CN215956265U - Anti-electromagnetic interference circuit for refrigerator control chip - Google Patents
Anti-electromagnetic interference circuit for refrigerator control chip Download PDFInfo
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- CN215956265U CN215956265U CN202121256104.0U CN202121256104U CN215956265U CN 215956265 U CN215956265 U CN 215956265U CN 202121256104 U CN202121256104 U CN 202121256104U CN 215956265 U CN215956265 U CN 215956265U
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Abstract
The utility model relates to an anti-electromagnetic interference circuit for a refrigerator control chip, wherein the refrigerator control chip comprises a first control chip and a second control chip which are used for controlling different working contents of a refrigerator; the anti-electromagnetic interference circuit comprises a first power supply output branch and a second power supply output branch; the first power output branch comprises a first capacitor, a first inductor and a first switch which are sequentially connected in series from a first end to a second end; the second power output branch comprises a second capacitor, a second inductor and a second switch which are sequentially connected in series from the first end to the second end; the first end of the first power supply output branch is connected to the second end of the second power supply output branch; the second end of the first power supply output branch is connected to the first end of the second power supply output branch; the power supply end of the first control chip is connected to two ends of the first capacitor; and the power supply end of the second control chip is connected to two ends of the second capacitor. The utility model can effectively eliminate high-frequency electromagnetic interference generated by various reasons and achieve better anti-interference effect.
Description
Technical Field
The utility model relates to the field of electronic circuits, in particular to an anti-electromagnetic interference circuit for a refrigerator control chip.
Background
In the prior art, the refrigerator is changed from early mechanical control to intelligent control, and the intelligent control needs to use an MCU (micro control unit) as a control core. However, when the MCU normally works, firstly there is a switch problem of the access circuit and the switch problem of the output circuit, and secondly, the MCU must also provide a clock signal by the high frequency crystal oscillator, both of these two working processes may generate an electromagnetic interference exceeding standard due to the high frequency pulse, but the electromagnetic interference exceeding standard is not allowed to occur in the general production process.
Conventionally, an electromagnetic interference filter circuit is added at an input end, and the adjustment of the electromagnetic interference filter circuit can suppress interference in a certain interval, but for a certain specific frequency point, the adjustment of a preceding stage circuit often fails to achieve the effect. In addition, in the existing intelligent refrigerator, not only one MCU is often provided inside, for example, in a system with patent number CN201621122847.8, which is named as a frequency conversion electronic control integrated board for a refrigerator and is communicated with a display board, it is mentioned that the frequency conversion electronic control integrated board of the refrigerator comprises two MCUs. The problem of how to evenly control the working voltage of each MCU and effectively shield the electromagnetic interference connected into the circuit under the condition of more than one MCU is also a problem.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects of the prior art, the utility model discloses an anti-electromagnetic interference circuit for a refrigerator control chip.
The technical scheme adopted by the utility model is as follows:
an anti-electromagnetic interference circuit for a refrigerator control chip comprises a first control chip and a second control chip which are used for controlling different working contents of a refrigerator; the anti-electromagnetic interference circuit comprises a first power supply output branch and a second power supply output branch; the first power output branch comprises a first capacitor, a first inductor and a first switch which are sequentially connected in series from a first end to a second end; the second power output branch comprises a second capacitor, a second inductor and a second switch which are sequentially connected in series from a first end to a second end; the first end of the first power supply output branch is connected to the second end of the second power supply output branch; the second end of the first power supply output branch is connected to the first end of the second power supply output branch; the anode of the first diode is connected with the common end of the first inductor and the first switch, and the cathode of the first diode is connected with the common end of the second inductor and the second switch; the power supply end of the first control chip is connected to two ends of the first capacitor; and the power supply end of the second control chip is connected to two ends of the second capacitor.
The further technical scheme is as follows: a first group of magnetic beads are connected in series at a power pin of the first control chip; and a second group of magnetic beads are connected in series at the power supply pin of the second control chip.
The further technical scheme is as follows: the anti-electromagnetic interference circuit comprises a third capacitor; the third capacitor is connected in parallel with two ends of the first power supply output branch circuit.
