JP2016149884A - Dc power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC power supply device in which, even if a short-circuit abnormality occurs at the side of a DC regulator being operated, the DC regulator can be promptly exchanged with a DC regulator being on hot-standby.SOLUTION: The DC power supply device comprises: a first DC regulator 20 by which an input DC voltage supplied from an input-side power supply circuit 10 to an input terminal is converted into a first predetermined voltage and outputted; a second DC regulator 30 which is connected in parallel with the first DC regulator and by which an input DC voltage is converted into a second predetermined voltage that is different from the first predetermined voltage, and outputted; and diodes D1 and D2 which are connected to output terminals of the DC regulators 20 and 30 in a forward direction and of which the cathodes are connected to a common output terminal. The DC power supply device is configured to output the DC voltage from the second DC regulator 30 if operation of the first DC regulator 20 is stopped. Between an input terminal Ti and each of the DC regulators 20 and 30, short-circuit protection circuits 40 and 50 are provided for disconnecting a corresponding feeder line if a short-circuiting state is detected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a DC power supply device including a short circuit protection circuit.

  As shown in FIG. 4, Patent Document 1 discloses a power supply device that can output DC short-circuit protection with a simple circuit by converting a DC voltage Vcc into a DC voltage of a different value, and outputs a reference voltage Vref. A reference voltage generation circuit for generating a voltage, a control circuit for stabilizing the output voltage by controlling the transistor Q1 according to the reference voltage, and detecting a short circuit when the output side is short-circuited to lower the reference voltage Vref to lower the output voltage Thus, there has been proposed a power supply device including a short circuit detection circuit that performs an output short circuit protection operation.

  As shown in FIG. 5, Patent Document 2 discloses a DC-DC having an overcurrent protection circuit that has high conversion efficiency and can detect and block overcurrent with high accuracy without being affected by ambient temperature. A DC-DC converter aimed at providing a converter is disclosed.

  The DC-DC converter connects the first switching means S1 connected to one electrode of the DC input power supply and performing on / off operation, the subsequent stage of the first switching means S1 and the other electrode of the DC input power supply, A second switching means S2 that performs an off / on operation in synchronization with an on / off operation of the first switching means S1, a control circuit that drives and controls the first switching means S1 and the second switching means S2, and a second Is connected to the subsequent stage of the switching means S2, and forms a DC output voltage, a smoothing circuit SC1, a first detection resistor R connected between the DC input power source and the first switching means S1, and a first detection resistance A current value flowing in a series circuit constituted by R and the first switching means S1 is detected, and the first switching means S is detected when the current value exceeds a predetermined value. And a detection circuit for outputting a signal for turning off the operation of the control circuit.

JP 2001-350529 A JP 2002-10627 A

  In recent years, loads that require high reliability, such as on-vehicle equipment and medical equipment, have been redundantly installed with direct current regulators such as switching power supplies so that power supply does not stop instantaneously. There is a need for a DC power supply apparatus that employs a configuration in which the other DC regulator is hot standby so that even if a failure occurs in the other DC regulator, the other DC regulator can be backed up.

  Usually, in such a DC power supply device, an AC / DC converter is installed upstream in order to supply DC power to a redundantly installed DC regulator. The AC / DC converter is also provided with an overcurrent protection circuit and a short circuit protection circuit in order to protect internal semiconductor elements and the like.

  However, the above-described conventional overcurrent protection circuit and short circuit protection circuit are configured for the purpose of detecting a short circuit abnormality on the load side connected to each power supply device, and are not configured to detect the own short circuit abnormality. Therefore, for example, when a short circuit abnormality occurs in the operating DC regulator, the overcurrent flowing through the DC regulator is detected, and the overcurrent protection circuit provided in the AC / DC converter is activated on the upstream side, so that the backup DC regulator There was a problem that power supply to the station was also stopped.

  When the AC / DC converter is not equipped with an overcurrent protection circuit, the AC / DC converter component is damaged due to a short circuit abnormality on the DC regulator side, or a load that requires high reliability connected to the DC regulator There is also a problem that it cannot be used as a power supply device for a load that requires high reliability.

