JP6196504B2 - Switch device - Google Patents

Description

  According to the present invention, a switching element is inserted into a power supply line that connects a high-potential side input terminal to which a DC power source is connected and a high-potential side output terminal to which a load circuit is connected. It is related to a switching device that supplies / cuts off DC power to the load circuit by switching to the conductive state, and more specifically, it is configured to suppress inrush current to the load circuit when switching from the non-conductive state to the conductive state. The present invention relates to a switch device.

  This type of switching device is inserted in the middle of the power supply line to suppress the inrush current to the load circuit (especially capacitive load) when a DC power supply is connected, and responds to changes in the state of the driving switching element. A switching element for connection / cutoff that can be switched between a conduction state and a non-conduction state, and a capacitor element and a resistance element for integration to moderate the rise of the drive voltage of the switching element for connection / cutoff. ing.

<First Conventional Example>
FIG. 3 is a circuit diagram showing the configuration of the switch device B of the first conventional example. In the drive stop state with respect to the load circuit 53, the switch control signal Sc is at the “L” level, and the drive switching element (NPN transistor) Q52 is in a non-conductive state. At this time, the connection / disconnection switching element (P-channel type MOS-FET) Q51 has a small control voltage (gate-source voltage) applied to its control terminal (gate). The switching element Q51 is in a non-conductive state, and no power is supplied to the load circuit 53. In this state, charging of the integrating capacitive element (capacitor) C51 is not performed.

  When the switch control signal Sc is switched to the “H” level, the driving switching element Q52 becomes conductive. Then, the input terminal T1p on the high potential side → the time constant circuit 51a (the charge / discharge resistance element R51a and the capacitive element C51 for integration) → the resistance element R52 → the switching element Q52 for driving → the input terminal T1n on the low potential side. Current flows through the path. The control voltage of the switching element Q51 for connection / cutoff starts to increase gradually after a certain time has elapsed after the switching element Q52 for driving is turned on, the control voltage exceeds the threshold voltage, and thereafter the connection / cutoff is connected. The output voltage and output current from the switching element Q51 for use increase gradually. Waveforms of the output voltage and output current at the time of turn-on are shown in FIG.

  As shown in FIG. 4 (a), the output voltage starts rising after about 13 [ms] (milliseconds) from the rising time of the switch control signal Sc, and is at the same level as the input voltage over about 5 [ms]. Rise up slowly (the response delay time at turn-on is about 18 [ms]), and DC power is supplied to the load circuit 53. In response to this, the input current gradually increases, and the inrush current to the capacitive load C53 in the load circuit 53 is suppressed. The inrush current is suppressed to about 5.4 [A].

  Note that the measurement data of about 13 [ms] and about 18 [ms] are circuit constants, the resistance value of the resistance element R51a is 6.8 [kΩ], the resistance value of the resistance element R52 is 15 [kΩ], 2. The capacitance value of the capacitive element C51 for integration is 10 [μF], the capacitance value of the capacitive load C53 is 300 [μF], the input voltage from the DC power supply E51 is 24 [V], and the output current to the load circuit 53 is 3. This value is for 5 [A]. Note that the circuit constants and rated values exemplified here are common to a plurality of examples described later.

  Next, in the first conventional example shown in FIG. 3, when the switch control signal Sc is switched to the “L” level, the driving switching element Q52 is turned off. Then, the discharge of the charge from the integrating capacitive element C51 starts. The discharge current is consumed by the charge / discharge resistance element R51a, and the voltage across the integration capacitor element C51, that is, the control voltage of the switching element Q51 for connection / disconnection gradually decreases. When this control voltage becomes equal to or lower than the threshold voltage, the connection / cutoff switching element Q51 is turned off, and the supply of DC power to the load circuit 53 is stopped. The waveform of the output voltage and output current at the time of turn-off is shown in FIG.

<Second Conventional Example>
FIG. 5 shows a second conventional switch device C disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 7-30394). This is because a one-shot pulse circuit 1, an oscillation circuit 2, an AND gate 3, and an exclusive OR gate 4 are used to generate a switch control signal Sc ′ for controlling on / off of a driving switching element (NPN type transistor) 6. Etc. are provided. As a switch control signal Sc ′ to be applied to the base of the driving switching element 6 using these circuit elements, a pulse waveform that repeats “H” and “L” at a high speed for an initial fixed period, and the end point of the pulse waveform To a signal having a combined waveform with a waveform that continues the “H” level. By this switch control signal Sc ′, the switching element 6 for driving, and thus the switching element for connection / disconnection (P-channel type MOS-FET) 7 can be switched for a certain period, and then can be made conductive. As a result, the switching element 7 for connection / disconnection is gradually transitioned from the non-conduction state to the conduction state, and the inrush current is suppressed. Reference numeral 8 denotes an integrating capacitive element (capacitor C).

