TW202123613A - Overvoltage protection circuit and method thereof - Google Patents

Abstract

An overvoltage protection circuit includes a first connection pin, a second connection pin, an overvoltage protection switch, a coupling element, a discharging module and a detecting module. A first terminal of the overvoltage protection switch is coupled to the first connection pin. A second terminal of the overvoltage protection switch is coupled to the second connection pin. The overvoltage protection switch is configured to control an electrical connection between the first connection pin and the second connection pin. The coupling element is configured to couple a surge voltage to a control terminal of the overvoltage protection switch when the surge voltage occurs on the first terminal of the overvoltage protection switch. The discharging module is configured to control an electrical connection between the control terminal of the overvoltage protection switch and a ground terminal. The detecting module is configured to enable the discharging module so as to conduct the electrical connection between the control terminal of the overvoltage protection switch and the ground terminal when detecting the surge voltage occurs on the control terminal of the overvoltage protection switch.

Description

Overvoltage protection circuit and method

The invention relates to an over-voltage protection technology, in particular to an over-voltage protection circuit and a method thereof that can quickly turn off an over-voltage protection switch when a surge voltage occurs.

In recent years, C-type universal serial bus (USB Type-C) ports have been widely used because they can provide ultra-high-speed data transmission rates, and have the advantages of being lighter, thinner, shorter, and symmetrical, and can be plugged in front and back. Applied to various electronic devices.

However, because the spacing between the pins in the C-type universal serial bus port is very small, it is easy to cause short circuits between the pins due to foreign objects such as liquid or dust or improper use of plugging and unplugging. For example, the bus power pin in the C-type universal serial bus port can support a voltage of up to 20 volts, but the configuration channel pin next to the bus power pin is only used to support a voltage of about 5 volts. Therefore, once the bus power pin is short-circuited to the configuration channel pin, the system circuit coupled to the configuration channel pin may be severely damaged due to overvoltage.

Generally speaking, the common over-voltage protection mechanism mainly achieves over-voltage protection by turning off the over-voltage protection switch. However, the longer it takes to turn off the over-voltage protection switch, the more damage to the system circuit will be. Therefore, how to turn off the overvoltage protection switch more quickly is very important in the overvoltage protection technology.

An embodiment of the present invention discloses an overvoltage protection circuit. The overvoltage protection circuit includes a first connection pin, a second connection pin, an overvoltage protection switch, a coupling element, a discharge module, and a detection module. The first end of the overvoltage protection switch is coupled to the first connection pin. The second end of the overvoltage protection switch is coupled to the second connecting pin. In addition, the overvoltage protection switch is used to control the electrical connection between the first connecting pin and the second connecting pin. The coupling element is coupled between the first terminal of the overvoltage protection switch and the control terminal of the overvoltage protection switch. When a surge voltage appears on the first terminal of the overvoltage protection switch, the coupling element is used to couple the surge voltage to the control terminal of the overvoltage protection switch. The relief module is coupled between the control terminal and the ground terminal of the overvoltage protection switch. In addition, the bleeder module is used to control the electrical connection between the control terminal and the ground terminal of the overvoltage protection switch. The detection module is used to enable the bleeder module when a surge voltage is detected at the control terminal of the overvoltage protection switch, so as to conduct the electrical connection between the control terminal of the overvoltage protection switch and the ground terminal.

An embodiment of the present invention discloses an overvoltage protection method. The overvoltage protection method includes: coupling the surge voltage appearing at the first terminal of the overvoltage protection switch to the control terminal of the overvoltage protection switch by using a coupling element, wherein the first terminal of the overvoltage protection switch is coupled to a first connection The second end of the overvoltage protection switch is coupled to the second connection pin, and the overvoltage protection switch is used to control the electrical connection between the first connection pin and the second connection pin; it has been detected by the detection module Whether there is a surge voltage on the control terminal of the overvoltage protection switch; and when a surge voltage is detected on the control terminal of the overvoltage protection switch, use the detection module to enable coupling to the control terminal and the ground terminal of the overvoltage protection switch The bleeder module between the two leads through the electrical connection between the control terminal and the ground terminal of the voltage protection switch.

