JP4388300B2 - 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 the 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 can supply a DC voltage to the external device by being connected to the AC power supply, but it 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 problems, the following means are employed in the present invention.
That is, in the invention according to claim 1, an AC input voltage into a predetermined AC voltage by the switching element, by applying the converted AC voltage to the primary winding of the transformer, taken from a secondary winding of the transformer In a switching power supply that smoothes and outputs the AC voltage to an external device connected to the output terminal, the power line of the AC power supply is used as a communication line for the external device connected to the output terminal of the secondary winding of the transformer. Communication means for transmitting and receiving communication signals, the communication means obtained through the power line to turn on / off the input power to the external device and to change the input voltage to the external device It characterized that you have a control circuit that selectively executed based on the communication signal from the outside.
[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 received by the external device via the communication means on the switching power supply side. Therefore, the external device on the one switching power supply side and the external device on the other switching power supply side Communication is possible, and when the external device is a personal computer, it is possible to perform good communication between one personal computer and the other personal computer. Further, not only can the power supply be selectively turned on / off with respect to the external device, but also the input voltage can be varied. For example, when the external device is a luminaire, the luminaire is turned on / off. In addition, the lighting device can be dimmed.
[0010]
In the invention according to claim 2 , the AC input voltage 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. In a switching power supply that smoothes and outputs to an external device connected to the output terminal, a communication signal is transmitted to the external device connected to the output terminal of the secondary winding of the transformer using the power line of the AC power supply as a communication line. Communication means for transmitting and receiving, wherein 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.
According to the switching power supply according to claim 2, 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 received by the external device via the communication means on the switching power supply side. Therefore, the external device on the one switching power supply side and the external device on the other switching power supply side Communication is possible, and when the external device is a personal computer, it is possible to perform good communication between one personal computer and the other personal computer. In addition, when the external devices connected via the switching power supply connected to the AC power supply are personal computers, it is possible to reliably communicate with each other, and with the encryption / decryption circuit, only the target communication partner is safe. And it can communicate reliably.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific examples of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a switching power supply according to the first embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of use of the switching power supply of FIG.
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).
[0012]
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 rectified by the diode 14, smoothed by the capacitor 15, and connected to an output terminal (not shown). A DC voltage is supplied to.
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.
[0013]
In the switching power supply, the coupling element 17 is connected to the input side of the primary side of the transformer 12 than the rectifier diode 16 connected in series to the FET 13, and the communication means 20 is connected via the coupling element 17. ing.
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, the communication data from the PC 1 flows through the power line 10 to the primary side of the switching power supplies 2 to N connected to the PCs 2 to PCN. 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 By using the power line 10 as an interface for communication, communication data from the personal computer PC1 can be transmitted to the personal computer PC2.
[0014]
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. Therefore, the personal computers PC1 and PC2 or the switching power supplies 1 and 2 and the power line 10 are used as interfaces. It is configured to be able to communicate. 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.
[0015]
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.
[0016]
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.
[0017]
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. Such communication means 20 operates based on a synthesizer 27 that oscillates a high frequency (carrier wave) having a predetermined frequency.
[0018]
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.
[0019]
At this time, when communication data is transmitted from one personal computer PC1 to the other personal computer PC2, the communication data output from the personal computer PC1 is the communication means 20 built in the switching power supply 1 connected to the personal computer PC1. And when converted into communication data via the coupling element 17 and transmitted via the power line 10, the communication means 20 built in the switching power supply 2 on the communication partner side decodes the communication data, By processing as a normal signal band used on the personal computer, the signal is output to the personal computer PC2 connected to the switching power supply 2.
[0020]
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. There is no need to connect computers with LAN cables. 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.
[0021]
Further, since the coupling means 17 is connected to the upstream side of the primary winding side of the transformer 12, that is, the input side of the rectifier diode 16 of the smoothing circuit, the communication means 20 is connected regardless of whether the FET 13 is on or off. The ring element 17 is always turned on, and a communication function can always be performed.
[0022]
3 and 4 show a switching power supply according to the second embodiment of the present invention. In the above-described embodiment, an example in which only the personal computers PC1, PC2,..., PCN are connected to one switching power supply is shown. 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.
[0023]
The communication means 20 incorporated in the switching power supplies 1 and 2 has not only a signal for outputting an on / off signal to an external device in response to a command from the personal computer, but also a signal for changing the light amount when in the on state. While being able to transmit via the power line 10, by taking in the signal transmitted via the power line 10, it is possible to turn on / off the power supply to the external device and also to change the amount of light in the on state. ing.
[0024]
Therefore, as shown in FIG. 4, 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 processes it, 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.
[0025]
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.
[0026]
In the above embodiment, the communication type between the personal computer, the lighting fixture, the refrigerator, and the like can be applied to the connectionless type and the connection type as well.
Moreover, although the example comprised by the transformer which consists of the secondary winding induced by the coil | winding provided in the front | former stage of the transformer 12 as the coupling element 17 of the communication means 20 was shown, it does not restrict to this Alternatively, for example, a photocoupler transistor and a diode can be substituted. In short, any device that can input signal power to the communication means 20 by connecting the switching power supply to the power line 10 may be used.
[0027]
【The invention's effect】
As described above, according to the present invention, when each switching power supply is connected to the power line of the AC power supply and an external device is connected to each 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 can be received via the communication means on the switching power supply side, so that the external device on one switching power supply side and the external device on the other switching power supply side This makes it possible to communicate well between one computer and the other when the external device is between computers, and regardless of whether the switching element is on, Since the coupling element is always on, there is an effect that the communication function can always be performed. 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 As shown in the second embodiment of the present invention, there is an advantage that the power output ON / OFF or the voltage adjustment function can be easily folded.
[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 of a usage example showing a switching power supply according to a second embodiment of the present invention.
4 is a circuit diagram showing a switching power supply in FIG. 3. FIG.
[Explanation of symbols]
1, 2 to N
DESCRIPTION OF SYMBOLS 10 ... Power line 12 ... 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

Claims (2)

The AC input voltage 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 to the output terminal. In switching power supplies that output to connected external devices,
A communication means for transmitting and receiving a communication signal using a power line of an AC power source as a communication line for an external device connected to the output terminal of the secondary winding of the transformer,
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 comprising a control circuit. The AC input voltage 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 to the output terminal. In switching power supplies that output to connected external devices,
A communication means for transmitting and receiving a communication signal using a power line of an AC power source as a communication line for an external device connected to the output terminal of the secondary winding of the transformer,
The 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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