  In the second conventional example, a special waveform (initially a pulse waveform and thereafter “H” level) is generated using the one-shot pulse circuit 1, the oscillation circuit 2, the AND gate 3, the exclusive OR gate 4, and the like. Since the switch control signal Sc ′ is generated, the rise of the output voltage at turn-on becomes faster.

<Third conventional example>
FIG. 6 shows a third conventional switching device D disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 10-55729). A time constant circuit 15 is added to the base side of the switching element (NPN transistor) TR12 for driving the input stage of the switch control signal Sc. The time constant circuit 15 includes an integrating capacitive element (capacitor) C13, an integrating resistive element R15, a rapid discharging resistive element R16, and a unidirectional conducting element (rectifier diode) D12. When the “H” level switch control signal Sc is applied to the input terminal of the time constant circuit 15, a base current that gradually increases from the time constant circuit 15 flows into the base of the driving switching element TR12. As a result, the collector current of the driving switching element TR12 gradually increases, and the control voltage of the connection / cutoff switching element (P-channel MOS-FET) TR11 is gradually increased. As a result, the drain current of the switching element TR11 for connection / cutoff gradually increases, and the output voltage to the capacitor C2 increases gently. Since the output voltage rises slowly, the inrush current at turn-on can be suppressed. At the time of turn-off, the switch control signal Sc is set to “L” level, and the capacitive element C13 for integration is discharged to the resistance element R16 for rapid discharge through the unidirectional energization element D12. Can be shortened. D11 is a voltage limiting Zener diode.

<Fourth Conventional Example>
The switch device E of the fourth conventional example shown in FIG. 7 is different from the switch device B of the first conventional example shown in FIG. 3 in that the rapid discharge resistance element R55 and the rapid discharge resistor R55 are shortened in order to shorten the response delay time at turn-off. A discharge switching element (NPN transistor) Q53 and a unidirectional energization element (rectifier diode) D52 are added. That is, a series circuit of a rapid discharge resistance element R55 and a switching element Q53 is connected in parallel to a gate-source integration capacitor C51 of the connection / cutoff switching element Q51, and an integration capacitance element A unidirectional energization element D52 is inserted between a connection point between C51 and the rapid discharge switching element Q53 and the resistance element R51.

  When the “L” level switch control signal Sc is input, the driving switching element Q52 is turned off, and the rapid discharge switching element Q53 is turned on with its base voltage rising. As a result, the rapid discharge resistance element R55 is connected in parallel to the integrating capacitive element C51 via the rapid discharge switching element Q53 which is turned on. Then, the electric charge accumulated in the integrating capacitive element C51 is rapidly discharged through the rapid discharge resistance element R55. The control voltage of the connection / disconnection switching element Q51 becomes equal to or lower than the threshold voltage after a very short time, the connection / disconnection switching element Q51 is immediately turned off, and the output to the load circuit 53 is interrupted.

  Since the rapid discharge switching element Q53 is in a non-conductive state when the connection / disconnection switching element Q51 is in a conductive state, the resistance value of the resistance element R55 can be made sufficiently small. This is because, if the switching element Q53 for rapid discharge is also conductive when the switching element Q51 for connection / disconnection is conductive, the control voltage of the switching element Q51 for connection / disconnection is kept above a certain level in order to maintain the conductive state. In this case, the resistance value of the resistance element R55 must be set large to some extent. However, instead, when the connection / disconnection switching element Q51 is in the conducting state, the rapid discharge switching element Q53 is in the non-conducting state, so that the resistance value of the resistance element R55 is allowed to be sufficiently small.

  When the resistance value of the rapid discharge resistance element R55 is sufficiently small, the discharge from the integration capacitive element C51 is rapidly performed when the drive switching element Q52 is turned off when the switch control signal Sc is switched to the “L” level. This makes it possible to significantly reduce the response delay time at turn-off. Incidentally, the response delay time at turn-off is significantly shortened to about 0.8 [ms] as shown in FIG. 8B.

