JPS63294212A - Power device - Google Patents

Abstract

PURPOSE:To maintain a loading device singly, and to monitor abnormality such as the overload of each device and cope with abnormality by installing an overload protector among a plurality of the devices and a main power supply section. CONSTITUTION:DC output voltages from terminals 17, 18 and terminals 19, 20 are fed to a plurality of magnetic tape devices 2 through overload protectors 3. The capacity of the overload protectors 3 is set to 110%-130% of maximum currents fed to each device 2. When abnormality is generated in a device A and the device A is brought to the state of overload, overcurrents flow through the overload protector 3 and the protector 3 is interrupted, and the supply of power to the device A is interrupted. Outputs from the terminals 17-20 are not cut off and are held in consideration of the response time of the over load protector 3 in the setting of time of a timing pulse delay-time generator 6 for a main power supply section 1 at that time, thus allowing the operation of a device B. When one device is maintained, the other device is stopped singly and can be maintained because the overload protector 3 can be cut by a relay contact 4 manually.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an overload protection system for a power supply device, and in particular -
The present invention relates to a power supply device employing a pulse width controlled switching power supply suitable for supplying power to a plurality of external storage devices mounted in a housing.

[Conventional technology]

When multiple external storage devices, such as magnetic tape devices, are installed in a single chassis, power supply to each device is conventionally handled by installing power supplies corresponding to the number of installed devices in each case. It is implemented by being installed inside the body, and each power supply device is generally configured with a sequence circuit that allows it to be turned on and off so that it can be maintained independently. be. Note that prior art related to this type of power supply device is disclosed in, for example, Japanese Patent Application Laid-Open No. 73226/1983,
JP-A No. 54-65324 is described in the official gazette.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, - When the number of devices installed in the housing increases, the number of power supplies must also increase, and the sequence circuit for turning on and off the power becomes complicated, which increases the number of parts and assembly man-hours for the entire device. There was a problem in that this resulted in a decrease in confidence and an increase in manufacturing costs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and provide a power supply device that has high reliability and is inexpensive to manufacture.

[Failure to solve the problem]

According to the present invention, the above objects include: - a switching type main power supply section having a function of supplying power to a plurality of devices mounted in a housing and monitoring the total power supply; This is achieved by providing an overload protection device corresponding to each device between each device receiving the supply and the main power supply section.

[Effect]

The switching type main power supply unit has the function of supplying the necessary power to each of the plurality of devices installed in the housing and monitoring the total power. When the monitoring function detects that the total power supply has exceeded a specified value, the main power supply section cuts off the power supply to each device. Furthermore, an overload protection device installed between the main power supply section and each device monitors the power supplied to each device, and automatically automatically protects the device if the power supplied exceeds a specified value. The device operates to cut off power to the device. Also,
This overload protection device can be disconnected by an external signal, and can also be manually disconnected from the power supply.
Inputs can be made.

With such a configuration, each device can be maintained independently, and the entire device can be constructed with high reliability and low cost, and it is possible to prevent overload of each device and maintenance of multiple devices. Abnormalities such as overload can be reliably monitored and dealt with.

〔Example〕

Hereinafter, one embodiment of the electric tX device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In Fig. 1, ■ is the main power supply section, 2 is the magnetic tape device, 3 is the overload protection device, 4 is the relay contact, 5 is the overcurrent identification and timing pulse delay time generator, 6 is the switching controller, 7.7A 1 is a commercial AC power input terminal, 8 is a diode stack, 9 is a capacitor, 10 is a current transformer, 11 is a transistor, 12 is a high frequency transformer, and 13 is a rectifier and smoothing circuit.

