PWM signal generator circuit

Abstract

The invention relates to the technical field of PWM signal generator circuits, in particular to a PWM signal generator circuit which comprises a triangular wave generator circuit, a direct-current voltage generator circuit and a comparison circuit, wherein the direct-current voltage generator circuit is electrically connected with the triangular wave generator circuit and the comparison circuit, and the comparison circuit is electrically connected with an external push-pull circuit. The push-pull circuit is electrically connected with an external BUCK step-down circuit. A PWM signal is generated through arranging the triangular wave signal generator circuit and the direct-current voltage generator circuit and through the comparison circuit for controlling the switch tube, and therefore theduty ratio of the system is slowly increased in the starting process of the system. In the power-down process of the system, the output duty ratio is slowly decreased; in the whole process from system startup and normal work to system power failure, the output duty ratio is not higher than 45%, so that the safety and reliability of the system are fundamentally ensured.

Description

technical field [0001] The invention relates to the technical field of PWM signal generator circuits, in particular to a PWM signal generator circuit. Background technique [0002] Nowadays, with the rapid development of the electronic industry, electronic products are developing towards miniaturization, convenience and high reliability; to meet these application requirements, the power conversion part involved in the product needs to have higher and higher switching frequencies, As we know, with the increase of the switching frequency, the size of the power inductor or transformer can be greatly reduced, so as to meet the needs of product miniaturization; however, with the increase of the switching frequency, problems such as EMI and output overshoot are also Then, in order to solve the EMI problem, the method of increasing shielding or isolation and dredging is generally adopted. In order to solve the problem of output overshoot, the feedback system of the system needs to ...

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Problems solved by technology

[0003] Existing technologies are generally processed during signal transmission or reception; these technologies will increase the complexity of the system in practical applications, which is not conducive to the mainstream trend of product miniaturization and higher cost performance; in traditional design schemes, comes out often Image 6 In the situation shown, that is, during the system startup process and power-off process, there will be a phenomenon that the duty cycle is greater than 45%, which will cause components such as MOS tubes and inductors to be burned due to overcurrent. Therefore, the traditional solution is used in actual product applications. There may be greater risks, especially in high-pressure systems, which are prone to bombing

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