JPH03124231A - Multiplex dc power supply - Google Patents

Abstract

PURPOSE:To relieve regulating work even for a load circuit to be driven with a low voltage power supply by connecting each power supply unit through a FET transistor with a corresponding load circuit and arranging a shunt regulator for controlling the gate voltage with the output voltage from the power source unit in each switch circuit. CONSTITUTION:A power supply unit comprising a voltage stabilizing section 2a and a switch circuit 5a and another power supply unit comprising a voltage stabilizing section 2b having identical circuitry and a switch circuit 5b are connected in parallel, and then one input power supply 1 and a load circuit 4a constituting an exchange are connected therewith. When the voltage at a terminal 21 drops below a predetermined level, a shunt regulator circuit 24 turns a transistor 11 OFF and interrupts the connection between the terminals 21, 22. The shunt regulator circuit 24 controls the gate voltage of the FET transistor 11. By such arrangement, regulation work can be relieved even for a load circuit to be driven with a low voltage power supply.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a multiplexed DC power supply device, and in particular, a multiplexed DC power supply device suitable for ensuring backup in the event of a failure and reducing the spread of the failure. Regarding power supplies.

[Conventional technology]

FIG. 5 is a block diagram of a device using a conventional multiplexed DC power supply. In this example, the voltage stabilizing section 2a is provided with the output voltages of one DC power supply 1 in parallel.

2b and 2c, and the respective outputs of the voltage stabilizing parts 2a and 2b are combined after passing through switch circuits 3a and 3b,
Two load circuits 4a and 4b are connected in parallel to the combined output line. Further, another load circuit 4c is independently connected to the output of the voltage stabilizing section 2c. In this conventional example,
Each of the switch circuits 3a and 3b is a diode switch circuit.

- For example, the voltage stabilizing section 2a.

2b fails, the output voltage of the failed voltage stabilizing section decreases. Then, the diode connected to that voltage stabilizing section becomes reverse biased with the output voltage of the non-faulty voltage stabilizing section, and this faulty voltage stabilizing section becomes disconnected from the load circuit. on the other hand,
The load circuit is continuously supplied with power from the voltage stabilizing section that is not faulty, and the load circuit maintains normal operation.

Furthermore, for example, if a circuit component of the load circuit 4a suffers from a short-circuit failure, the influence of this failure will also spread to the load circuit 4b. Therefore, in this conventional example, the load circuit 4c with a high priority is connected to a separate independent voltage stabilizing section 2C to prevent the failure from spreading.

In addition, as related to the prior art,
There is No. 778.

[Problem to be solved by the invention]

In the conventional multiplexed DC power supply device described above, a diode constituting a switch circuit is inserted in series with the output of the voltage stabilizing section. For this reason, the voltage drop of this diode cannot be tolerated in a load circuit such as a TTL logic circuit whose power source is a low voltage of about 5 V, and the load circuit often does not operate normally. For this reason, in the conventional multiplexed DC power supply, it is necessary to adjust the output voltage in consideration of the amount of variation in load current and voltage drop, and the adjustment work is troublesome.

Furthermore, when the load current is high, the power loss also increases, and therefore the heat sink for cooling the diode becomes large, which also causes the problem that the cost increases.

Furthermore, the above-mentioned power loss means a decrease in efficiency, which leads to an increase in the output power capacity of the input power source 1, which is disadvantageous in reducing the size and cost of a multiplexed DC power source.

Furthermore, providing an independent dedicated power supply unit in order to prevent the spread of failures increases the number of power supply units, which is economically disadvantageous.

Switches powered by the conventional multiplexed DC power supplies mentioned above have a problem of low reliability against failures when providing services online all the time, and as switching machines continue to become smaller, it is necessary to downsize the power supplies. is also requested.

The purpose of the present invention is to reduce the burden of adjustment work even for load circuits driven by low-voltage power supplies, reduce power loss, and eliminate the need to provide a dedicated power supply unit to prevent the spread of failures. It is an object of the present invention to provide a small, low-cost multiplexed DC power supply device, a power supply unit 1 to constitute this power supply device, and a highly reliable exchange using this power supply device.

