CN206865350U - A kind of filter circuit and power supply adaptor - Google Patents
A kind of filter circuit and power supply adaptor Download PDFInfo
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- CN206865350U CN206865350U CN201720328202.8U CN201720328202U CN206865350U CN 206865350 U CN206865350 U CN 206865350U CN 201720328202 U CN201720328202 U CN 201720328202U CN 206865350 U CN206865350 U CN 206865350U
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Abstract
The utility model embodiment discloses a kind of filter circuit and power supply adaptor, and the filter circuit includes：Direct-flow input end, DM EMI suppression module and common mode disturbances suppression module；Wherein, the DM EMI suppression module is connected with direct-flow input end, and the DC signal for being inputted to the direct-flow input end carries out DM EMI suppression；The common mode disturbances suppression module, it is connected by the DM EMI suppression module with direct-flow input end, for carrying out common mode disturbances suppression to the DC signal.By new the provided filter circuit of this implementation need not increase bleeder resistance, therefore the open circuit loss of power supply can be reduced by using foregoing circuit, improve the average efficiency of power supply, the design of circuit can also be simplified under conditions of six grades of efficiency requirements of European Union are met.
Description
Technical Field
The embodiment of the utility model provides a relate to power technical field, especially relate to a filter circuit and power adapter.
Background
With the increasing global energy shortage, energy conservation and emission reduction become the common pursuit targets of people. It is also important to improve the average efficiency of the switching power supply, reduce the power loss during idle operation, and reduce the power consumption of the terminal system during standby. These are driving the development of electronic products towards "high efficiency and low standby power consumption". The power supply is a heart and a power source of the electronic product, and is a key point for improving the efficiency of the electronic product and reducing the power consumption.
The power source itself generates EMI (Electromagnetic Interference) to other peripheral devices, and also receives Electromagnetic Interference generated by other devices and propagated through the power source. The EMI filter circuit will play a very important role in the use of the power supply. In the prior art, differential mode interference is suppressed in the EMI filter circuit by an X capacitor (CX 1). Usually, the X capacitor is a safety capacitor, and is bridged between an alternating current L line (live line) and an N line (zero line) to suppress differential mode interference noise at an alternating current incoming line end. Because the X capacitor is positioned at the alternating current end in front of the rectifier bridge, certain charges are still stored in the X capacitor after the power supply is powered off, so that a discharge resistor must be added below the X capacitor to meet the discharge test requirement defined by safety regulations, and further, the electric shock hazard generated by the charges stored in the X capacitor to a contacter of power supply equipment after the power supply is powered off is avoided.
However, the increase of the bleeder resistance increases the no-load loss after the power supply is powered off, the requirement of no-load loss in six-level energy efficiency is difficult to realize, and the design difficulty is increased.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a filter circuit and power adapter can reduce the no-load loss after the power outage when satisfying EMI filtering.
The embodiment of the utility model provides a filter circuit, this circuit includes: the device comprises a direct current input end, a differential mode interference suppression module and a common mode interference suppression module; wherein,
the differential mode interference suppression module is connected with the direct current input end and is used for performing differential mode interference suppression on the direct current signal input by the direct current input end;
the common mode interference suppression module is connected with the direct current input end through the differential mode interference suppression module and used for performing common mode interference suppression on the direct current signals.
Further, the differential mode interference suppression module comprises two electrolytic capacitors, and the common mode interference suppression module comprises a common mode inductor; wherein,
two ends of the first electrolytic capacitor are connected between the two direct current input ends and are respectively connected with the two input ends of the common mode inductor;
and two ends of the second electrolytic capacitor are respectively connected with two output ends of the common mode inductor.
The embodiment of the utility model provides a power adapter, including rectifier circuit and transformer, still include filter circuit; the direct current input end of the filter circuit is connected with the output end of the rectification circuit, and the output end of the filter circuit is connected with the input end of the transformer.
