Step-down switching power supply and control method thereof

Abstract

The invention discloses a step-down switching power supply and a control method thereof. By squaring an input voltage sampled signal, a waveform of average current inputted by a step-down circuit follows the input voltage, so that the harmonic component of input current of a step-down switching power supply is reduced, the THD (Total Harmonic Distortion) is lowered, and the power factor of the step-down switching power supply is improved.

Description

technical field

[0001] Embodiments of the present invention relate to electronic circuits, in particular, to a step-down switching power supply and a control method thereof. Background technique

[0002] Today, switching power supplies are widely used to power electronic devices. Generally, a switching power supply obtains an AC voltage from the power grid, converts the AC voltage into an uncontrolled DC voltage through a rectifier bridge, and then converts the uncontrolled DC voltage into a required signal through a switching circuit to drive a load.

[0003] However, with the widespread application of switching power supplies, more and more harmonic currents are injected into the grid. The generation of high-order harmonics increases the harmonic loss of electric energy, reduces the power factor of the system, and causes great harm to the power grid. It not only affects the quality of the power grid, but also has a great impact on the reliability of the power grid. In se...

Examples

Embodiment Construction

[0015] Specific embodiments of the present invention will be described in detail below, and it should be noted that the embodiments described here are only for illustration, not for limiting the present invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other instances, well-known circuits, materials or methods have not been described in detail in order to avoid obscuring the present invention.

[0016] Throughout this specification, reference to "one embodiment," "an embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in the present invention. In at least one embodiment. Thus, appearances of the phrases "in...

technical field

[0001] Embodiments of the present invention relate to electronic circuits, in particular, to a step-down switching power supply and a control method thereof. Background technique

[0002] Today, switching power supplies are widely used to power electronic devices. Generally, a switching power supply obtains an AC voltage from the power grid, converts the AC voltage into an uncontrolled DC voltage through a rectifier bridge, and then converts the uncontrolled DC voltage into a required signal through a switching circuit to drive a load.

[0003] However, with the widespread application of switching power supplies, more and more harmonic currents are injected into the grid. The generation of high-order harmonics increases the harmonic loss of electric energy, reduces the power factor of the system, and causes great harm to the power grid. It not only affects the quality of the power grid, but also has a great impact on the reliability of the power grid. In se...

Examples

Embodiment Construction

[0015] Specific embodiments of the present invention will be described in detail below, and it should be noted that the embodiments described here are only for illustration, not for limiting the present invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other instances, well-known circuits, materials or methods have not been described in detail in order to avoid obscuring the present invention.

[0016] Throughout this specification, reference to "one embodiment," "an embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in the present invention. In at least one embodiment. Thus, appearances of the phrases "in...

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