The further technical scheme is as follows: the anti-electromagnetic interference circuit comprises a fourth capacitor and a fifth capacitor; the circuit also comprises a third resistor, a second diode, a fourth resistor and a third diode; the first end of the third resistor is connected to the common end of the fourth capacitor and the fifth capacitor, the second end of the third resistor is connected to the anode of the second diode, and the cathode of the second diode is connected to the common end of the second inductor and the second switch; the first end of the fourth resistor is connected to the common end of the fourth capacitor and the fifth capacitor, the second end of the fourth resistor is connected to the cathode of the third diode, and the anode of the third diode is connected to the common end of the first inductor and the first switch.
The further technical scheme is as follows: the capacitance values of the fourth capacitor and the fifth capacitor are equal.
The further technical scheme is as follows: the input power supply is connected in parallel with two ends of the first power supply output branch circuit after passing through the rectifying circuit.
The further technical scheme is as follows: the first switch and the second switch are active switching devices which are controlled to be switched on and off through high and low levels.
The further technical scheme is as follows: the first switch and the second switch are field effect transistors.
The further technical scheme is as follows: the first control chip is a main control chip; the second control chip is a variable frequency driving chip.
The further technical scheme is as follows: the inductance values of the first inductor and the second inductor are equal; the capacitance values of the first capacitor and the second capacitor are equal.
The utility model has the following beneficial effects:
the utility model can provide a power supply circuit with balanced voltage and anti-electromagnetic interference for the two MCUs by designing the electromagnetic shielding circuit. And through the buffering branch circuit, the condition that the voltage output branch circuits of the two MCUs generate large current can be avoided, and the switch device is prevented from being damaged. Furthermore, the magnetic beads are connected in series with the ports of the power pins of the MCU, so that the interference of specific frequency generated by the crystal oscillator signals received by the MCU can be further shielded. Through double filtering, the whole electromagnetic interference phenomenon of high-frequency signals in the MCU is reduced
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
FIG. 2 is a schematic view of the installation of magnetic beads according to the present invention.
In the figure: 1. a third capacitor; 2. a fourth capacitor; 3. a fifth capacitor; 4. a third resistor; 5. a fourth resistor; 6. a second diode; 7. a third diode; 8. a first capacitor; 9. a first inductor; 10. a first switch; 11. a first diode; 12. a second switch; 13. a second capacitor; 14. a second inductor; 15. a first control chip; 16. a second control chip; 17. a first set of magnetic beads; 18. a second set of magnetic beads.
Detailed Description
The following describes embodiments of the present invention with reference to the drawings.
Fig. 1 is a schematic structural diagram of an embodiment of the present invention. As shown in fig. 1, in the anti-electromagnetic interference circuit for the refrigerator control chip, the refrigerator control chip includes a first control chip 15 and a second control chip 16 for controlling different working contents of the refrigerator. In a common intelligent refrigerator, the first control chip 15 is often a main control chip, and the second control chip 16 is a variable frequency driving chip. Of course, the control chip may be of other kinds, possibly depending on the specific technology. The first control chip 15 and the second control chip 16 are both MCU.
The anti-electromagnetic interference circuit comprises a first power supply output branch and a second power supply output branch. The first power output branch comprises a first capacitor 8, a first inductor 9 and a first switch 10 which are sequentially connected in series from a first end to a second end. The second power output branch comprises a second capacitor 13, a second inductor 14 and a second switch 12 which are sequentially connected in series from the first end to the second end. The first end of the first power output branch is connected to the second end of the second power output branch. The second end of the first power output branch is connected to the first end of the second power output branch. The anode of the first diode 11 is connected to the common terminal of the first inductor 9 and the first switch 10, and the cathode of the first diode 11 is connected to the common terminal of the second inductor 14 and the second switch 12. The power supply terminal of the first control chip 15 is connected to both ends of the first capacitor 8. The power supply terminal of the second control chip 16 is connected to both ends of the second capacitor 13.
When the main power is turned on, generally, the first control chip 15 and the second control chip 16 are turned on at the same time under the condition that the refrigerator normally works, and when the main power is turned off, generally, the first control chip 15 and the second control chip 16 are also turned off at the same time. Since the first control chip 15 and the second control chip 16 are both MCU, the working voltage is generally the same. The output voltages of the first power supply output branch and the second power supply output branch of the anti-electromagnetic interference circuit are equal.