Further, the transformer includes a primary coil, an auxiliary coil, and a secondary coil; wherein,
the primary coil is connected with the output end of the filter circuit and used for providing an input voltage signal;
the secondary coil is connected with a load and used for outputting power supply voltage according to the input voltage signal and supplying power to the load;
the auxiliary coil and the primary coil are arranged according to the same name end and are used for converting the power supply voltage into an auxiliary voltage signal according to the turn ratio of the transformer.
Further, the power adapter further comprises: the starting circuit is connected with the filter circuit and used for generating a starting voltage signal according to the electric signal after the filtering processing;
the sampling circuit is connected with the auxiliary coil of the transformer and used for detecting the auxiliary voltage signal and generating a sampling voltage signal;
the IC chip is connected with the starting circuit and used for acquiring the starting voltage signal and working under the driving of the starting voltage signal; the IC chip is connected with the sampling circuit and the primary coil of the transformer and used for acquiring the sampling voltage signal, chopping the rectified direct-current voltage signal through an MOS (metal oxide semiconductor) tube packaged in the IC chip according to the sampling voltage signal to obtain a pulse voltage signal so as to adjust the input voltage signal, and adjusting the voltage output by the secondary coil through the transformer.
Further, the power adapter further comprises: the RCD absorption circuit is connected with the IC chip and used for absorbing a voltage spike generated by the MOS tube during the turn-off period;
and the secondary rectification filter circuit is connected with a secondary coil of the transformer and used for rectifying the power supply voltage to obtain a direct current signal to supply power to a load.
Further, the rectifying circuit is a full-wave rectifying circuit, wherein the rectifying circuit further comprises a fuse, a voltage dependent resistor and a thermistor, and is used for protecting the power adapter.
Further, the starting circuit comprises a starting resistor and a third capacitor, wherein,
the starting resistor is connected with the third capacitor in series and is connected between the direct-current positive electrode output end of the filter circuit and the ground wire;
and the positive end of the third capacitor is connected with the IC chip and used for driving the IC chip to work when the third capacitor is charged to form a starting voltage signal. Further, the sampling circuit comprises a first resistor, a second resistor and a first diode; wherein,
a circuit formed by connecting the first resistor and the second resistor in series is connected in parallel to two ends of the auxiliary coil of the transformer;
the positive end of the first diode is connected with the auxiliary coil of the transformer, and the negative end of the first diode is connected with the positive end of the third capacitor;
and a connection point between the first resistor and the second resistor is used as a sampling point and is connected to the IC chip for acquiring a sampling voltage signal from the sampling point.
Further, the RCD snubber circuit includes: a fourth capacitor, a third resistor and a fourth resistor which are connected in parallel in sequence are connected in series with the second diode; wherein,
the first end of the fourth capacitor and the positive end of the second diode are respectively connected with the primary coil of the transformer, and the negative end of the second diode is connected with the second end of the fourth capacitor;
and meanwhile, the positive end of the second diode is connected with the drain end of the MOS tube.
Further, the secondary rectifying and filtering circuit comprises a third diode, an RC absorption circuit, a fifth capacitor and a sixth capacitor; wherein,
the positive end of the third diode is connected with the secondary coil of the transformer, and the negative end of the third diode is connected with the positive end of the fifth capacitor;
the RC absorption circuit is connected in parallel to two ends of the third diode;
the negative electrode of the fifth capacitor is connected with the secondary ground;
and the sixth capacitor is connected in parallel at two ends of the fifth capacitor.
The embodiment of the utility model provides a filter circuit and power adapter, link to each other with the direct current input through the differential mode interference suppression module, can carry out differential mode interference suppression to the direct current signal of direct current input; the common-mode interference suppression module is connected with the direct-current input end through the differential-mode interference suppression module and is used for performing common-mode interference suppression on the direct-current signals. In the filter circuit provided by the novel implementation, the differential mode interference suppression module is not directly connected with the alternating current input end but connected to the direct current input end, so that accumulated charges do not exist after power failure, and a discharge resistor does not need to be added, so that no-load loss of a power supply can be reduced, the average efficiency of the power supply is provided, and the design of the circuit can be simplified under the condition of meeting the requirement of European Union six-level energy efficiency.
