JP4392191B2 - Switching power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a switching power supply, and in particular, converts an AC input voltage into a predetermined AC voltage by a switching element, applies the converted AC voltage to a primary winding of the transformer, and is taken out from the secondary winding of the transformer. The present invention relates to a switching power supply that smoothes a voltage and outputs a DC voltage to an output terminal.
[0002]
[Prior art]
In a conventional switching power supply, for example, when connected to a power line of an AC power supply, it is converted into a predetermined AC voltage by a switching element such as a field effect transistor (FET), and the converted AC voltage is the primary voltage of the transformer. A voltage is generated in the secondary winding of the transformer by being applied to the winding. The generated voltage is output to the output terminal as a DC voltage by being smoothed.
[0003]
Various electrical products, for example, a TV, a refrigerator, a personal computer (hereinafter abbreviated as a personal computer), etc. are connected to the output terminal. On the other hand, in a workplace such as a company, when a plurality of personal computers are connected to communicate with each other via LAN (Local Area Network) communication, a LAN card and a terminal adapter are installed on both personal computers and a LAN cable is connected. It is necessary to connect with.
[0004]
[Problems to be solved by the invention]
As described above, the conventional switching power supply is connected to the AC power supply so that the DC power supply can be supplied to the external device. However, the power supply is merely a power supply to the external device. It did not have the function of.
When the external device connected to the switching power supply is a personal computer, both computers can communicate with each other by means of a LAN cable or the like, but communication data is transmitted / received if the LAN cable is not connected. There were problems such as being unable to do so. If the communication between both computers is wireless, such as a wireless LAN, there will be no wiring, but communication data will be sent and received if there is no base station equipment such as an access point or repeater required for the wireless LAN. There were problems such as being unable to.
[0005]
An object of the present invention is to provide a switching power supply to which not only power is supplied to an external device but also a function of transmitting / receiving a signal to / from the external device.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, the AC input voltage of the power line of the AC power source is converted into a predetermined AC voltage by the switching element, the converted AC voltage is applied to the primary winding of the transformer, and is taken out from the secondary winding of the transformer. In a switching power supply that smoothes the output AC voltage to an external device connected to the output terminal, when the AC voltage converted by the switching element is applied to the primary winding of the transformer, Communication means connected between the primary winding of the transformer and the switching element so as to transmit / receive a communication signal to / from an external device connected to the output terminal of the secondary winding using the power line of the AC power supply as a communication line. Features.
[0007]
According to the switching power supply according to claim 1, when the switching power supply is connected to the power line of the AC power supply and an external device is connected to the respective switching power supply, from the external device on the one switching power supply side, When the communication signal is transmitted to the other switching power supply, it is transmitted to the external device via the communication means on the switching power supply side, so that the external device on the one switching power supply side and the external device on the other switching power supply side Communication can be performed.
[0008]
The invention according to claim 2 is the switching power supply according to claim 1, wherein the communication means includes a coupling element connected between the primary winding of the transformer and the switching element.
According to the switching power supply according to claim 2, it is possible not only to obtain the power of the external device by the transformer, the coupling element can be obtained a communication vehicle, also when the switching element is in the ON state, Communication can be performed reliably.
[0009]
According to a third aspect of the present invention, in the switching power supply according to the first or second aspect, based on the duty cycle of the switching power supply, the compressed communication is transmitted while being compressed with a value slightly larger than the reciprocal of the duty cycle. It is characterized by having means for decompressing and capturing communication data.
[0010]
According to the switching power supply according to claim 3, the communication means transmits the communication data compressed with a value slightly larger than the reciprocal of the duty cycle based on the duty cycle of the switching power supply, or decompresses the compressed data. Therefore, when a compressed communication signal is input, a so-called seamless signal can be received on the receiving side, and stable communication can be performed. Even if communication is performed synchronously only at times, the risk of communication data leaking can be eliminated.
[0011]
According to a fourth aspect of the present invention, in the switching power supply according to any one of the first to third aspects, the communication means turns on / off a power source for the external device and a power source for the external device. It is characterized by comprising a control circuit that selectively executes the variable voltage by an external communication signal obtained through the power line.