[Means to solve the problem]

The purpose of the tenth item is to provide power supply units 1 to 10 comprising at least a voltage stabilizing section and a switch circuit constituting a multiplexed DC power supply.
By configuring the switch circuit with a field effect transistor that connects the power supply unit and the load circuit, and a shunt regulator that turns off the field effect transistor when the output voltage of the power supply unit 1 to becomes lower than a predetermined voltage value. , achieved.

18 [Function] Some field effect transistors have a small conduction resistance when conducting, so the voltage drop can be reduced by using such a field effect transistor. Also, by arranging multiple field effect transistors in parallel,
Even if the load current is large, the voltage drop can be reduced, and fluctuations in the output voltages of the power supply units 1 to 1 can be suppressed within an allowable range. Therefore, it can be easily applied to load circuits driven by low voltage power supplies. Furthermore, since there is little power loss, it becomes easy to achieve low cost and miniaturization.

In addition, the shunt regulator detects the occurrence of a fault using voltage, and when a fault occurs, the field effect transistor is immediately turned off, thereby preventing the fault from spreading to other circuits. Furthermore, by setting the operating voltage of the shunt regulator according to the priority of the load circuit connected to the switch circuit, even if a failure occurs in either power supply or load circuit, the voltage will be applied to the load circuit with the higher priority. This makes it possible to guarantee power supply, and there is no need to provide a dedicated power supply for this purpose.

Note that in a field effect transistor, a parasitic diode is inserted in parallel between the drain and source (an external diode may also be used). (is in a cut-off state), the current is slowly supplied to the load circuit, and it acts to suppress sudden changes in voltage due to inrush current when the field effect transistor becomes conductive.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a circuit diagram of a switch circuit constituting a multiplexed DC power supply device according to an embodiment of the present invention.

In this switch circuit 5, the drain of the field effect transistor 11 is connected to the input terminal 21, and the source terminal is connected to the output terminal 22. A forward diode 12 connected in parallel between the drain and source is a parasitic diode of this field effect transistor 11. The gate voltage of the field effect transistor J1 is the voltage of the shunt regulator circuit 2.
4.

The shunt regulator circuit 24 turns off the field effect transistor 1 when the voltage appearing at the terminal 21 becomes less than a predetermined voltage.
is turned off to cut off the connection between terminal 2 and terminal 22. This predetermined voltage is adjusted by the values of the resistors 6 and 7 that constitute the shunt regulator circuit 24. still,
8 is a shunt regulator element, and 9.10 is a transistor.

FIG. 2 is an operational waveform diagram of the switch circuit 5 shown in FIG. 1. The waveform Vo is an input terminal waveform appearing between the input terminal 21 and the ground terminal 23, and VDS is the voltage waveform appearing between the drain and source of the field effect transistor 11. The input voltage is shunt regulator circuit 24
exceeds the detection level (predetermined voltage mentioned above) Vs, the shunt I-regulator element 8 operates and the transistor 9.
10 is made conductive, the gate potential of the field effect transistor 11 is made lower than the source potential, and the field effect transistor II is made conductive. Here, as described above, the values of the resistors 6 and 7 are determined so that the voltage value compared with the shunt regulator element 8 appears at the connection point between the resistors 6 and 7.

Voltage drop Vl when the field effect transistor is in conduction state
)S is the product of the conduction resistance value Ran and the load current Io. Therefore, by configuring the field effect transistor 11 to have a low resistance, for example, even when Ron=10 mQ and Io=]-OA, vns=0 and IV. This value is 15 to 10 times smaller than the voltage drop of a conventional diode switch. Therefore, the field effect I
- As shown in Fig. 2, the voltage drop VDS of the transistor 11 becomes the voltage drop VF of the parasitic diode 12 only when the input voltage rises and falls, and when the field effect transistor TI is conductive, VDS = Ron・■0 Therefore, the voltage drop can be reduced.