Drawings
Fig. 1 is a schematic structural diagram of a filter circuit according to a first embodiment of the present invention;
fig. 2 is a preferred EMI filter circuit according to an embodiment of the present invention;
fig. 3a is a block diagram of a power adapter according to a second embodiment of the present invention;
fig. 3b is a circuit diagram of a preferred rectification and EMI filter circuit according to the second embodiment of the present invention;
fig. 4 is a schematic structural diagram of a power adapter circuit according to a third embodiment of the present invention;
fig. 5 is a schematic diagram of a preferred power adapter circuit according to a third embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Example one
Fig. 1 is a schematic structural diagram of a filter circuit according to a first embodiment of the present invention; the circuit can be integrated into a power adapter or an open switching power supply for supplying power to a terminal device. As shown in fig. 1, the circuit specifically includes: a dc input 110, a differential mode interference rejection module 120 and a common mode interference rejection module 130.
The differential mode interference suppression module 120 is connected to the dc input terminal 110, and configured to perform differential mode interference suppression on a dc signal input by the dc input terminal; the common mode interference rejection module 130 is connected to the dc input terminal through the differential mode interference rejection module 120, and is configured to perform common mode interference rejection on the dc signal.
Wherein, the differential mode interference and the common mode interference signal belong to EMI interference. For example, when a switching power supply is in operation or other electronic equipment is in a switching state, noise may appear at the input of the power supply, which may cause radiated and conducted interference, i.e., EMI interference. EMI interference can also enter the ac power grid and interfere again with other electronic devices. Therefore, effective measures are required to suppress EMI interference to ensure that the electronic equipment operates normally and effectively. The embodiment of the utility model provides a contain the EMI filter circuit of X electric capacity among the prior art through differential mode interference suppression module and common mode interference suppression module, realized the suppression to EMI interference. Because the embodiment of the utility model provides an among the filter circuit, differential mode interference suppression module does not directly link to each other with AC input end, but is connected to DC input end, so after the outage, can not have accumulative charge, consequently can reduce the no-load loss of power, improves the average efficiency of power, also can simplify the design of circuit simultaneously under the condition that satisfies six grades of efficiency requirements of European Union.
Illustratively, the differential mode interference suppression module includes two electrolytic capacitors C1 and C2, and the common mode interference suppression module includes a common mode inductor LF 1; two ends of the first electrolytic capacitor C1 are connected between two direct current input ends and are respectively connected with two input ends of the common mode inductor LF 1; two ends of the second electrolytic capacitor C2 are respectively connected with two output ends of the common mode inductor LF 1. Fig. 2 is a preferred EMI filter circuit according to an embodiment of the present invention. As shown in fig. 2, by matching C1, C2, and LF1, filtering of EMI interference in the circuit can be achieved.
For example, the filter circuit provided by the present embodiment may be integrated into a power adapter for filtering EMI interference in the power adapter circuit.
The embodiment provides a filter circuit, which comprises a direct current input end, a differential mode interference suppression module and a common mode interference suppression module, wherein the differential mode interference suppression module is connected with the direct current input end, so that differential mode interference suppression can be performed on a direct current signal input by the direct current input end; and the common-mode interference suppression module is connected with the direct current input end through the differential-mode interference suppression module, so that common-mode interference suppression can be performed on direct current signals. Because the filter circuit provided by the novel implementation does not need to increase a discharge resistor, the no-load loss of the power supply can be reduced, the average efficiency of the power supply is improved, and the design of the circuit can be simplified under the condition of meeting the requirement of European Union six-level energy efficiency.