  In view of the above-described problems, an object of the present invention is to provide a DC power supply apparatus in which a hot standby DC regulator can be quickly replaced even if a short circuit abnormality occurs on the operating DC regulator side.

  In order to achieve the above object, the first characteristic configuration of the DC power supply device according to the present invention is the input DC supplied from the input side power supply circuit to the input terminal as described in claim 1 of the claims. A first DC regulator that converts the voltage to a first predetermined voltage and outputs the first DC regulator, and the input DC voltage connected in parallel with the first DC regulator is converted to a second predetermined voltage that is different from the first predetermined voltage. And a second DC regulator that is forward-connected to the output terminals of the DC regulators and a cathode that is connected to a common output terminal. The second DC regulator is provided when the operation of the first DC regulator is stopped. A DC power supply device configured to output a DC voltage from a regulator, and corresponding to detection of a short circuit state between the input terminal and each DC regulator. In that it includes a short-circuit protection circuit for disconnecting the power supply line.

  Of the first DC regulator and the second DC regulator, the DC regulator with the higher output voltage functions as a main DC regulator that preferentially supplies power to the load, and the DC regulator with the lower output voltage is the sub DC that is in hot standby. Functions as a regulator. Since a diode is connected to each output terminal in the forward direction, no current flows from the main DC regulator to the sub DC regulator.

  If a short circuit abnormality occurs on the first DC regulator side during operation of the first DC regulator, the power supply line to the first DC regulator side is disconnected by the short circuit protection circuit provided in the first DC regulator. Even if an overcurrent protection circuit is provided in the power supply circuit, the overcurrent protection circuit does not operate, and power is immediately supplied to the load side from the second DC regulator in which the power supply from the input side power supply circuit in the previous stage is maintained. It becomes like this.

  In addition, when a short circuit abnormality occurs on the second DC regulator side during the hot standby, the power supply line to the second DC regulator side is disconnected by the short circuit protection circuit provided in the second DC regulator. The state where power is stably supplied to the load side is continued.

  According to the second characteristic configuration, as described in claim 2, in addition to the first characteristic configuration described above, the short circuit protection circuit includes a switch provided on a power supply line from the input terminal to each DC regulator. An element, a current limiting element connected in parallel to each switch element, and each DC regulator by closing the switch element based on a voltage transmitted through the current limit element when the DC regulator side is not short-circuited. A control circuit that supplies power and opens the switch element when a short circuit occurs on each DC regulator side is provided.

  When the switch element is closed by the control circuit, power is supplied to the DC regulator, and when the switch element is opened, power supply to the DC regulator is blocked. When the DC regulator side is not short-circuited, the voltage applied to the input terminal is input to the control circuit via the current limiting element, and when the DC regulator side is short-circuited, a voltage lower than the voltage applied to the input terminal is input to the control circuit. The switch element provided in the power supply line to the regulator is controlled to be closed or opened. If the switch element is opened due to a short circuit on the DC regulator side, the current limiting element limits the current that flows from the input-side power supply circuit to the DC regulator side, so an overcurrent protection circuit is temporarily provided in the previous input-side power supply circuit. The overcurrent protection circuit will not operate.

  The third feature configuration is that, as described in claim 3, in addition to the second feature configuration described above, the current limiting element is configured by a fuse that blows when each DC regulator side is short-circuited. is there.

  A fuse can be suitably used as the current limiting element. When a short circuit abnormality occurs on the DC regulator side, the fuse is instantaneously blown, so that the power supply to the DC regulator is reliably cut off.

  In the fourth feature configuration, as described in claim 4, in addition to any of the first to third feature configurations described above, the input-side power supply circuit includes an overcurrent protection circuit, The operation time of the short circuit protection circuit is set to be shorter than the operation time of the protection circuit.