FIG. 3 shows a power supply unit including a voltage stabilizing section 2a and a switch circuit 5a shown in FIG. A single input power source 1 and a load circuit 4a constituting an exchange are connected to these. Assume that a switching transistor (not shown) provided inside the voltage stabilizing section 2a of the power supply unit is destroyed, and its output voltage becomes non-voltage. Or voltage stabilizing section 2
Assume that the output voltage of the unillustrated capacitor a becomes non-voltage due to a fault such as an output short circuit. Then, the switch circuit 5a
The shunt regulator circuit detects this and cuts off the field effect transistor 11 of the switch circuit 5a.

However, since the load circuit 4a is supplied with power from the other power supply unit, the load circuit 4a continues to operate normally.

Note that when configuring the switch circuit, if a field effect transistor is selected in consideration of the maximum value of the load current, it is possible to eliminate the need for correction of the output voltage from the voltage stabilizing section. Furthermore, since the voltage drop of the field effect 1 helangistor is small, power loss is also small, and a P1 sink for cooling is not required.

FIG. 4 is a configuration diagram of a power supply device according to an embodiment of the present invention installed in an exchange. Switching equipment must always be on-line for service, and power supplies must be multiplexed for safety. Among the various load circuits that make up the exchange, there are particularly important load circuits such as processor-equipped circuits and clock-equipped circuits, and even if other load circuits go down due to a failure, this failure will spread over them. This will affect the entire exchange. Now, in FIG. 4, it is assumed that the load circuit 13 has the highest importance, that is, the highest priority, and the load circuits 14 and 15 have lower priority than that. In this embodiment, switch circuits 5a and 5 shown in FIG.
Switch circuits 5a and 5b are provided in parallel with the switch circuits 5a and 5c provided corresponding to the load circuits 13.1.4.15.

5c is connected to one voltage stabilizing section 2, and the output voltage of the human power source 1 is stabilized by this voltage stabilizing section 2.

In each switch circuit 5a, 5b, 5c, load circuit 1
Since No. 3 has a high priority, the detection level of the switch circuit 5a is set slightly lower than the detection levels of the other switch circuits 5b and 5c. Particularly, if a short-circuit fault occurs in the capacitor 16 of the load circuit 5, an excessive current flows through the corresponding switch circuit 5c, and the output voltage of the voltage stabilizing section 2 starts to decrease. This decrease is caused by the switch circuit 5
The fault is immediately detected by the shunt regulator circuit 5c, the field effect transistor of the switch circuit 5c is cut off, and the faulty load circuit 15 is disconnected from the power supply. At this time, if the detection level of the switch circuit 5b is higher than the detection level of the switch circuit 5c, the switch circuit 5b first disconnects the load circuit 14 from the power supply device. Since the load circuit 14 is a low-priority load circuit, even if it is disconnected from the power supply in such a case, the entire exchange will not be affected. However, if the high-priority load circuit J3 were similarly disconnected, the entire exchange would be affected. but.

In this embodiment, the detection level of the switch circuit 5c is set to the lowest level, so the switch circuit 5a remains conductive until the switch circuit 5c disconnects the load circuit 15. Then, when the switch circuit 5c disconnects the load circuit 15, the output of the voltage stabilizing section 2 begins to rise by 1 and returns to the original normal level. As a result, the power level decreases slightly immediately after a fault occurs, but immediately returns to the normal level, so that the fault is less likely to spread to others. In particular, there is no effect on the load circuit 13, which lowers the detection level depending on the priority.

〔Effect of the invention〕

According to the present invention, there is no need to adjust the output voltage correction of the power supply unit, there is little power loss, and furthermore, it is possible to prevent the spread of failures without providing a dedicated power supply unit for preventing the spread of failures. A multiplexed DC power supply can be constructed.

