JPH01133570A - Overvoltage detector circuit - Google Patents

Abstract

PURPOSE:To display the function of redundancy operation positively by taking in the rectifying smoothing output of the secondary voltage of a transformer as the output voltage of a converter. CONSTITUTION:A converter for a power supply has converters 10, 16, and the converter 10 has a transformer 22, a switching transistor 24, a driver circuit 26 for the switching transistor 24, a capacitor 28, diodes 30, 32 for rectification, a choke coil 34 and a capacitor 36. The induced voltage of a secondary winding for the transformer 22 is rectified, and fed to load 14. The converter 16 is also constituted similarly. Overvoltage detector circuits 46, 46a for the converters 10, 16 take in the secondary voltage of the transformers 22, 22a through rectify ing smoothing circuits 52, 52a at that time. Even when the converter 10 under operation gets trouble and load (output) voltage V rises at that time, the voltage V is blocked by a rectifying smoothing circuit 30a to the overvoltage detector circuit 46a for the converter 16 under standby, and does not intrude into the detector circuit 46a.

Description

[Detailed Description of the Invention] [Summary] Regarding an overvoltage detection circuit for a power supply converter that performs redundant operation, when an overvoltage occurs due to a failure in an operating converter, a standby converter is reliably switched to an operating state. A converter that is equipped with a transformer, a switching element that switches on/off its primary current, a circuit that rectifies and smoothes the secondary output, and an overvoltage detection circuit that stops operation when the converter output voltage is excessive. In an overvoltage detection circuit in a redundant power supply facility in which multiple units of the transformer are installed in parallel to supply power to a load, a circuit for rectifying and smoothing the secondary voltage of the transformer is provided, and the output of the rectifying and smoothing circuit is taken in as the converter output voltage. do.

[Industrial application field]

The present invention relates to an overvoltage detection circuit for a power supply converter that performs redundant operation.

DC-DC is used to supply a constant voltage from a DC power source to a load.
converter is used.

[Conventional technology]

FIG. 3 shows an example of this type of converter. 0 is the converter, 12 is a DC power supply, and 14 is a load. The converter 10 includes a transformer 22 and a switching transistor 2
4. The drive port [i! 826, capacitor 28, rectifying diodes 30, 32, smoothing choke coil 34
, and a capacitor 36. The drive circuit 26 outputs a width-controlled rectangular wave, and the transistor 24 is turned on and off by this rectangular wave to cut off and turn on the current from the power source 12. Since this intermittent current flows through the primary winding of the transformer 220, an alternating current is induced in the secondary winding of the transformer, which is caused by the diode 3.
0.32, smoothed by a choke coil 34 and a capacitor 36, and supplied to the load 14. Control the width of the above rectangular wave according to the difference between the load voltage and the reference voltage,
The voltage supplied to the load can be controlled to be constant and equal to the reference voltage.

The converter 10 of FIG. 3 also performs overvoltage limiting. Resistors 38, 40, reference voltage 42, and comparator 44
constitutes the overvoltage detection circuit, and the load voltage ■ is connected to the resistor 38.4
The comparator 44 compares the voltage divided by 0 with the reference voltage 42, and if the divided voltage is greater than or equal to the reference voltage, the drive circuit 26 stops producing the output S1 that turns the transistor 24 on and off, and also applies an overvoltage to the terminal 48. A detection signal OVA is generated to inform the outside that the converter has stopped outputting due to overvoltage.

When the load 14 is a computer, stability of the power supply is required from the viewpoint of high reliability of the computer system, and redundant operation of the power supply is frequently performed. As shown in FIG. 4, two converters each having a power capacity sufficient to drive a load (total watts) are installed in parallel, and one is operated on standby or under light load. l0116 is the two converters, 12.18
is each DC power supply. Converters 10.16 have the same construction and corresponding parts have the same reference numerals with the suffix a.

