Current-mode control method to eliminate current dead zone of buck-type converter

Abstract

The invention relates to the field of power management and integrated circuit design, and aims to eliminate the current dead zones and substantially improve performance of an integrated circuit on the basis of maintaining the inherent advantages of the Buck type topology. According to a current mode control method for eliminating current dead zones of a Buck type converter, based on the Buck type converter, a switch tube is additionally arranged on an output node and called a secondary switch Q2, an original switch is called a master switch Q1, the secondary switch Q2 is used for enabling the output end to be in a short circuit state within a time range when the input voltages are lower than output voltages, and therefore inductive currents can change continuously. Specifically, the alternating input end of a circuit is connected with a rectifier bridge formed by four diodes, and a voltage distribution structure formed by connecting in series two resistors is connected in parallel behind the rectifier bridge. The current mode control method is mainly applied to power management and integrated circuit deign.

Description

technical field [0001] The invention relates to the field of power management and integrated circuit design, in particular to the research of power factor correction circuit and the design modeling of its controller. Specifically, it relates to a current-mode control device for eliminating the current dead zone of a Buck-type converter. technical background [0002] Currently, out of energy and environmental considerations, the power supply industry has set a series of standards. For example: the IEC91000-3-2 standard is used to limit harmonic currents; the EU Code of Conduct (CoC) stipulates the average efficiency of external power supplies under 25%, 50%, 75% and 100% full load conditions. A power factor converter (PFC) is beneficial to improve the overall performance of a switching power supply circuit. Therefore, it is very necessary to apply power factor correction technology for current correction in AC / DC (AC / DC) converters. [0003] Currently, Boost PFC is the mos...

AI Technical Summary

Problems solved by technology

However, since the Buck topology has zero current when the input voltage is lower than the output voltage, this topology cannot always obtain a high power factor when used as a PFC converter.

In addition to this, this current deadband increases total harmonic crosstalk (THD)

[0006] In the traditional Buck topology, the switch tube is not turned on when the input voltage is lower than the output voltage. Therefore, the Buck topology has many advantages that other topologies do not have, but it is still rarely used in AC-DC converters.

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