ESD (Electro-Static Discharge) protection circuit for enhancing source driver
By introducing fuse circuits and low-voltage working circuits into the ESD protection circuit, real-time monitoring and processing of ESD voltages are solved, and the problem of insufficient protection capabilities of traditional ESD protection methods is achieved, and higher ESD protection capabilities and IC safety are achieved.
Patent Information
- Application Number
- CN202421351085.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-13
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-06-13
AI Technical Summary
When facing large ESD energy, the traditional ESD protection method has limited protection capabilities and is prone to damage the protection circuit and subsequent output buffer circuits, resulting in the IC that may burn.
An enhanced ESD protection circuit is designed, including an ESD path, a fuse circuit and a low voltage operating circuit. The fuse circuit monitors the ESD voltage in real time through the overvoltage detection circuit. When the ESD voltage exceeds the threshold, the fuse switch is turned off to protect the output buffer; the low-voltage working circuit absorbs the ESD voltage when the ESD voltage is less than the threshold.
It significantly enhances the anti-ESD protection capability, can achieve ESD protection capability of more than ±7KV, avoids circuit damage when ESD energy is too large, and ensures the safety of the IC.
Smart Images
Figure CN222655159U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of electronic component circuit protection, and in particular to an ESD protection circuit for enhancing a source driver. Background Art
[0002] The output buffer is the most important component of the source driver chip. Electrostatic discharge (ESD) occurs due to triboelectric charging (friction between materials) or electrostatic induction. When the ESD voltage difference is large enough, a huge current pulse will be generated, which can easily damage the device. Therefore, ESD protection is required. The ESD protection method provided by related technologies is to place an ESD protection circuit in the path where the ESD passes. See Figure 1 , absorbing ESD energy to protect the output buffer from ESD damage.
[0003] This type of ESD protection is limited by the capability of the protection circuit and cannot withstand too much ESD energy. Once the capability of the protection circuit is exceeded, it will not only damage the protection circuit, but also the output buffer circuit connected thereto, causing the IC to generate large current or even burn out, thus failing to achieve the purpose of effective protection. Summary of the invention
[0004] To this end, the present invention provides an ESD protection circuit for enhancing a source driver, aiming to solve the problem of limited protection capability in traditional ESD protection methods.
[0005] An embodiment of the present application provides an ESD protection circuit for enhancing a source driver, wherein the ESD protection circuit is coupled between an output buffer and a ground terminal, and includes: an ESD path, a fuse circuit, and a low-voltage working circuit; wherein the ESD path is used to receive an ESD voltage; the fuse circuit is arranged between the ESD path and the protection circuit, and includes a fuse switch and an overvoltage detection circuit, and is used to protect the output buffer; a low-voltage working circuit is connected in series between the fuse circuit and the output buffer, and is used to absorb the ESD voltage when the ESD voltage is less than a threshold value.
[0006] In some embodiments, the overvoltage detection circuit is used to detect the ESD voltage in real time, and when the ESD voltage is greater than or equal to a threshold, the fuse switch is controlled to be disconnected to protect the output buffer.
[0007] In some embodiments, the fuse switch includes a fuse and a fuse breaker, and the fuse is cut off by the fuse breaker to disconnect the fuse switch.
[0008] In some embodiments, the fuse is a metal wire.
[0009] In some embodiments, the overvoltage detection circuit includes: a comparator and a set of RC voltage divider circuits. When the voltage on the RC voltage divider circuit is greater than the voltage on the comparator, the comparator activates the fuse to cut off the fuse.
[0010] In some embodiments, the low-voltage working circuit includes: a first Schottky diode and a second Schottky diode connected in parallel, wherein one end of the first Schottky diode is coupled to the fuse circuit, and the other end is coupled to the ground end, and one end of the second Schottky diode is coupled to the fuse circuit, and the other end is coupled to the power supply end; the first Schottky diode and the second Schottky diode are used to absorb the ESD voltage when the ESD voltage is less than a threshold value.
[0011] In some embodiments, the other end of the output buffer is connected to a source driver output path for outputting the ESD voltage.
[0012] The ESD protection circuit provided by the present invention adds a fuse circuit. When the ESD energy reaches a certain level, the fuse will be disconnected to protect the subsequent circuits without affecting the output signal of the output buffer. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 It is a schematic diagram of an ESD protection circuit in the related art;
[0014] Figure 2 A schematic diagram of an ESD protection circuit provided in an embodiment of the present application;
[0015] Figure 3 A schematic diagram of a fuse circuit provided in an embodiment of the present application. DETAILED DESCRIPTION
[0016] The specific implementation of the present invention will be described in more detail below in conjunction with the schematic diagram. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.
[0017] The embodiment of the present application provides an ESD protection circuit for enhancing a source driver. Figure 2 For the ESD protection circuit diagram provided in the embodiment of the present application, refer to Figure 2 The ESD protection circuit 100 is coupled between an output buffer 140 and a ground terminal 150, and includes: an ESD path 110, a fuse circuit 120, and a low-voltage working circuit 130, wherein the ESD path 110 is used to receive an ESD voltage, such as an ESD voltage from an ESD access point 111.
