Method for generating PWM signal through oscillation

Abstract

The invention discloses a method for generating a PWM signal through oscillation. The method comprises the following steps: constructing a hysteresis comparator in a PWM signal control system, whereinthe hysteresis comparator comprises an input and an output and internally contains a high triggering threshold value and a low triggering threshold value, and a high level and a low level are outputby comparing an input value with the threshold values; constructing a first-order system module, a transitional time constant of which is T; connecting the hysteresis comparator with the first-order system module in a feedback form to form oscillation. An output mode of the PWM signal generated by the method has no time delay, and the duration of the high level or the low level can be prolonged orshortened by changing the high threshold value and the low threshold value at any moment, so as to change a duty ratio of the output PWM signal. A transitional process of a first-order system is independent of the total time, but only depends on a calculation interval; furthermore, an exponent operation part of the first-order system can be completed in advance for direct use, so that the operation efficiency is greatly improved.

Description

technical field [0001] The invention relates to a method for generating a PWM signal through oscillation, and belongs to the technical field of controller output control. Background technique [0002] In the field of controllers, most of the controlled objects are analog signals. Although the signal can be controlled by analog, it is not a very good control method. The analog circuit tends to drift with time, so it is difficult to adjust, and it is also particularly sensitive to noise. Any disturbance may have a large impact on the output. Impact. However, if the analog signal is controlled in a digital way, the above problems can be solved, and it is more convenient for the realization of the microprocessor. Pulse Width Modulation is a very effective technique for controlling analog circuits using the digital output of a microprocessor. It is widely used in many fields from measurement, communication to power control and conversion. [0003] PWM is a method of digitally ...

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Problems solved by technology

Therefore, this output method will cause a great delay for the scene with slow PWM signal frequency, and it cannot meet the requirements for the system that needs fast response.

[0013] It can be seen from the above description that for the current PWM output mode, the output of the control signal cannot be synchronized with the control period of the controller, but the control period is fast, the output of the

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