In order to make the above-mentioned objects, features and advantages of the embodiments of the present invention more obvious and understandable, the following detailed descriptions will be made in conjunction with the accompanying drawings.

It must be understood that the words "include", "include" and other words used in this manual are used to indicate the existence of specific technical features, values, method steps, operations, elements, and/or components, but they do not exclude Add more technical features, values, method steps, job processing, components, components, or any combination of the above.

Words such as "first" and "second" are used to modify elements, not to indicate the order of priority or antecedent relationship between them, but only to distinguish elements with the same name.

FIG. 1 is a schematic diagram of an embodiment of an overvoltage protection circuit connected between the transmission port and the system circuit 300. Please refer to FIG. 1, the over-voltage protection circuit 100 can usually be arranged between the transmission port 200 and the system circuit 300. In addition, the overvoltage protection circuit 100 can be used to disconnect the connection path between the system circuit 300 and the transmission port 200 when the surge voltage Vs occurs (for example, a short circuit occurs) at the transmission port 200 to prevent the surge voltage Vs from passing through the connection The path goes to damage to the system circuit 300.

Figure 2 Figure 1 is a schematic diagram of an embodiment of an overvoltage protection circuit. Please refer to Figure 2, the over-voltage protection circuit 100 may include two connecting pins (hereinafter referred to as the first connecting pin 111 and the second connecting pin 112), an over-voltage protection switch 120, a coupling element 130, and a bleeder module 140 And the detection module 150.

The first connection pin 111 of the overvoltage protection circuit 100 can be connected to the transmission port 200 through the connection line 210, and the second connection pin 112 of the overvoltage protection circuit 100 can be connected to the system circuit 300 through the connection line 310. In some embodiments, the over-voltage protection circuit 100 may be a chip manufactured using integrated circuit manufacturing technology, and the first connecting pin 111 and the second connecting pin 112 are both pins of the chip. In addition, the connecting line 210 and the connecting line 310 may be printed circuit lines on a printed circuit board (PCB). However, the present invention is not limited to this.

The overvoltage protection switch 120 has a first terminal, a second terminal and a control terminal. The first end of the overvoltage protection switch 120 is coupled to the first connecting pin 111. The second end of the overvoltage protection switch 120 is coupled to the second connecting pin 112. In addition, the control terminal of the overvoltage protection switch 120 is coupled to the relief module 140. Here, the overvoltage protection switch 120 is used to control the electrical connection between the first connecting pin 111 and the second connecting pin 112. Under normal circumstances, for example, when there is no surge voltage Vs at the first end of the overvoltage protection switch 120, the overvoltage protection switch 120 will be enabled (or turned on) to establish the first connection pin 111 and the second connection pin 112 The electrical connection between. Conversely, under abnormal conditions, for example, when a surge voltage Vs appears at the first end of the overvoltage protection switch 120, the overvoltage protection switch 120 will be disabled to disconnect the first connection pin 111 and the second connection pin 112. The electrical connection.

In some embodiments, the overvoltage protection switch 120 may be implemented by a transistor, such as a metal oxide semiconductor field effect transistor (MOSFET, may be referred to as a metal oxide half field effect transistor), a bipolar transistor, or the like. In some embodiments, the overvoltage protection switch 120 may be an N-type MOSFET, but the invention is not limited to this. In the following, the overvoltage protection switch 120 is an N-type MOSFET as an example. However, those with ordinary knowledge in the technical field of the present invention should understand how to use other types of transistors to replace the operation.

