TWI416926B - Demagnetization circuit of electrical device - Google Patents

Abstract

The present invention relates to a demagnetization circuit of an electrical device. The demagnetization circuit includes a wave filter and a VF displaying circuit. The wave filter includes a first input terminal and a first output terminal. The VF displaying circuit includes a VF displayer having a first signal receiving terminal and a second signal receiving terminal. The demagnetization circuit includes a magnetic field producing circuit including a third input terminal and a third output terminal, and a coil assembly. The coil assembly includes a first coil, a second coil, a first connecting terminal and a second connecting terminal. The third input terminal is coupled with first output terminal of the wave filter, the first connecting terminal and the first signal receiving terminal. The second connecting terminal of the coil assembly is coupled with the third output terminal of the magnetic field producing circuit. The third output terminal of the magnetic field producing circuit is coupled with the second signal receiving terminal of the VF displayer.

Description

Degaussing circuit of electronic device

The invention relates to a degaussing circuit for an electronic device.

With the rapid development of mobile communication technology, mobile phones have been rapidly developed and popularized around the world. The development and popularization of mobile phones have greatly facilitated people's lives. For the average person, the phone does bring great convenience to them. However, there are still some hearing-impaired people in our lives. They must wear hearing aids to achieve normal human hearing.

However, some hearing aid wearers cannot directly answer the phone. This is because when the hearing aid wearer puts the mobile phone on the head to answer the phone, a magnetic field is generated around the mobile phone itself. If the magnetic field is too strong, interference noise will be generated in the hearing aid, thereby affecting the hearing aid wearer to answer the mobile phone normally.

In view of the above, it is necessary to provide a degaussing circuit for an electronic device that can reduce magnetic field interference.

A degaussing circuit for an electronic device includes a filter and an audio playback circuit, the filter including a first input end, a first output end, and a second output end. The audio playback circuit includes an audio player, and the audio player includes a first signal end and a second signal end. The first signal end and the second signal end are respectively used for receiving signals to drive the audio player to make a sound. The degaussing circuit of the electronic device further includes a magnetic field generating circuit, the magnetic field generating circuit includes a third input end, a third output end, a coil set, a first resistor, a second resistor, a first chip resistor, and a Second chip resistor, a fourth input terminal and a fourth output terminal. The coil set includes a first coil, a second coil, a first connecting end and a second connecting end, the first coil and the second coil being wound in the same direction and arranged in parallel. The first coil is connected between the first connection end and the second connection end. The second coil is connected between the first connection end and the second chip resistor. The third input end is respectively connected to the first output end of the filter, the first connection end of the coil set, and the first signal end of the audio player. The fourth input is respectively connected to the first output end of the filter and the second connection end of the coil set. The first resistor is connected between the third input end and the first connection end. The second resistor is connected between the second connection end and the third output end, the first chip resistor is connected between the fourth input end and the second connection end, and the second chip resistor is connected to the second coil group Between the fourth output and the fourth output.

Compared with the prior art, the degaussing circuit of the electronic device uses the energized coil set of the magnetic field generating circuit to generate a magnetic field opposite to the direction of the magnetic field generated by the electronic device itself, and the two opposing magnetic fields cancel each other to achieve the purpose of degaussing.

The invention will be further described in detail below with reference to the accompanying drawings.

FIG. 1 is a degaussing circuit 100 for an electronic device according to a preferred embodiment of the present invention for reducing magnetic field interference for an electronic device. In this embodiment, the electronic device takes a mobile phone as an example. In practical applications, it can also be a radio, a walkie-talkie, and the like. The degaussing circuit 100 of the electronic device includes a filter 10 electrically connected in sequence, a high frequency filter circuit 20, a magnetic field generating circuit 30, and an audio playing circuit 40.

The filter 10 includes a first input terminal I1 and a second input terminal I2. A first output terminal O1, a second output terminal O2 and a ground terminal. In this embodiment, the filter 10 is a band pass filter whose passband is the same as the audio response range, that is, 20HZ-20KHZ.

The high frequency filter circuit 20 includes a first capacitor C1 and a second capacitor C2. The first capacitor C1 is connected at one end to the first output terminal O1 of the filter 10, and the other end is grounded to form a loop. The second capacitor C2 has one end connected to the second input terminal I2 of the filter 10 and the other end grounded to form a loop. The high frequency filter circuit 20 is configured to filter out high frequency interference signals.

