Method for preventing error programming of nonvolatile memory

Abstract

The invention discloses a method for preventing error programming of a nonvolatile memory, and belongs to the field of integrated circuits, the method comprises a DVDD domain monitoring module, the DVDD domain monitoring module works in an SAVDD voltage domain and stably monitors a DVDD in real time, and no matter whether the AVDD exists or not, when the DVDD is abnormal and exceeds the normal working voltage range of the DVDD domain monitoring module, the AVDD is forcibly closed. According to the invention, the DVDD domain is monitored in real time by adding the monitoring module for the DVDD domain, and the AVDD is forcibly closed when the DVDD domain is unstable, the unstable time reaches a certain length and mistaken programming is probably caused, so that the possibility of mistaken programming is effectively avoided.

Description

Technical Field

[0001] The invention relates to the field of integrated circuits, and in particular to a method for preventing a non-volatile memory from being mistakenly burned. Background Art

[0002] Chips are usually designed with non-volatile memories, such as OTP (One Time Programable) or EFUSE (Electrical Fuse Macro IP), to store some chip settings, which are used to configure different parameters and settings when the chip is initialized.

[0003] Non-volatile memory usually has a burn function, which requires burn control and burn / program voltage (hereinafter referred to as AVDD), such as Figure 1 In the existing design, AVDD comes from a pin or a power module. When AVDD comes from a power module, the power module has an AVDD control module that can selectively control AVDD to turn on or off; AVDD control / burning control may all belong to the core voltage (hereinafter referred to as DVDD) domain.

[0004] In the existing solution, when AVDD is stably powered and the voltage domain DVDD of the programming control circuit is unstable, the power-off sequence is uncertain during the power-off process and the power-off may be very slow. Figure 2 As shown in the figure, the programming control signal may be unstable, which may lead to the possibility of erroneous programming; or when AVDD is turned off (no power is supplied), but the voltage domain of the AVDD control circuit and the programming control circuit is unstable, such as Figure 3 As shown in the figure, the programming control signal is unstable, and the AVDD control signal is unstable, which makes AVDD open by mistake, resulting in the possibility of mis-programming. Mis-programming is fatal to the chip and can directly cause the chip to not work properly. Summary of the invention

[0005] The object of the present invention is to provide a method for preventing a non-volatile memory from being miswritten, so as to solve the problems in the background technology.

[0006] In order to solve the above technical problems, the present invention provides a method for preventing a non-volatile memory from being accidentally burned, comprising a DVDD domain monitoring module, The DVDD domain monitoring module works in the SAVDD voltage domain and stably monitors DVDD in real time. Regardless of whether AVDD exists, when DVDD is abnormal and exceeds the normal working voltage range of the control module, AVDD is forced to be turned off; wherein the control module includes AVDD control and burning control.

[0007] In one implementation, when DVDD is greater than a high threshold, or less than a low threshold, the DVDD domain monitoring module determines that the DVDD domain is abnormal and forces AVDD to be turned off; when the DVDD domain is normal, AVDD is independently controlled to be turned on or off through the AVDD control in the control module; AVDD is turned on only during normal burning, and is turned off when burning is not required.

[0008] In one implementation, the DVDD domain monitoring module has two high and low comparison thresholds, which cannot be equivalent to the thresholds of the monitoring function of the DVDD domain during the power-on and power-off processes; the burning process requires DVDD to give a stable value, and during the entire burning process, DVDD has up and down waveforms as the working process, and the highest value that appears is recorded as Vhigh, and the lowest value that appears is recorded as Vlow; the high threshold is greater than Vhigh and less than or equal to the maximum value of the normal operation of the circuit; the low threshold is less than Vlow and greater than or equal to the minimum value of the normal operation of the circuit.

[0009] In one embodiment, the DVDD domain monitoring module provides a glitch filtering function. When the abnormal time is short, AVDD is not turned off; when the abnormal time is long and greater than the dangerous time threshold, AVDD is turned off; the dangerous time threshold is configurable and less than the time of a burning operation.

[0010] In one embodiment, the DVDD domain monitoring module is a SAVDD voltage domain. Since AVDD is generated by SAVDD, when SAVDD is unstable, AVDD required for burning cannot be generated, and the possibility of erroneous burning will not occur. When SAVDD is stable, AVDD is protected by monitoring DVDD to avoid the possibility of erroneous burning caused by DVDD instability.

[0011] The present invention provides a method for preventing a non-volatile memory from being miswritten. By adding a monitoring module for a DVDD domain, the DVDD domain is monitored in real time. When the DVDD domain is unstable and the instability time reaches a certain length, and there is a probability of miswriting, the AVDD is forcibly turned off, thereby effectively eliminating the possibility of miswriting. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of non-volatile memory programming.

[0013] Figure 2 This is a schematic diagram of AVDD stable power supply.

[0014] Figure 3 This is a schematic diagram of AVDD not providing power.

[0015] Figure 4 It is a schematic diagram of a non-volatile memory including a DVDD domain monitoring module.

[0016] Figure 5 This is a schematic diagram of the DVDD domain monitoring module.

