High-voltage protection circuit, chip and device

Abstract

The application provides a high-voltage protection circuit, a chip and a device. The high-voltage protection circuit is connected in series with a chip pin and an internal circuit of the chip, and comprises a substrate selection circuit, a high-voltage detection circuit and a protection switch. The high-voltage detection circuit receives a supply voltage and a chip pin voltage, detects the chip pin voltage and outputs a control signal. The substrate selection circuit receives the supply voltage and the chip pin voltage and outputs a substrate voltage. The protection switch receives the control signal and the substrate voltage and controls the on-off of the high-voltage protection circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of integrated circuits, in particular, to a high-voltage protection circuit, a chip and a device. BACKGROUND

[0002] Modern chips tend to use advanced node processes to meet the demand for improved performance and reduced power consumption. Advanced processes reduce the withstand voltage capability of CMOS devices within the chip through thinner gate oxide thickness and higher carrier injection concentration.

[0003] In many chip application scenarios, non-ideal use environment can cause the voltage of the chip pin to be higher than the chip supply voltage; in more serious cases, the pin voltage can also exceed the withstand voltage of the chip. For example, in the motor application environment, the three-phase alternating current of the motor has a relatively high energy, and through the coupling effect of parasitic capacitance and inductance, a relatively high voltage can be coupled to the pin end of the control chip of the motor. This type of high voltage is usually between 4V and 5V, while the standard supply voltage of the mainstream micro control processor (MCU) on the market is 3.3V, and the upper limit of the pin withstand voltage is 3.63V. If these MCUs are applied to motor control, once the internal devices of the chip receive a high voltage, the chip will be damaged.

[0004] The above information disclosed in the background section is only used to enhance the understanding of the background of the present application, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The present application proposes a high-voltage protection circuit, a chip and a device. When the voltage of the chip pin is higher than the supply voltage of the chip, the delivery of the voltage to the internal circuit of the chip can be cut off, achieving the purpose of protecting the chip.

[0006] According to an aspect of the present application, a high-voltage protection circuit is provided, which is used in a chip, and is connected in series with a chip pin and an internal circuit of the chip, and includes a substrate selection circuit, a high-voltage detection circuit and a protection switch:

[0007] The high-voltage detection circuit receives a supply voltage and a chip pin voltage, detects the chip pin voltage, and outputs a control signal;

[0008] The substrate selection circuit receives a supply voltage and a chip pin voltage, and outputs a substrate voltage;

[0009] The protection switch receives the control signal and the substrate voltage, and controls the on-off of the high-voltage protection circuit.

[0010] According to some embodiments, if the chip pin voltage is higher than the supply voltage, the high voltage detection circuit outputs the control signal to control the protection switch to be off;

[0011] If the chip pin voltage is lower than the supply voltage, the high voltage detection circuit outputs the control signal to control the protection switch to be on.

[0012] According to some embodiments, if the chip pin voltage is higher than the supply voltage, the substrate selection circuit outputs the substrate voltage to be equal to the chip pin voltage;

[0013] If the chip pin voltage is lower than the supply voltage, the substrate selection circuit outputs the substrate voltage to be equal to the supply voltage.

[0014] According to some embodiments, the high voltage detection circuit further comprises a P-MOS tube, which inputs the substrate voltage output by the substrate selection circuit.

[0015] According to some embodiments, the protection switch comprises a first switch and a second switch in parallel, wherein:

[0016] The first switch is an N-MOS tube, the gate end of which is connected to the supply voltage, and the substrate of which is connected to the ground;

[0017] The second switch is a P-MOS tube, the gate end of which is connected to the control signal, and the substrate of which is connected to the substrate voltage.

[0018] According to some embodiments, if the chip pin voltage is higher than the supply voltage, the high voltage detection circuit outputs the control signal to be a first control signal;

[0019] If the chip pin voltage is lower than the supply voltage, the high voltage detection circuit outputs the control signal to be a second control signal.

[0020] According to some embodiments, if the chip pin voltage is higher than the supply voltage, the first switch is off;

[0021] If the chip pin voltage is lower than the supply voltage, the first switch is on.

[0022] According to some embodiments, if the control signal is the first control signal, the second switch is off;

[0023] If the control signal is the second control signal, the second switch is on.

[0024] According to some embodiments, the protection switch has a voltage withstand protection function.

[0025] According to another aspect of the present application, a chip is provided, comprising the high voltage protection circuit according to any one of the preceding aspects.

[0026] According to another aspect of the present application, a device is provided, comprising a chip as described above.

