Hysteresis comparator with programmable hysteresis width

Abstract

The invention discloses a hysteresis comparator with a programmable hysteresis width and an implementation method of hysteresis comparator. The hysteresis comparator comprises an input control logic, a hysteresis threshold value control logic, a positive and negative jumping threshold value selection logic, a mixed folding type cascode structure module and other modules. Under a test mode, the hysteresis comparator obtains the positive and negative jumping hysteresis capacity within a full reference voltage range via configuration of the hysteresis threshold value control logic and the positive and negative jumping threshold value selection logic; under a normal working mode, the hysteresis comparator selects the corresponding folding type cascode structures based on different reference voltages and configures corresponding hysteresis threshold values, so as to ensure that the hysteresis comparator realizes normal work within a rail-to-rail reference voltage range. The hysteresis comparator has the characteristics of hysteresis capacity testability, hysteresis width programmability, rail-to-rail reference voltage working range, high reference voltage generation module isolation degree, high interference resistance and the like, and is relatively high in use flexibility and applicable to the field of design of digital-analog interface chips.

Description

technical field [0001] The present invention mainly relates to the field of digital-analog hybrid circuit design, in particular to a hysteresis comparator structure with programmable hysteresis width. . Background technique [0002] As one of the common modules in the digital-analog hybrid integrated circuit, the comparator is widely used in the field of digital-analog interface chip design to deal with the comparison of various voltage or current signals, and its design directly affects the performance of the system. Therefore, in order to enhance the anti-interference ability of the comparator, the comparator is often designed as a hysteresis comparator. The hysteresis comparator mainly adopts the threshold voltage technology of changing the positive and negative transitions of the comparator's output to eliminate the output error transition caused by noise interference, and realize the correct response to the input signal with noise. This technology of changing the posi...

AI Technical Summary

Problems solved by technology

However, the condition for the above expression to hold is that Vin and Vref are equal. There is no problem when it is applied in a low-frequency or DC environment, but when Vin is a high-frequency signal, the hysteresis comparator requires a high gain of the op amp and has a very high gain. Bandwidth product, which is difficult to achieve in many cases, so the scope of use of this type of hysteresis comparator has great limitations;

[0010] In addition, since the positive and negative transition thresholds of the above-mentioned hysteresis comparator are related to the maximum and minimum values ​​of the resistors R1, R2, the output voltage, and the reference voltage, and the values ​​of R1 and R2 will affect the gain value of the hysteresis comparator, the hysteresis The ability is limited, and the hysteresis ability of this type of hysteresis comparator cannot be directly tested, which increases the unknown output result when used, and the comparator also shows the disadvantage of a narrow range of use

Images