JPH0145302B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a multiplexed power supply system.

In recent years, as integrated circuits have been widely adopted in electronic devices, the reliability of these electronic devices has improved dramatically. On the other hand, DC power supply circuits that supply DC power to electronic devices require step-down or step-up operation or handle large amounts of power, so they are forced to use individual parts, and electronic devices that use integrated circuits The disparity in reliability has become a problem.

In order to alleviate this reliability disparity, the output from multiple DC power supply circuits is commonly supplied to the same load, and a failure of one DC power supply circuit is compensated for by another DC power supply circuit. The standard power supply system is widely used.

An example of a conventional multiplex power supply system of this type is two DC power supply circuits, as shown in Figure 1.
Two diodes D1 and D2 whose anodes are connected to the outputs of SP1 and SP2 and whose cathodes are commonly connected to the load LOA, and two alarm circuits AL1 and D2 whose anodes are connected to the outputs of SP1 and SP2 respectively, and two alarm circuits AL1 and D2 are connected to the outputs of the DC power supply circuits SP1 and SP2, respectively. It is equipped with AL2.

Each of the DC power supply circuits SP1 and SP2 transforms and stabilizes the voltage of the input DC power supply E1, and supplies the voltage to the load via diodes D1 and D2.
By supplying it to LOA, we aim to improve reliability through redundancy. DC power supply circuit SP1
Abnormalities in SP2 and SP2 are caught from their respective outputs by alarm circuits AL1 and AL2, respectively, and transmitted to the outside as an alarm signal ALA.
The diodes D1 and D2 prevent the outputs of the DC power supply circuits SP2 and SP1 from being routed to the alarm circuits AL1 and AL2, respectively, thereby preventing generation of a false alarm signal ALA.

In such a conventional configuration, since diodes are inserted in the outputs of the DC power supply circuits SP1 and SP2, the first problem is that power loss occurs in these diodes and the efficiency of DC power supply deteriorates. . This first problem is the load
This problem becomes serious when the output voltage value to be supplied to the LOA is low and the load current is large.

The second problem with the conventional configuration is that when the DC power supply circuits SP1 and SP2 stabilize the output against load fluctuations, the load
The problem is that the voltage fluctuation value applied to the LOA cannot be accurately fed back, resulting in poor output stability.

An object of the present invention is to provide a multiplex power supply system that improves power loss and load fluctuation stability by eliminating the need for diodes that are conventionally inserted into the output of a DC power supply circuit.

The system of the present invention includes voltage dividing resistors R1 and R2 that divide the output voltage, a reference voltage E3, and an error amplifier DAM that receives the divided voltage of the output voltage and the reference voltage as inputs, and the output of the amplifier and the sawtooth waveform. In a multiplex power supply system that commonly supplies outputs from a plurality of DC power supply circuits to the same load by controlling the switching element T1 of the transformer TRS to control the output voltage by comparing the voltage of the voltage dividing resistor. a resistance R3 connected to a point, and a transistor T2 that connects the resistance R3 in parallel to the voltage dividing resistor when turned on, and fluctuation generating means that periodically fluctuates the output within a permissible fluctuation range; detection means for drawing in and detecting the output voltage of the power supply circuit, and controlling the on/off of the fluctuation generating means to adjust the value of the voltage dividing resistor so that the output of the DC power supply circuit is within an allowable fluctuation range. When the output fluctuation of the DC power supply circuit detected by the detection means is not within a predetermined range when the DC power supply circuit is periodically changed, an abnormality in the DC power supply circuit is reported to the outside and the DC power supply circuit is The present invention is characterized by further comprising a test means for stopping the operation of the power supply circuit.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 2 shows an embodiment of the invention. This embodiment is provided with two DC power supply circuits SP3 and SP4 and alarm circuits AL3 and AL4 corresponding to the DC power supply circuits SP3 and SP4. Each of the DC power supply circuits SP3 and SP4 steps down and smoothes the voltage of the input DC power source E1, and supplies the output DC power source E2 to the load LOA. DC power supply circuit
The outputs of SP3 and SP4 are directly connected, and the output DC power source E2 is commonly supplied to the load LOA.
Alarm circuits AL3 and AL4 act on DC power supply circuits SP3 and SP4, respectively, so as to vary the voltage of output DC power supply E2 within an allowable fluctuation range,
A reasonable variation in the output DC power source E2 in response to this variation is detected. Fluctuations in the output DC power supply E2 are commonly input to the alarm circuits AL3 and AL4, but the fluctuation is performed so that the DC power supply circuits SP3 and SP4 have time periods in which they act separately. Circuits AL3 and AL4 are output DC power supply E2
It is possible to identify which DC power supply circuit's response is due to the fluctuation in . If the alarm circuit detects a reasonable fluctuation, it has been proven that the DC power supply circuit is operating normally. On the other hand, if a reasonable fluctuation is not detected, the DC power supply circuit is in an abnormal state and outputs an alarm signal ALA to the outside. alarm signal
The ALA is used, for example, to light up a lamp on a maintenance panel and alert a maintenance person to an abnormality in the DC power supply circuit.