[0027] The technical solutions according to some embodiments of the present application can have one or more of the following beneficial effects:

[0028] A protection circuit is added between the internal circuit of the chip and the chip pin, when the voltage of the chip pin is detected as high voltage, the high voltage protection circuit is disconnected, blocking the high voltage from entering the internal circuit of the chip; when the voltage of the chip pin is less than the supply voltage, the high voltage protection circuit is turned on.

[0029] 1. When the voltage V1 of the chip pin is higher than the supply voltage, the N-type switch and the P-type switch themselves withstand high voltage, and have a protection mechanism and a voltage withstand design.

[0030] 2. When the voltage of the chip pin is higher than the supply voltage, the substrate voltage is the pin voltage, so that the parasitic diode of the P-MOS tube will not be forward conducting, preventing the phenomenon of reverse flow of chip pin current.

[0031] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[0033] Figure 1 A schematic block diagram showing the connection of the high voltage protection circuit of the example embodiment of the present application is shown;

[0034] Figure 2 A structural schematic diagram of a high voltage protection circuit of the example embodiment of the present application is shown;

[0035] Figure 3 Another embodiment of a structural schematic diagram of a high voltage protection circuit of the example embodiment of the present application is shown;

[0036] Figure 4 A structural schematic diagram of a substrate selection circuit of the example embodiment of the present application is shown;

[0037] Figure 5 A structural schematic diagram of a high voltage detection circuit of the example embodiment of the present application is shown. DETAILED DESCRIPTION

[0038] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0039] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0040] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0041] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0042] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.

[0043] The following describes an apparatus embodiment of this application, which can be used to perform the method embodiment of this application. For details not disclosed in the apparatus embodiment of this application, please refer to the method embodiment of this application.

[0044] Figure 1 A schematic block diagram showing the high-voltage protection circuit connection of an example embodiment of this application is provided.

[0045] like Figure 1 As shown, a high-voltage protection circuit 101 is connected between the internal circuit 105 and the chip pin 103 inside the chip.

[0046] According to an example embodiment, if the voltage on the chip pin 103 is lower than the chip supply voltage, the high voltage protection circuit 101 presents a conductive state, and voltage or current can be transmitted between the chip pin 103 and the chip internal circuit 105.

[0047] According to an example embodiment, if the voltage on the chip pin 103 is higher than the chip supply voltage, the high voltage protection circuit 101 presents a cut-off state, and the voltage or current on the chip pin 103 cannot be transmitted to the chip internal circuit 105.

[0048] According to an example embodiment, the high voltage protection circuit 101 has the function of preventing the current of the chip pin 103 from flowing backward, and when the voltage of the chip pin 103 is higher than the chip supply voltage, no current will flow from the chip pin 103 to the power supply.

[0049] Figure 2 A structural schematic diagram of a high voltage protection circuit according to an example embodiment of the present application is shown.

[0050] As shown in Figure 2 , the high voltage protection circuit 101 includes a high voltage detection circuit 201, a protection switch 203, and a substrate selection circuit 205.

[0051] According to an example embodiment, the chip pin 103 is electrically connected with the high voltage detection circuit 201, the substrate selection circuit 205, and the protection switch 203, the high voltage detection circuit 201 is electrically connected with the protection switch 203, and the protection switch 203 is electrically connected with the chip internal circuit 105.

[0052] According to an example embodiment, the high voltage detection circuit 201 inputs the substrate voltage VPB, the supply voltage, and the chip pin voltage V1. The high voltage detection circuit 201 detects whether the voltage V1 of the chip pin 103 is higher than the supply voltage, if the voltage V1 of the chip pin 103 is less than or equal to the supply voltage, outputs the control signal SW1 as a first control signal, controls the protection switch 203 to be closed, so that the voltage is transmitted between the chip pin 103 and the chip internal circuit 106; if the voltage V1 of the chip pin 103 is greater than the supply voltage, outputs the control signal SW1 as a second control signal, controls the protection switch 203 to be opened, at this time the voltage of the chip pin 103 is cut off and cannot be transmitted to the chip internal circuit 105, so the chip internal circuit 105 is protected.

[0053] According to an example embodiment, the first control signal is high and the second control signal is low in the present application, but the present application is not limited thereto.

[0054] According to an example embodiment, the substrate selection circuit 205 inputs the supply voltage and the chip pin voltage V1, and outputs the substrate voltage VPB. If the voltage V1 of the chip pin 103 is higher than the supply voltage, the output substrate voltage VPB is equal to the voltage V1 of the chip pin 103; if the voltage V1 of the chip pin 103 is less than or equal to the supply voltage, the output substrate voltage VPB is equal to the supply voltage.

