Excessive electrical stress protection device

Abstract

An over-voltage protection device is provided. A detection circuit detects an input voltage from a pad. When the input voltage is higher than a default voltage, the detection circuit provides a first discharge path and provides an enable voltage to a discharge protection circuit to control the discharge protection circuit to provide at least a second discharge path.

Description

Technical Field

[0001] This invention relates to a protective device, and more particularly to an excessive electrical stress protection device. Background Technology

[0002] Electrical over stress (EOS) events can generate high electric fields that cause circuits to temporarily or permanently lose their function. EOS events can be caused by, for example, electromagnetic pulses, electrostatic discharge, lightning, or induced by the operation of other electronic components.

[0003] Generally, excessive electrical stress events are prevented by external circuitry. However, if the external circuitry is insufficient or no external protection circuitry is provided, protection can only be provided by the internal circuitry of the chip itself. Summary of the Invention

[0004] This invention provides an excessive electrical stress protection device that can detect and release voltage or current in response to excessive electrical stress events, so as to avoid damage to internal components of the chip.

[0005] The present invention provides an over-stress protection device for protecting the internal circuitry of a chip. The internal circuitry receives input voltage through solder pads. The over-stress protection device includes a first protection resistor circuit, a detection circuit, a voltage divider circuit, and a discharge protection circuit. The first protection resistor circuit is coupled to the solder pads of the chip. The detection circuit is coupled to the first protection resistor circuit, detects the input voltage, and provides a turn-on voltage when the input voltage is higher than a default voltage. The voltage divider circuit is coupled to the detection circuit and a ground terminal. The first protection resistor circuit, the detection circuit, and the voltage divider circuit form a first discharge path when the input voltage is higher than the default voltage. The discharge protection circuit is coupled to the solder pads, the detection circuit, and the ground terminal, and provides at least one second discharge path based on the turn-on voltage.

[0006] In one embodiment of the present invention, the detection circuit includes a transistor, the first end of which is coupled to a first protection resistor circuit and a voltage divider circuit respectively, the control end of which is coupled to a control voltage, and the transistor is turned on when the input voltage is higher than the default voltage.

[0007] In one embodiment of the present invention, the discharge protection circuit includes a second protection resistor circuit, a switching circuit, and a third protection resistor circuit. The second protection resistor circuit is coupled to the chip's solder pads. The switching circuit is coupled to the second protection resistor circuit and the detection circuit. The third protection resistor circuit is coupled between the switching circuit and the ground terminal. The switching circuit is turned on by a turn-on voltage to provide a second discharge path.

[0008] In one embodiment of the present invention, the switching circuit described above includes a transistor coupled between a second protection resistor circuit and a third protection resistor circuit. The control terminal of the transistor is coupled to a detection circuit. The transistor is turned on by a turn-on voltage to provide a second discharge path.

[0009] In one embodiment of the present invention, the discharge protection circuit includes a second protection resistor circuit, a plurality of switching circuits, and a plurality of third protection resistor circuits. The second protection resistor circuit is coupled to the pad of the chip. The plurality of switching circuits are coupled to the second protection resistor circuit and the detection circuit. The plurality of third protection resistor circuits are respectively coupled between the corresponding switching circuit and the ground terminal, and the plurality of switching circuits are turned on by a turn-on voltage to provide a plurality of second discharge paths.

[0010] In one embodiment of the present invention, each switching circuit includes a transistor, each transistor being coupled between a second protection resistor circuit and a corresponding third protection resistor circuit, the control terminal of each transistor being coupled to a detection circuit, and each transistor being turned on by a turn-on voltage to provide multiple second discharge paths.

[0011] In one embodiment of the present invention, the plurality of transistors described above have different threshold voltages.

[0012] In one embodiment of the present invention, the voltage divider circuit divides the turn-on voltage to generate at least one divided voltage. The discharge protection circuit includes a second protection resistor circuit, a plurality of switching circuits, and a plurality of third protection resistor circuits. The second protection resistor circuit is coupled to the chip's solder pads. The plurality of switching circuits are coupled to the second protection resistor circuit, the detection circuit, and the voltage divider circuit. The plurality of third protection resistor circuits are respectively coupled between the corresponding switching circuit and the ground terminal. Each switching circuit is turned on by the turn-on voltage or the corresponding divided voltage to provide a plurality of second discharge paths.