[0017] Figure 6 This is a schematic diagram of threshold selection. DETAILED DESCRIPTION

[0018] The following is a further detailed description of a method for preventing a non-volatile memory from being accidentally burned in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0019] By summarizing the characteristics of the two existing practices, it is found that when the voltage domain (such as the DVDD domain) where the control module is located is unstable, the control signal and the burning control signal that control whether AVDD is turned on are unstable. For example, in the process of powering off the DVDD domain, the power-off process is very slow. When the voltage is not enough for the combinational logic to work normally, it is impossible to ensure that the control signal sent to the power module and the non-volatile memory burning control signal are stable, so there is a probability of triggering the burning sequence, resulting in erroneous burning. Therefore, the present invention adds a DVDD domain monitoring module, which works in the SAVDD voltage domain. This DVDD domain monitoring module is not in the DVDD domain, and can stably detect DVDD. When DVDD is abnormal, such as exceeding the voltage range of normal operation of the control module (including AVDD control and burning control), AVDD is forced to be turned off. Regardless of whether AVDD exists at this time.

[0020] like Figure 4 As shown in the figure, a DVDD domain monitoring module of the SAVDD domain is added. This module will monitor the DVDD domain in real time. When DVDD is greater than the high threshold or less than the low threshold, the DVDD domain is judged to be abnormal and the AVDD will be forced to close. Figure 5 As shown. The DVDD domain monitoring module also provides a glitch filtering function. When the abnormal time is relatively short, AVDD can be left unattended. Only when the abnormal time is relatively long and greater than the dangerous time threshold, such as slightly less than the time of a programming operation, AVDD is turned off. When the DVDD domain is normal, AVDD can be independently controlled to be turned on or off through the AVDD control module. AVDD is turned on only during the normal programming process, and it is turned off when programming is not required.

[0021] like Figure 5 As shown, for the DVDD domain monitoring module, there will be two comparison thresholds, high and low. The selection of these two thresholds is relatively strict and cannot be equated with the thresholds of the monitoring function of the DVDD domain during the power-on and power-off processes, such as Figure 6 As shown, the burning process can stabilize DVDD to a value. During the entire burning process, DVDD will have up and down waveforms as the working process, and the highest value that appears is recorded as Vhigh, and the lowest value that appears is recorded as Vlow. The high threshold is greater than Vhigh, less than or equal to the maximum value of the normal working circuit; the low threshold is less than Vlow, greater than or equal to the minimum value of the normal working circuit. This selection can ensure that the burning process is carried out normally, and can also ensure that the control signal will not be unstable due to the instability of DVDD, resulting in erroneous burning.

[0022] The present invention adds a monitoring module for the DVDD domain to monitor DVDD in real time; the DVDD domain monitoring module has two thresholds, a high threshold and a low threshold. When DVDD is greater than the high threshold, or less than the low threshold, DVDD is considered abnormal. In addition, the DVDD domain monitoring module has a glitch filtering function. When the DVDD abnormal time is relatively short, it is not necessary to turn off AVDD. When the DVDD abnormal time is relatively long, such as approaching the duration of a complete burning process, AVDD will be forced to turn off, regardless of the state of AVDD at this time. The selection of the high threshold needs to be greater than the maximum value of DVDD in the entire burning process and needs to be less than the maximum value of the normal operation of the circuit. For example, the DVDD typical value * 110%; the selection of the low threshold needs to be less than the minimum value of DVDD in the entire burning process and needs to be greater than the minimum value of the normal operation of the circuit. For example, the DVDD typical value * 90%.

[0023] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for preventing a non-volatile memory from being accidentally burned, characterized in that: Including DVDD domain monitoring module, The DVDD domain monitoring module works in the SAVDD voltage domain and stably monitors DVDD in real time. Regardless of whether AVDD exists, when DVDD is abnormal and exceeds the normal working voltage range of the control module, AVDD is forced to be turned off; wherein the control module includes AVDD control and burning control.

2. The method for preventing a non-volatile memory from being accidentally burned as claimed in claim 1, characterized in that: When DVDD is greater than the high threshold or less than the low threshold, the DVDD domain monitoring module determines that the DVDD domain is abnormal and forces AVDD to be turned off; when the DVDD domain is normal, AVDD is independently controlled to be turned on or off through the AVDD control in the control module; AVDD is turned on only during the normal burning process, and is turned off when burning is not required.

3. The method for preventing a non-volatile memory from being accidentally burned as claimed in claim 1, characterized in that: The DVDD domain monitoring module has two comparison thresholds, high and low, which cannot be equated with the thresholds of the monitoring function of the DVDD domain during the power-on and power-off processes; the programming process requires DVDD to give a stable value, and during the entire programming process, DVDD has up and down waveforms as the working process, and the highest value that appears is recorded as Vhigh, and the lowest value that appears is recorded as Vlow; the high threshold is greater than Vhigh and less than or equal to the maximum value of the normal operation of the circuit; the low threshold is less than Vlow and greater than or equal to the minimum value of the normal operation of the circuit.

4. The method for preventing a non-volatile memory from being accidentally burned as claimed in claim 1, characterized in that: The DVDD domain monitoring module provides a glitch filtering function. When the abnormal time is short, AVDD is not turned off; when the abnormal time is long and greater than the dangerous time threshold, AVDD is turned off; the dangerous time threshold is configurable and less than the time of a programming operation.

5. The method for preventing a non-volatile memory from being accidentally burned as claimed in claim 1, characterized in that: The DVDD domain monitoring module is a SAVDD voltage domain. Since AVDD is generated by SAVDD, when SAVDD is unstable, AVDD required for burning cannot be generated, and there is no possibility of erroneous burning. When SAVDD is stable, AVDD is protected by monitoring DVDD to avoid the possibility of erroneous burning caused by DVDD instability.

Images