[0055] According to an example embodiment, the substrate selection circuit 205 provides the substrate voltage VPB for the P-MOS tube in the high-voltage protection circuit 101, and the voltage is always the highest voltage of the circuit, which ensures that when the voltage V1 of the chip pin 103 is higher than the supply voltage of the chip, the parasitic diode of the P-MOS tube will not be forward-biased, and the phenomenon of reverse flow of the chip pin current will not occur.

[0056] According to some embodiments, the high-voltage detection circuit 201 includes a P-MOS tube, and therefore the high-voltage detection circuit 201 needs to input the substrate voltage VPB.

[0057] According to some embodiments, the protection switch 203 has a voltage resistance function.

[0058] Figure 3 Another embodiment of a structure schematic diagram of a high-voltage protection circuit according to an example of the present application is shown.

[0059] As Figure 3 described above, the high-voltage protection circuit 101 includes a transmission gate switch 207, a high-voltage detection circuit 201, and a substrate selection circuit 205.

[0060] According to an example embodiment, the transmission gate switch 207 includes a P-type switch 2071 and an N-type switch 2073, which can ensure the conduction characteristics in the full voltage range (ground potential to supply voltage), and when the transmission gate switch 207 is turned on, the transmission gate switch 207 can provide a smaller conduction impedance when the voltage V1 of the chip pin approaches the power supply or ground potential.

[0061] According to an example embodiment, the N-type switch 2073 includes an N-MOS tube, and the gate terminal thereof is electrically connected to the supply voltage. The P-type switch 2071 includes a P-MOS tube, and the gate terminal thereof is connected to a control signal SW1. If the control signal SW1 is at a low level or ground potential, the P-type switch is turned on; if the control signal SW1 is at a high level or supply voltage, the P-type switch is turned off.

[0062] According to an example embodiment, the N-type switch 2073 and the P-type switch 2071 are connected in parallel, one end of which is an input terminal electrically connected to the chip pin 103, and the other end of which is an output terminal electrically connected to the internal circuit 105 of the chip.

[0063] According to an example embodiment, the high-voltage detection circuit 201 inputs the chip pin voltage V1, the supply voltage and the substrate voltage VPB, and outputs the control signal SW1. The high-voltage detection circuit 201 detects whether the chip pin voltage V1 is higher than the supply voltage. If the chip pin voltage V1 is less than or equal to the supply voltage, the control signal SW1 is output as the second control signal. If the chip pin voltage V1 is greater than the supply voltage, the control signal SW1 is output as the first control signal.

[0064] According to an example embodiment, the first control signal is high and the second control signal is low in the present application, but the present application is not limited thereto.

[0065] According to an example embodiment, the substrate selection circuit 205 inputs the chip pin voltage V1 and the supply voltage, and outputs the substrate voltage VPB. The substrate selection circuit 205 provides the substrate voltage VPB for all P-MOS tubes connected to the pin. If the chip pin voltage V1 is higher than the supply voltage, the output substrate voltage VPB is equal to the chip pin voltage V1. If the chip pin voltage V1 is less than or equal to the supply voltage, the output substrate voltage VPB is equal to the supply voltage.

[0066] According to an example embodiment, the substrate selection circuit 205 provides the substrate voltage VPB for all P-MOS tubes connected to the pin, and the voltage is always the highest voltage in the circuit. When the chip pin voltage is higher than the chip supply voltage, the parasitic diode of the P-MOS tube cannot be forward-biased, and the chip pin current backflow phenomenon can be avoided.

[0067] According to an example embodiment, if the chip pin voltage V1 is lower than the supply voltage, the output control signal SW1 is low, and the P-type switch 2071 is turned on. When the chip pin voltage V1 is less than or equal to the supply voltage, the N-type switch 2073 is turned on. The voltage or current is transmitted to the chip internal circuit 105 through the transmission gate switch 207. At this time, the substrate voltage VPB is output as the supply voltage.

[0068] According to an example embodiment, if the chip pin voltage V1 is higher than the supply voltage, the output control signal SW1 is high, and the P-type switch 2071 is turned off. When the chip pin voltage V1 is greater than the supply voltage, the N-type switch 2073 is turned off. The voltage or current cannot be transmitted to the chip internal circuit 105 through the transmission gate switch 207. At this time, the substrate voltage VPB is output as the pin voltage.