Example two
Fig. 3a is a block diagram of a power adapter according to a second embodiment of the present invention. The present embodiment may integrate the filter circuit provided in the above embodiments, and as shown in fig. 3a, the power adapter 200 includes a rectifier circuit 210, a filter circuit 220 and a transformer 230. Wherein,
the dc input 221 of the filter circuit 220 is connected to the output of the rectifier circuit 210, and the output of the filter circuit 220 is connected to the input of the transformer 230.
It should be noted that the transformer 230 preferably includes a primary coil, an auxiliary coil, and a secondary coil; the primary coil is connected with the output end of the filter circuit and used for providing an input voltage signal; the secondary coil is connected with the load and used for outputting power supply voltage according to the input voltage signal and supplying power to the load; and the auxiliary coil and the primary coil are arranged according to the same name end and are used for converting the power supply voltage into an auxiliary voltage signal according to the turn ratio of the transformer. The auxiliary voltage signal may be used for sampling or other auxiliary processing functions. Since the transformer is located between the primary and secondary of the power adapter, it can serve to isolate the primary high voltage from the secondary low voltage.
Illustratively, the rectifier circuit in the present embodiment may be a full-wave rectifier circuit. Fig. 3b is a circuit diagram of a preferred rectification and EMI filter circuit according to the second embodiment of the present invention. As shown in fig. 3b, when the output terminal of the rectifying circuit is connected to the input terminal of the filter circuit, since the diode in the rectifying circuit is in the reverse cut-off state, the charge stored in the electrolytic capacitor of the filter circuit cannot be fed back to the secondary winding terminal of the transformer in the case of power failure, and therefore, the electric shock phenomenon caused by the contact of a contactor with the power adapter after the power failure can be avoided. The safety of the power adapter can be effectively improved.
Further, as shown in fig. 3b, the rectifying circuit may also include a fuse F1, a voltage dependent resistor MOV1 and a thermistor NTC 1. The device can be used as a protection device for the circuit to resist 4KV lightning stroke, so that the safety of the circuit can be further improved through the device.
The embodiment provides a power adapter, which can obtain a direct current voltage by rectifying an alternating current voltage input by a power grid through a rectifying circuit, can filter EMI interference in a circuit after the direct current voltage is subjected to a filtering circuit, and can supply power to a load by taking a transformer as an energy conversion device. By adopting the circuit, the power adapter can supply power to the terminal equipment.
EXAMPLE III
Fig. 4 is a schematic structural diagram of a power adapter circuit provided by the third embodiment of the present invention, and this embodiment is further optimized on the basis of the above embodiment, as shown in fig. 4, this power adapter 300 includes a rectifying circuit 310, a filtering circuit 320, a starting circuit 330, an RCD absorption circuit 340, a transformer 350, a sampling circuit 360, an IC chip 370, and a secondary rectifying and filtering circuit 380. Each circuit is described in detail below:
(1) the starting circuit 330 is connected with the filtering circuit 320 and is used for generating a starting voltage signal according to the electric signal after filtering processing;
fig. 5 is a schematic diagram of a preferred power adapter circuit according to a third embodiment of the present invention. As shown in fig. 5, the starting circuit 330 includes a starting resistor 331 and a third capacitor C3; the starting resistor 331 is connected in series with the third capacitor C3 and is connected between the direct-current positive electrode output end of the filter circuit and the ground wire; the positive terminal of the third capacitor C3 is connected to the IC chip 370, and is used for driving the IC chip 370 to operate when the third capacitor C3 is charged to form a start voltage signal. Specifically, the starting resistor 331 may include an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10.
It should be noted that, when the circuit normally works, a part of loss exists in the starting resistor, and if the total resistance of the starting resistor is defined as Rin, the rectified dc high voltage is defined as VdcThe loss of the starting resistor Rin is then:
therefore, when the capacitance of the third capacitor C3 is properly reduced, the resistance of the starting resistor is increased, so that the loss in the starting resistor can be reduced, the no-load loss of the power adapter can be reduced, and the efficiency of the power supply can be improved. Preferably, the value of the third capacitor C3 is 6.8 μ F.