  If there is no switching element Q53 for rapid discharge (the drain and source of the element Q53 are short-circuited), the current flowing from the DC power source E51 to the input terminal T1p on the high potential side when the driving switching element Q52 is turned on. Most of the current flows through the resistor element R55 for rapid discharge and the charging speed of the integrating capacitor element C51 is greatly reduced, and the response delay time at turn-on becomes excessively long. Therefore, the rapid discharge switching element Q53 is indispensable when the rapid discharge resistance element R55 is connected in parallel to the integration capacitor element C51 on the input side (source side) of the connection / cutoff switching element Q51. It has become. In addition, the unidirectional energization element D52 flows the charging current from the capacitive element C51 when the switching element Q52 is turned on.

JP 7-30394 A Japanese Patent Laid-Open No. 10-55729

  In the case of the first conventional example of FIG. 3 described above, the waveforms of the output voltage and the output current when the switching element Q51 for connection / cutoff is turned off are shown in FIG. Although the output voltage falls sharply and the output current also decreases abruptly, the response delay time at turn-off is as long as about 93 [ms], and the cutoff characteristic is not good. That is, as means for avoiding the inrush current to the capacitive load C53, the integrating capacitive element C51 is interposed between the gate and the source of the switching element Q51 for connection / cutoff. There is a problem that it takes a long time to establish the cutoff of the output voltage.

  In the case of the second conventional example shown in FIG. 5, the waveform of the switch control signal Sc ′ is specialized (initially a pulse waveform and thereafter “H” level). For this purpose, the one-shot pulse circuit 1 and the oscillation circuit 2 are used. The AND gate 3 and the exclusive OR gate 4 are required, and the circuit configuration is considerably complicated. In addition, due to the integrating capacitive element 8 and charge / discharge resistive element 5 connected in parallel, a sufficient reduction in response delay time at turn-off cannot be expected. The response delay time at turn-off can be shortened by reducing the capacitance value of the capacitive element for integration or the resistance value of the resistance element for charge / discharge, but the inrush current at turn-on is excessive or the response delay at turn-on is delayed. Incurs longer time.

  Further, in the case of the third conventional example of FIG. 6, no integrating capacitive element is connected between the gate and source of the switching element TR11 for connection / cutoff, but the time constant of the input stage of the switch control signal Sc. In order to discharge the electric charge of the integrating capacitive element C13 in the circuit 15, the rapid discharge resistance element R16 and the unidirectional energization element D12 are used. That is, the time constant circuit 15 includes an integrating circuit composed of an integrating capacitive element C13 and an integrating resistive element R15, a unidirectional energizing element D12 that bypasses between both ends of the integrating resistive element R15, and a rapid discharge circuit. The resistor element R16 includes a large number of parts and a complicated circuit configuration.

  In order to moderately control the change in the control voltage of the switching element TR11 for connection / disconnection, a time constant circuit is not added directly to the switching element TR11, but a switching element for driving provided separately. A time constant circuit 15 is added to the base of TR12. In order to achieve the fine adjustment of the control voltage of the connection / cutoff switching element TR11, the base current of the driving switching element TR12 which is actually positioned away is finely adjusted. However, since the time constant circuit 15 has a large number of components and individual components vary, fine adjustment in the time constant circuit 15 is correctly reflected in fine adjustment of the control voltage of the switching element TR11 for connection / disconnection. There is a problem that it is very difficult. That is, there are problems that the inrush current increases due to variations in the components of the time constant circuit 15, and that variations in the response delay time when the output voltage is turned on and the response delay time when the output voltage is turned off increase.

  In the case of the fourth conventional example in FIG. 7, compared with the first conventional example in FIG. 3 having the basic configuration, the response delay time at the time of turn-off is greatly shortened. However, as an additional configuration for that purpose, there is a problem in that the three components of the rapid discharge resistance element R55, the switching element Q53, and the unidirectional energization element D52 are required and the number of additional parts is large, resulting in a complicated circuit configuration. . Nevertheless, the technical request for shortening the response delay time at turn-off does not actually need to be so extremely short (approximately 0.8 [ms]), and there is no problem if it can be shortened to about half. It is the actual situation. In other words, the addition of the three components of the rapid discharge resistance element R55, the switching element Q53, and the unidirectional energization element D52 is an excessive measure.