One embodiment of the power supply device according to the present invention, as shown in FIG. The devices A and B each include, for example, a magnetic tape device 2 and an overload protection device 3 provided between the main power supply section 1 and the magnetic tape device 2, respectively. The main power supply unit 1 also includes a diode stack 8 that rectifies AC power from a commercial AC input terminal 7.7A, an electrolytic capacitor 9 that removes AC bones contained in the DC voltage rectified by the diode stack 8, and a DC voltage a switching transistor 11 that converts the voltage into a high-frequency AC voltage, a current transformer 10 that detects the collector current of the switching transistor 11, and a transistor 1.
1, a rectifier and smoothing circuit 13 that is connected to the secondary winding of the pulse transformer 12 and generates a DC voltage to be supplied to the magnetic tape device 2, and a current transformer. The main components include an overcurrent detection and timing pulse delay time generator 5 that receives a signal from the transistor 10, detects an overcurrent, and delays the timing pulse, and a switching controller 6 that controls the transistor 11. There is.

In the above configuration, each of the constituent elements is further configured as follows. The rectifying and smoothing circuit 13 is a center-tapped type circuit in order to perform DC insulation from the negative circuit side and to rectify and smooth the pulse voltage of the secondary winding of the pulse transformer 12 that generates a predetermined voltage in the secondary winding. It is composed of a diode 14, a choke coil 15, and an electrolytic capacitor 16, and its output DC voltage is supplied to the magnetic tape device 2 via terminals 17-20. The overcurrent detection and timing pulse delay time generator 5 includes a Zener diode 2
4. Consists of resistors 25 to 27, a transistor 28, and a timing pulse delay time generator 29, and the output of the current transformer 10 is connected to a diode 21 and a capacitor 22.
monitors the voltage between the terminals of the resistor 23, which is applied as a DC voltage proportional to the primary current of the pulse transformer,
When this voltage exceeds a predetermined constant value, a delayed timing signal is given to the switching controller 6.

The switching controller 1-roller 6 is a switching IC for a switching regulator, and is a fixed frequency oscillator 44 whose oscillation frequency is determined by three resistors and a capacitor 35.
, a reference voltage generator 43, a flip-flop circuit 45, a NOR circuit 46, and a transistor 47, and controls switching of the switching transistor 11 so that the DC voltage supplied to the magnetic tape device 2 becomes a predetermined value. Wholesale. This switching controller 6
are an auxiliary power transformer 30 and a diode stack 31
, smoothing electrolytic capacitor 32. 3-terminal regulator 33
It is operated by power from an auxiliary power supply consisting of.

The operation of one embodiment of the power supply device according to the present invention configured as described above will be described below.

Commercial AC power input terminal (hereinafter simply referred to as terminal) 7.7
When a commercial variable power input voltage is applied to A, this applied voltage is rectified by the diode stack 8 and converted to a DC voltage, which is applied to both ends of the electrolytic capacitor 9. This DC voltage is applied to the city 114 by the switching controller 6.
The voltage is converted into a high frequency AC voltage by the 1-transistor 11 and applied to the primary winding of the pulse transformer 12.

In addition, the commercial AC input voltage applied to terminal 7.7A is
The voltage is stepped down by the transformer 30 and the diode stack 31
The voltage is rectified by and applied to both ends of the electrolytic capacitor 32. This DC voltage is stabilized by a three-terminal regulator 33 and supplied to the switching controller 6.

The reference voltage generator 43 in the switching controller 6 is supplied with the above-mentioned stabilized DC voltage to generate a further stabilized reference voltage and supplies it to each main part inside the switching controller 6. As a result, the fixed frequency oscillator 44 is connected to the resistor 34 and the capacitor 35.
generates a clock pulse and a sawtooth voltage determined by This clock pulse and sawtooth voltage are sent to flip-flop 45 and comparator 42. Comparator 42
is to compare this sawtooth wave voltage with the output of the error amplifier 41 which compares the voltage obtained by dividing the reference voltage by the resistors 36 and 37 and the voltage output from the rectifier and smoothing circuit 13 to the terminal 19. generates a pulse width modulated output. Then, this pulse width modulation output is time-divided by the output of the flip-flop 45 in the NOR circuit 46, and
It is divided into two pulses. As a result, the pulse width modulated outputs from the comparator 42 appear alternately at the output of the NOR circuit 46 once every two periods of the clock pulse, but the width of these pulses depends on the value of the capacitor 35. The pulse width is narrowed by a predetermined pulse width. The output of the NOR circuit 46 controls the switching transistor 11 to be turned on or off via the transistor 47.