(2) And the sampling circuit 360 is connected with the auxiliary coil of the transformer and used for detecting the auxiliary voltage signal and generating a sampling voltage signal.
Illustratively, as shown in fig. 5, the sampling circuit 360 includes a first resistor R1, a second resistor R2, and a first diode D1; the circuit formed by connecting the first resistor R1 and the second resistor R2 in series is connected in parallel at two ends of the auxiliary coil of the transformer; the positive terminal of the first diode D1 is connected to the auxiliary winding of the transformer, and the negative terminal of the first diode D1 is connected to the positive terminal of the third capacitor C3. And a connection point between the first resistor R1 and the second resistor R2 is used as a sampling point and is connected to the IC chip for acquiring a sampling voltage signal from the sampling point.
It should be noted that after the IC chip is started, the third capacitor C3 is charged through the auxiliary winding of the transformer to maintain the operating state of the IC chip. As shown in fig. 5, since the third capacitor is an electrolytic capacitor and needs to operate in a dc circuit, the ac signal of the auxiliary winding of the transformer can be rectified into a dc signal through the first diode D1 to charge the third capacitor C3.
Further, the sampling circuit 360 may further include an eighth capacitor C8, where two terminals of the eighth capacitor C8 are connected in parallel to two terminals of the auxiliary coil of the transformer, and are used for filtering out EMC (Electro Magnetic Compatibility) interference in the circuit.
Furthermore, the sampling circuit 360 may further include a ninth capacitor C9, and two ends of the ninth capacitor C9 are connected in parallel to two ends of the first resistor R1, so as to prevent an interference signal in the circuit from entering the IC chip, and further ensure the normal operation of the IC chip.
(3) The IC chip 370 is connected to the start circuit 330, and is configured to obtain a start voltage signal and operate under the driving of the start voltage signal; the IC chip 370 is connected to the sampling circuit 360 and the primary coil of the transformer, and is configured to obtain a sampling voltage signal, chop the dc voltage through a MOS transistor packaged in the IC chip according to the sampling voltage signal to obtain a pulse voltage, adjust the input voltage signal, and adjust the voltage output by the secondary coil through the transformer.
Furthermore, two resistors R11 and R12 which are connected in parallel can be connected with a current detection pin which has an overcurrent protection function in the IC chip, and the primary peak current flowing through the MOS tube is converted into voltage through the current detection resistor R11 and R12 and fed back to the current detection pin of the IC chip, so that the overcurrent protection effect is realized.
The working principle of the start-up circuit, the sampling circuit and the IC chip is specifically explained below:
when the high voltage signal rectified by the rectifying circuit passes through the starting resistor, the third capacitor C3 can be charged, as shown in fig. 5, since the positive terminal of the third capacitor C3 is connected to the power supply pin VDD of the IC chip, when the voltage at the VDD terminal reaches the starting voltage of the IC chip, the IC chip will start and drive the whole power supply system to operate. When the IC chip is started, the auxiliary coil of the transformer supplies power to the IC chip through the third capacitor C3.