Preferably, the first switch 10 and the second switch 12 are active switching devices that are controlled to be opened and closed by high and low levels. For example, the first switch 10 and the second switch 12 may be field effect transistors. The first switch 10 and the second switch 12 may be turned off by the driving circuit, so that the first power output branch and the second power output branch are simultaneously turned on.
Initially, the current in the first inductor 9 and the second inductor 14 increases at the same rate when the first switch 10 and the second switch 12 are closed. The first capacitor 8 and the second capacitor 13 are connected in parallel. The voltages across the first capacitor 8 and the second capacitor 13 are output to the first control chip 15 and the second control chip 16. The first inductor 9, the second inductor 14, the first capacitor 8 and the second capacitor 13 effectively avoid high-frequency noise caused by the turning on and off of the first switch 10 and the second switch 12.
When the first switch 10 and the second switch 12 are turned on, the first inductor 9 and the second inductor 14 are connected in series, and the currents of the first inductor 9 and the second inductor 14 are slowly reduced, so that the output voltages of the first capacitor 8 and the second capacitor 13 can be ensured to be the same even if the access impedances of the first control chip 15 and the second control chip 16 are different.
Further, the anti-electromagnetic interference circuit comprises a fourth capacitor 2 and a fifth capacitor 3. And further comprises a third resistor 4, a second diode 6, a fourth resistor 5 and a third diode 7. A first terminal of the third resistor 4 is connected to the common terminal of the fourth capacitor 2 and the fifth capacitor 3, a second terminal of the third resistor 4 is connected to the anode of the second diode 6, and the cathode of the second diode 6 is connected to the common terminal of the second inductor 14 and the second switch 12. A first terminal of the fourth resistor 5 is connected to the common terminal of the fourth capacitor 2 and the fifth capacitor 3, a second terminal of the fourth resistor 5 is connected to the cathode of the third diode 7, and the anode of the third diode 7 is connected to the common terminal of the first inductor 9 and the first switch 10. The capacitance values of the fourth capacitor 2 and the fifth capacitor 3 are equal. The inductance values of the first inductor 9 and the second inductor 14 are equal. The capacitance values of the first capacitor 8 and the second capacitor 13 are equal.
The third resistor 4, the second diode 6, the fourth resistor 5 and the third diode 7 further provide a buffered path for the two branches, when the switching of the first switch 10 and the second switch 12 is not particularly synchronized due to some reasons (for example, parameters of an electronic device are unbalanced, or the switching device is lost), a larger current is easily generated to load on the switching device which is not disconnected yet due to the existence of the voltage on the first capacitor 8 and the second capacitor 13, and damage to the switch is easily caused, but the two buffered paths respectively formed by the third resistor 4, the second diode 6, the fourth resistor 5 and the third diode 7 are added, so that the occurrence of a large current can be reduced, and the loss of the switching device is reduced.
The anti-electromagnetic interference circuit comprises a third capacitor 1. The third capacitor 1 is connected in parallel to two ends of the first power output branch. The third capacitor 1 can further control the voltage at the two ends of the first power output branch and the second power output branch, so that the voltage is stable.
Further, in the present invention, a first set of magnetic beads 17 is connected in series to a power pin of the first control chip 15, specifically, one magnetic bead is respectively connected to a power terminal and a ground terminal of the first control chip 15. A second set of magnetic beads 18 is connected in series to a power pin of the second control chip 16, specifically, one magnetic bead is respectively connected to a power terminal and a ground terminal of the second control chip 16. The magnetic beads are connected at the position close to the input end of the power supply, the magnetic beads have low impedance to normal direct current, so that normal power supply current cannot be influenced, but different impedance can be presented to signals with higher frequency, and the maximum impedance can be presented at a certain frequency point. The test value of the electromagnetic interference can be analyzed, for example, a tested object can be connected into test equipment in an electromagnetic interference shielding room, the coupling clamp scans back and forth on a power line, the maximum value of the interference is displayed by a waveform through a receiver, and the exceeding of the interference at the frequency point can be seen through the waveform. The proper magnetic beads are selected for the frequency points (impedance presents the maximum value), interference signals can be greatly attenuated after passing through the magnetic beads, and finally the radiated energy is greatly reduced, so that a better anti-electromagnetic interference effect is obtained.