[0018] The fuse circuit 120 is disposed between the ESD path 110 and the low voltage working circuit 130 to protect the output buffer 140. Figure 3 , is a schematic diagram of a fuse circuit 120, wherein the fuse circuit 120 includes a fuse switch 121 and an overvoltage detection circuit 122. The overvoltage detection circuit 122 is used to detect the ESD voltage in real time. When the ESD voltage is greater than or equal to a threshold value, the fuse switch 121 is controlled to be disconnected to protect the output buffer 140. The fuse switch circuit 121 includes a fuse 123 and a fuse 124. The fuse 123 is disconnected by cutting off the fuse 124 to disconnect the fuse switch 121. The fuse 123 is a metal wire. The overvoltage detection circuit 122 includes: a comparator 125 and a set of RC voltage divider circuits 126. When the voltage on the RC voltage divider circuit 126 is greater than the voltage on the comparator 125, the comparator 125 activates the fuse 124 to cut off the fuse 123. It is understandable that when the ESD voltage is less than the threshold, the overvoltage detection circuit 122 is not activated, and the current continues to flow to the low voltage working circuit 130 and the output buffer 140 .
[0019] The low voltage working circuit 130 is connected in series between the fuse circuit 120 and the output buffer 140, and is used to absorb the ESD voltage when the ESD voltage is less than a threshold value. The threshold value is the maximum carrying voltage of the low voltage working circuit 130. When the ESD voltage is lower than the maximum carrying voltage of the low voltage working circuit 130, the low voltage working circuit 130 absorbs the ESD voltage to protect the output buffer 140. The low voltage working circuit 130 includes: a first Schottky diode 131 and a second Schottky diode 132 connected in parallel, wherein one end of the first Schottky diode 131 is coupled to the fuse circuit, and the other end is coupled to the ground terminal, and one end of the second Schottky diode 132 is coupled to the fuse circuit, and the other end is coupled to the power supply terminal 160; the power supply terminal 160 here can be any one of VCC, VDD, AVCC, and AVDD.
[0020] The first Schottky diode 131 and the second Schottky diode 132 are used to absorb the ESD voltage when the ESD voltage is less than the threshold value to protect the subsequent circuit from being damaged. When the ESD voltage exceeds the maximum carrying voltage of the low-voltage working circuit 130, the overvoltage detection circuit 122 in the fuse circuit 120 controls the fuse switch 121 to be disconnected to protect the output buffer 140, while protecting the low-voltage working circuit 130 from being damaged by the overvoltage ESD voltage.
[0021] In the embodiment of the present application, the other end of the output buffer 140 is connected to a source driver output path 112 for outputting the ESD voltage.
[0022] The ESD protection circuit provided in the embodiment of the present application is provided with a fuse circuit. When the ESD voltage is not strong enough, the low-voltage working circuit is responsible for reducing the ESD energy and protecting the output buffer. When the ESD voltage exceeds the threshold of the low-voltage working circuit, the fuse circuit will be disconnected first to prevent the subsequent circuit from being damaged and generating a large current to burn the IC. The anti-ESD protection capability is significantly enhanced, and the ESD protection capability can reach more than ±7KV.
[0023] The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any technician familiar with the profession may make various changes, modifications, substitutions and variations to these embodiments without departing from the principle and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.
Claims
1. An ESD protection circuit for enhancing a source driver, characterized in that: The ESD protection circuit is coupled to the output buffer, and the ESD protection circuit includes: an ESD path, a fuse circuit, and a low-voltage working circuit; Wherein, the ESD path is used to receive the ESD voltage; The fuse circuit is arranged between the ESD path and the protection circuit, and includes a fuse switch and an overvoltage detection circuit, and is used to protect the output buffer; The low voltage working circuit is connected in series between the fuse circuit and the output buffer, and is used for absorbing the ESD voltage when the ESD voltage is less than a threshold value.
2. The ESD protection circuit according to claim 1, characterized in that: The overvoltage detection circuit is used to detect the ESD voltage in real time, and when the ESD voltage is greater than or equal to a threshold, the fuse switch is controlled to be disconnected to protect the output buffer.
3. The ESD protection circuit according to claim 2, characterized in that: The fuse switch comprises a fuse and a fuse, and the fuse is cut off by the fuse to disconnect the fuse switch.
4. The ESD protection circuit according to claim 3, characterized in that: The fuse is a metal wire.
5. The ESD protection circuit according to claim 4, characterized in that: The overvoltage detection circuit comprises: A comparator and a set of RC voltage divider circuits, when the voltage on the RC voltage divider circuit is greater than the voltage on the comparator, the comparator activates the fuse to cut off the fuse.
6. The ESD protection circuit according to claim 5, characterized in that: The low voltage working circuit comprises: A first Schottky diode and a second Schottky diode connected in parallel, wherein one end of the first Schottky diode is coupled to the fuse circuit and the other end is coupled to the ground terminal, and one end of the second Schottky diode is coupled to the fuse circuit and the other end is coupled to the power terminal; The first Schottky diode and the second Schottky diode are used to absorb the ESD voltage when the ESD voltage is less than a threshold value.
7. The ESD protection circuit according to claim 1, characterized in that: The other end of the output buffer is connected to a source driver output path for outputting the ESD voltage.