The magnetic field generating circuit 30 includes a first chip resistor R11, a second chip resistor R12, a third input terminal I3, a third output terminal O3, a fourth input terminal I4, and a fourth output terminal O4. The first resistor R1, a coil group L and a second resistor R2. The coil group L includes a first coil L1, a second coil L2, a first connecting end 31 and a second connecting end 32. The fourth input terminal I4 and the fourth output terminal O4 are respectively connected to the first capacitor C1 and the second capacitor C2. The first resistor R1 is connected between the first connection end 31 and the third input end I3. The second resistor R2 is connected between the second connection end 32 and the third output end O3. The first chip resistor R11 is connected between the first capacitor C1 and the second connection end 32. The second chip resistor R12 is connected between the first resistor R1 and the fourth output terminal O4. The resistance of the first chip resistor R11 is much smaller than the resistance of the first resistor R1, and the resistance of the second chip resistor R12 is much smaller than the resistance of the second resistor R2. In this embodiment, the first coil L1 and the second coil L2 are arranged in the same direction and in parallel, the first coil L1 is connected between the first resistor R1 and the second resistor R2, and the second coil L2 is connected to the first The resistor R1 is between the second chip resistor R12.

In this embodiment, the audio playback circuit 40 includes a first voltage dividing resistor R3, a second voltage dividing resistor R4, and an audio player 41. The audio player 41 includes a first signal end 42 and a second signal end 43. The third input terminal I3 of the magnetic field generating circuit 30 is connected to the first signal terminal 42 via the first voltage dividing resistor R3. The third output terminal O3 is connected to the second signal terminal 43 via the second voltage dividing resistor R4.

When the first chip resistor R11 and the second chip resistor R12 are both disconnected, the first input terminal I1 of the filter 10 receives an audio signal S1, and after being filtered by the filter 10, is output from the first output terminal O1. The high frequency filtering is performed on the first capacitor C1, the high frequency interference signal is filtered out, and then shunted at the third input terminal I3, and the first voltage dividing resistor R3 is input to the first signal terminal 42 of the audio player 41 to drive the audio. The player 41 emits a sound; the other path is input to the first connection end 31 of the coil group L via the first resistor R1, and the signal passes through the first coil L1 and then passes through the second resistor R2, the third output terminal O3, and the fourth output terminal O4. The second capacitor C2 is input to the second output terminal I2 of the filter 10 to form a signal loop or is input to another circuit or processing chip (not shown) via the second output terminal O2 of the filter 10 for further processing. At this time, the signal is output from the third input terminal I3 through the first resistor R1 through the first coil L1 and through the third output terminal O3, and the first coil L1 of the coil group L generates a magnetic field in one direction.

When the first chip resistor R11 and the second chip resistor R12 are both turned on, the audio signal S1 is filtered by the filter 10, and then output to the first capacitor C1 through the first output terminal O1 for high-frequency filtering. The fourth input terminal I4 of the magnetic field generating circuit 30 is input to the second connecting end 32 and shunted at the second connecting end 32, and the second circuit is connected to the third output terminal O3 via the second resistor R2. The voltage dividing resistor R4 is input to the second signal terminal 43 of the audio player 41 to drive the audio player 41 to emit sound, and the other circuit is input to the coil group L, and the signal is input from the first coil L1 through the first connecting end 31 to the first The second coil L2 is further input to the second output terminal I2 of the filter 10 via the second chip resistor R12, the fourth output terminal O4 and the second capacitor C2 to form a signal loop or the second output terminal O2 of the filtered 10 input. Go to other circuits or process wafers (not shown) for further processing. At this time, since the signal flows from the fourth input terminal I4 through the first coil L1 and then through the second coil L2 to the second chip resistor R12, it is output through the fourth output terminal O4. At this time, the first coil L1 and the second coil L2 respectively generate a magnetic field in the opposite direction. Therefore there will be a magnetic field.

Before the phone is produced, it needs to be tested first. First, the third input terminal I3, the fourth input terminal I4, the third output terminal O3, and the fourth output terminal O4 are disconnected, the mobile phone is answered, and the magnetic field strength of the mobile phone in the receiving state is tested and recorded. Assume that at this time, the recorded magnetic field strength is 100 Gauss.