According to the switching power supply of the fourth aspect, not only can the power supply be turned on / off with respect to the selected external device, but also the input voltage can be varied. For example, when the external device is a lighting fixture In addition, the lighting fixture can be turned on / off and the lighting fixture can be dimmed.
[0012]
According to a fifth aspect of the present invention, in the switching power supply according to any one of the first to fourth aspects, the communication means includes a high frequency transmission / reception circuit, an encryption / decryption circuit, a scramble circuit, a modulation / demodulation circuit, and a signal processing circuit. It is characterized by having.
According to the switching power supply according to the fifth aspect, when the external devices connected via the switching power supply connected to the AC power supply are personal computers, mutual communication can be performed reliably, and encryption / decryption can be performed. It is possible to communicate safely and reliably only with the target communication partner by the circuit.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific examples of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a switching power supply according to the first embodiment of the present invention, and FIG. 2 is a circuit diagram showing communication means provided in the switching power supply.
The switching power supply according to the present embodiment is for supplying power to an external device by being connected to the power line 10 of the AC power supply shown in FIG. 2, and as shown in FIG. A field effect transistor (hereinafter referred to as FET) as a switching element having a smoothing circuit including a smoothing capacitor 11 and a rectifier diode 16 in the previous stage and switching an AC power source to a predetermined AC voltage in the subsequent stage of the primary side. 13).
[0014]
A diode 14 and a smoothing capacitor 15 are provided on the secondary side of the transformer 12, and when the FET 13 is periodically on / off controlled on the primary side of the transformer 12, an AC voltage is applied to the primary side accordingly. As a result, a secondary voltage is induced on the secondary side of the transformer 2, the secondary voltage is half-wave rectified by the diode 14, smoothed by the capacitor 15, and connected to an output terminal (not shown). DC voltage is supplied to external equipment.
As shown in FIG. 2, the external device is composed of, for example, personal computers PC1, PC2,... PCN, and each of PC1, PC2,... PCN is connected to an output terminal of a switching power source connected to a power line 10 of an AC power source. 2, reference numerals 1, 2,... N represent respective switching power supplies.
[0015]
In the switching power source, on the primary side of the transformer 12, when the coupling element 17 is connected in series between the primary winding and the FET 13, and the FET 13 is in the ON state, the external device is the power line 10 of the AC power source. Is provided as a communication interface 20 for transmitting and receiving communication data to and from each other.
[0016]
When the personal computer PC1, PC2,... PCN are connected to the power line 10 as shown in FIG. 2 and are in the ON state, the communication means 20 outputs communication data from one PC1 to the other PC2, for example. Then, communication data from the PC 1 flows to the primary side of the switching power supplies 2 to N connected to the PCs 2 to PCN via the power line 10. The other switching power supply 2 selectively receives communication data from the PC 1, and the communication means 20 provided in the other switching power supply 2 outputs the communication data from the personal computer PC1 to the other personal computer PC2, thereby Communication data from the personal computer PC1 can be transmitted to the personal computer PC2.
[0017]
In this case, the transmission information from the personal computer PC2 is output in the reverse form to the personal computer PC1 so as to be able to communicate, so that the personal computers PC1 and PC2 interface the switching power supplies 1 and 2 and the power line 10 with each other. Is configured to be communicable. Therefore, although not shown in detail, the personal computers PC1, PC2,... PCN are configured to transmit and receive communication data when connected to the output terminal of the switching power supply.
[0018]
More specifically, as shown in FIG. 1, the communication means 20 includes a high frequency transmission / reception circuit (RF) 21, a scramble circuit 25, a modulation / demodulation circuit (MODEM) 23, and a signal processing circuit 24, and is connected to an external terminal. When the personal computer PC1, PC2,... PCN transmits communication data, the transmission data is modulated and scrambled and output as a high frequency by being superimposed on the AC voltage, while the communication data superimposed on the AC voltage is input. Are decoded and demodulated based on the communication data and input to PC1, PC2,... PCN connected to the external terminals.
