JP2000152498A - Rush current preventive circuit and dc actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the rush current by the smoothing capacitor of an input part, and also remove the wasteful power consumption at waiting, in a device for inputting DC voltage. SOLUTION: The series circuit of a resistor R1 for limiting a rush current and a switch element SW1 for intermitting DC input power is interposed in the power supply line from a DC power source 1 to a device 2, and also a switch element SW2 is connected in parallel with this series circuit. Then, when it gets in usual operation time from waiting time, the switch element SW1 is turned on by the signal S1 from the device 2, and the rush current is suppressed by the resistor R1. After that, the switch element SW2 is closed by the signal S2 from the device 2, and the specified section of the device 2 is supplied with power. Moreover, when the device 2 is not used, the switches SW1 and SW2 are turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inrush current prevention circuit using a DC power supply as an input source and a DC operation device therefor.

[0002]

2. Description of the Related Art In a device which operates by inputting a DC voltage, a relatively large-capacity smoothing capacitor is usually arranged to stabilize the input voltage. For this reason, an excessive rush current flows at the time of startup when a DC voltage is applied. As a preventive measure, it is common practice to use a resistor to suppress excessive current only at the time of starting the device.In normal times, both ends of the resistor are made conductive by a switch element, and line voltage drop and loss due to the resistor are reduced. It does not happen.

FIG. 4 is a diagram showing a schematic configuration of an apparatus in which such a rush current prevention measure is taken. A resistor R1 for suppressing current is interposed in a DC input line from the DC power supply 1 to the device 2, and a contact 4b of a relay 4 is connected as a switch element in parallel with the resistor R1. In addition, as this switch element, in addition to the relay 4 described above, a triac,
Thyristors, transistors, MOSFETs and the like are also used.

At the time of startup, the resistor R1 limits the flow of an excessive rush current. When the capacitor is charged and the input voltage starts to stabilize, a predetermined voltage is supplied from the device and the relay 4 is turned on. The coil 4a is energized, and the contact 4b is turned on to bring it into a normal state. In this case, a1-a
Between the two, power is supplied by the resistor R1 even when the device 2 is stopped.

FIG. 5 is a diagram showing another conventional example.
In this example, the switch element SW3 interposed in the DC input line from the DC power supply 1 to the device 2 is controlled by a signal from the device 2, so that energy is saved.

That is, even if the device 2 is stopped, the power supply to a predetermined portion inside the device 2 is turned off by a signal from the device 2, the switch element SW3 is turned off, and the loss of the predetermined portion in the device is reduced to 0 to save energy. It is trying to make it. in this case,
When the apparatus 2 is on standby, the voltage between b1 and b2 is set to the minimum necessary voltage for the apparatus 2 and the apparatus 2 is operated. Also, b3-b4
A rush current can be suppressed by interposing a parallel circuit of a switch element and a resistor therebetween.

[0007]

Incidentally, the suppression of the inrush current is caused by the operation of the breaker of the commercial power supply, the firing of the electric wire due to the drop in the line voltage, the influence on other devices due to the distortion of the commercial voltage, and the breakage of the device. Is necessary to protect each part from them.

However, in the above-described conventional example, there is a problem that the rush current can be prevented, and at the same time, the loss due to the resistance and the like can be prevented, so that the energy saving cannot be further promoted.

That is, in the example shown in FIG. 4, power is supplied through the resistor R1 even when the apparatus is stopped, and the loss due to the resistor R1 cannot be ignored. In the example shown in FIG. 5, the inrush current can be suppressed by connecting a parallel circuit of the switch element and the resistor between b3 and b4. However, even in the normal state, there is always a loss (ON loss) of the switch element SW3, and the apparatus is on standby. Unnecessary power is consumed even when not actually used, such as at the time, and the ratio of such a loss during standby is relatively high and cannot be ignored.

The present invention has been made in view of the above-described problems, and suppresses an inrush current flowing at the time of signal switching from start-up of the apparatus to normal operation and from standby to normal operation. It is an object of the present invention to provide an inrush current prevention circuit and a DC operation device that can promote energy saving without loss due to resistance or the like.

[0011]

The inrush current prevention circuit and the DC operating device according to the present invention are constructed as follows.

(1) An inrush current prevention circuit for preventing an inrush current input from a DC power supply, wherein a series circuit of a switch element and a resistor intermittently input current by a first signal;
A switch element that is opened and closed by a second signal different from the first signal and connected in parallel with the series circuit.

(2) An inrush current prevention circuit for preventing an inrush current input from a DC power supply, wherein a series circuit of a switch element and a resistor for interrupting an input current by a predetermined signal;
A switching element connected in parallel with the series circuit and opened and closed by a signal obtained by delaying the predetermined signal.

(3) In a DC operating device that operates by inputting a DC voltage, a series circuit of a switch element and a resistor that interrupts a DC input current according to a first signal, and the second circuit connected in parallel with the series circuit. A switching element that is opened and closed by a second signal different from the first signal.

(4) In a DC operating device which operates by inputting a DC voltage, a series circuit of a switch element and a resistor for interrupting a DC input current by a predetermined signal, and the predetermined circuit connected in parallel with the series circuit. A switching element that opens and closes with a delayed signal.

[0016]

FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention. An inrush current prevention circuit for preventing an inrush current input from a DC power supply, and a DC voltage input from the DC power supply. 1 shows a schematic configuration of a direct-current (DC) operating device that operates according to the present invention.