Because the MOS tube is packaged in the IC chip, the IC chip can realize the chopping of voltage by controlling the on and off of the MOS tube, namely, the direct current voltage input to the primary coil is chopped into pulse voltage. Wherein, the amplitude of the pulse voltage is equal to the amplitude of the input direct current voltage. Since the feedback terminal of the IC chip is connected between the first resistor R1 and the second resistor R2, the voltage of the auxiliary coil of the transformer can be detected by the first resistor R1 and the second resistor R2, and a sampling voltage signal is generated and fed back to the IC chip. Because the voltage at the two ends of the auxiliary coil of the transformer and the voltage output at the two ends of the secondary coil of the transformer have a certain proportional relation, the IC chip can detect the output voltage of the transformer according to the sampling voltage signal and adjust the duty ratio according to the sampling voltage signal, so as to control the on-time and the off-time of the MOS tube and ensure that the transformer has stable output voltage. For example, when the voltage output by the secondary coil of the transformer is higher, the sampling voltages obtained through R1 and R2 are also higher correspondingly, and if the sampling voltage is greater than the preset reference voltage of the IC chip, the IC chip reduces the duty ratio, and further reduces the on-time of the MOS transistor, so as to reduce the output voltage of the transformer. By adopting the technical scheme, the transformer can output stable voltage to supply power to the load.
(4) And the RCD absorption circuit 340 is connected with the IC chip 370 and is used for absorbing voltage spikes generated by the MOS tube during the turn-off period.
Specifically, the RCD snubber circuit 340 includes: a fourth capacitor C4, a third resistor R3, a fourth resistor R4 and a second diode D2 which are connected in parallel in sequence; a first end of the fourth capacitor C4 and a positive end of the second diode D2 are respectively connected to the primary coil of the transformer, and a negative end of the second diode D2 is connected to a second end of the fourth capacitor C4; while the positive terminal of the second diode D2 is connected to the IC chip 370.
Illustratively, the value ranges of R3 and R4 are preferably 200K Ω -390K Ω, and the value range of the fourth capacitor C4 is preferably: 1nF-2.2 nF.
The RCD absorption circuit has the following functions: during the turn-off period of the absorption MOS tube, the voltage spike generated by the leakage inductance of the transformer at the drain electrode of the MOS tube is avoided, the breakdown of the MOS tube by the voltage spike is avoided, the safe work of the MOS tube can be ensured through the RCD absorption circuit, and the reliability of the circuit is improved.
(5) And the secondary rectifying and filtering circuit 380 is connected with the secondary coil of the transformer and is used for rectifying the power supply voltage to obtain a direct current signal to supply power to the load.
Specifically, the secondary rectifying and smoothing circuit 380 includes a third diode D3, an RC absorption circuit 381, a fifth capacitor C5, and a sixth capacitor C6; the positive terminal of the third diode D3 is connected to the secondary winding of the transformer, and the negative terminal of the third diode D3 is connected to the positive terminal of the fifth capacitor C5; the RC absorption circuit 381 is connected in parallel to two ends of the rectifying diode D3; the negative terminal of the fifth capacitor C5 is connected to the secondary ground; the sixth capacitor C6 is connected in parallel across the fifth capacitor C5.
The third diode D3 is used as a path through which a large current can flow for the power device. Since reducing the loss in the diode is an important component for achieving the overall six-stage energy efficiency of the power supply, the third diode D3 should be a low-voltage drop type diode.
Specifically, the RC snubber circuit 381 includes a seventh capacitor C7 and a fifth resistor R5; the seventh capacitor C7 is connected in series with the fifth resistor R5. The RC absorption circuit has the following functions: the reverse voltage spike of the third diode D3 during the turn-off of the MOS transistor is absorbed, so that the reverse spike voltage of the third diode D3 is operated below the specification value of the third diode D3, and the safe operation of the third diode D3 is ensured. Preferably, the value range of the fifth resistor R5 is preferably: the value range of the seventh capacitor C7 is preferably 220-1000 pF.
It should be noted that, the secondary rectifying and filtering circuit can rectify the voltage induced by the secondary coil of the transformer through the third diode D3, and then obtain a smooth and stable dc voltage after filtering processing through the filter capacitor (C5 and C6), so as to provide a high-precision and stable power supply for the use of the terminal product.