[0019]
In this case, the communication contents between the personal computers are performed by using the same protocol as that in the case of Internet communication that is normally performed. Therefore, the communication means 20 has the same function as a general communication LAN card or terminal adapter provided in the personal computers PC1, PC2,... PCN, and transmits / receives data transmitted and received through the power line 10 to the target personal computer. It is designed to send and receive with.
[0020]
Further, in order to transmit and receive communication data more safely and reliably, for example, an encryption / decryption circuit 22 is provided between the scramble circuit 25 and the modulation / demodulation circuit 23 in order to accurately perform communication only between the corresponding personal computers. It is preferable to connect. Further, although not shown in the figure, when the power line communication is narrowband communication, a circuit having a carrier sense function for determining the use status of the carrier frequency (carrier) frequency or whether or not transmission at that frequency is possible, and the received signal A bit error rate (BER) or frame error rate (FER) monitoring function is provided, and a circuit for determining whether or not transmission is possible depending on the situation, and when power line communication is broadband communication, a bit of a received signal Needless to say, better communication can be achieved by providing a monitoring function for error rate (BER) or frame error rate (FER) and adding a circuit for determining whether or not transmission is possible depending on the situation. As shown in FIG. 1 , the high-frequency circuit 21 oscillates a high-frequency wave having a predetermined frequency according to a command from a control circuit 26 connected between the secondary winding of the transformer 12 and the gate of the FET 13. It operates based on the synthesizer 27.
[0021]
Such communication means 20 is turned on in conjunction with the turning on of the FET by the control circuit 26, but at the time of communication, at the time of switching of the power source, that is, at the time of turn-on / turn-off so that the communication signal can be surely synchronized at the time of communication. It is preferable not to transmit / receive.
[0022]
Since the switching power supply of the present embodiment is configured as described above, switching power supplies 1, 2,... N are connected to the power line 10 of the AC power supply as shown in FIG. PC2... PCN are connected to each other and are in the ON state.
[0023]
At this time, when transmitting communication data from one personal computer PC1 to the other personal computer PC2, when the FET 13 on the primary side of the transformer 12 is on in the switching power supply 1 on the personal computer PC1 side, the data is output from the personal computer PC1. When communication data is converted into communication data via the communication means 20 and the coupling element 17 incorporated in the switching power supply 1 connected to the personal computer PC1 and transmitted via the power line 10, the communication partner The communication means 20 incorporated in the switching power supply 2 on the side decrypts the communication data and processes it as a normal signal band used on the personal computer, thereby outputting it to the personal computer PC2 connected to the switching power supply 2 It will be.
[0024]
As a result, communication data from the personal computer PC1 is transmitted to the personal computer PC2 via the switching power supplies 1 and 2 and the power line 10, and this is performed in the same manner between the personal computers PC1 to PCN. It becomes unnecessary to connect with a cable. Therefore, it is not necessary for the personal computer to install an adapter such as a LAN card or a modem for communication, and the internal configuration of the personal computer can be simplified accordingly, so that the personal computer can be reduced in size and cost. This is the same not only for wired LANs but also for wireless LANs. Instead of wiring, base station equipment such as access points required for wireless LAN or equipment such as repeaters becomes unnecessary, and wireless communication is performed on a personal computer. It is no longer necessary to add communication equipment, and the internal configuration of the personal computer can be simplified accordingly, so that the personal computer can be reduced in size and cost. The same applies to a LON (Local Operating Network) system that realizes communication between various sensors and various actuators.
[0025]
Further, although the coupling element 17 is connected between the primary winding of the transformer 12 and the FET 13, the communication means 20 is configured so as to be able to reliably transmit a signal in synchronization with the communication partner. Thereby, communication can be performed satisfactorily.
[0026]
FIG. 3 shows a switching power supply according to the second embodiment of the present invention. This embodiment is different from the above-described embodiment in that a compression / expansion circuit 28 for compressing or expanding data is provided between the modem 23 and the signal processing circuit 24 of the communication unit 20.