[0013] In one embodiment of the present invention, each switching circuit includes a transistor, each transistor being coupled between a second protection resistor circuit and a corresponding third protection resistor circuit, the control terminal of each transistor being coupled to a detection circuit or a corresponding voltage divider, and each transistor being turned on by a turn-on voltage or a corresponding voltage divider to provide multiple second discharge paths.

[0014] In one embodiment of the present invention, the control voltage is the system power supply voltage.

[0015] Based on the above, the detection circuit of this embodiment can detect the input voltage. When the input voltage is higher than the default voltage, it provides a first discharge path and provides an activation voltage to the discharge protection circuit to control the discharge protection circuit to provide a second discharge path. This effectively and quickly dissipates excessive voltage or current through the first and second discharge paths when an excessive electrical stress event occurs, preventing damage to the internal circuitry.

[0016] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an excessive electrical stress protection device according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of an excessive electrical stress protection device according to another embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of an excessive electrical stress protection device according to another embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of an excessive electrical stress protection device according to another embodiment of the present invention. Detailed Implementation

[0021] To make the content of this invention more readily apparent, the following specific embodiments are provided as examples on which this invention can indeed be practiced. Furthermore, wherever possible, components / members referred to by the same reference numerals in the drawings and embodiments represent the same or similar parts.

[0022] Figure 1 This is a schematic diagram of an excessive electrical stress protection device according to an embodiment of the present invention. Please refer to it. Figure 1 An over-stress protection device 100 is disposed inside the chip to protect the chip's internal circuitry 110, which receives an input voltage VIN via a pad P1. The over-stress protection device 100 may include a protection resistor circuit 102, a detection circuit 104, a voltage divider circuit 106, and a discharge protection circuit 108. The protection resistor circuit 102 is coupled to the chip's pad P1 and the detection circuit 104. The detection circuit 104 is coupled to the voltage divider circuit 106 and the discharge protection circuit 108. The voltage divider circuit 106 is also coupled to a ground terminal VSS. Furthermore, the discharge protection circuit 108 is coupled to the pad P1 and the ground terminal VSS.

[0023] The detection circuit 104 detects the input voltage VIN. When the input voltage VIN is higher than the default voltage, i.e., when an excessive electrical stress event occurs, it provides a first discharge path to discharge the excessive voltage or current from the solder pad P1. Specifically, the first discharge path can be formed by the protection resistor circuit 102, the detection circuit 104, and the voltage divider circuit 106, which provides a discharge path from the solder pad P1 to the ground terminal VSS. Simultaneously, the detection circuit 104 can also provide an enable voltage to the discharge protection circuit 108 to control the discharge protection circuit 108 to provide a second discharge path from the solder pad P1 to the ground terminal VSS.

[0024] By detecting the input voltage VIN through the detection circuit 104, providing a first discharge path, and controlling the discharge protection circuit 108 to provide a second discharge path, the occurrence of excessive electrical stress events can be quickly responded to. Excessive voltage or current from the solder pad P1 can be discharged through the first discharge path and the second discharge path, thereby effectively preventing damage to the internal circuit 110.

[0025] Figure 2 This is a schematic diagram of an excessive electrical stress protection device according to another embodiment of the present invention. Further, Figure 1 In this embodiment, the protection resistor circuit 102, detection circuit 104, and voltage divider circuit 106 can be implemented using resistor RPH, transistor MP1, and resistor RPL, respectively. Resistor RPH is coupled between the pad P1 and the first terminal of transistor MP1, resistor RPL is coupled between the second terminal of transistor MP1 and ground terminal VSS, and the control terminal of transistor MP1 is coupled to the control voltage VCTRL. Furthermore, the discharge protection circuit 108 in this embodiment may include protection resistor circuit 202, switching circuit 204, and protection resistor circuit 206. Protection resistor circuit 202, switching circuit 204, and protection resistor circuit 206 can be implemented, for example, using resistor RNH, transistor MN1, and resistor RNL, respectively. Resistor RNH, transistor MN1, and resistor RNL are connected in series between the pad P1 and ground terminal VSS, and the control terminal of transistor MN1 is coupled to the second terminal of transistor MP1. The ground terminal VSS can be, for example, a ground plane connected to the outside of the chip, such as the ground plane of a printed circuit board or a metal plate, but is not limited thereto.