According to the working process, the anti-electromagnetic interference circuit mainly solves the electromagnetic interference caused by high-frequency signals generated by switches for controlling the access voltage and the output voltage of the chip, and the magnetic beads are connected at the positions close to the power supply pins of the chip, so that the high-frequency interference caused by high-frequency crystal oscillator clock signals when the MCU works can be eliminated. If only one means is used, the effect may not be very good due to different frequency positions and frequency ranges of the high-frequency electromagnetic interference, and the high-frequency electromagnetic interference generated by various reasons can be effectively eliminated through multiple filtering of the utility model, so that a better anti-interference effect is achieved.
The foregoing description is illustrative of the present invention and is not to be construed as limiting the utility model, which is defined by the scope of the appended claims, as the utility model may be modified in any manner without departing from the essential structure thereof.
Claims (10)
1. The utility model provides an anti-electromagnetic interference circuit for refrigerator control chip which characterized in that: the refrigerator control chip comprises a first control chip (15) and a second control chip (16) which are used for controlling different working contents of the refrigerator; the anti-electromagnetic interference circuit comprises a first power supply output branch and a second power supply output branch; the first power output branch comprises a first capacitor (8), a first inductor (9) and a first switch (10) which are sequentially connected in series from a first end to a second end; the second power output branch comprises a second capacitor (13), a second inductor (14) and a second switch (12) which are sequentially connected in series from a first end to a second end; the first end of the first power supply output branch is connected to the second end of the second power supply output branch; the second end of the first power supply output branch is connected to the first end of the second power supply output branch; the anode of the first diode (11) is connected with the common end of the first inductor (9) and the first switch (10), and the cathode of the first diode (11) is connected with the common end of the second inductor (14) and the second switch (12); the power supply end of the first control chip (15) is connected to two ends of the first capacitor (8); and the power supply end of the second control chip (16) is connected to two ends of the second capacitor (13).
2. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: a first group of magnetic beads (17) are connected in series at a power supply pin of the first control chip (15); and a second group of magnetic beads (18) are connected in series at a power supply pin of the second control chip (16).
3. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: the anti-electromagnetic interference circuit comprises a third capacitor (1); and the third capacitor (1) is connected in parallel with two ends of the first power supply output branch circuit.
4. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: the anti-electromagnetic interference circuit comprises a fourth capacitor (2) and a fifth capacitor (3); the circuit also comprises a third resistor (4), a second diode (6), a fourth resistor (5) and a third diode (7); the first end of the third resistor (4) is connected to the common end of the fourth capacitor (2) and the fifth capacitor (3), the second end of the third resistor (4) is connected to the anode of the second diode (6), and the cathode of the second diode (6) is connected to the common end of the second inductor (14) and the second switch (12); the first end of the fourth resistor (5) is connected to the common end of the fourth capacitor (2) and the fifth capacitor (3), the second end of the fourth resistor (5) is connected to the cathode of the third diode (7), and the anode of the third diode (7) is connected to the common end of the first inductor (9) and the first switch (10).
5. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 4, wherein: the capacitance values of the fourth capacitor (2) and the fifth capacitor (3) are equal.
6. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: the input power supply is connected in parallel with two ends of the first power supply output branch circuit after passing through the rectifying circuit.
7. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: the first switch (10) and the second switch (12) are active switching devices which are controlled to be switched on and off through high and low levels.
8. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 7, wherein: the first switch (10) and the second switch (12) are field effect transistors.
9. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: the first control chip (15) is a main control chip; the second control chip (16) is a variable frequency driving chip.
10. The anti-electromagnetic interference circuit for the refrigerator control chip of claim 1, wherein: the inductance values of the first inductor (9) and the second inductor (14) are equal; the capacitance values of the first capacitor (8) and the second capacitor (13) are equal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121256104.0U CN215956265U (en) | 2021-06-04 | 2021-06-04 | Anti-electromagnetic interference circuit for refrigerator control chip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121256104.0U CN215956265U (en) | 2021-06-04 | 2021-06-04 | Anti-electromagnetic interference circuit for refrigerator control chip |
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| Publication Number | Publication Date |
|---|---|
| CN215956265U true CN215956265U (en) | 2022-03-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121256104.0U Active CN215956265U (en) | 2021-06-04 | 2021-06-04 | Anti-electromagnetic interference circuit for refrigerator control chip |
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| CN (1) | CN215956265U (en) |
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- 2021-06-04 CN CN202121256104.0U patent/CN215956265U/en active Active
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