Thereby, as mentioned above, the DC voltage applied across the electrolytic capacitor 9 is converted into a high-frequency AC voltage, applied to the pulse transformer 12, and after being stepped down, the voltage is applied to the diode '14, the choke coil 15, and the electrolytic capacitor 16.
is converted into a DC voltage by a rectifying and smoothing circuit 13 consisting of
It is supplied to the magnetic tape device 2 via terminals 17-20. The DC voltage at terminal 19 is input to error amplifier 41, compared with a reference voltage, and output 1111 so that the output voltage is always constant.

When the total supply voltage to the magnetic tape device 2 increases,
Since the collector current of the switching transistor 11 increases and the current flowing through the current transformer 10 also increases,
The voltage generated across the resistor 23 also increases. Then, when the voltage reaches the Zener voltage of the Zener diode 24 or higher, that is, when the total power supply becomes overloaded, the transistor 28 is turned on, and this on signal is applied to the timing pulse delay time generator 29.

Timing pulse delay time generator 29 outputs a signal with a delay time determined by resistor 48 and capacitor 49. This signal is the switching transistor 11
This is a signal obtained by expanding the peak value of the collector current of , and is input to the shutdown circuit 50 in the switching controller 6 to turn on the transistor 40. This results in
One input of the comparator 42 decreases, the on/off operation of the transistor 11 via the transistor 47 is stopped, and the voltage supplied to the magnetic tape device 2 from the terminals 17 to 20 drops. The power supply will be cut off.

The DC output voltage from terminals 17, 18 and 19, 20 is supplied to a plurality of magnetic tape devices via overload protection device 3. Although the illustrated embodiment shows a case where there are two DC output voltage channels, the number of channels is arbitrary. The capacity of the overload protection device 3 is set between 110% and 130% of the maximum current supplied to each device 2. Now, if one of the magnetic disk devices 2, for example, device A, experiences an abnormality and becomes overloaded, an excessive current flows through the overload protection device 3 connected to device A.
This overload protection device is turned off and cuts off the power supply to device A. In this case, by setting the delay time of the timing pulse delay time generator in the main power supply section 1 in consideration of the response time of the overload protection device 3, the DC output of the terminals 17 to 20 can be cut off. The device B is able to operate normally because it is held constant without any change.

It goes without saying that even if an abnormality occurs in device B, it operates in the same manner as described above.

In addition, when performing maintenance on the device B while it is in use, it is possible to disconnect the overload protection device 3 manually or automatically from another device via the relay contact 4, and the magnetic tape device 2 can be disconnected independently. It is possible to stop the system for maintenance.

In the embodiments described above, the device including the power supply device is a magnetic tape device, but the present invention is not limited to the magnetic tape device, but can be used in any way to supply power to the device.

〔Effect of the invention〕

As explained above, according to the present invention, the number of parts and the number of assembly steps can be reduced by half or less compared to conventional devices, and the device can be made to have high reliability and be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a drawing showing the configuration of an embodiment of the present invention. 1...Main power supply unit, 2...Magnetic tape device, 3...Overload protection device, 4...Relay contact, 5...・Overcurrent identification and timing pulse delay time generator, 6...Switching controller, 7.7A...Commercial AC power supply input terminal, 8...Diode stack, 9...・・・・・・
Capacitor, 10...Current transformer, 11
...Transistor, 12...High frequency transformer, 13...Rectifier smoothing circuit. Many

Claims (1)

[Claims] 1. In a power supply device for a plurality of devices installed in a housing, a switching type main power supply unit has a function of supplying power to the plurality of devices and monitoring the total power supply, and from this main power supply unit. A power supply device comprising an overload protection device provided corresponding to each device between each device to which power is supplied and a main power supply section.