connected to the system power supply. When the voltage received by the forward input terminal is less than the voltage received by the reverse input terminal, the voltage comparator outputs a negative voltage signal to turn off the first transistor.

In one embodiment, the reset circuit further includes a resistor electrically connected to the forward input end of the voltage comparator, and the other end of the circuit is electrically connected to an output end of the voltage comparator. Speed up the positive feedback of the voltage comparator.

In an embodiment, the enabling circuit includes a second transistor and a third transistor. The second transistor is electrically connected to the system power supply. The third transistor is electrically connected to the second transistor, the system power supply, and the buck converter. When the voltage of the system power supply rises to be greater than the first voltage, the second transistor is turned on and the third transistor is turned off, and the enabling circuit outputs the enable signal.

In an embodiment, when the system power supply is less than a third voltage, the second transistor and the third transistor are turned off, and the power supply voltage is divided by the system to obtain the enable signal; when the system power supply rises When the voltage is greater than the third voltage but less than the first voltage, the third transistor is turned on, and the enabling signal is The number is 0 volts; and when the system power supply rises above the first voltage, the second transistor is turned on, and the third transistor is turned off, and the effective enable signal is output.

In an embodiment, the enabling circuit further includes a delay circuit electrically connected to the second transistor and the system power supply for delaying conduction of the second transistor.

Another aspect of the present invention is to provide a reset method for a microcontroller. First, when the voltage of a system power supply rises above a first voltage, the coincidence circuit is triggered to output a consistent energy signal with a rising edge. Therefore, according to the received enable signal, a buck conversion circuit is triggered to step down the system power supply to output a microcontroller power supply to supply power to a microcontroller. Finally, when the voltage of the system power supply drops to less than a second voltage but greater than the first voltage, triggering a reset circuit to output a reset signal to the microcontroller for resetting and the enabling circuit keeps outputting the The enable signal is controlled to control the buck converter to output the microcontroller power supply to the microcontroller, so that the microcontroller is still in operation.

In an embodiment, the reset circuit includes: a first transistor and a voltage comparator. The first transistor is electrically connected to the microcontroller. a voltage comparator electrically connected to the first transistor. When the voltage of the power supply of the system drops to be lower than the second voltage, the voltage comparator outputs a positive voltage signal to turn on the first transistor, when the first transistor When the crystal is turned on, the first transistor outputs a reset signal to reset the microcontroller.

In an embodiment, the enabling circuit includes a second transistor and a The third transistor. The second transistor is electrically connected to the system power supply. The third transistor is electrically connected to the second transistor, the system power supply, and the buck converter. When the voltage of the system power supply rises to be greater than the first voltage, the second transistor is turned on and the third transistor is turned off, and the enabling circuit outputs the enable signal.

In summary, the technical solution of the present invention has obvious advantages and beneficial effects compared with the prior art. With the above technical solution, when the system is powered off and the voltage of the system power supply starts to drop to less than a specific voltage, the reset circuit outputs a reset signal to cause the microcontroller to start the reset process, and the enabling circuit remains. The enable signal is output, so that the microcontroller is still working. Let the microcontroller reset while it is working.

The above description will be described in detail in the following embodiments, and further explanation of the technical solutions of the present invention will be provided.

100‧‧‧Reset system

110‧‧‧System power supply

120‧‧‧Enable circuit

121‧‧‧Second transistor

122‧‧‧ Third transistor

123‧‧‧Time delay circuit

130‧‧‧ Buck converter

140‧‧‧Reset circuit

141‧‧‧First transistor

142‧‧‧Voltage comparator

143‧‧‧resistance

150‧‧‧Microcontroller power supply

160‧‧‧Microcontroller

401, 402, 403‧ ‧ steps

R1, R2, R3, R4, R5 and R6‧‧‧ resistors

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood. FIG. 2 is a schematic diagram of a reset circuit in accordance with a preferred embodiment of the present invention; and FIG. 3 is a schematic diagram of an enable circuit in accordance with a preferred embodiment of the present invention; Figure 4 is a diagram showing a reset method in accordance with an embodiment of the present invention. flow chart.

In order to make the description of the present invention more complete and complete, reference is made to the accompanying drawings and the accompanying drawings. However, the embodiments provided are not intended to limit the scope of the invention, and the description of the operation of the structure is not intended to limit the order of its execution, and any device that is recombined by the components produces equal devices. The scope covered by the invention.