In the first case, the third input terminal I3 is connected to the third input terminal O3, and the mobile phone is received. The signal is output from the third input terminal I3 via the first coil L1 and then through the second resistor R2 via the third output terminal O3. A coil L1 also generates a magnetic field in one direction. Assuming that the magnetic field intensity recorded at this time is 120 Gauss, the magnetic field intensity generated by the first coil L1 tested at this time is 20 Gauss and is the same as the direction of the magnetic field generated by the mobile phone itself. The magnetic field generated by itself and the combined magnetic field generated by the first coil L1 at this time are 120 Gauss, which increases with respect to the previously recorded magnetic field strength. Assuming a magnetic field strength of 90 gauss will interfere with other electronic devices, which will increase noise interference with some electronic devices, such as hearing aids.

In the second case, the fourth input terminal I4 and the fourth output terminal O4, the first chip resistor R11 and the second chip resistor R12 are both turned on, and the signal passes from the fourth input terminal I4 through the first chip resistor R11. The first coil L1 is further outputted through the first connection end 31 to the second coil L2, and then through the second chip resistor R12 to the fourth output terminal O4. Since the current direction through the first coil L1 is opposite to the current direction in the first case test, the magnetic field strength generated by the first coil L1 is 20 Gauss, and the direction is opposite to the direction of the magnetic field tested in the first case. At this time, the magnetic field generated by the mobile phone itself and the magnetic field generated by the first coil L1 are 80 Gauss. Because at this time, the magnetic field generated by the second coil L2 is the same as the direction of the magnetic field generated by the mobile phone itself, which will enhance the interference. By the formula: H = NI / L (where H is the magnetic field strength, N is the number of turns of the coil, I is the current on the coil, L is the length of the coil winding), it can be concluded that the number of turns of the coil of the second coil L2 can be changed Or the length of the winding to control the strength of the magnetic field generated by the second coil L2. At this time, the magnetic field intensity generated by the second coil L2 should be controlled to be 10 gauss or less.

In the third case, the third input terminal I3 is first connected to the third input terminal O3, and the mobile phone is received. The signal is output from the third input terminal I3 via the first coil L1 and then through the second resistor R2 via the third output terminal O3. The first coil group L1 generates a magnetic field of one direction and the magnetic field strength is 20 Gauss. Assuming that the magnetic field strength recorded at this time is 80 Gauss, the combined magnetic field of the test is weakened relative to the magnetic field strength recorded in the first case. Thereafter, the fourth input terminal I4 and the fourth output terminal O4, the first chip resistor R11 and the second chip resistor R12 are both turned on, and the signal is sent from the fourth input terminal I4 through the first chip resistor R11, first. The coil L1 passes through the first connection end 31 to the second coil L2, and then passes through the second chip resistor R12 to the first Four output O4 output. Since the current direction through the first coil L1 is the same as the current direction in the first case test, the first coil L1 generates the same magnetic field direction as in the first case and the magnetic field strength is also 20 Gauss. At this time, the magnetic field generated by the mobile phone itself and the magnetic field generated by the first coil L1 are 120 Gauss. Because at this time, the magnetic field of the second coil L2 after the birth is opposite to the direction of the magnetic field generated by the mobile phone itself, which will reduce the interference. By the formula: H = NI / L (where H is the magnetic field strength, N is the number of turns of the coil, I is the current on the coil, L is the length of the coil winding), it can be concluded that the number of turns of the coil of the second coil L2 can be changed Or the length of the winding to control the strength of the magnetic field generated by the second coil L2. At this time, the magnetic field intensity generated by the second coil L2 should be controlled between 30-120 Gauss, so that the magnetic field strength generated between the magnetic field generated by the mobile phone answering the telephone itself and the coil group L is controlled below 90 Gauss. Thereby avoiding interference with other electronic devices.