[0069] According to an example embodiment, the high and low levels of the control signal SW1 output by the high-voltage detection circuit 201 are changed according to the types of MOS switches of the transmission gate switch. The present application takes the N-type switch and the P-type switch as an example, but the present application only shows one of them, but the present application is not limited thereto, and other design methods cannot avoid the patent subject matter scheme of the present application.

[0070] According to an example embodiment, the transmission gate switch 207 has a voltage withstand function. When the chip pin voltage V1 is higher than the supply voltage, the N-type switch 2073 and the P-type switch 2071 will also withstand high voltage, and have a self-protection mechanism:

[0071] According to some embodiments, when the chip pin voltage V1 is higher than the supply voltage, the N-type switch 2073 will withstand three voltages: the voltage from the active region V1 end to the gate end, the voltage from the active region V1 end to the active region V2 end, and the voltage from the active region V1 end to the substrate end.

[0072] The voltage from the active region V1 end to the gate end, since the gate end is electrically connected to the supply voltage, the active region V1 end voltage needs to be higher than the supply voltage by one device withstand voltage, which is the range that can damage the N-type switch. Usually, the coupled high voltage will not exceed this range.

[0073] The voltage from the active region V1 end to the active region V2 end, since the active region V1 end voltage rises to the supply voltage, the transmission gate switch 207 will be cut off, and the active region V2 end voltage will remain at the supply voltage. Therefore, the active region V1 end voltage needs to be higher than the supply voltage by one device withstand voltage, which is the range that can damage the N-type switch. Usually, the coupled high voltage will not exceed this range.

[0074] The voltage from the active region V1 end to the substrate end, the N-MOS tube substrate is grounded, so the voltage from the active region V1 end to the substrate end is V1. However, the substrate has a low injection concentration, so the parasitic diode from the active region V1 end to the substrate end has a high reverse withstand voltage capability. Usually, the coupled high voltage of the chip pin will not exceed this value.

[0075] According to some embodiments, when the chip pin voltage V1 is higher than the supply voltage, the P-type switch 2071 will withstand three voltages: the voltage from the active region V1 end to the gate end, the voltage from the active region V1 end to the active region V2 end, and the voltage from the active region V1 end to the substrate end.

[0076] The voltage from the active region V1 end to the gate end, since the active region V1 end voltage is greater than the supply voltage, the output voltage provided by the control signal SW1 is equivalent to the voltage of V1, so the voltage difference from the active region V1 end to the gate end is 0.

[0077] The voltage from the active region V1 end to the active region V2 end, when the active region V1 end voltage rises to the supply voltage, the transmission gate switch 207 will be cut off, so the active region V2 end voltage will remain at the supply voltage. Therefore, the active region V1 end voltage needs to be higher than the supply voltage by one device withstand voltage, which is the range that can damage the P-type switch. Usually, the coupled high voltage of the chip pin will not exceed this range.

[0078] The voltage from the active region V1 end to the substrate end, when V1 is greater than the supply voltage, the substrate voltage VPB of the P-MOS tube is equal to the voltage at the active region V1 end, so the voltage difference from the active region V1 end to the substrate end is 0, and there is no risk.

[0079] Figure 4 A structure diagram of a substrate selection circuit is shown.

[0080] As shown in Figure 4 , the substrate selection circuit includes switches PM1 and PM2. The substrate selection circuit can select a high voltage between the supply voltage and the chip pin voltage V1 for output, and the output voltage VPB provides the P-MOS substrate voltage for the high voltage protection circuit.

[0081] If the supply voltage is greater than V1, the switch PM1 is turned on, and the supply voltage is conducted to VPB through the switch PM1.

[0082] If the supply voltage is less than V1, the switch PM1 is cut off, the active region (drain and source) voltage of the switch PM2 is the highest voltage, the parasitic diode of the active region to the substrate region of the switch PM2 is turned on, and V1 is conducted to VPB through the parasitic diode.

[0083] The substrate selection circuit has high voltage resistance.

[0084] For the switch PM1: when the chip pin voltage V1 is high, V1 = VPB, so the gate to VPB voltage difference of PM1 is 0, and there is no voltage resistance problem; and the gate voltage needs to be higher than the supply voltage by one device voltage resistance, so as to possibly damage the PN junction of V1 to the supply voltage end. Usually, the coupled high voltage of the chip pin will not exceed this range.

[0085] For the switch PM2: when the chip pin voltage V1 is high, the four-terminal voltage of PM2 is equal, so there is no risk.