[0027]
The communication means 20 can communicate only intermittently because it communicates only when the FET 13 is on and synchronously with the other party.
[0028]
Therefore, as shown in FIG. 4B, for example, when transmitting communication data, the compression / decompression circuit 28 compresses the transmission data D by delaying it by one cycle, and transmits the compressed data D1. . The control circuit 26 monitors the duty cycle of the switching power supply and compresses the communication data to the compression / expansion circuit 28 at a value slightly larger than the value obtained by dividing one cycle of the switching power supply by the primary side power energization time. Is supposed to be done. At the time of reception, as shown in FIG. 5C, the received compressed data is expanded based on the compression rate on the transmission side that is folded as information in the received signal, and expanded data D2 (= D ) And the decompressed data D2 is obtained.
Therefore, when transmitting, the communication means 20 transmits the transmission data as compressed data delayed by one cycle. On the other hand, when the compressed transmission data is input, the data is expanded and read by the compression / decompression circuit. It is like that.
In the case of the switching power supply, the FET 13 is turned on (T on) and turned off (T off), and includes a large and wideband noise, and communication between the turn on and the turn off is avoided. The reason why the compression ratio is set to a value slightly larger than the value obtained by dividing one cycle of the switching power supply in the primary-side power energization time is to avoid transmission at the turn-on and turn-off.
[0029]
According to this embodiment, based on the duty cycle of the switching power supply, when communication data compressed by a value slightly larger than a value obtained by dividing one cycle of the duty cycle is transmitted or received when compressed data is received, Since it is configured to expand at the transmission side compression rate built in the signal, when a compressed communication signal is input, the receiving side can receive a so-called seamless signal and perform stable communication. be able to.
[0030]
5 and 6 show a switching power supply according to another embodiment of the present invention. In the embodiment described above, an example is shown in which only the personal computers PC1, PC2,..., PCN are connected to one switching power supply. However, in this embodiment, the switching power supply 1 is connected to the power line 10 as shown in FIG. The personal computer PC1 is connected through the switching power supply 2, and the personal computer PC2, the lighting fixture 30, and the refrigerator 40 are connected through the switching power supply 2. That is, a plurality of electrical products such as personal computers (PC1, PC2), lighting fixtures 30, and refrigerators 40 are connected to the switching power supply as external devices, and power can be supplied to each of them. In this example, the lighting fixture 30 in this case has a light control function capable of changing the amount of light.
[0031]
The communication means 20 built in the switching power supplies 1 and 2 not only outputs a signal for outputting an on / off signal to an external device in response to a command from the personal computer PC1, but also a signal for changing the amount of light when in the on state. Can be transmitted through the power line 10, and by capturing the signal transmitted through the power line 10, the power to the external device can be turned on / off, and the light quantity can be changed in the on state. It has become.
[0032]
Therefore, as shown in FIG. 5, the communication means 20 of the switching power supply 2 is provided with an FET 19 for turning on / off the power to an external device or changing the voltage by the control circuit 26, and is transmitted from one personal computer PC1. Based on the received signal, the signal processing circuit 24 on the personal computer PC2 side performs processing, so that the control circuit 26 selectively controls the FET 19 accordingly, that is, the lighting apparatus 30 and the refrigerator 40 are turned on and off. Or can be dimmed by changing the input voltage to the luminaire 30.
[0033]
Therefore, as the communication means 20 of this embodiment, the signal processing circuit 24 not only transmits and receives communication signals from the personal computer as in the above-described embodiment, but also includes the lighting device 30 and the refrigerator 40 connected to the switching power supply. It is possible to turn on / off the input power to such an external device and change the input voltage. Such a thing can be similarly applied not only to the lighting fixture 30 and the refrigerator 40 but also when other electrical products such as a TV are connected.