Figure 3 shows DC power supply circuit SP3 and alarm circuit AL
3 is shown together with the input DC power source E1. The details of the DC power supply circuit SP4 and the alarm circuit AL4 have the same configuration as in this figure. Referring to FIG. 3, the DC power supply circuit SP3 includes a switching transistor T1, a transformer TRS, and a
diodes D3 and D4, a choke coil L, a capacitor C, two resistors R1 and R2, a differential amplifier DAM, and a voltage comparator.
COM, oscillation circuit OSC, and sawtooth wave generation circuit
This is a known switching regulator composed of a SAW and a reference power source E3. Here, the input DC power source E1 is stepped down to a predetermined value by a transformer TRS, rectified by diodes D3 and D4, and smoothed by a choke coil L and a capacitor C. Fluctuations in the output DC power source E2 due to load fluctuations are caught as differential amplification in the differential amplifier DAM between the voltage of the output DC power source E2 divided by resistors R1 and R2 and the voltage of the reference DC power source E3. . The output of the differential amplifier DAM is compared in the voltage comparator COM with the output of the sawtooth wave generation circuit SAW, which generates sawtooth wave pulses in response to the output of the oscillation circuit OSC.
Controls the pulse width of the sawtooth pulse output by Switching transistor T1 is a voltage comparator
It turns on and off in response to sawtooth wave pulses from COM to control the supply time width of the input DC power source E1. In this way, fluctuations in the output DC power source E2 due to load fluctuations are adjusted.

In FIG. 3, the microprocessor MPS constitutes a testing means, the analog/digital converter ADV constitutes a detection means, and the switching transistor T2 and resistor R3 constitute a fluctuation generating means.

FIGS. 4 and 5 show functional blocks and flowcharts, respectively. First, a control signal is sent from the microprocessor MPS to the fluctuation generating means VOS.
Output SWT and switch transistor T2
Turn on and off. In response to the on/off of the switching transistor T2, the parallel connection between the resistor R3 and the resistor R2 is disconnected, so that the voltage value of the output DC power source E2 fluctuates. This fluctuation value is kept within the allowable range of the output DC power source E2. Voltage fluctuations of the output DC power source E2 are detected by a detection means (analog-to-digital converter ADV) and converted into a digital value. Testing means
TET checks whether this digital value is within a predetermined range. If the result of this test shows that the value is not within the predetermined range, the test means TET sends an alarm signal ALA to the outside.
On the other hand, if the value is within a predetermined range, the switching transistor T2 is turned off, and a time is awaited until the switching transistor T2 is turned on next time.

Prepare two circuits as shown in Figure 3, connect their outputs to the load in common, and turn them on and off at a cycle such that one cycle is not an integral multiple of the other cycle, as shown in Figure 6. Set it as follows. As a result of such period setting, the intervals between times t ₁ and t ₂ , between t ₃ and t ₄ , between t ₄ and t ₅ , and between t ₆ and t ₇ in FIG. As such, fluctuations in the output DC power source E2 occur only in one alarm circuit, and the test means TET can recognize this from the signal from the fluctuation generating means VOS. Since only the testing means TET that has recognized this will perform the above-mentioned testing, there will be no possibility that the alarm signal ALA will be unduly output.