The coupling element 130 is coupled between the first terminal of the overvoltage protection switch 120 and the control terminal of the overvoltage protection switch 120. Here, the coupling element 130 can be used to provide a signal coupling path from the first terminal of the overvoltage protection switch 120 to the control terminal of the overvoltage protection switch 120. For example, when a surge voltage Vs appears at the first terminal of the overvoltage protection switch 120, the coupling element 130 can couple the surge voltage Vs to the control terminal of the overvoltage protection switch 120, so that the overvoltage protection switch 120 The potential of the control terminal can be increased instantaneously due to the coupling of the surge voltage Vs.

In some embodiments, the coupling element 130 may be realized by using a capacitor. In some embodiments, the coupling element 130 may be the parasitic capacitance of the overvoltage protection switch 120 itself. In this way, the over-voltage protection circuit 100 does not need to be additionally provided with a capacitive element, and the cost can be reduced.

The discharge module 140 has a first end, a second end and a control end. The first terminal of the bleeder module 140 is coupled to the control terminal of the overvoltage protection switch 120. The second terminal of the bleeder module 140 is coupled to the ground terminal GND. In addition, the control end of the discharge module 140 is coupled to the detection module 150. Among them, the ground terminal GND is used to receive the ground voltage. In some embodiments, the ground voltage may be 0 volts (V).

Here, the bleeder module 140 is controlled by the detection module 150, and can control the electrical connection between the control terminal of the overvoltage protection switch 120 and the ground terminal GND according to the control of the detection module 150.

In some embodiments, the bleeder module 140 may be implemented by a transistor, such as a metal oxide semiconductor field effect transistor, a bipolar transistor, or the like. In some embodiments, the bleeder module 140 may be an N-type metal oxide half field effect transistor, but the present invention is not limited to this, and those skilled in the art to which the present invention belongs should be able to understand how to use other types Transistor to replace operation.

The detection module 150 is coupled to the control terminal of the overvoltage protection switch 120 and can be used to detect the control terminal of the overvoltage protection switch 120. When the detection module 150 detects a surge voltage Vs at the control terminal of the overvoltage protection switch 120, the detection module 150 can turn on (or establish) the overvoltage protection switch through the enable release module 140 The electrical connection between the control terminal of 120 and the ground terminal GND enables the charge accumulated on the control terminal of the overvoltage protection switch 120 to be quickly discharged to the ground terminal GND through the discharge module 140. In addition, the over-voltage protection switch 120 can also be disabled (or turned off) more quickly because the charge at its control terminal has been quickly discharged through the discharge module 140.

In this way, with the rapid response of the detection module 150, the time required to turn off the overvoltage protection switch 120 can be greatly shortened, and the damage of the system circuit 300 by the surge voltage Vs can be reduced. Moreover, the rapid closing of the overvoltage protection switch 120 also protects the overvoltage protection switch 120 itself, so as to avoid the overvoltage protection switch 120 from breakdown. In addition, with the arrangement of the over-voltage protection circuit 100 of any embodiment of the present case, there is no need to additionally provide a transient voltage suppressor (TVS) on the first connecting pin 111 on the printed circuit board, which can effectively save cost.

In some embodiments, due to the rapid response of the detection module 150 of the overvoltage protection circuit 100 of any embodiment of the present invention, the time required to turn off the overvoltage protection switch 120 may be much less than 50 nanoseconds (ns). Therefore, the overvoltage protection circuit 100 of any embodiment of the present invention helps to pass the IEC 61000-4-2 specification of the International Electrotechnical Commission.

In one embodiment, the detection module 150 may include a voltage drop element 151 and a detection switch 152. The detection switch 152 has a first terminal, a second terminal, and a control terminal. The first terminal of the detection switch 152 is coupled to the control terminal of the discharge module 140. The second terminal of the detection switch 152 is coupled to the control terminal of the overvoltage protection switch 120. Moreover, the voltage drop element 151 is coupled between the control terminal of the detection switch 152 and the second terminal of the detection switch 152. Here, the detection switch 152 is used to detect the control terminal of the overvoltage protection switch 120, and can determine whether the control terminal of the overvoltage protection switch 120 is present according to whether the pressure drop difference on the pressure drop element 151 is greater than a conduction threshold. Surge voltage Vs.