  The short-circuit protection circuit provided on each DC regulator side operates before the overcurrent protection circuit provided on the input-side power supply circuit, so power supply from the input-side power supply circuit does not stop and it is reliably in hot standby. The power supply from the DC regulator to the load is continued.

  As described above, according to the present invention, it is possible to provide a DC power supply apparatus in which a hot standby DC regulator can be quickly replaced even if a short circuit abnormality occurs on the operating DC regulator side. It was.

Block diagram of a DC power supply device according to the present invention The circuit diagram of the short circuit protection circuit which detects the short circuit abnormality in the direct current regulator side of the direct current power supply device by this invention Circuit diagram of a short-circuit protection circuit showing another embodiment Explanatory drawing of conventional short circuit detection circuit Illustration of a conventional overcurrent detection circuit

A DC power supply device according to the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of a DC power supply device 100 according to the present invention. The DC power supply device 100 includes a first DC regulator 20 that converts the input DC voltage Vi fed from the input-side power supply circuit 10 to the input terminal Ti of the DC power supply device 100 into a first predetermined voltage Vo1, and outputs the first DC regulator Vi. A second DC regulator 30 connected in parallel with the DC regulator 20 and converting the input DC voltage Vi to a second predetermined voltage Vo2 different from the first predetermined voltage Vo1; and output terminals of the DC regulators 20 and 30 Diodes D1 and D2 connected in the forward direction to each cathode and connected to a common output terminal To.

  The input-side power supply circuit 10 is composed of an AC / DC converter that converts AC power supplied from, for example, an AC 100 V commercial power source into DC power, and an AC that converts an output voltage to a predetermined DC voltage Vi, which is DC 20 V in this embodiment. A DC / DC converter and an overcurrent protection circuit that detects an excessive current flowing in a load connected to the AC / DC converter and stops the output. In this embodiment, the load is the DC regulators 20 and 30.

  The first DC regulator 20 and the second DC regulator 30 are constituted by an insulating DC / DC converter in which transformers 24 and 34 are incorporated, and electrolytic capacitors 21 and 31 that absorb noise such as ripples of input voltage, and a transformer 24. , 34 connected to the primary side coil of the switching circuit 22, 32 provided with switching elements such as FET, switching control units 23, 33 for controlling the switching elements of the switching circuits 22, 32, and transformers 24, 34 Secondary side circuits 25 and 35 connected to the secondary side coil.

  The output voltage Vo1 of the first DC regulator 20 is set to DC15V, and the output voltage Vo2 of the second DC regulator 30 is set to around DC14.5V slightly lower than Vo1. The output terminals of the first DC regulator 20 and the second DC regulator 30 are connected to a common output terminal To via diodes D1 and D2, and the output of one DC regulator is configured not to flow backward to the other DC regulator. Yes.

  The first DC regulator 20 and the second DC regulator 30 are always operating by being supplied with the DC voltage Vi from the input-side power supply circuit 10, but normally the output voltage Vo1 is slightly higher than the output voltage Vo2. A load device L connected to the output terminal To from the second DC regulator 30 when power is supplied from the DC regulator 20 to the load device L connected to the output terminal To and the output of the first DC regulator 20 is stopped for some reason. It is comprised so that it may be fed to.

  That is, the first DC regulator 20 with a high output voltage functions as a main DC regulator that preferentially supplies power to the load, and the second DC regulator 30 with a low output voltage functions as a sub DC regulator during hot standby.

  When a short circuit failure occurs in the first DC regulator 20 and the overcurrent protection circuit provided in the input-side power supply circuit 10 is activated, the power supply to the second DC regulator 30 is inevitably stopped. When a vehicle-mounted device is connected to the vehicle, safety is lost due to the stoppage of power supply, which may affect human life.

  Therefore, short-circuit protection circuits 40 and 50 are provided between the input terminal Ti and each of the DC regulators 20 and 30 to disconnect the corresponding power supply lines when a short-circuit state is detected.