Therefore, in a switching system driven by the multiplexed DC power supply according to the present invention, the entire system is less likely to go down, and especially when the detection level is set according to the priority, failures do not spread to important load circuits. Since it is possible to reliably prevent this, the reliability of the switching equipment is improved, and furthermore, since the power supply is made smaller, the switching equipment itself can also be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a switch circuit constituting a power supply unit according to an embodiment of the present invention, FIG. 2 is an operating waveform diagram of the switch circuit shown in FIG. 1, and FIGS. 3 and 4 are respectively according to the present invention. FIG. 5 is a block diagram of a device using a multiplexed DC power supply according to an embodiment of the present invention, and FIG. 5 is a block diagram of a device using a conventional multiplexed DC power supply. 1... Input power supply, 2.2a to 2c voltage stabilization section, 4a
. 1.3.1.4.1.5...Load circuit, 5, 5a-5
c... Switch circuit, 8... Shunt regulator element, 11... Field effect transistor, 24... Shunt regulator circuit.

Claims (1)

[Claims] 1. A switch circuit is provided on the output side of each power supply unit of the multiplexed power supply device, and when a fault occurs in the load circuit connected to the power supply unit via the switch circuit, the load circuit is connected to the power supply unit through the switch circuit. In a multiplexed DC power supply that disconnects the faulty load circuit from the power supply by turning off the connected switch circuit, each power supply unit is connected to the corresponding load circuit using a field-effect transistor with low resistance when conducting, and A multiplexed DC power supply device characterized in that each of the switch circuits is configured by providing a shunt regulator that controls the gate voltage of a field effect transistor with the output voltage of a corresponding power supply unit. 2. A power supply device configured such that the output of one DC power supply is used as each input of a plurality of power supply units provided in parallel, and a load circuit is connected to each power supply unit via a switch circuit,
In a multiplexed DC power supply device that turns off a connected switch circuit to disconnect the load circuit from the power supply device when a load circuit fails, each switch circuit is configured to include a field effect transistor that connects the power supply unit and the load circuit, and a power supply unit. and a shunt regulator that turns off the field effect transistor when the output voltage of the field effect transistor becomes lower than a predetermined voltage value. 3. When a fault occurs in a power supply unit in which a switch circuit is provided on the output side of each power supply unit of a multiplexed power supply unit and a common load circuit is connected to each switch circuit, and a failure occurs in one of the power supply units. In a multiplex DC power supply device that disconnects the faulty power supply unit from the load circuit by turning off the switch circuit connected to the faulty power supply unit, each power supply unit and the load circuit are connected to each other by a field effect transistor with low resistance when conducting. A multiplexed DC power supply device characterized in that each of the switch circuits is configured by providing a shunt regulator that connects the field effect transistors and controls the gate voltage of the field effect transistor with the output voltage of the corresponding power supply unit. 4. A power supply device having a configuration in which the output of one DC power supply is used as each input of a plurality of power supply units provided in parallel, and a common load circuit is connected to each power supply unit via a switch circuit, and any one of the power supplies In a multiplexed DC power supply device that disconnects the power supply unit from the load circuit by turning off a switch circuit connected to the power supply unit when a unit fails, each switch circuit is connected to a field effect transistor that connects the power supply unit and the load circuit. and a shunt regulator that turns off the field effect transistor when the output voltage of the power supply unit becomes lower than a predetermined voltage value. 5. In a power supply unit that supplies the output voltage of one stabilized power supply through a switch circuit provided in parallel to a load circuit provided corresponding to the switch circuit, each switch circuit is connected to the electric field connecting the power supply unit and the load circuit. A multiplex DC power supply device comprising an effect transistor and a shunt regulator that turns off the field effect transistor when the output voltage of the power supply unit becomes lower than a predetermined voltage value. 6. Claim 2, Claim 4, or Claim 5, wherein the predetermined voltage set in the shunt regulator is set for each switch circuit according to the priority of the load circuit connected to each switch circuit. A multiplexed DC power supply. 7. A power supply unit constituting the multiplexed DC power supply device according to any one of claims 1 to 6, comprising an input voltage stabilizing circuit section and one of claims 1 to 6. A power supply unit comprising a switch circuit composed of the field effect transistor described in 1 and a shunt regulator. 8. Any one of claims 1 to 6, wherein the switching equipment is equipped with a plurality of load circuits that supply power supply voltage and performs circuit switching services online at all times, wherein the power supply voltage is supplied to each of the load circuits constituting the exchange. A switching equipment characterized by being provided with the multiplexed DC power supply device according to .