The drawings are for illustrative purposes only and are not drawn to the original dimensions. On the other hand, well-known elements and steps are not described in the embodiments to avoid unnecessarily limiting the invention.

1 is a schematic diagram of a reset system of a microcontroller in accordance with a preferred embodiment of the present invention. The reset system 100 of the microcontroller of the present invention includes a coincidence circuit 120, a buck converter 130, and a reset circuit 140. The enabling circuit 120 is electrically connected to a system power supply 110, and when the voltage of the system power supply 110 rises to be greater than a first voltage, the enabling circuit 120 outputs a steep enable signal (En). The buck converter 130 is also electrically connected to the system power supply 110. The buck converter 130 can receive the enable signal (En) output from the enable circuit 120 to output the voltage of the system power supply 110 (V1). A buck conversion is performed to output a voltage (V2) to the microcontroller power supply 150 to power a microcontroller 160. The reset circuit 140 electrically connects the system power supply 110 and the microcontroller power supply 150, and when the system power supply 110 is powered When the voltage drops below a second voltage, the reset circuit 140 outputs a reset signal (Reset) to reset the microcontroller 160. Wherein the first voltage is less than the second voltage.

In other words, according to the above-described reset system 100 of the present invention, when the reset system 100 enters the power-down state, the output voltage (V1) of the system power supply 110 begins to drop. Therefore, the output voltage (V2) supplied to the microcontroller power supply 150 by the buck converter 130 is also reduced. When the output voltage (V1) of the system power supply 110 drops below the second voltage but greater than the first voltage, the reset circuit 140 outputs a reset signal (Reset), and because the output voltage (V1) of the system power supply 110 at this time Still greater than the first voltage, the enable circuit 120 will still maintain the enable signal (En). Since the buck converter 130 is controlled by the enable signal (En), the buck converter 130 will continue to operate to step down the output voltage (V1) of the system power supply 110 to provide an output voltage (V2). Powering the power supply 150 to the microcontroller, so that the microcontroller 160 is still in operation, and receiving a reset signal (Reset) output by the reset circuit 140 to perform resetting, thereby implementing a weight before the microcontroller is powered off. Set the target of the program.

2 is a schematic diagram of a reset circuit in accordance with a preferred embodiment of the present invention. The reset circuit 140 further includes a first transistor 141 and a voltage comparator 142. The first transistor 141 is a three-terminal component including a control terminal. One end is electrically connected to the microcontroller 160, and the other end is grounded. The control terminal is electrically connected to the output of the voltage comparator 142. The voltage comparator 142 includes a forward input (+), an inverted input (-), and an output. Wherein, the positive input terminal (+) is electrically connected to the microcontroller for supplying power The voltage is divided by the source 150, the reverse input terminal (-) is electrically connected to the system power supply 110, and the output terminal is electrically connected to the control terminal of the first transistor 141. The voltage divider voltage formed by the microcontroller power supply 150 received through the resistors R1 and R2 when the forward input terminal (+) is received is smaller than the voltage divider voltage formed by the system power supply 110 received by the reverse input terminal (-) through the resistors R3 and R4. The voltage comparator 142 outputs a negative voltage signal to the control terminal of the first transistor 141 to turn off the first transistor 141. Conversely, when the microcontroller input power supply 150 received by the forward input terminal (+) forms a divided voltage formed by the resistors R1 and R2, the system power supply 110 received by the reverse input terminal (-) is formed by the resistors R3 and R4. When the voltage is applied, the voltage comparator 142 outputs a positive voltage signal to the control terminal of the first transistor 141 to turn on the first transistor 141. In an embodiment, when the voltage of the system power supply 110 drops to less than the second voltage, the power supply of the microcontroller received by the forward input terminal (+) is appropriately designed by the resistors R1, R2, R3, and R4. When the divided voltage of 150 is greater than the divided voltage of the system power supply 110 received by the inverting input terminal (-), the voltage comparator 142 outputs a positive voltage signal to the control terminal of the first transistor 141 to turn on the first transistor 141. . When the first transistor 141 is turned on, the first transistor 141 outputs a reset signal (Reset) to the microcontroller 160 for a reset procedure. In addition, the reset circuit 140 further includes a resistor 143, wherein one end of the resistor 143 is electrically connected to the positive input terminal (+) of the voltage comparator 142, and the other end of the resistor 143 is electrically connected to the output terminal of the voltage comparator 142. The 143 is mainly used to speed up the positive feedback speed of the voltage comparator 142.

