An Adaptive Off-time Generation Circuit for Boost Converter

Abstract

The invention relates to an adaptive off-time generating circuit suitable for a boost converter, which belongs to the technical field of electronic circuits. The voltage value at the positive input of the comparator introduces real duty cycle information, avoiding the influence of the load current on the frequency; the negative input of the comparator is connected to a fixed clock generator, when the voltage at the negative input of the comparator When the voltage at the positive input terminal of the comparator is touched, the output signal of the adaptive off-time generation circuit will output an upward pulse to change the switching signal, thereby controlling the boost converter to turn on. The present invention introduces real duty ratio information, avoids the influence of load current on frequency, stabilizes switching frequency, facilitates the processing of electromagnetic interference, and reduces design cost.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and in particular relates to an adaptive off-time (ACOT:adaptive constant-off-time) generating circuit suitable for a boost converter (boost). Background technique [0002] In recent years, with the rapid development of power electronics and electronic technology, boost converters are more widely used in the fields of computers, communications, industrial automation, electronics or electrical instruments. [0003] Traditional boost converters have two loop control modes, current mode and voltage mode. The advantage of current mode is that it has simpler loop compensation and higher linear regulation and load regulation. But on the other hand, because the current mode is very sensitive to noise, especially when the duty cycle is greater than 50%, there may be sub-harmonic oscillation, so slope compensation is generally required. Compared with the general peak current mode boost conver...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problem of insufficient stability caused by the change of the operating frequency of the boost converter system, the present invention provides an adaptive constant off-time generation circuit for the boost converter, which directly samples the information of the duty cycle, Ensure constant frequency under different duty cycles, which is beneficial to the treatment of electromagnetic interference EMI, reduces design cost, and avoids the influence of load current on frequency

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