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PWM control circuit

A control circuit and chaotic circuit technology, applied in the direction of electrical components, output power conversion devices, etc., can solve the problems of limited and unexpanded suppression of EMI by frequency jitter, and achieve the effect of suppressing electromagnetic interference

Inactive Publication Date: 2011-09-07
杨汝
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the frequency shaking PWM can partially reduce the peak value of the PWM pulse power spectrum, it still obtains a discrete spectrum, and the energy is concentrated in the nf s ±kf m The specific frequency point at the center has not been fully expanded, and the effect of frequency jitter to suppress EMI is still limited, which often cannot meet people's requirements

Method used

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Embodiment

[0028] see figure 1 As shown, a PWM control circuit includes a PWM chip U1, and also includes a chaotic circuit for generating a chaotic signal, and the chaotic circuit is electrically connected to the crystal oscillator control terminal RI of the PWM chip U1. After the chaotic signal is generated, it is superimposed from the crystal oscillator control terminal of the PWM control chip to the internal constant current source of the chip, thereby generating a chaotic PWM operating frequency, making the chip work in a chaotic state, and reducing the EMI of the system.

[0029] The chaotic circuit includes a negative impedance circuit 102 , a filter circuit 101 , and a gyrator 103 electrically connected in sequence. The negative impedance circuit 102 is output to the crystal oscillator control terminal RI of the PWM chip U1 after impedance conversion by the gyrator 103 .

[0030] According to the nonlinear theory, an autonomous circuit can generate chaos and must meet three condit...

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PUM

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Abstract

The invention discloses a PWM control circuit which comprises a PWM chip and a chaotic circuit used for generating chaotic signals, wherein, the chaotic circuit is electrically connected with a crystal oscillator control end of the PWM chip. The chaotic circuit comprises a negative impedance circuit and a gyrator which are sequentially connected with each other, wherein, the negative impedance circuit is output into the crystal oscillator control end of the PWM chip after impedance conversion of the gyrator. After being generated, the chaotic signals are superimposed onto a constant flow source inside the chip from the crystal oscillator control end of the PWM chip, thus generating chaotic PWM working frequency, leading the chip to work in a chaotic state and reducing the EMI of the system. A chaotic PWM controller is different from conventional fixed-frequency PWM controller, and the PWM controller of the invention can fundamentally inhibit electromagnetic interference of a switch converter from the source.

Description

technical field [0001] The invention relates to the technical field of switching converters, in particular to a PWM control circuit based on chaos theory. Background technique [0002] Most of the existing EMI suppression measures for switching converters start from eliminating the coupling and radiation between the interference source and the disturbed equipment, and cutting off the propagation path of EMI. For example, using metal or polymer materials to shield the electromagnetic coupling radiation of the switching converter; using resistive, dielectric and magnetic dielectric absorbing materials to convert the electromagnetic radiation energy generated by the switching converter into other energies (mainly heat) and consume less energy. Dissipate; use various filters or use high power factor rectifiers to suppress the conduction electromagnetic interference of switching converters, and use grounding, floating, photoelectric coupling, and PCB board wiring technologies to ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M1/44
Inventor 杨汝
Owner 杨汝