Figure 3 is a schematic illustration of an enabling circuit in accordance with a preferred embodiment of the present invention. The enabling circuit 120 further includes a second transistor 121 And a third transistor 122. The second transistor 121 is a three-terminal component including a control terminal. One end is electrically connected to the control end of the third transistor 122, and the other end is grounded. The control terminal is electrically connected to the system power supply 110. The third transistor 122 is also a three-terminal component including a control terminal. One end is electrically connected to the system power supply 110 and the buck converter 130, and the other end is grounded, and the control terminal is electrically connected to the second transistor 121.

In one embodiment, the buck converter 130 is fully enabled when the voltage of the enable signal En is about 2 volts. The enable signal En is obtained by the output of the third transistor 122 and the voltage dividing resistors R5 and R6 according to the voltage output from the system power supply 110. In this embodiment, the resistance of the resistor R5 is 11K, and the resistance of the resistor R6 is 2K. Accordingly, when the voltage (V1) output by the system power supply 110 is less than a third voltage, for example, 2 volts, the second transistor 121 and the third transistor 122 are both in an off state, at which time the system power supply 110 transmits through the resistor R5. The voltage supplied to the buck converter 130 by the divided voltage of R6 must be less than 2 volts, and in this embodiment, 0 to 0.36 volts, so that the buck converter 130 cannot be enabled. When the system power supply 110 rises to be greater than the third voltage but less than the first voltage, in this embodiment, it is greater than 2 volts and less than 9.83 volts, at which time the third transistor 122 is turned on, but the second transistor 121 is not. When the enable signal En of the buck converter 130 is grounded via the turned-on third transistor 122, it is 0 volts, and the enable signal En is in an inactive state, so the buck converter 130 cannot be enabled. When the voltage of the system power supply 110 rises to be greater than the first voltage, 9.83 volts, the divided voltage formed by the system power supply 110 causes the second transistor 121 to be turned on while passing through the second transistor 121. Pulling the control terminal of the third transistor 122 to the ground voltage causes the third transistor 122 to be turned off. At this time, the system power supply 110 supplies the enable signal En through the voltage dividers R5 and R6. In this embodiment, the voltage obtained by the voltage division is obtained. It is 1.8~2 volts (the actual voltage value obtained here is close to 2 volts due to the resistance accuracy of the resistor itself). Accordingly, the enable signal En is from 0 to 2 volts, and a steep enable signal is formed on the rising edge, which can cause the buck converter 130 to start up quickly. In another embodiment, the enabling circuit 120 further includes a delay circuit 123 electrically connected to the second transistor 121 and the system power supply 110 for delaying the conduction of the second transistor 121 to delay the third transistor 122. Thus, the enable signal En obtained by dividing the voltages of the resistors R5 and R6 can be obtained.

Figure 4 is a flow chart showing a reset method in accordance with an embodiment of the present invention. The reset method of the microcontroller of the present invention. First, in step 401, when the voltage of a system power supply rises above a first voltage, the coincidence circuit is triggered to output a stable energy signal with a rising edge. Next, in step 402, a buck conversion circuit is triggered according to the received enable signal. In one embodiment, the buck converter circuit bucks the system power supply to output a microcontroller power supply to power a microcontroller. Then, in step 403, when the voltage of the system power supply drops to less than a second voltage but greater than the first voltage, triggering a reset circuit to output a reset signal to the microcontroller to reset, and at the same time The enable circuit keeps outputting the enable signal to control the buck converter to output the microcontroller power supply to the microcontroller. In this way, the microcontroller can be reset while it is in operation.

In summary, when the system is powered off and the voltage of the system power supply starts to drop to less than a specific voltage, the reset circuit outputs a reset signal to cause the microcontroller to start the reset process, and the enabling circuit remains. The enable signal is output, so that the microcontroller is still working. Let the microcontroller reset while it is working.