[0026] Transistor MP1 can be used to detect whether a surge signal occurs in the input voltage VIN. For example, when the voltage value at the first terminal of transistor MP1 is higher than the sum of the control voltage VCTRL and the threshold voltage of transistor MP1, transistor MP1 will be turned on. This indicates that the input voltage VIN is higher than the default voltage. The control voltage VCTRL can be set to, for example, the chip's system power supply voltage (system maximum voltage), but is not limited to this. In other embodiments, the control voltage VCTRL can also be set to, for example, any other voltage from 0 to the system power supply voltage. When transistor MP1 is turned on, transistor MP1 can provide a turn-on voltage VDN to transistor MN1 at its second terminal. Simultaneously, the turned-on transistor MP1, along with resistors RPH and RPL, can form a first discharge path to vent the surge signal to the ground terminal VSS. Furthermore, transistor MN1 can be turned on by the turn-on voltage VDN, forming a second discharge path with resistors RNH and RNL to further and quickly vent the surge signal to the ground terminal VSS.

[0027] In this circuit, resistors RPH and RPL limit the current flowing through the first discharge path to prevent transistor MP1 from being damaged by excessive current. Similarly, resistors RNH and RNL limit the current flowing through the second discharge path to prevent transistor MN1 from being damaged by excessive current. The resistance values ​​of resistors RPH and RNH can, for example, reach several hundred ohms, while the resistance values ​​of resistors RPL and RNL can, for example, reach several tens of ohms. However, these are not limitations, and users can design the resistance values ​​of resistors RPH, RNH, RPL, and RNL according to actual conditions. Furthermore, the protection resistor circuit and voltage divider circuit in the above embodiment are implemented with a single resistor, but this is not a limitation. In other embodiments, the protection resistor circuit and voltage divider circuit can also be composed of, for example, multiple resistors connected in parallel or series.

[0028] Figure 3 This is a schematic diagram of an excessive electrical stress protection device according to another embodiment of the present invention. This embodiment is similar to... Figure 2 The difference in this embodiment lies in that the discharge protection circuit 108 may include multiple switching circuits 204-1 to 204-Z and multiple protection resistor circuits 206-1 to 206-Z, where Z is a positive integer. Each switching circuit 204-1 to 204-Z and its corresponding protection resistor circuit 206-1 to 206-Z are connected in series between the protection resistor circuit 202 and the ground terminal VSS. The switching circuits 204-1 to 204-Z may be implemented, for example, with transistors MN1 to MNZ, and the protection resistor circuits 206-1 to 206-Z may be implemented, for example, with resistors RNL1 to RNLZ, but are not limited thereto. The number and size of transistors MN1 to MNZ can be adjusted as needed; for example, the sizes of transistors MN1 to MNZ may be equal, or they may increase sequentially in multiples of 2.

[0029] When the voltage at the first terminal of transistor MP1 is higher than the sum of the control voltage VCTRL and the threshold voltage of transistor MP1, that is, when the input voltage VIN is higher than the default voltage, transistor MP1 is turned on. Simultaneously, the turn-on voltage VDN is provided to the control terminals of transistors MN1-MNZ, thus turning on transistors MN1-MNZ at the same time. The turned-on transistors MN1-MNZ can form multiple second discharge paths with resistors RNH and their corresponding resistors RNL1-RNLZ, respectively, thereby significantly improving the ability of the overcurrent protection device to discharge surge signals. In some embodiments, transistors MN1-MNZ can be designed with different threshold voltages, allowing the overcurrent protection device to provide different numbers of second discharge paths for surge signals of different voltage values. This allows the overcurrent protection device to discharge surge signals at an appropriate speed, avoiding damage to components on the discharge path from excessive discharge current.