  In the case of the first conventional example shown in FIG. 3, in order to shorten the response delay time at turn-off, the capacitance value of the integrating capacitive element may be reduced. However, in this case, the inrush current at turn-on becomes excessively large. It is also possible to shorten the response delay time at the turn-off time by reducing the resistance value of the charge / discharge resistance element connected in parallel to the integration capacitor element to accelerate the discharge. However, if so, the response delay time of the output voltage at turn-on becomes excessively long.

  The present invention has been created in view of such circumstances, and it is possible to reduce the response delay time at turn-off without suppressing inrush current and deteriorating the response delay time at turn-on by a simple configuration with respect to the switch device. The goal is to be able to proceed.

  The present invention solves the above problems by taking the following measures.

The switch device according to the present invention comprises:
A power supply line connecting a high potential side input terminal to which a DC power source is connected and a high potential side output terminal to which a load circuit is connected;
A ground line connecting an input terminal on the low potential side to which the DC power supply is connected and an output terminal on the low potential side to which the load circuit is connected;
A connection / disconnection switching element inserted in the middle of the power supply line;
An integral for suppressing inrush current at the time of turn-on of the connection / cutoff switching element connected in parallel between the input side terminal and the control terminal in the current path of the connection / cutoff switching element . A capacitive element and a resistive element;
A switching device comprising a driving switching element connected between a connection point between the control terminal of the switching element for connection / cutoff, the capacitive element for integration and the resistance element, and the ground line, ,
A rapid discharge resistance element connected between an output side terminal and a control terminal in the current path of the connection / cutoff switching element for rapidly discharging the charge of the integration capacitor element and one-way It has a series circuit of conductive elements.

  In the switch device of the present invention configured as described above, when the driving switching element is in a non-conducting state, the connection / disconnection switching element is also in a non-conducting state. At this time, since there is a rectifying action (energization blocking action) of the unidirectional energization element, the resistance connected to the control terminal of the switching element for connection / cutoff by the DC voltage applied to the input terminal on the high potential side Current does not flow from the element toward the rapid discharge resistance element. That is, although a resistance element for rapid discharge is additionally connected to the output side of the switching element for connection / cutoff, this is because there is a rectification action (energization prevention action) of the unidirectional conduction element. / It does not affect the power supply line cutoff function when the switching element for cutoff is in a non-conduction state.

  When the driving switching element is switched to the conductive state, a current flows from the resistance element to the driving switching element, and the integrating capacitive element is charged. The control voltage increases slowly. That is, the connection / disconnection switching element gradually transitions from the high resistance state to the low resistance state. Eventually, the switching element for connection / cutoff reverses from the non-conductive state and becomes conductive, but since the resistance change is gentle as described above, the inrush current to the capacitive load of the load circuit is suppressed.

Next, when the driving switching element is reversed from the conducting state and switched to the non-conducting state, discharge from the integrating capacitive element is started, but the connecting / cutting switching element is immediately brought into the non-conducting state. Instead of being switched, in order to maintain a conducting state for a while (for a while), the charge of the integrating capacitive element is unidirectionally connected to the switching element for connection / cutoff and the resistive element for rapid discharge that are still conducting. Is discharged through the conductive element. That is, although the resistor element for rapid discharge for rapidly discharging the charge from the integrating capacitor element exists on the output side of the switching element for connection / disconnection, the connection / disconnection element described above is used. The switching element contributes to the rapid discharge by maintaining the conduction state for a while, thereby realizing the rapid discharge. After this rapid discharge, the connection / disconnection switching element is reversed from the conductive state and switched to the non-conductive state.

If a series circuit of a resistance element for rapid discharge and a unidirectional energization element is provided on the input side of the switching element for connection / cutoff, the capacitor element for integration is used when the switching element for driving is inverted. In the case of the present invention, a series circuit of a rapid discharge resistance element and a unidirectional energization element is connected to the output side of the switching element for connection / cutoff. Since it is provided, the response delay time at turn-on is not deteriorated.
That is, when switching the driving switching element, the connection / cutoff switching element does not immediately turn off but continues to be in a conductive state for a while, and the rapid discharge resistance element is connected. / The structure of connecting to the output side of the switching element for blocking is established.