In some embodiments, the detection switch 152 can be implemented by a transistor, such as a metal oxide semiconductor field effect transistor, a bipolar transistor, or the like. In some embodiments, the detection switch 152 may be a P-type MOSFET, but the present invention is not limited to this, and those skilled in the art to which the present invention belongs should be able to understand how to use other types of transistors. Crystal to replace operation. In the following, the detection switch 152 is a P-type MOSFET as an example for description.

Under normal conditions, for example, when there is no surge voltage Vs at the first terminal of the overvoltage protection switch 120, the potential of the control terminal of the detection switch 152 is similar to the potential of the second terminal (that is, the voltage drop across the voltage drop element 151 Very small). At this time, the detection switch 152 will be disabled (or turned off), and the release module 140 will also be disabled. In addition, in one embodiment, the detection module 150 may further include a protection element 153. The protection element 153 is coupled between the control terminal of the bleeder module 140 and the ground terminal GND. The protection element 153 can normally establish a connection path between the control terminal of the bleeder module 140 and the ground terminal GND, so that the bleeder module 140 can be disabled because the control terminal of the bleeder module 140 receives the ground voltage normally. Therefore, under normal circumstances, the detection module 150 and the relief module 140 will not affect the operation of the overvoltage protection switch 120.

Conversely, in an abnormal situation, for example, when a surge voltage Vs appears at the first terminal of the overvoltage protection switch 120, the surge voltage Vs will be coupled to the control terminal of the overvoltage protection switch 120 through the coupling element 130, causing the overvoltage protection switch 120 to The potential of the control terminal and the potential of the second terminal of the detection switch 152 rise instantaneously. At this time, the potential of the second terminal of the detection switch 152 and the potential of its control terminal will be very different (which can be called the source-gate voltage difference, and is often _{expressed as V SG} , and the voltage drop on the voltage drop element 151 at this time The difference is the source-gate voltage difference), so that the source-gate voltage difference of the detection switch 152 is greater than the conduction threshold of the detection switch 152, and the detection switch 152 is turned on. Here, after the detection switch 152 is turned on, the potential of the second terminal of the detection switch 152 and the potential of the control terminal of the bleeder module 140 will be pulled up, so that the bleeder module 140 can be turned on, and the stack is The charge on the control terminal of the overvoltage protection switch 120 can be quickly discharged to the ground terminal GND through the discharge module 140, so as to quickly turn off the overvoltage protection switch 120.

In addition, the charge stacked to the control terminal of the discharge module 140 through the detection switch 152 can be discharged to the ground terminal through the connection path normally established by the protection element 153 to prevent the discharge module 140 from being damaged by the gate oxide layer.

In some embodiments, the protection element 153 can be implemented by a transistor, such as a metal oxide semiconductor field effect transistor, a bipolar transistor, etc., or a resistor. In some embodiments, the protection element 153 may be an N-type MOSFET. At this time, the protection element 153 has a first end, a second end and a control end. The first end of the protection element 153 is coupled to the first end of the detection switch 152 and the control end of the discharge module 140. The second terminal of the protection element 153 is coupled to the ground terminal GND. In addition, the control terminal of the protection element 153 can be coupled to a power terminal VDD to receive the power supply voltage. Here, the power supply voltage is used to turn on the protection element 153, and the potential of the power supply voltage is higher than the potential of the ground voltage.

It should be noted that the present invention is not limited to this, and those skilled in the art to which the present invention pertains should be able to understand how to replace the protection element 153 with other types of transistors or suitable replacement elements.