The degaussing circuit of the electronic device utilizes a magnetic field generated by the energized coil group of the magnetic field generating circuit and a magnetic field opposite to the direction of the magnetic field generated by the electronic device itself, and the two opposing magnetic fields cancel each other to achieve the purpose of degaussing.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

Degaussing circuit ‧‧100

Filter ‧‧10

High frequency filter circuit ‧‧20

Magnetic field generating circuit ‧‧30

Audio playback circuit ‧‧40

Coil set ‧‧‧L

First coil ‧‧‧L1

Second coil ‧‧‧L2

First patch resistor ‧‧‧R11

Second patch resistor ‧‧‧R12

Third output ‧‧‧O3

Fourth output ‧‧‧O4

First connection ‧‧31

Second connection ‧‧‧32

Audio player ‧‧41

First signal end ‧‧‧42

Second signal end ‧‧43

First resistance ‧‧‧R1

Second resistance ‧‧‧R2

First voltage divider resistor ‧‧‧R3

Second voltage divider resistor ‧‧‧R4

1 is a circuit diagram of a degaussing circuit of an electronic device provided by a preferred embodiment of the present invention.

Degaussing circuit ‧‧100

Filter ‧‧10

High frequency filter circuit ‧‧20

Magnetic field generating circuit ‧‧30

Audio playback circuit ‧‧40

Coil set ‧‧‧L

First coil ‧‧‧L1

Second coil ‧‧‧L2

First patch resistor ‧‧‧R11

Second patch resistor ‧‧‧R12

Third output ‧‧‧O3

Fourth output ‧‧‧O4

First connection ‧‧31

Second connection ‧‧‧32

Audio player ‧‧41

First signal end ‧‧‧42

Second signal end ‧‧43

First resistance ‧‧‧R1

Second resistance ‧‧‧R2

First voltage divider resistor ‧‧‧R3

Second voltage divider resistor ‧‧‧R4

Claims (6)

A degaussing circuit for an electronic device, comprising: a filter and an audio playing circuit, the filter comprising a first input end, a first output end and a second output end, the audio playing circuit comprising an audio player, the audio playing The device includes a first signal end and a second signal end, wherein the first signal end and the second signal end are respectively used for receiving signals to drive the audio player to make an audible sound. The improvement is that the degaussing circuit of the electronic device further comprises a a magnetic field generating circuit, the magnetic field generating circuit comprising a third input end, a third output end, a coil set, a first resistor, a second resistor, a first chip resistor, a second chip resistor, and a fourth An input end and a fourth output end, the coil set includes a first coil, a second coil, a first connecting end and a second connecting end, the first coil and the second coil are wound in the same direction and arranged in parallel, the first coil Connected between the first connection end and the second connection end, the second coil is connected between the first connection end and the second chip resistor, and the third input end is respectively connected to the first output end of the filter a first connection end of the coil set and a first signal end of the audio player, the fourth input end being respectively connected to the first output end of the filter and the second connection end of the coil set, the first resistor being connected to the third input The second resistor is connected between the second connection end and the third output end, and the first chip resistor is connected between the fourth input end and the second connection end, the second A chip resistor is coupled between the second coil set and the fourth output end. The degaussing circuit of the electronic device of claim 1, wherein the degaussing circuit of the electronic device further comprises a high frequency filtering circuit, the high frequency filtering circuit comprising a first capacitor and a second capacitor, the filter further The step includes a second input end, the first capacitor is connected to the first output end of the filter, and the other end is grounded. The second end of the second capacitor is connected to the second input end of the filter, and the other end is grounded. The high frequency filter The circuit is used to filter out high frequency interference signals of the circuit. The degaussing circuit of the electronic device of claim 1, wherein: the resistance of the first chip resistor is much smaller than the resistance of the first resistor, and the resistance of the second chip resistor is less than the second resistor. Resistance value. The degaussing circuit of the electronic device of claim 1, wherein the audio playback circuit further comprises a first voltage dividing resistor and a second voltage dividing resistor, wherein the third input end of the magnetic field generating circuit is A voltage dividing resistor is connected to the audio player, and the third output terminal is connected to the second signal terminal via the second voltage dividing resistor. The degaussing circuit of the electronic device according to claim 1, wherein the filter is a band pass filter having a passband and an audio response range. The degaussing circuit of the electronic device of claim 1, wherein the magnetic field generating circuit changes the strength and direction of the magnetic field generated by the coil assembly by changing the number of turns of the first coil or the second coil.