Nondestructive inductor current detection circuit applicable to high-frequency step-down type voltage converter

Abstract

The invention belongs to the technical field of integrated circuit design, and particularly discloses a nondestructive inductor current detection circuit applicable to a high-frequency step-down type voltage converter. Circuits of the high-frequency step-down type voltage converter consist of a power-level circuit and a control-level circuit. The nondestructive inductor current detection circuit comprises a four-input operational amplifier OP, four voltage division resistors Rf1, Rf2, Rf3 and Rf4 and an integrated element consisting of three pairs of Rc and Cc, and is used for detecting current flowing through an inductor L. In the circuit, corresponding inductor current information is obtained by integrating voltage at the two ends of the inductor in the switching step-down type voltage converter, so that nondestructive detection of the inductor current is realized. Compared with the conventional current detection circuit, the circuit has the advantages of realizing no additional power consumption in the high-frequency step-down type voltage converter and low-cost inductor current detection and making the conventional current control method possible to be applied to high switching frequency.

Description

Technical field [0001] The invention belongs to the technical field of integrated circuit design, and specifically relates to a lossless inductor current detection circuit for a high-frequency step-down voltage converter. technical background [0002] In today's consumer electronics market, battery-powered portable devices such as smart phones, tablets, MP3, etc. are playing an increasingly important role in people's lives. Due to the continuous development of integrated circuit technology along with Moore's Law, the driving voltage of the MOS tube also continues to decrease in order to reduce the power density and other issues. However, the battery voltage of the power supply does not drop accordingly. Therefore, as a step-down voltage converter that converts a high voltage to a low voltage, it has become the most widely used power converter in portable devices. As the switching frequency is increased, under the same output ripple, the inductance and capacitance that need to be...

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Problems solved by technology

However, when this control method is applied to a high-frequency step-down voltage converter, due to the increase in switching frequency, it becomes more and more difficult to detect the necessary inductor current, and the performance requirements for components such as operational amplifiers are also getting higher and higher. It directly leads to the increase of current detection cost and power consumption, which limits the application of this control method in high-frequency step-down voltage converters

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