In an embodiment, the overvoltage protection circuit 100 may further include a control module 160. The control module 160 can detect whether a surge voltage Vs appears on the first end of the overvoltage protection switch 120, and can control the overvoltage protection switch 120 according to the detection result. Here, when the control module 160 does not detect the surge voltage Vs at the first end of the overvoltage protection switch 120, the control module 160 will conduct the overvoltage protection switch 120 so that the system circuit 300 can pass the overvoltage The protection circuit 100 is electrically connected to the transmission port 200. When the control module 160 detects the surge voltage Vs at the first end of the overvoltage protection switch 120, the control module 160 disables the overvoltage protection switch 120 to disconnect the system circuit 300 and the transmission port 200 Electrical connection between.

In an embodiment, the control module 160 may include a voltage divider 161, a comparator 162 and a control unit 163. The voltage divider 161 is coupled to the first terminal of the overvoltage protection switch 120, and the voltage divider 161 is used to generate a divided voltage Vd according to the terminal voltage on the first terminal of the overvoltage protection switch 120. In some implementation aspects, the voltage divider 161 may be implemented as a resistive voltage divider, a capacitive voltage divider, or other suitable types of voltage dividers.

The comparator 162 is coupled to the voltage divider 161. The comparator 162 can be used to compare the divided voltage Vd with the reference voltage Vref, and generate a control signal Vc with a corresponding potential to the control unit 163 according to the comparison result. Here, when the comparison result of the comparator 162 is that the divided voltage Vd is less than the reference voltage Vref, the comparator 162 outputs the control signal Vc having the first potential to the control unit 163. When the comparison result of the comparator 162 is that the divided voltage Vd is greater than or equal to the reference voltage Vref, the comparator 162 outputs the control signal Vc with the second potential to the control unit 163. Wherein, the first potential is different from the second potential. In some embodiments, the first potential can be equal to the potential of the power supply voltage, and the second potential can be equal to the potential of the ground voltage, but the invention is not limited to this.

The control unit 163 is used for controlling the enabling or disabling of the overvoltage protection switch 120 according to the control signal Vc of the comparator 162. Here, when the control signal Vc has the first potential, the control unit 163 will enable the overvoltage protection switch 120. When the control signal Vc has the second potential, the control unit 163 disables the overvoltage protection switch 120.

In some implementations, in order to avoid consuming too much current or affecting the overall circuit performance, the control signal Vc output by the comparator 162 usually has a small driving force on the control unit 163. Based on this, the control module 160 may further include a driver 164. The driver 164 is coupled between the comparator 162 and the control unit 163, and is used to increase the driving force of the control signal Vc. In this way, the time for the control signal Vc to be transmitted to the control unit 163 can be shortened, thereby speeding up the control of the control unit 163 on the overvoltage protection switch 120, for example, shortening the closing time of the overvoltage protection switch 120 (in the output control signal Vc has At the second potential), but because of the shortened turn-off time, the current required by the 160 modules is relatively increased.

In an embodiment, the control unit 163 may include a charging pump 1631 and a control logic 1632. The control logic 1632 is coupled to the output terminal of the driver 164, and the charging pump 1631 is coupled between the control logic 1632 and the control terminal of the overvoltage protection switch 120. The control logic 1632 is used to control the charging pump 1631. Here, when the control signal Vc received by the control logic 1632 has the first potential, the control logic 1632 will cause the charging pump 1631 to output an enabling voltage to the control terminal of the overvoltage protection switch 120, so as to enable the overvoltage protection switch 120 . When the control signal Vc received by the control logic 1632 has the second potential, the control logic 1632 will cause the charging pump 1631 to output a disable voltage to the control terminal of the overvoltage protection switch 120 to disable the overvoltage protection switch 120. .

It should be noted that the response speed of the detection module 150 is faster than that of the control module 160. Therefore, when a surge voltage Vs appears at the first end of the overvoltage protection switch 120, the detection module 150 will act first (that is, the discharge module 140 is enabled so that the charge accumulated on the control terminal of the overvoltage protection switch 120 is discharged to the ground terminal GND through the discharge module 140, and the overvoltage protection switch 120 is turned off at the same time), and then The control module 160 will only operate (that is, output the disable voltage to the control terminal of the overvoltage protection switch 120 through the charging pump 1631).