The embodiment provides a power adapter circuit, on the basis of the above embodiment, the starting circuit, the sampling circuit and the IC chip are combined with the rectifying circuit, the filtering circuit and the transformer provided by the above embodiment, so that the voltage output by the secondary coil of the transformer can be fed back to the IC chip, the duty ratio is adjusted by the IC chip to control the on and off of the internal MOS transistor, and further the output voltage of the transformer can be stabilized. The RCD absorption circuit can absorb the voltage peak of the leakage inductance of the transformer generated on the drain electrode of the MOS tube during the turn-off period of the MOS tube so as to avoid the failure of the MOS tube. Meanwhile, smooth and stable direct-current voltage can be obtained after the secondary rectifying and filtering circuit is used for processing, and stable electric energy supply is provided for the load. The power adapter circuit provided by the novel embodiment not only meets the basic requirement of European Union six-level energy efficiency, but also has the characteristics of high energy efficiency and low power consumption, and is high in reliability.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A filter circuit, comprising: the device comprises a direct current input end, a differential mode interference suppression module and a common mode interference suppression module; wherein,
the differential mode interference suppression module is connected with the direct current input end and is used for performing differential mode interference suppression on the direct current signal input by the direct current input end;
the common mode interference suppression module is connected with the direct current input end through the differential mode interference suppression module and used for performing common mode interference suppression on the direct current signals.
2. The circuit of claim 1, wherein the differential mode interference rejection module comprises two electrolytic capacitors, and the common mode interference rejection module comprises a common mode inductor; wherein,
two ends of the first electrolytic capacitor are connected between the two direct current input ends and are respectively connected with the two input ends of the common mode inductor;
and two ends of the second electrolytic capacitor are respectively connected with two output ends of the common mode inductor.
3. A power adapter comprising a rectifying circuit and a transformer, characterized by further comprising the filter circuit of claim 1 or 2; the direct current input end of the filter circuit is connected with the output end of the rectification circuit, and the output end of the filter circuit is connected with the input end of the transformer.
4. The power adapter as claimed in claim 3, wherein the transformer includes a primary coil, an auxiliary coil, and a secondary coil; wherein,
the primary coil is connected with the output end of the filter circuit and used for providing an input voltage signal;
the secondary coil is connected with a load and used for outputting power supply voltage according to the input voltage signal and supplying power to the load;
the auxiliary coil and the primary coil are arranged according to the same name end and are used for converting the power supply voltage into an auxiliary voltage signal according to the turn ratio of the transformer.
5. The power adapter as claimed in claim 4, further comprising:
the starting circuit is connected with the filter circuit and used for generating a starting voltage signal according to the electric signal after the filtering processing;
the sampling circuit is connected with the auxiliary coil of the transformer and used for detecting the auxiliary voltage signal and generating a sampling voltage signal;
the IC chip is connected with the starting circuit and used for acquiring the starting voltage signal and working under the driving of the starting voltage signal; the IC chip is connected with the sampling circuit and the primary coil of the transformer and used for acquiring the sampling voltage signal, chopping the rectified direct-current voltage signal through an MOS (metal oxide semiconductor) tube packaged in the IC chip according to the sampling voltage signal to obtain a pulse voltage signal so as to adjust the input voltage signal, and adjusting the voltage output by the secondary coil through the transformer.
6. The power adapter as claimed in claim 5, further comprising:
the RCD absorption circuit is connected with the IC chip and used for absorbing a voltage spike generated by the MOS tube during the turn-off period;
and the secondary rectification filter circuit is connected with a secondary coil of the transformer and used for rectifying the power supply voltage to obtain a direct current signal to supply power to a load.
7. The power adapter as claimed in claim 5, wherein: the starting circuit comprises a starting resistor and a third capacitor; wherein,
the starting resistor is connected with the third capacitor in series and is connected between the direct-current positive electrode output end of the filter circuit and the ground wire;
and the positive end of the third capacitor is connected with the IC chip and used for driving the IC chip to work when the third capacitor is charged to form a starting voltage signal.