  According to the present invention, for a switch device for connecting / disconnecting a load circuit including a capacitive load and a DC power supply, a series circuit of a resistance element for rapid discharge and a unidirectional conducting element is connected / disconnected. With the arrangement on the output side of the switching element, the effect of suppressing the inrush current, maintaining good rising characteristics, and shortening the response delay time at turn-off can be realized with a simple configuration.

The circuit diagram which shows the structure of the switch apparatus of the Example of this invention The timing chart (a) which shows the operation waveform at the time of turn-on in the switch apparatus of the Example of this invention, and the timing chart (b) which shows the operation waveform at the time of turn-off 1 is a circuit diagram showing the configuration of a first conventional switch device Timing chart (a) showing operation waveforms at turn-on and timing chart (b) showing operation waveforms at turn-off in the switch device of the first conventional example The circuit diagram which shows the structure of the switch apparatus of the 2nd prior art example (patent document 1 indication) The circuit diagram which shows the structure of the switch apparatus of the 3rd prior art example (patent document 2 disclosure) 4 is a circuit diagram showing the configuration of a switch device of a fourth conventional example. Timing chart (a) showing operation waveform at turn-on and timing chart (b) showing operation waveform at turn-off in switch device of fourth conventional example The circuit diagram which shows the structure of the switch apparatus of a comparative example

  The switch device of the present invention having the above configuration has several preferred modes as follows.

  The switching element for connection / cutoff inserted in the middle of the power supply line is preferably a P-channel MOS-FET (field effect transistor made of a metal oxide semiconductor). In the case of a bipolar transistor, electric power for maintaining a conductive state is required, whereas in the case of a MOS-FET, electric power for maintaining a conductive state is not necessary. However, in the present invention, the connection / cutoff switching element is not limited to the MOS-FET, and a bipolar transistor (NPN type or PNP type) may be used. In the case of a MOS-FET, either an N channel type or a P channel type may be used. The control terminal is a gate terminal in the case of a MOS-FET and a base terminal in the case of a bipolar transistor.

  In addition to the bipolar transistor of the above-described embodiment, a MOS-FET may be used as the driving switching element for controlling on / off of the connection / cutoff switching element. In the case of a bipolar transistor, either an NPN type transistor or a PNP type transistor may be used. In the case of a MOS-FET, either an N channel type or a P channel type may be used.

  The unidirectional energization element may be a thyristor in addition to a rectifier diode, or a diode-connected transistor. In the case of a bipolar transistor, the one in which the collector and the base are short-circuited is a unidirectional energization element, and in the case of the MOS-FET, the one in which the drain and the gate are short-circuited is a unidirectional energization element.

  The DC power source may be any battery (lithium ion battery, nickel metal hydride battery, etc.), battery (storage battery), solar battery, fuel cell, DC-DC converter, AC-DC converter, super capacitor, etc. .

  As a load circuit, a load circuit having a capacitive load and a resistive load is generally used, but the load circuit may be mainly composed of a capacitive load.

  Hereinafter, an embodiment of a switch device according to the present invention will be described with reference to FIGS.

  FIG. 1 is a circuit diagram showing a configuration of a switch device according to an embodiment of the present invention. First, the components are listed. In FIG. 1, A is a switching device, T1p and T1n are first and second input terminals of a DC power source in the switching device A, T2p and T2n are first and second output terminals of a DC voltage in the switching device A, Q51. Is a switching element for connection / disconnection, 51 is a time constant circuit, 52 is a drive control circuit, 53 is a load circuit, and E51 is a DC power source such as a battery. As components of the time constant circuit 51, C51 is a capacitive element for integration, R51 is a resistance element, R54 is a resistance element for rapid discharge, and D51 is a unidirectional energization element. Here, a rectifier diode is used as the unidirectional energization element D51. As constituent elements of the drive control circuit 52, Q52 is a switching element for driving, R52 is a resistance element for current limiting that charges the capacitive element C51 while being for bias. It is assumed that the load circuit 53 includes a capacitive load C53 and a resistive load R53. Here, a P-channel type MOS-FET is used as the switching element Q51 for connection / cutoff, and an NPN type transistor is used here as the switching element Q52 for driving.

  The pair of input terminals T1p and T1n are connected to a DC power source E51 to input a DC current, and the pair of output terminals T2p and T2n are supplied with DC power to the load circuit 53 connected thereto. To supply. The high-potential side input terminal T1p and the high-potential side output terminal T2p are connected via the power supply line L51, and a connection / cutoff switching element Q51 is inserted in the middle thereof. The low potential side input terminal T1n and the low potential side output terminal T2n are connected via a ground line L52.