In this embodiment, the fluctuation generating means VOS is provided for each alarm circuit, but in the present invention,
For example, a fluctuation generating means that alternately generates upper and lower fluctuations of the reference voltage value of the output DC power source E2.
The VOS may be provided in only one side of the alarm circuit. In this case, when the fluctuation is on the positive side, the DC power supply circuit on the alarm circuit side with the fluctuation generating means VOS is used, and when the fluctuation is on the negative side, the fluctuation generating means is used.
This means that each DC power supply circuit on the VOS removal alarm circuit side is tested.

In addition, in this embodiment, when the output fluctuation detected by the detection means ADV is not within a predetermined range, the test means TET externally sends an alarm signal ALA.
However, it is easy to configure the inspection means to output the alarm signal ALA and stop the output of the DC power supply circuit.

According to the present invention, by employing the above-described configuration, a diode that has been conventionally inserted into the output of a DC power supply circuit is not required, so that voltage loss and load fluctuation stability can be improved.

[Brief explanation of drawings]

Fig. 1 is an example of the conventional technology, Fig. 2 is an embodiment of the present invention, Figs. 3 and 4 are detailed views of the embodiment, and Figs. 5 and 6 are diagrams showing the operation of the embodiment. Diagrams for explanation are shown respectively. SP1, SP2, SP3, SP4...DC power supply circuit, AL1, AL2, AL3, AL4...Alarm circuit, LOA...Load, E1...Input DC power supply, E
2...Output DC power supply, E3...Reference DC power supply, T
1, T2...Switching transistor, TRS
...Transformer, D1, D2, D3, D4
...Diode, L...Chiyoke coil, C...
Capacitor, R1, R2, R3...Resistor,
DAM...Differential amplifier, COM...Voltage comparator,
OSC...Oscillation circuit, SAW...Sawtooth wave generation circuit (detection means), MPS...Microprocessor,
ADV……analog digital converter, VOS……
Fluctuation generating means, TET...Testing means, ALA...Alarm signal, SWT...Control signal.

Claims (1)

[Claims] 1. A voltage dividing resistor R1, R2 that divides the output voltage, a reference voltage E3, and an error amplifier DAM that receives the divided voltage of the output voltage and the reference voltage as input, and outputs the output of the amplifier and the sawtooth waveform. Transformer TRS by comparison with
In a multiplex power supply system in which the outputs from a plurality of DC power supply circuits are commonly supplied to the same load by controlling the switching element T1 of the voltage dividing resistor to control the output voltage, Resistance R
3 and a transistor T2 that connects the resistor R3 in parallel to the voltage dividing resistor when turned on, and fluctuation generating means that periodically fluctuates the output within a permissible fluctuation range; and an output voltage of the DC power supply circuit. detection means for drawing in and detecting this, and controlling the on/off of the fluctuation generating means to periodically adjust the value of the voltage dividing resistor so that the output of the DC power supply circuit changes within an allowable fluctuation range. If the output fluctuation of the DC power supply circuit detected by the detection means when the DC power supply circuit changes is not within a predetermined range, the abnormality of the DC power supply circuit is reported to the outside and the operation of the DC power supply circuit is controlled. A multiplexed power supply system characterized by comprising a testing means for stopping the power supply. 2. A patent claim characterized in that the fluctuation generating means are provided corresponding to the DC power supply circuit, each of which has a time period for generating the same fluctuation without overlapping with any of the other fluctuations. A multiplexed power supply system according to scope 1. 3. The fluctuation generating means is provided with two of the DC power supply circuits and the fluctuation value is set to two values above and below the reference value of the output, and is provided in correspondence with only one of the DC power supply circuits. A multiplexed power supply system according to claim 1, characterized in that: