Power Type EMI Suppression Filter

Abstract

The invention discloses a power supply type electromagnetical interference suppression filter. The power supply type electromagnetical interference suppression filter is electrically coupled between a power supply line of a master chip and a load terminal; after the master chip is powered by the power supply line, an output voltage noise and an output current noise are generated due to operation of the internal circuit of the master chip; under resonance influence of the power supply noise, phase difference exists between the output voltage noise and the output current noise. The electromagnetical interference suppression filter comprises a level reference circuit and at least one filtering modulation circuit connected with the level reference circuit in parallel, wherein the level reference circuit generates a level reference signal according to the output voltage noise or the output current noise of the master chip; the at least one filtering modulation circuit calculates the voltage and current characteristic vector values according to the level reference signal to control the strength and the phase difference between the output voltage noise and the output current noise to be gradually close to zero. Therefore, a signal received by the load terminal can be regulated into a DC signal of which noise is filtered.

Description

technical field [0001] The invention relates to an electromagnetic interference suppression filter; in particular, it relates to a suppression filter for solving electromagnetic interference generated at a power supply end. Background technique [0002] The design of printed circuit board (PCB) based on electronic products is faced with the transmission of many signals, and the superposition of various resonance (harmonic) frequencies, not only affects the quality of the signal, but also causes interference between signals . In addition to the above problems, the culprit of the interference signal is also one of the main problems that is coupled with complex resonance frequency waves at the power supply end. The source of these frequency waves is mainly from the operation of the internal circuit of the main functional integrated circuit chip (main functional IC). Here, these resonance waves are the main source of electromagnetic interference (electromagnetic interference) i...

AI Technical Summary

Problems solved by technology

But this has become quite difficult in today's fine division of labor

In order to achieve such co-simulation (co-simulation) design, it is difficult for system designers to obtain complete information on chip characteristics, and chip designers can only design their signal characteristics to obtain better results. Analysis of the characteristics of the system, and the relative mastery of the problems connected to the system is not high

The characteristic part of the resonant frequency noise of the power supply, whether it is the system design side or the chip design side, is an unknown and unsolvable problem. At most, it can only be avoided in the setting of the logic circuit in the main chip.

In addition, under the fierce price competition of many electronic products, the design of circuit substrates is reduced from six-layer boards to four-layer boards, and four-layer boards are reduced to two-layer boards. In this case, the power integrity (PI) The design is even more difficult, and the existing filter components are obviously not suitable for use. Therefore, most of the current solutions in the industry to deal with the noise and EMI problems on the power supply end can only use the relatively low efficiency of trial and error (try and error). error) way, quite uneconomical and cost-effective

[0004] Furthermore, because the EMI problem at the power supply terminal mainly occurs, the resonant noise of the power supply at a certain frequency is coupled with other noise waves, causing the small voltage signal and current small signal at this frequency to not proceed synchronously in most states , and after the voltage noise passes through the single-path capacitor, the phase of the current noise cannot be completely coupled out, or even worse, there will be a serious problem such as the peak to the trough of the signal

Such a combined current not only causes the power supply path passing through this node to other positions on the circuit substrate, but also produces the characteristics of parasitic inductance effect on the wire, which seriously affects the chain reaction of voltage characteristic changes.

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