CN203398984U - Filtering structure reducing ripples of power supply - Google Patents

Abstract

The utility model relates to a filtering structure reducing ripples of a power supply. The filtering structure comprises a pi-shaped filter for filtering output of the power supply, wherein the pi-shaped filter includes a printed circuit board (PCB) printed inductor, and the PCB printed inductor is formed by successively connecting multiple U-shaped or S-shaped wires. The filtering structure reduces output ripples of the power supply; solves the problems that high ripple voltage may cause harmonic waves and modulation of electronic products, that normal work state is interfered, that efficiency of the power supply is reduced, that logic relation of digital circuits is influenced, and that normal signal transmission is interfered; and reduces the risk that surge voltage or current generated by the strong ripples burns out an electric appliance.

Description

A kind of filter structure that reduces power supply ripple

Technical field

The utility model relates to filter structure.

Background technology

In electronic product, conventional power supply mainly contains linear power supply and the large class of Switching Power Supply two, and the direct voltage of output is a fixed value, by alternating voltage, after rectification, filtering, voltage stabilizing, is obtained.Because filtering is unclean, in direct voltage, contain alternating component, this has just produced ripple.Ripple is a kind of noise signal of complexity, and it is the cyclical signal fluctuating back and forth up and down around output dc voltage, but cycle and amplitude are not definite values, become in time, and the ripple waveform of different electrical power is different.Switching Power Supply switching tube is in conducting and cut-off at present, have a rising and falling time, the noise that at this time just there will be the identical or odd number frequency multiplication of frequency with the switch rise and fall time in circuit, be generally tens KHz, signal is by the transformer coupled power supply outlet side that arrives, if ripple voltage height, likely makes electronic product produce harmonic wave, modulation etc., disturb normal operating state; Cause power-efficient to reduce; Affect the logical relation of digital circuit; Normal delivery of interference signal etc.Stronger ripple can produce surge voltage or electric current, likely burns power consumption equipment.

Current power supply output filtering, adopt traditional CLC structure (as shown in Figure 1), be pi type filter, C is the electric capacity of capacitor, and L is the inductance of inductance coil, utilize inductive impedance characteristic to suppress frequency electromagnetic waves, direct current is formed to path, utilize the logical characteristic exchanging of large bulk capacitance stopping direct current, high-frequency pulse is filtered, make the level and smooth and stable of electric power outputting current change, close to steady direct current.Adopt this kind of filtering mode, cost is higher, and volume is bigger than normal.

Utility model content

The purpose of this utility model is to propose a kind of filter structure that reduces power supply ripple, and it can high, the bulky problem of workout cost.

In order to achieve the above object, the technical scheme that the utility model adopts is as follows:

Reduce a filter structure for power supply ripple, it comprises the pi type filter for power supply output filtering, and the inductance of pi type filter is PCB printed inductor.

Preferably, described PCB printed inductor is connected and composed successively by a plurality of U font lines or S font line.

The utlity model has following beneficial effect:

Reduce power supply output ripple, solved ripple voltage high, likely make electronic product produce harmonic wave, modulation, the normal operating state of interference, power-efficient to reduce, affect the logical relation of digital circuit, the problems such as normal delivery of interference signal, surge voltage or electric current that stronger ripple produces have been reduced, the risk of burning power consumption equipment.

The utility model can be applicable in power supply adaptor, charger product and other electronic products that contains speed-sensitive switch, can also dwindle small product size, reduce product cost, increase PCBA reliability, reduce the possibility of the disconnected pin of element, and then improved product competitiveness.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of the filter structure of prior art;

Fig. 2 is the induction structure schematic diagram of filter structure of the reduction power supply ripple of the utility model embodiment mono-;

Fig. 3 is the induction structure schematic diagram of filter structure of the reduction power supply ripple of the utility model embodiment bis-.

Embodiment

Below, by reference to the accompanying drawings and embodiment, the utility model is described further.

Embodiment mono-

As shown in Figure 2, a kind of filter structure that reduces power supply ripple, it comprises the pi type filter for power supply output filtering, the inductance of pi type filter is PCB printed inductor.

Described PCB printed inductor is connected and composed successively by a plurality of U font lines, adopts U-shaped wire laying mode.

Shown in Fig. 1, in fact, the present embodiment replaces with PCB printed inductor by the plug-in unit inductance L 1 of traditional pi type filter, utilize PCB printed inductor impedance operator to suppress frequency electromagnetic waves, direct current is formed to path, utilize the logical characteristic exchanging of large bulk capacitance stopping direct current, high-frequency pulse is filtered, make the level and smooth and stable of electric power outputting current change, close to steady direct current.PCB printed inductor is relevant with track lengths and deposited copper thickness irrelevant, and the angle of wiring is adjusted folding degree radius R size according to actual space.

PCB printed inductor computing formula is:

$L=2l\×(\ln \frac{2l}{W}+0.5+0.2235\frac{W}{l})\mathrm{nH}$

Wherein, W is trace width, and l is track lengths.

Embodiment bis-

The present embodiment is only that from the difference of embodiment mono-wire laying mode of PCB printed inductor is different.As shown in Figure 3, the PCB printed inductor of the present embodiment is connected and composed successively by a plurality of S font lines, adopts S type wire laying mode.

In addition, can also adopt fold-type wire laying mode to realize PCB printed inductor.

Generally speaking, in fact the utility model, is on pcb board, adopts fold-type wire laying mode, U-shaped wire laying mode or S type wire laying mode, an integrated inductance L on pcb board.

For a person skilled in the art, can make other various corresponding changes and distortion according to technical scheme described above and design, and these all changes and distortion all should belong to the protection range of the utility model claim within.

Claims (2)

1. reduce a filter structure for power supply ripple, it comprises for the pi type filter of power supply output filtering, it is characterized in that, the inductance of pi type filter is PCB printed inductor.

2. the filter structure of reduction power supply ripple as claimed in claim 1, is characterized in that, described PCB printed inductor is connected and composed successively by a plurality of U font lines or S font line.

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