[0030] Figure 4 This is a schematic diagram of an excessive electrical stress protection device according to another embodiment of the present invention. This embodiment is similar to... Figure 3 The difference in this embodiment lies in that the voltage divider circuit 106 includes multiple resistors RPL1 to RPLK connected in series between transistor MP1 and ground terminal VSS, where K is an integer greater than 1. Resistors RPL1 to RPLK can divide the turn-on voltage VDN1 to generate divided voltages VDN2 to VDNK. The turn-on voltage VDN1 and the divided voltages VDN2 to VDNK can be provided to transistors MN1 to MNZ to control transistors MN1 to MNZ to provide a second discharge electrical path. It is worth noting that K can be less than or equal to Z, that is, the turn-on voltage VDN1 and each divided voltage VDN2 to VDNK are not limited to being provided to only one corresponding transistor. A single turn-on voltage VDN1 or divided voltage can be provided to multiple transistors. For example, the divided voltage VDN2 can be provided to transistors MN2 and MN3, so that transistors MN2 and MN3 respectively provide corresponding second discharge paths.

[0031] Since the turn-on voltage VDN1 and the voltage divider voltages VDN2 to VDNK are different, when transistors MN1 to MNZ have the same critical voltage, the higher the voltage value of the surge signal appearing at the input voltage VIN, the more transistors MN1 to MNZ can be turned on. In other words, by using the voltage divider circuit 106 to divide the turn-on voltage VDN1 to obtain the voltage divider voltages VDN2 to VDNK for controlling the number of second discharge paths, the excessive electrical stress protection device can also discharge the surge signal at an appropriate speed, avoiding excessive discharge current damage to the components on the discharge path. Furthermore, in some embodiments, transistors MN1 to MNZ may also have different critical voltages, and are not limited to this embodiment.

[0032] In summary, the detection circuit of the embodiments of the present invention can detect the input voltage. When the input voltage is higher than the default voltage, it provides a first discharge path and provides an activation voltage to the discharge protection circuit to control the discharge protection circuit to provide a second discharge path. This effectively and quickly dissipates excessive voltage or current through the first and second discharge paths when an excessive electrical stress event occurs, preventing damage to the internal circuitry.

[0033] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. An excessive electrical stress protection device for protecting the internal circuitry of a chip, wherein the internal circuitry receives input voltage through solder pads, characterized in that, include: A first protective resistor circuit is coupled to the solder pads of the chip; The detection circuit, coupled to the first protection resistor circuit, detects the input voltage and provides an enable voltage when the input voltage is higher than the default voltage. A voltage divider circuit is coupled to the detection circuit and the ground terminal. When the input voltage is higher than the default voltage, the first protection resistor circuit, the detection circuit, and the voltage divider circuit form a first discharge path. as well as A discharge protection circuit, coupled to the solder pad, the detection circuit, and the ground terminal, provides at least one second discharge path based on the turn-on voltage. The voltage divider circuit divides the turn-on voltage to generate at least one voltage divider. The discharge protection circuit includes: The second protection resistor circuit is coupled to the solder pads of the chip; Multiple switching circuits are coupled to the second protection resistor circuit, the detection circuit, and the voltage divider circuit; and Multiple third protection resistor circuits are respectively coupled between the corresponding switching circuit and the ground terminal. Each switching circuit is turned on by the turn-on voltage or the corresponding voltage divider to provide multiple second discharge paths.

2. The excessive electrical stress protection device according to claim 1, characterized in that, The detection circuit includes: A transistor, the first terminal of which is coupled to the first protection resistor circuit and the voltage divider circuit respectively, the control terminal of which is coupled to the control voltage, and the transistor is turned on when the input voltage is higher than the default voltage.

3. The excessive electrical stress protection device according to claim 1, characterized in that, Each switching circuit includes a transistor, each transistor being coupled between the second protection resistor circuit and the corresponding third protection resistor circuit. The control terminal of each transistor is coupled to the detection circuit or the corresponding voltage divider. Each transistor is turned on by the turn-on voltage or the corresponding voltage divider to provide the plurality of second discharge paths.

4. The excessive electrical stress protection device according to claim 2, characterized in that, The control voltage is the system power supply voltage.

Images