  In the drive control circuit 52, one terminal of the resistor element R52 is connected to the collector of the driving switching element Q52, and the other terminal is connected to the gate which is the control terminal of the switching element Q51 for connection / cutoff. The emitter of the switching element Q52 is connected to the ground line L52. A switch control signal Sc is input to the base of the driving switching element Q52. The switch control signal Sc is a simple “H” / “L” switching type signal.

  The time constant circuit 51 further includes a rapid discharge resistance element R54 and a unidirectional energization element D51 in addition to the integration capacitor element C51 and the resistance element R51. That is, the integrating capacitive element C51 is connected between the gate and the source of the switching element Q51 for connection / disconnection, and the resistive element R51 is further connected in parallel to the integrating capacitive element C51. In addition, on the output side of the switching element Q51 for connection / cutoff, a series circuit of a resistance element R54 for rapid discharge and a unidirectional energization element D51 is connected between its drain and gate. That is, one terminal of the resistance element R54 for rapid discharge is connected to the drain of the switching element Q51 for connection / cutoff and the output terminal T2p on the high potential side, and the other terminal is connected to the anode of the unidirectional conducting element D51. Has been. The cathode of the unidirectional energization element D51 is connected to the gate of the switching element Q51 for connection / cutoff and the negative terminal of the capacitive element C51 for integration.

  As described above, the switch device A according to the embodiment of the present invention connects / disconnects the rapid discharge resistance element R54 and the unidirectional energization element D51 to the switch device B of the first conventional example of FIG. This corresponds to the element added to the output side of the switching element Q51. There are two additional circuit elements.

  Next, the operation of the switch device A configured as described above will be described with reference to the timing chart (operation waveform diagram) of FIG. FIG. 2A is a waveform diagram showing the rising characteristics of the switch device A according to the embodiment of the present invention, and FIG. 2B is a waveform chart showing the falling characteristics.

[1] <“L” Level State of Switch Control Signal Sc>
Now, the switching element Q51 for connection / cutoff is in a non-conductive state, the power supply line L51 is cut off, and the load circuit 53 is in a load stop state in which power supply from the DC power supply E51 is not performed. And At this time, in the drive control circuit 52, the switch control signal Sc is at the “L” level, and the driving switching element Q52 is in a non-conductive state.

  The rapid discharge resistance element R54 added to the time constant circuit 51 in the embodiment of the present invention is connected to the anode of the unidirectional energization element D51, and the cathode is connected to the resistance element R51. No current flows toward the resistance element R54 for rapid discharge. This is because the unidirectional energization element D51 blocks the flow of current. In addition, the integrating capacitive element C51 is not charged. That is, the voltage between both ends of the integrating capacitive element C51 is zero, and the control voltage (gate-source voltage) of the switching element Q51 for connection / cutoff is also zero.

[2] <Rise of switch control signal Sc to “H” level>
Next, when the power from the DC power source E51 is supplied to the load circuit 53 to enter the load operating state, the switch control signal Sc is changed from “L” level to “H” as shown in FIG. Launch to level. Then, the driving switching element Q52 is turned on, and the DC power source E51 applied to the input terminal T1p on the high potential side drives the resistive element R52 from the resistive element R51 and the integrating capacitive element C51 in the time constant circuit 51 to drive the resistive element R52. Current flows through the switching element Q52. Charging of the integrating capacitive element C51 is started under a time constant determined by the resistance value of the resistive element R51 and the capacitive value of the integrating capacitive element C51. As shown in FIG. 2 (a), the control voltage of the switching element Q51 for connection / disconnection exceeds the threshold voltage when a predetermined time of about 13 [ms] has elapsed from the rising timing of the switch control signal Sc, Thereafter, the output voltage and output current from the connection / cutoff switching element Q51 gradually increase. Since the increase is gradual, the inrush current of the load circuit 53 to the capacitive load C53 is suppressed.

[3] <Turn-on of switching element Q51 for connection / disconnection>
Further, after the elapse of a predetermined time (about 5 [ms]), the connection / cutoff switching element Q51 is completely turned on, and the output voltage is applied to the high potential side input terminal T1p (in this case, about 24 [ V]) and the output current stabilizes after the inrush current (5.44 [A]). At this time, the influence of the inrush current is alleviated, and a normal level current is stably supplied to the capacitive load C53 and the resistive load R54 in the load circuit 53.