At this point, the converter 10 is operating (supplying most of the load power) and the converter 16 is operating with a light load (
(The ratio of load sharing can be set by the reference voltage ratio of the constant voltage control system, etc.).Considering the case where the output voltage increases due to a failure of the converter 10, the ratio of load sharing can be set by the reference voltage ratio of the constant voltage control system.
Since the overvoltage detection circuits 46 and 46a receive the same load voltage (converter output voltage), the overvoltage detection circuits 46a and
If the reference voltage of the overvoltage detection circuit 46 is lower than the reference voltage of the overvoltage detection circuit 46 (due to variations in components, etc.), the comparator 46a of the overvoltage detection circuit of the converter 16 on standby sends a signal from the comparator 46a of the overvoltage detection circuit of the converter 16 to the drive circuit 26a to control the on/off of the transistor 24a. A signal is sent to stop sending out the signal Sla, and the converter 16, which is normal and on standby, stops operating. Then, the converter 10 also stops operating, and the load 14
The power supply is cut off, and the overvoltage detection signal qov8 is output from the terminal 48.48a.

[Problem that the invention seeks to solve]

In this way, the conventional system has a problem in that even though it has cutting angle redundant operation equipment, if one converter fails, the standby converter also stops operating, and both converters stop and the power is cut off. Normally, in this case, of course, the failed converter would have to stop operating, and the standby converter would have to be automatically switched into operation.

It is an object of the present invention to improve this point and to enable, by relatively simple means, a converter on standby to be reliably switched to an operating state when an overvoltage occurs due to a failure in an operating converter. That is.

[Means for solving problems]

As shown in FIG. 1, in the present invention, overvoltage detection circuits 46 and 463 of converter 10.16 take in not the load voltage (converter output voltage) but the secondary voltage of the transformer of the converter through rectification and smoothing circuit 52.52a. The rest is the same as the conventional circuit, 12°18 is the DC power supply, 14 is the load,
42, 422 are reference voltages, and 50.50a are rectifier and smoothing circuits (30, 32, 34, . . . in Fig. 4) that supply power to the load.
36 etc.).

[Effect]

If the overvoltage detection circuit 46.46a takes in the secondary voltage of the converter transformer 22, 22a instead of the load voltage ■, when the converter in operation breaks down and the output voltage becomes high, the overvoltage detection circuit 46. The standby converter will not stop operating due to excessive output voltage. That is, as above, there are 10 converters in operation.
, the standby converter is 16, and even if the operating converter 10 fails and the load (output) voltage V increases,
The rectifying and smoothing circuit 30a prevents the load voltage V from entering the overvoltage detection circuit 46a of the converter 16 on standby. What enters the overvoltage detection circuit 46.46a is the secondary voltage of the transformer 22゜22H of both converters 10 and 16, and this has a certain relationship with the load (output) voltage during operation, so overvoltage does not occur. The operation of the converter can be stopped in the conventional manner.

〔Example〕

FIG. 2 shows an embodiment of the present invention. As throughout the design, parts that are the same as in other figures are numbered the same. 5
2.54 is a rectifier diode, 56 is a capacitor,
Together with the choke coil 34, the rectifying and smoothing circuit 52 is configured. The same applies to the converter 16 side.

Although not shown, the converter's constant voltage control system uses, for example, a triangular wave generation circuit, which compares the triangular wave generated by the circuit with the converter output voltage (rectified and smoothed), and converts the portion of the former exceeding the latter into a rectangular wave. It consists of a comparator etc. that outputs . The reason why the converter output voltage increases due to a failure is that the comparator has failed and generates a rectangular wave with a significantly wide pulse width (for example, the converter output voltage is not fed back (and becomes zero). (so) case etc.

〔Effect of the invention〕

As explained above, according to the present invention, by simple means,
Even if the operating converter increases its output voltage, the standby converter will not detect an overvoltage and stop operating (this will ensure that the redundant operation function can be achieved).

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is a circuit diagram showing an embodiment of the present invention, and FIGS. 3 and 4 are circuit diagrams showing a conventional example. In Figure 1, 10.16 is a converter, 12.18 is a DC power supply, 14 is a load, 22.22a is a transformer, 46, 46
2 is an overvoltage detection circuit, and 52 and 52a are rectification and smoothing circuits.

Claims (1)

[Claims] A transformer (22), a switching element (24) that switches on and off its primary current, and a circuit (50) that rectifies and smoothes the secondary output.
, and a converter equipped with an overvoltage detection circuit (46) that stops operation when the converter output voltage is excessive. In the overvoltage detection circuit in a redundant power supply facility in which a plurality of converters are installed in parallel to supply power to a load, two of the transformers (22) An overvoltage detection circuit characterized in that a circuit (52, 52a) for rectifying and smoothing the next voltage is provided, and the output of the rectifying and smoothing circuit is taken in as the converter output voltage.