Breakage time control circuit of step-down circuit and step-down circuit
By designing an on-time control circuit in the buck circuit, using the combination of an operational amplifier, a ramp voltage generation circuit and a comparator to control the on-time of the main power tube, it solves the problem of fifth harmonics and higher harmonics in the existing technology that is difficult to meet the IEC61000-3-2 standard, and achieves smaller harmonic currents and better standard compliance.
CN222638170UActive Publication Date: 2025-03-18JOULWATT TECH INC LTD
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Patent Information
- Application Number
- CN202421173782.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-03-18
- Estimated Expiration
- 2034-05-27
AI Technical Summary
Technical Problem
In the constant on-time control scheme of the existing step-down circuit, it is difficult to meet the fifth harmonic and higher harmonic requirements in the IEC61000-3-2 standard.
Method used
An on-time control circuit is designed to control the on-time of the main power tube through a combination of an operational amplifier, a ramp voltage generation circuit and a comparator. The rate of change of the ramp voltage is proportional to the duty cycle, and the ramp voltage is generated through the integration circuit, which is used to compare and control the shutdown time of the main power tube.
Benefits of technology
This solution effectively reduces the fifth harmonic and higher harmonics of the system, making it easier to meet the requirements of IEC61000-3-2 standard.
✦ Generated by Eureka AI based on patent content.
Smart Images
Figure CN222638170U_ABST
Abstract
The utility model provides a turn-on time control circuit of a step-down circuit and the step-down circuit, which are used for performing error amplification on an output feedback signal and a reference signal to obtain a compensation voltage; generating a ramp voltage according to the duty ratio of the main power tube, wherein the change rate of the ramp voltage is in direct proportion to the duty ratio; and comparing the ramp voltage with the compensation voltage to control the turn-off moment of the main power tube. For the step-down circuit, the five-order and higher-order harmonic waves of the system can be reduced, and the international related standard can be met more easily.
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