  Part of the current returns to the input terminal T1n on the low potential side through the path of the rapid discharge resistance element R54 → the unidirectional energization element D51 → the resistance element R52 → the driving switching element Q52.

  As described in the operations of [2] and [3] above, the presence of the rapid discharge resistance element R54 added in the embodiment of the present invention has an influence on the operation at the beginning of the switching device A to the connection state. Never give. That is, the response delay time (about 17 [ms]) when the switch device A is turned on is approximately the same as the response delay time (about 18 [ms]) when the switch device A is turned on in the first conventional example shown in FIG. The difference is within the so-called tolerance range). In addition, the suppression effect against the inrush current is not inferior and is good.

[4] <Falling of switch control signal Sc to “L” level>
Next, when the operation of the load circuit 53 is to be stopped, the switch control signal Sc is lowered from the “H” level to the “L” level as shown in FIG. Then, the driving switching element Q52 is turned off. However, the switching element Q51 for connection / disconnection does not turn off immediately. This is because the state where the control voltage of the switching element Q51 for connection / cutoff exceeds the threshold voltage for a while due to the charging performed for the integrating capacitive element C51. The charge of the integrating capacitive element C51, whose negative terminal is disconnected from the ground line L52 by the turn-off of the driving switching element Q52, is discharged from the positive terminal toward the negative terminal. At this time, since the connecting / disconnecting switching element Q51 is still in the conducting state, the discharging current is in the conducting state of the connecting / disconnecting switching element Q51 → the rapid discharging resistive element R54 → the unidirectional conducting element D51. It flows along the route. A part of the current is discharged through the resistance element R51. However, since there is the resistance element R54 for rapid discharge, the accumulated charge of the integrating capacitance element C51 can be discharged faster than the discharge of only the resistance element R51. Along with this, the control voltage of the switching element Q51 for connection / disconnection drops rapidly. However, the output voltage and the output current are both maintained at the “H” level (until an elapsed time of 45 [ms]) as long as the connection / disconnection switching element Q51 is kept conductive. In this embodiment, the resistance value of the resistance element R51 is 6.8 [kΩ], and the resistance element R54 for rapid discharge is 10 [kΩ]. The resistance element R54 for rapid discharge has a resistance value set such that power consumption does not become excessive when the switching element Q51 is conductive.

[5] <Turn-off of switching element Q51 for connection / disconnection>
When the control voltage becomes equal to or lower than the threshold voltage, the connection / disconnection switching element Q51 is turned off. As a result, the current flowing from the DC power source E51 via the high potential side input terminal T1p is cut off, and the power supply to the load circuit 53 is stopped. Eventually, the discharge of the integrating capacitive element C51 is completed. The non-conducting state of connection / disconnection switching element Q51 is held until a response delay time at a predetermined turn-on time elapses after switch control signal Sc rises to "H" level next time.

  In the switch device A of the embodiment of the present invention, the response delay time at the turn-off time can be considerably shortened as compared with the first conventional example shown in FIG. Incidentally, in the switching device A, as shown in FIG. 2B, the response delay time at the time of turn-off is about 45 [ms], which is the first conventional example shown in FIG. 4B (FIG. 3). The response delay time at the turn-off time is significantly shortened compared to about 93 [ms] (reduction to about 48.4%).

  In the above operation state [4], the discharge itself through the rapid discharge resistance element R54 of the charging charge of the integrating capacitive element C51 is possible without the unidirectional energization element D51. However, if there is no unidirectional energization element D51, in the operation state [1] in which the connection / cutoff switching element Q51 is in the non-conducting state, the resistance element R51 → rapidly from the input terminal T1p on the high potential side. It flows into the load circuit 53 through the path of the discharge resistive element R54. This contradicts the non-conduction state of the switching element Q51 for connection / disconnection. For this reason, the unidirectional energization element D51 is necessary.

  The resistor element R54 for rapid discharge can be connected to the power supply line L51 at the output side of the switching element Q51 for connection / cutoff, that is, between the drain and the output terminal T2p on the high potential side. This is because, when the signal Sc is switched from the “H” level to the “L” level, the connection / cutoff switching element Q51 does not turn off immediately, but makes good use of the characteristic that it is in a conductive state for a while. .