In FIG. 1, reference numeral 1 denotes a DC power supply, and 2 denotes a device such as a DC power supply device which receives power supply from the DC power supply 1, and a DC power supply line (input line) of the device is supplied with a first signal S1 from the device 2. A series circuit of a switching element SW1 for interrupting an input current and a current limiting resistor R1 is interposed, and is opened and closed by a second signal S2 different from the first signal S1 from the device 2 in parallel with the series circuit. The switch element SW2 is connected. And the switch element S
Power is supplied from W1 and SW2 to a predetermined unused portion such as when the device 2 is on standby.

In the above configuration, when the device 2 enters a normal operation from a state where it is not actually used, such as at the time of start-up or standby, the switch element SW1 is first turned on by a signal S1 from the device 2, and the rush generated at that time is performed. The current is limited by the resistor R1. At this time, the switching element SW2
Remains open.

If the above state is maintained, the resistance R
1, the switch element SW1 is kept conducting for a predetermined period of time during which an inrush current flows (a period until the smoothing capacitor of the input portion of the device is charged) or longer. After the elapse of the period, the switch element SW2 is turned on by the signal S2 from the device 2. At this time, since the input section of the device 2 is stable, no rush current flows.

FIG. 2 is a timing chart showing the operation of the present embodiment. The signals S1 and S2 from the device 2 and the input current I from the DC power supply 1 to the device 2 at the time of transition from start-up to normal operation are shown. Shows the relationship. 2A and 2B, H (high level) and L of the signals S1 and S2
(Low level) indicates the opposite case, and any one may be used. After shifting to the normal operation, the level of the signal S1, that is, the state of the switch element SW1 may be any state.

As described above, in this embodiment, two signals S
By using 1, S2, it is possible to suppress the rush current that flows when the signal is switched from the start of the device 2 to the normal operation, or from the time of not using the device 2 to the time of the normal operation, such as during standby. At the same time, when the switching device SW1 is connected in series with the resistor R1 and the device 2 is not in use, the switching device SW1 can be made non-conductive, so that there is no loss due to the resistor R1 and energy saving is further promoted. Can be.

FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention, and the same reference numerals as in FIG. 1 denote the same components. In FIG. 3, reference numeral 3 denotes a delay circuit for delaying a predetermined signal S from the device 2 for controlling the switching element SW1, and the switching element SW2 is opened and closed by the delayed signal. Also, as in the embodiment of FIG. 1, the output of the switch elements SW1 and SW2 is configured to be input to a predetermined unused portion such as when the apparatus 2 is in a standby state. The delay circuit 3 is a general circuit in which a transistor, a capacitor, an operational amplifier (operational amplifier), a resistor, and the like are combined, or a logic circuit may be used.

In the above configuration, when the device 2 enters a normal operation from a state where it is not actually used, such as when the device 2 is started up or in a standby state, the switch element SW1 is first turned on by a signal S from the device 2, and this occurs. The inrush current is limited by the resistor R1. At this time, the switch SW2 remains open.

A period during which an inrush current flows (a period until the smoothing capacitor in the input section of the device is charged).
Alternatively, when a predetermined period of time has elapsed, a signal obtained by delaying the signal S is output from the delay circuit 3, and the switch element SW2 is turned on by this signal. At this time, device 2
Since the input section is stable, no rush current flows.

In this embodiment, the same operation and effect as those of the embodiment of FIG. 1 can be obtained, and the rush current can be prevented and the energy saving can be promoted. Only one is required, and timing control is simplified.

Although the embodiments of the present invention have been described above, in the present invention, as described above, with a simple configuration using the switch element and its control signal, it is possible to simultaneously prevent inrush current and promote energy saving. . When shifting from the normal operation to the standby state or the stop state, there is naturally no problem of the rush current.

[0027]

As described above, according to the present invention, a switch element is connected in series with a resistor, a switch element is connected in parallel with this series circuit, and these switch elements are controlled by a signal from the device. With this configuration, it is possible to suppress the inrush current flowing at the time of signal switching when the device enters a normal operation from a time when the device is not actually used, such as at the time of start-up or standby, with a simple configuration, and at the same time, a loss due to a resistance or the like is reduced. Therefore, there is an effect that energy saving can be further promoted.

Further, by using the signal from the device with a delay, only one signal is required and the timing control becomes easy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of the first embodiment;

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a conventional example.

FIG. 5 is a configuration diagram showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2 Device 3 Delay circuit R1 Resistance SW1 Switch element SW2 Switch element

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuhiro Yoshino, 3rd name Shinmeido, Shimada-cho, Shibata-cho, Shibata-gun, Miyagi Prefecture 1 Tohoku Ricoh Co., Ltd. 3 Shinmeido No. 1 Tohoku Ricoh Co., Ltd. F-term (reference) 5G065 AA01 BA00 BA04 EA01 HA07 JA02 KA02 KA03 KA05 LA07 MA07 MA10 NA02

Claims (4)

[Claims] 1. An inrush current prevention circuit for preventing an inrush current input from a DC power supply, wherein the inrush current is interrupted by a first signal and a series circuit of a switch element and a resistor is connected in parallel with the series circuit. A switching element that is opened and closed by a second signal different from the first signal. 2. An inrush current prevention circuit for preventing an inrush current input from a DC power supply, comprising: a series circuit of a switch element and a resistor for interrupting an input current according to a predetermined signal; and a parallel circuit connected to the series circuit. A switching element that opens and closes with a signal obtained by delaying the predetermined signal. 3. A DC operating device that operates by inputting a DC voltage, wherein a series circuit of a switch element and a resistor that interrupts a DC input current by a first signal, and the first circuit connected in parallel with the series circuit. And a switch element that opens and closes with a second signal different from the first signal. 4. A DC operating device which operates by inputting a DC voltage, wherein a series circuit of a switch element and a resistor for interrupting a DC input current by a predetermined signal, and the predetermined signal connected in parallel with the series circuit. And a switch element that opens and closes with a delayed signal.