[0086] The substrate selection circuit has various design methods, and this application only shows one of them, but this application is not limited thereto, and other design methods cannot avoid the patent subject scheme of this application.

[0087] Figure 5 A structure diagram of a high voltage detection circuit is shown.

[0088] As shown in Figure 5 , the high voltage detection circuit includes switches PM3, PM4, resistor R and inverter INV in series.

[0089] When the chip pin voltage V1 is greater than the chip supply voltage, SW1 outputs a first control signal; when the chip pin voltage V1 is less than or equal to the chip supply voltage, SW1 outputs a second control signal.

[0090] According to the example embodiments, the first control signal can be high and the second control signal can be low, but the present application is not limited thereto.

[0091] When the chip pin voltage V1 is less than the supply voltage, PM4 is cut off, INV outputs low, PM3 is turned on, and the potential of SW1 is equal to ground, i.e., low potential.

[0092] When the chip pin voltage V1 is greater than the supply voltage, PM4 is turned on, INV outputs high, PM3 is cut off, and the potential of SW1 is equal to V1, i.e., high potential.

[0093] The high-voltage detection circuit has various design methods, and the present application only shows one of them, but the present application is not limited thereto, and other design methods cannot avoid the patent subject matter scheme of the present application.

[0094] The high-low logic of SW1 is matched with the switching action, and should not limit the patent protection scope.

[0095] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. Instead, based on the teachings of the disclosure of the present application, these principles can be applied to many other embodiments.

[0096] In addition, it should be noted that the above-described figures are only schematic illustrations of the processes included in the method according to the example embodiments of the present application, and are not for limiting purposes. It is easy to understand that the processes shown in the above-described figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be executed synchronously or asynchronously, for example, in multiple modules.

[0097] The example embodiments of the present application are specifically shown and described above. It should be understood that the present application is not limited to the detailed structure, arrangement or implementation method described herein; on the contrary, the present application is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the appended claims.

Claims

1. A high voltage protection circuit, characterized by, The high-voltage protection circuit is used for a chip, and is connected in series with a chip pin and an internal circuit of the chip, and comprises a substrate selection circuit, a high-voltage detection circuit and a protection switch. The high-voltage detection circuit receives a supply voltage and a chip pin voltage, and outputs a control signal according to the chip pin voltage and the supply voltage. The substrate selection circuit receives the supply voltage and the chip pin voltage, and outputs a substrate voltage according to the supply voltage and the chip pin voltage. If the chip pin voltage is higher than the supply voltage, the substrate selection circuit outputs the substrate voltage equal to the chip pin voltage. If the chip pin voltage is lower than the supply voltage, the substrate selection circuit outputs the substrate voltage equal to the supply voltage. The protection switch receives the control signal and the substrate voltage to control on-off of the high-voltage protection circuit, and comprises a first switch and a second switch connected in parallel, wherein: The first switch is an N-MOS tube, the gate end of which is connected to the supply voltage, and the substrate of which is grounded. The second switch is a P-MOS tube, the gate end of which is connected to the control signal, and the substrate of which is connected to the substrate voltage.

2. The high-voltage protection circuit according to claim 1, wherein: If the chip pin voltage is higher than the supply voltage, the high-voltage detection circuit outputs the control signal to control the protection switch to be cut off. If the chip pin voltage is lower than the supply voltage, the high-voltage detection circuit outputs the control signal to control the protection switch to be turned on.

3. The high voltage protection circuit of claim 1, wherein, The high-voltage detection circuit further comprises a P-MOS tube, which inputs the substrate voltage output by the substrate selection circuit.

4. The high-voltage protection circuit according to claim 1, wherein: If the chip pin voltage is higher than the supply voltage, the high-voltage detection circuit outputs the control signal as a first control signal. If the chip pin voltage is lower than the supply voltage, the high-voltage detection circuit outputs the control signal as a second control signal.

5. The high-voltage protection circuit according to claim 4, wherein: If the chip pin voltage is higher than the supply voltage, the first switch is cut off. If the chip pin voltage is lower than the supply voltage, the first switch is turned on.

6. The high-voltage protection circuit according to claim 4, wherein: If the control signal is the first control signal, the second switch is cut off. If the control signal is the second control signal, the second switch is turned on.

7. The overvoltage protection circuit of claim 1, wherein, The protection switch has a voltage-withstanding protection function.

8. A chip, characterized by The chip comprises the high-voltage protection circuit according to any one of claims 1-7.

9. An apparatus, comprising: The chip comprises the high-voltage protection circuit according to claim 8.

Images