8. The power adapter as claimed in claim 7, wherein: the sampling circuit comprises a first resistor, a second resistor and a first diode; wherein,
a circuit formed by connecting the first resistor and the second resistor in series is connected in parallel to two ends of the auxiliary coil of the transformer;
the positive end of the first diode is connected with the auxiliary coil of the transformer, and the negative end of the first diode is connected with the positive end of the third capacitor;
and a connection point between the first resistor and the second resistor is used as a sampling point and is connected to the IC chip for acquiring a sampling voltage signal from the sampling point.
9. The power adapter as claimed in claim 6, wherein: the RCD absorption circuit includes: a fourth capacitor, a third resistor and a fourth resistor which are connected in parallel in sequence are connected in series with the second diode; wherein,
the first end of the fourth capacitor and the positive end of the second diode are respectively connected with the primary coil of the transformer, and the negative end of the second diode is connected with the second end of the fourth capacitor;
and meanwhile, the positive end of the second diode is connected with the drain end of the MOS tube.
10. The power adapter as claimed in claim 6, wherein: the secondary rectifying and filtering circuit comprises a third diode, an RC absorption circuit, a fifth capacitor and a sixth capacitor; wherein,
the positive end of the third diode is connected with the secondary coil of the transformer, and the negative end of the third diode is connected with the positive end of the fifth capacitor;
the RC absorption circuit is connected in parallel to two ends of the third diode;
the negative electrode of the fifth capacitor is connected with the secondary ground;
and the sixth capacitor is connected in parallel at two ends of the fifth capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201720328202.8U CN206865350U (en) | 2017-03-30 | 2017-03-30 | A kind of filter circuit and power supply adaptor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201720328202.8U CN206865350U (en) | 2017-03-30 | 2017-03-30 | A kind of filter circuit and power supply adaptor |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109039054A (en) * | 2018-06-04 | 2018-12-18 | 敏华家具制造(惠州)有限公司 | Power module for intelligent sofa and intelligent sofa |
| CN111398655A (en) * | 2020-03-08 | 2020-07-10 | 苏州浪潮智能科技有限公司 | Input current detection circuit and method |
| CN112994440A (en) * | 2021-02-04 | 2021-06-18 | 珠海格力电器股份有限公司 | Electromagnetic interference suppression device and method of power adapter and power adapter |
| CN115051453A (en) * | 2022-06-06 | 2022-09-13 | 西安合能电气科技有限公司 | Be used for ultralow interference photovoltaic charge management circuit |
| CN117118221A (en) * | 2023-10-24 | 2023-11-24 | 荣耀终端有限公司 | Hybrid filter, switching power supply, charging device, charging method, and charging system |
-
2017
- 2017-03-30 CN CN201720328202.8U patent/CN206865350U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109039054A (en) * | 2018-06-04 | 2018-12-18 | 敏华家具制造(惠州)有限公司 | Power module for intelligent sofa and intelligent sofa |
| CN111398655A (en) * | 2020-03-08 | 2020-07-10 | 苏州浪潮智能科技有限公司 | Input current detection circuit and method |
| CN111398655B (en) * | 2020-03-08 | 2022-12-09 | 苏州浪潮智能科技有限公司 | Input current detection circuit and method |
| CN112994440A (en) * | 2021-02-04 | 2021-06-18 | 珠海格力电器股份有限公司 | Electromagnetic interference suppression device and method of power adapter and power adapter |
| CN115051453A (en) * | 2022-06-06 | 2022-09-13 | 西安合能电气科技有限公司 | Be used for ultralow interference photovoltaic charge management circuit |
| CN117118221A (en) * | 2023-10-24 | 2023-11-24 | 荣耀终端有限公司 | Hybrid filter, switching power supply, charging device, charging method, and charging system |
| CN117118221B (en) * | 2023-10-24 | 2024-03-26 | 荣耀终端有限公司 | Hybrid filter, switching power supply, charging device, charging method, and charging system |
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