[0034]
Moreover, although the example comprised with the transformer which consists of the secondary winding induced by the coil | winding provided in the primary winding side of the transformer 12 as the coupling element 17 of the communication means 20 was shown, it does not restrict to this Alternatively, the secondary winding of the power conversion transformer 12 can be used. For example, a transistor and a diode of a photocoupler can be substituted. In short, the communication means 20 is turned on by turning on the FET 13 as a switching element. As long as the communication becomes possible.
[0035]
【The invention's effect】
As described above, according to the present invention, when a communication signal from an external device on one side of the switching power supply connected to the power line is transmitted to the other switching power supply connected to the power line, the switching is performed. Since it is configured so that it can be received by the external device via the communication means on the power supply side, it can communicate with the external device on the one switching power supply side and the external device on the other switching power supply side. In addition to being able to obtain a power source, there is an effect that communication can be reliably performed when the switching element is in an ON state.
Further, since the power line is used as a communication line, a communication line that has been necessary separately from the power line until now becomes unnecessary.
Switching power obtained by adding a function of transmitting and receiving signals to an external device of the present invention, than when using separately a single communication device using power line, also serves as a lightning protection circuit and safety equipment to be mounted to a normal internal power supply The power conversion transformer can be used as a coupling element, and as shown in the second embodiment of the present invention, the power output ON / OFF or the voltage adjustment function can be easily folded. Have.
[0036]
In addition, when a compressed communication signal is input at the time of transmission, the receiving side can receive the signal continuously, so that stable communication can be performed, so that only when the power is on is synchronized Even if it communicates, there exists an effect which can eliminate the possibility that communication data may leak.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a switching power supply according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing an example of use of the switching power supply of FIG.
FIG. 3 is a circuit diagram showing a switching power supply according to a second embodiment of the present invention.
4A and 4B are diagrams illustrating the operation of a compression / decompression circuit provided in a communication unit, where FIG. 4A is an explanatory diagram illustrating communication data, FIG. 4B is an explanatory diagram illustrating a transmission signal, and FIG. It is explanatory drawing which shows data.
FIG. 5 is a circuit diagram showing a switching power supply according to another embodiment of the present invention.
6 is a circuit diagram showing an example of use of the switching power supply of FIG. 5;
[Explanation of symbols]
1, 2 to N ... switching power supply 10 ... power line 12 of AC power supply ... transformer 13 ... switching element (FET)
DESCRIPTION OF SYMBOLS 17 ... Coupling element 20 ... Communication means 21 ... High frequency circuit 22 ... Encryption / decryption circuit 23 ... Modulation / demodulation circuit 24 ... Signal processing circuit 25 ... Scramble circuit 26 ... Control circuit 28 ... Compression / decompression circuit

Claims (5)

The AC input voltage of the power line of the AC power supply is converted into a predetermined AC voltage by the switching element, the converted AC voltage is applied to the primary winding of the transformer, and the AC voltage taken out from the secondary winding of the transformer is smoothed. In switching power supplies that output to external devices connected to the output terminal,
When an AC voltage converted by the switching element is applied to the primary winding of the transformer, communication is performed using an AC power line as a communication line to an external device connected to the output terminal of the secondary winding of the transformer. A switching power supply comprising communication means connected between a primary winding of the transformer and the switching element so as to transmit and receive signals. The switching power supply according to claim 1,
The switching power supply, wherein the communication means includes a coupling element connected between a primary winding of the transformer and a switching element. The switching power supply according to claim 1 or 2,
The communication means has means for transmitting communication compressed at a value slightly larger than the reciprocal of the duty cycle based on the duty cycle of the switching power supply, and having means for expanding and taking in the compressed communication data Switching power supply. In the switching power supply according to any one of claims 1 to 3,
The communication means selectively executes turning on / off the input power to the external device and varying the input voltage to the external device based on an external communication signal obtained through the power line. A switching power supply characterized by having a control circuit. In the switching power supply according to any one of claims 1 to 4,
A switching power supply characterized in that the communication means includes a high frequency transmission / reception circuit, an encryption / decryption circuit, a scramble circuit, a modulation / demodulation circuit, and a signal processing circuit.

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