In some embodiments, the over-voltage protection circuit 100 may further include an electrostatic protection element 170. The electrostatic protection element 170 is coupled to the first end of the overvoltage protection switch 120. Here, the static electricity protection element 170 can provide static electricity protection capability to enhance the protection capability of the overvoltage protection circuit 100.

In some embodiments, when the port 200 is a C-type universal serial bus port, the first connection pin 111 of the overvoltage protection circuit 100 can usually be connected to the configuration channel pin of the C-type universal serial bus port (generally It is often represented by the symbol CC), but the present invention is not limited to this.

FIG. 3 and FIG. 4 are schematic flowcharts of an embodiment of an overvoltage protection method. Please refer to FIGS. 2 to 4, the over-voltage protection circuit 100 can perform the over-voltage protection method according to any embodiment of the present invention. In an embodiment of the overvoltage protection method, the overvoltage protection circuit 100 can make the surge voltage Vs appearing at the first end of the overvoltage protection switch 120 coupled to the control terminal of the overvoltage protection switch 120 through the coupling element 130 ( Step S10). In addition, the overvoltage protection circuit 100 can use the detection module 150 to detect whether the surge voltage Vs is present at the control end of the overvoltage protection switch 120 (step S20).

In an embodiment of step S20, the over-voltage protection circuit 100 can use the detection switch 152 in the detection module 150 to determine whether the over-voltage protection switch 120 is based on whether the pressure drop difference on the pressure drop element 151 is greater than the conduction threshold. Whether there is a surge voltage Vs at the control terminal. Moreover, when the pressure drop difference on the pressure drop element 151 is greater than the turn-on threshold, the detection switch 152 can determine that the surge voltage Vs is present at the control terminal of the overvoltage protection switch 120.

When the detection module 150 detects the surge voltage Vs at the control terminal of the overvoltage protection switch 120, the overvoltage protection circuit 100 can reuse the detection module 150 to enable the bleeder module 140 to conduct the voltage The electrical connection between the control terminal of the protection switch 120 and the ground terminal GND (step S30). In this way, the charge accumulated on the control terminal of the overvoltage protection switch 120 can be quickly discharged to the ground terminal GND through the discharge module 140, and thereby the overvoltage protection switch 120 can be quickly opened and closed. The charge stacked to the control terminal of the discharge module 140 through the detection switch 152 can be discharged to the ground terminal through the connection path normally established by the protection element 153 to prevent the discharge module 140 from being damaged by the gate oxide layer.

In an embodiment of the overvoltage protection method, the overvoltage protection circuit 100 can further use the control module 160 to detect whether the surge voltage Vs is present at the first end of the overvoltage protection switch 120 (step S40). Wherein, when the surge voltage Vs is not detected at the first end of the overvoltage protection switch 120, the overvoltage protection circuit 100 can use the control module 160 to pass the voltage protection switch 120 (step S50). Moreover, when the surge voltage Vs is detected at the first end of the overvoltage protection switch 120, the overvoltage protection circuit 100 can use the control module 160 to disable the overvoltage protection switch 120 (step S60).

In an embodiment of step S40, the overvoltage protection circuit 100 may first use the voltage divider 161 in the control module 160 to generate the divided voltage Vd according to the terminal voltage of the first terminal of the overvoltage protection switch 120, and then use the control The comparator 162 in the module 160 determines whether a surge voltage Vs is present at the first end of the overvoltage protection switch 120 according to the divided voltage Vd and the reference voltage Vref. Wherein, when the divided voltage Vd is less than the reference voltage Vref, the comparator 162 can determine that the surge voltage Vs does not appear at the first end of the overvoltage protection switch 120. Moreover, when the divided voltage Vd is greater than or equal to the reference voltage Vref, the comparator 162 can determine that the surge voltage Vs is present at the first end of the overvoltage protection switch 120.