  If a short circuit abnormality occurs on the first DC regulator 20 side during the operation of the first DC regulator 20, the power supply line to the first DC regulator 20 side is disconnected by the short circuit protection circuit 40. Even if a current protection circuit is provided, the overcurrent protection circuit does not operate, and power is immediately supplied to the load device L from the second DC regulator 30 in which power supply from the input-side power supply circuit 10 is maintained. .

  In addition, when a short circuit abnormality occurs on the second DC regulator 30 side during hot standby, the power supply line to the second DC regulator 30 side is disconnected by the short circuit protection circuit 50, so that the first DC regulator 20 in operation is stable. Thus, the state where power is supplied to the load device L is continued.

  Note that the short circuit failure of the DC regulators 20 and 30 is not only a failure such as a short circuit of the electrolytic capacitors 21 and 31 or a short circuit of a switching element provided in the switching circuit, but also an external conductive member is grounded to the power source side of the circuit. Includes short circuit accidents that touch the side.

  As shown in FIG. 2, each short circuit protection circuit 40, 50 includes a switch element TR1 provided on a power supply line from the input terminal Ti to each DC regulator 20, 30, and a current limit connected in parallel to each switch element TR1. The switch element TR1 is closed based on the voltage transmitted through the current limiting element R1 when the DC regulator side and the DC regulator side are not short-circuited to supply power to the DC regulators 20, 30, respectively. Control circuits 45 and 55 for opening the switch element TR1 when the side is short-circuited. In the present embodiment, a resistance element having a high resistance value of about several hundred Ω to 1 kΩ is used for the current limiting element R1.

  Each of the control circuits 45 and 55 includes transistors TR2 and TR3 and a bias circuit that adjusts the base voltage of each of the transistors TR2 and TR3. When the power is turned on when the switch element TR1 is opened (off), the input voltage Vi (= DC20V) is applied to the voltage dividing circuit of the resistor R2, the diode D3, and the resistor R3 via the current limiting element R1, and the transistor TR3 is turned on. When the transistor TR3 is turned on, the transistor TR2 is turned off and the switch element TR1 is closed (turned on). As a result, the DC voltage Vi is applied from the input-side power supply circuit 10 to the subsequent supply DC regulators 20 and 30 via the control circuits 45 and 55.

  If a short circuit accident occurs on either DC regulator 20, 30 side, the voltage across capacitor C1 (21, 31) drops abruptly, so the voltage applied to the voltage divider circuit drops and transistor TR3 turns off. . When the transistor TR3 is turned off, the transistor TR2 is turned on and the charge accumulated in the gate is discharged, so that the switch element TR1 is opened (turned off). As a result, the power supply line from the input side power supply circuit 10 to the subsequent supply DC regulator is opened, and the subsequent DC regulator is stopped.

  When the switching element TR1 is opened due to a short circuit on the DC regulators 20 and 30 side, the current flowing from the input side power supply circuit 10 to the DC regulators 20 and 30 side is limited by the current limiting element R1. Even if the overcurrent protection circuit is provided, the overcurrent protection circuit does not operate. If the short circuit protection circuits 40 and 50 are provided, it is not necessary to provide an overcurrent protection circuit in the input side power supply circuit 10 uniquely.

  Further, when the power is turned on, the switch element TR1 of the short-circuit protection circuits 40 and 50 is opened, and the voltage is divided with the internal resistance R7 of the switching controllers 23 and 33 of the DC regulators 20 and 30 via the current limiting element R1. It is necessary to set R1 so that the voltage determined by is higher than the operating voltage of each switching control unit 23, 33.

  When a short circuit abnormality has occurred on the DC regulators 20 and 30 side, the current flowing to the DC regulators 20 and 30 side is limited via the current limiting element R1, so that an overcurrent flows out from the input side power supply circuit 10. There is no such thing.

  In this embodiment, the switching control units 23 and 33 are set to start at DC 10 V, and when a short circuit abnormality occurs on the DC regulator 20 or 30 side, the short circuit resistance value on the DC regulator 20 or 30 side is several hundred mΩ or less. Therefore, the circuit composed of the resistor R2, the Zener diode ZD1, the resistor R3, and the transistor TR3 does not operate, the transistor TR3 is opened, and the transistor TR1 is also opened.

