Single inductance multi-output buck converter as well as control circuit and control method of single inductance multi-output buck converter

Abstract

The invention discloses a single inductance multi-output buck converter as well as a control circuit and a control method of the single inductance multi-output buck converter. The control method comprises the steps of comparing a first feedback signal with a first reference signal and generating a first comparing signal; comparing a second feedback signal with a second reference signal and generating a second comparing signal; if the appearance of the first comparing signal is earlier than that of the second comparing signal, conducting a first switch tube, disconnecting a second switch tube, conducting a third switch tube, disconnecting a fourth switch tube, and disconnecting the first switch tube and conducting the second switch tube when the conducting time of the first switch tube achieves a first time threshold value; if the appearance of the second comparing signal is earlier than the first comparing signal, conducting the first switch tube, disconnecting the second switch tube, disconnecting the third switch tube, conducting the fourth switch tube and disconnecting the first switch tube and conducting the second switch tube when the conducting time of the first switch tube achieves a second time threshold value.

Description

technical field [0001] Embodiments of the present invention relate to electronic circuits, and in particular to a single-inductance multi-output step-down converter and its control circuit and control method. Background technique [0002] Many systems, such as computer motherboards, require multiple bus voltages, such as 3.3V and 2V. The traditional approach is to use separate buck converters for each bus voltage, and each buck converter includes an integrated control circuit, two switching transistors, an inductor, an output capacitor, and other auxiliary components. These components, especially inductors, cost a lot. For this reason, people have been demanding a multi-output solution with a simpler structure and lower cost. Contents of the invention [0003] The technical problem to be solved by the invention is to provide a single-inductance multi-output step-down converter with simple structure and low cost, as well as its controller and control method. [0004] Acc...

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Problems solved by technology

These components, especially inductors, require significant cost

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