In an embodiment of step S50, the overvoltage protection circuit 100 can use the comparator 162 to output the control signal Vc having the first potential when the divided voltage Vd is less than the reference voltage Vref, and then the overvoltage protection circuit 100 can reuse the control module The control unit 163 in the 160 conducts the voltage protection switch 120 according to the control signal Vc having the first potential. In some embodiments, the control unit 163 causes the charging pump 1631 to output an enabling voltage to the control terminal of the overvoltage protection switch 120 through the control logic 1632 according to the control signal Vc having the first potential, so as to pass through the voltage protection switch 120.

In an embodiment of step S60, the over-voltage protection circuit 100 can use the comparator 162 to output the control signal Vc having the second potential when the divided voltage Vd is greater than or equal to the reference voltage Vref, and then the over-voltage protection circuit 100 reuses the control signal. The control unit 163 in the module 160 disables the overvoltage protection switch 120 according to the control signal Vc having the second potential. In some embodiments, the control unit 163 causes the charging pump 1631 to output a disable voltage to the control terminal of the overvoltage protection switch 120 through the control logic 1632 according to the control signal Vc having the second potential, so as to disable the overvoltage protection switch 120. .

In some embodiments, in order to avoid consuming too much current or affecting the overall circuit performance, the control signal Vc output by the comparator 162 in the control module 160 usually has a small driving force on the control unit 163, which causes the control module 160 There will be a delay effect. Therefore, when a surge voltage Vs appears at the first end of the overvoltage protection switch 120, since the reaction speed of the detection module 150 is faster than that of the control module 160, the execution of the steps S10 to S30 is usually earlier than the steps S40 to the execution of step S60.

In summary, the embodiments of the present invention provide an overvoltage protection circuit and method thereof, which couple the surge voltage to the control terminal of the overvoltage protection switch through a coupling element, so as to quickly drive the detection module to deactivate The discharge module enables the charge accumulated on the control terminal of the overvoltage protection switch to be quickly discharged through the discharge module, and at the same time, the overvoltage protection switch can be quickly turned off to avoid damage to the subsequent system circuits. Moreover, this also protects the over-voltage protection switch itself to avoid the over-voltage protection switch from collapsing. In addition, if the overvoltage protection circuit and the method of the embodiment of the present invention are used, there is no need to additionally provide a transient voltage suppressor on the printed circuit board, which can effectively save costs. Furthermore, the over-voltage protection circuit and method of the embodiments of the present invention have an extremely fast shutdown (over-voltage protection switch) mechanism, which is more conducive to passing the IEC 61000-4-2 specification of the International Electrotechnical Commission.

The embodiments of the present invention are disclosed as above, but they are not intended to limit the scope of the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, the protection scope of the present invention shall be subject to those defined by the attached patent application scope.

100: Overvoltage protection circuit 111: first connecting pin 112: second connecting leg 120: Overvoltage protection switch 130: coupling element 140: Relief module 150: Detection module 151: Pressure drop element 152: Detection switch 153: Protection element 160: control module 161: Voltage divider 162: Comparator 163: control unit 1631: Charging pump 1632: control logic 164: Drive 170: Electrostatic protection components 200: Transmission port 210: connection line 300: system circuit 310: connection line GND: ground terminal Vc: control signal VDD: power supply terminal Vd: divided voltage Vref: Reference voltage Vs: surge voltage S10-S60: steps

Figure 1 is a schematic diagram of an embodiment of an overvoltage protection circuit connected between the transmission port and the system circuit. Figure 2 Figure 1 is a schematic diagram of an embodiment of an overvoltage protection circuit. FIG. 3 and FIG. 4 are schematic flowcharts of an embodiment of an overvoltage protection method.

no

100: Overvoltage protection circuit

111: first connecting pin

112: second connecting leg

120: Overvoltage protection switch

130: coupling element

140: Relief module

150: Detection module

151: Pressure drop element

152: Detection switch

153: Protection element

160: control module

161: Voltage divider

162: Comparator

163: control unit

1631: Charging pump

1632: control logic

164: Drive

170: Electrostatic protection components

GND: ground terminal

Vc: control signal

VDD: power supply terminal

Vd: divided voltage

Vref: Reference voltage

Vs: surge voltage

Claims (6)