  Since the current from the input terminal Ti is in series with the resistor R1 and the short-circuit resistance value on the DC regulator 20 and 30 side (about several tens to several hundreds mΩ or less), the current during short-circuit is limited by the resistor R1.

  FIG. 3 shows another embodiment of the short-circuit protection circuits 40 and 50 incorporated in the DC power supply device 100 according to the present invention. 2 is different from the short-circuit protection circuits 40 and 50 shown in FIG. 2 in that a fuse F1 that melts when the DC regulators 20 and 30 are short-circuited is used as a current limiting element instead of a high-resistance resistor.

  When the fuse F1 is used as the current limiting element, a short-circuit current flows to the fuse F1 when a short-circuit abnormality occurs on the DC regulator 20, 30 side, so that the DC regulator 20, 30 is surely supplied with power. Will be blocked.

  The example in which the input-side power supply circuit 10 is provided with the overcurrent protection circuit has been described, but it is preferable that the operation time of the short circuit protection circuits 40 and 50 is set shorter than the operation time of the overcurrent protection circuit. .

  For example, although the current flows through the fuse F1 when the short-circuit protection circuits 40 and 50 are started up, TR1 is turned on in a steady state and the current does not flow through F1, so that the operating time can be shortened by setting the F1 fusing current value low. It becomes possible.

  Since the short-circuit protection circuits 40 and 50 provided on the DC regulators 20 and 30 side are activated earlier than the overcurrent protection circuit provided on the input-side power supply circuit 10, the power supply from the input-side power supply circuit 10 may be stopped. Therefore, the power supply from the DC regulator during hot standby to the load device is surely continued.

  In the above-described embodiment, an example in which an insulated DC / DC converter is used as the DC regulators 20 and 30 has been described. However, a non-insulated DC / DC converter may be used. Either a step-down type or a step-up type DC / DC converter may be used corresponding to the input voltage of the load device. Furthermore, a series regulator may be used as the DC regulators 20 and 30 in addition to using a switching power supply such as a DC / DC converter.

  The above-described embodiments are merely examples of the present invention, and the present invention is not limited to the specific examples described above. The specific configuration of each block and the like are within the scope of the present invention. Needless to say, the design can be changed as appropriate.

10: input side power supply circuit 20: first DC regulator 30: second DC regulator 40: first short circuit protection circuit 50: second short circuit protection circuit 100: DC power supply devices D1, D2: diodes

Claims (4)

A first DC regulator that converts an input DC voltage fed from an input-side power supply circuit to an input terminal into a first predetermined voltage and outputs the first DC voltage, and is connected in parallel to the first DC regulator, and the input DC voltage is converted into the first DC voltage. A second DC regulator that converts and outputs a second predetermined voltage different from the predetermined voltage, and a diode that is forward-connected to the output terminal of each DC regulator and has each cathode connected to a common output terminal, A DC power supply configured to output a DC voltage from the second DC regulator when the operation of the first DC regulator is stopped;
A DC power supply device comprising a short-circuit protection circuit that disconnects a corresponding power supply line when a short-circuit state is detected between the input terminal and each DC regulator.   The short-circuit protection circuit includes a switch element provided in a power supply line from the input terminal to each DC regulator, a current limiting element connected in parallel to each switch element, and the current limiting element when the DC regulator side is not short-circuited 2. A control circuit is provided that closes the switch element based on a voltage transmitted via the power supply to supply power to each DC regulator and opens the switch element when a short circuit occurs on each DC regulator side. The direct current power supply device described.   3. The DC power supply device according to claim 2, wherein the current limiting element is constituted by a fuse that is blown when a short circuit occurs on each DC regulator side.   The overcurrent protection circuit is provided in the said input side power supply circuit, The operation time of the said short circuit protection circuit is set so that it may become shorter than the operation time of the said overcurrent protection circuit. DC power supply.

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