The present invention has been disclosed in the above embodiments, and is not intended to limit the invention, and it is intended that various modifications and changes may be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Reset system

110‧‧‧System power supply

120‧‧‧Enable circuit

130‧‧‧ Buck converter

140‧‧‧Reset circuit

150‧‧‧Microcontroller power supply

160‧‧‧Microcontroller

Claims (10)

A reset system of a microcontroller, comprising: a uniform energy circuit electrically connected to a system power supply, wherein when the voltage of the power supply of the system rises to be greater than a first voltage, the output circuit outputs a rising edge with a steep consistency a buck converter, according to the received signal, the system power supply is step-down converted to output a microcontroller power supply to the microcontroller; and a reset circuit, electricity The power supply of the system and the power supply of the microcontroller are connected. When the voltage of the power supply of the system drops to less than a second voltage, the reset circuit outputs a reset signal, and the reset signal resets the microcontroller. Wherein the first voltage is less than the second voltage, when the reset system enters a power-down state, the voltage of the system power supply begins to decrease, and then the voltage of the power supply of the microcontroller begins to decrease, when the system power supply When the voltage drops to be less than the second voltage and greater than the first voltage, the reset circuit outputs the reset signal and the enable circuit still keeps outputting the enable signal Because the enable signal controls the buck converter to output the microcontroller power supply to the microcontroller, so that the microcontroller is still in operation, and the microcontroller receives the reset signal for resetting, Thereby resetting the microcontroller before powering down. The reset system of claim 1, wherein the reset circuit comprises: a first transistor electrically connected to the microcontroller; and a voltage comparator electrically connected to the first transistor, the voltage comparator output when the voltage of the system power supply drops below the second voltage A positive voltage signal is applied to turn on the first transistor. When the first transistor is turned on, the first transistor outputs a reset signal to reset the microcontroller. The reset system of claim 2, wherein one of the voltage comparators is electrically connected to a voltage division of the microcontroller power supply, and one of the voltage comparators is electrically connected to the reverse input terminal. The partial voltage of the system power supply. When the voltage received by the forward input terminal is less than the voltage received by the reverse input terminal, the voltage comparator outputs a negative voltage signal to turn off the first transistor. The reset system of claim 3, wherein the reset circuit further comprises a resistor, one end of the resistor is electrically connected to the forward input end of the voltage comparator, and the other end of the circuit is electrically connected to the voltage comparator At one of the outputs, the resistor speeds up the positive feedback of the voltage comparator. The reset system of claim 1, wherein the enabling circuit comprises: a second transistor electrically connected to the system power supply; and a third transistor electrically connected to the second transistor, the system a power supply and the buck converter; wherein when the voltage of the system power supply rises above the first voltage, the second transistor is turned on and the third transistor is turned off, the enabling current The road outputs the enable signal. The reset system of claim 5, wherein when the system power supply is less than a third voltage, the second transistor and the third transistor are turned off, and the enabling signal is obtained by dividing the power supply of the system; When the system power supply rises above the third voltage but is less than the first voltage, the third transistor is turned on, the enable signal is 0 volt; and when the system power supply rises above the first voltage, The second transistor is turned on, and the third transistor is turned off to output an effective enable signal. The reset system of claim 6, wherein the enabling circuit further comprises: a delay circuit electrically connected to the second transistor and the system power supply for delaying conduction of the second transistor. A method for resetting a microcontroller, comprising: when a voltage of a system power supply rises above a first voltage, triggering a matching circuit to output a sharply consistent energy signal; according to the received enable signal, Triggering a step-down conversion circuit to step down the system power supply to output a microcontroller power supply to supply power to a microcontroller; when the voltage of the system power supply drops to less than a second voltage but greater than the first voltage Triggering a reset circuit to output a reset signal to the microcontroller for resetting and the enabling circuit keeps outputting the enable signal to control The buck converter outputs the microcontroller power supply to power the microcontroller such that the microcontroller is still active. The reset method of claim 8, wherein the reset circuit comprises: a first transistor electrically connected to the microcontroller; and a voltage comparator electrically connected to the first transistor when the system When the voltage of the power supply drops to be less than the second voltage, the voltage comparator is triggered to output a positive voltage signal to turn on the first transistor, and when the first transistor is turned on, the first transistor outputs a reset signal. To reset the microcontroller. The reset method of claim 8, wherein the enabling circuit comprises: a second transistor electrically connected to the system power supply; and a third transistor electrically connected to the second transistor, the system The power supply and the buck converter; wherein when the voltage of the system power supply rises above the first voltage, the second transistor is turned on and the third transistor is turned off, the enabling circuit outputs the enable signal.