An overvoltage protection circuit, including: A first connecting pin; A second connecting pin; An overvoltage protection switch, the first end of the overvoltage protection switch is coupled to the first connection pin, the second end of the overvoltage protection switch is coupled to the second connection pin, and the overvoltage protection switch is used for Controlling the electrical connection between the first connecting pin and the second connecting pin; A coupling element, coupled between the first terminal of the overvoltage protection switch and a control terminal of the overvoltage protection switch, when a surge voltage appears on the first terminal of the overvoltage protection switch, the The coupling element is used for coupling the surge voltage to the control terminal of the overvoltage protection switch; A bleeder module, coupled between the control terminal and a ground terminal of the overvoltage protection switch, and the bleed module is used to control the electrical properties between the control terminal and the ground terminal of the overvoltage protection switch Link; and A detection module is used to enable the bleeder module to conduct the control terminal of the overvoltage protection switch and the ground when the surge voltage is detected at the control terminal of the overvoltage protection switch The electrical connection between the terminals. The overvoltage protection circuit described in item 1 of the scope of patent application, wherein the detection module includes: A pressure drop element; and A detection switch, the first end of the detection switch is coupled to the control end of the bleeder module, and the second end of the detection switch is coupled to the control end of the overvoltage protection switch, wherein the pressure The drop element is coupled between the second end of the detection switch and the control end of the detection switch, and the detection switch is used to determine whether a pressure drop across the pressure drop element is greater than a conduction threshold Whether the surge voltage appears on the control terminal of the overvoltage protection switch, and the detection switch determines that the surge voltage appears on the control terminal of the overvoltage protection switch when the pressure drop difference is greater than the conduction threshold. For the overvoltage protection circuit described in item 2 of the scope of patent application, the detection module further includes: A protection element is coupled between the control terminal and the ground terminal of the bleeder module, and establishes a connection path from the control terminal to the ground terminal of the bleed module. An overvoltage protection method, including: A coupling element is used to couple the surge voltage appearing at the first terminal of an overvoltage protection switch to the control terminal of the overvoltage protection switch, wherein the first terminal of the overvoltage protection switch is coupled to a first connecting pin , The second end of the overvoltage protection switch is coupled to a second connection pin, and the overvoltage protection switch is used to control the electrical connection between the first connection pin and the second connection pin; Use a detection module to detect whether the surge voltage appears on the control terminal of the overvoltage protection switch; and When the surge voltage is detected at the control terminal of the overvoltage protection switch, the detection module is used to enable a bleeder coupled between the control terminal and a ground terminal of the overvoltage protection switch The module is used to conduct the electrical connection between the control terminal and the ground terminal of the overvoltage protection switch. The over-voltage protection method described in item 4 of the scope of patent application, wherein the detection module includes a voltage drop element and a detection switch, and the first end of the detection switch is coupled to the control of the bleeder module Terminal, the second terminal of the detection switch is coupled to the control terminal of the overvoltage protection switch, and the voltage drop element is coupled between the second terminal of the detection switch and the control terminal of the detection switch , Wherein the step of using the detection module to detect whether the surge voltage is present on the control terminal of the overvoltage protection switch includes: Using the detection switch to determine whether the surge voltage is present on the control terminal of the overvoltage protection switch according to whether a pressure drop difference on the pressure drop element is greater than a turn-on threshold; and When the pressure drop difference is greater than the conduction threshold, the detection switch determines that the surge voltage is present at the control terminal of the overvoltage protection switch. According to the overvoltage protection method described in item 5 of the scope of patent application, the detection module further includes a protection element, and the protection element is coupled between the control terminal and the ground terminal of the bleeder module, and A connection path from the control terminal to the ground terminal of the bleeder module is established.

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