  The countermeasure in the embodiment of the present invention has a simpler circuit configuration than the third conventional example having the time constant circuit 15 having a complicated circuit configuration shown in FIG. Further, since the resistance element R54 for rapid discharge and the unidirectional energization element D51 are directly added to the switching element Q51 for connection / cutoff, the following advantages are obtained. That is, in comparison with the case where the time constant circuit 15 is added to the base side of the driving switching element TR12 in a state separated from the connection / cutoff switching element TR11 in FIG. Adjustment of the control voltage of the switching element Q51 for connection / cutoff performed to suppress the variation can be performed more easily.

  Further, in the case of the fourth conventional example shown in FIG. 7 intended to solve the problem of the long response delay time at the turn-off of the first conventional example shown in FIG. The response delay time is greatly shortened to about 0.8 [ms]. However, as an additional configuration for that purpose, three components of a rapid discharge resistance element R55, a rapid discharge switching element Q53, and a unidirectional energization element D52 are necessary, and the number of additional components is large, resulting in a complicated circuit configuration. There is a problem of inviting. On the other hand, the additional configuration in the embodiment of the present invention only requires two components, that is, the rapid discharge resistance element R54 connected between the drain and the gate of the connection / disconnection switching element Q51 and the unidirectional energization element D51. Therefore, the circuit configuration can be simplified.

  Regarding the effect of shortening the response delay time at turn-off, the fourth conventional example shown in FIG. 7 is superior (see FIG. 8B). For example, the circuit constants and rated values are the same as described above, and the response delay time at turn-off in the case of the first conventional example shown in FIG. 3 is about 93 [ms] ( In the case of the fourth conventional example shown in FIG. 7, it is about 0.8 [ms] as shown in FIG. 8B, and in the case of the embodiment of the present invention, it is shown in FIG. As shown in b), there is measurement data of about 45 [ms]. According to the fourth conventional example (FIGS. 7 and 8), the response delay time at the turn-off time can be greatly shortened, but the practical technical request is not so extreme, and there is a problem if it can be reduced to about half. In the case of the switch device A having no specifications, sufficiently satisfactory results can be obtained in the embodiment of the present invention.

  In summary, according to the embodiment of the present invention, the response delay time at turn-on and the inrush current suppression action are not inferior to the first conventional example shown in FIGS. Compared with the first conventional example shown in FIG. 3 and FIG. 4, a considerable shortening is realized, and yet, in terms of the number of parts and the circuit configuration, simplification is realized as compared with the fourth conventional example shown in FIG. Yes.

  By the way, in the third conventional example shown in FIG. 6, a rapid discharge resistance element for rapidly discharging the charge of the integrating capacitive element C13 in the time constant circuit 15 in order to shorten the response delay time at turn-off. R16 and a unidirectional energization element D12 are provided. However, for the rapid discharge of the integrating capacitive element, an additional measure of the series circuit comprising the rapid discharge resistance element and the unidirectional energization element is the connection / disconnection of the first conventional example shown in FIG. It cannot be simply applied to the capacitive element C51 for integration between the gate and the source of the switching element Q51. Hereinafter, this point will be described with reference to FIG.

  In the switching device F of the comparative example shown in FIG. 9, the resistor for rapid discharge is applied to the power supply line L51 at the input side of the switching element Q51 for connection / cutoff, that is, the portion between the source and the input terminal T1p on the high potential side. A series circuit of the element R56 and the unidirectional conducting element D52 is connected in parallel to the integrating capacitive element C51. This is an application of the concept of the fourth conventional example shown in FIG. Since the series circuit of the rapid discharge resistance element R56 and the unidirectional energization element D52 is directly connected in parallel to the integration capacitance element C51, the rapid discharge resistance immediately after the driving switching element Q52 is turned on. A current flows through a series circuit of the element R56 and the unidirectional energization element D52. The parallel combined resistance value of the resistance element R51 and the rapid discharge resistance element R56 is smaller than the resistance value of the resistance element R51 alone. Therefore, there is an action of rapid discharge when the switching element for driving Q52 is turned off, and the response delay time at the time of turn-off can be shortened. However, on the other hand, the voltage drop at the combined resistance of the resistor element R51 and the rapid discharge resistor element R56 is small, and the rise of the voltage across the integrating capacitor element C51 and thus the control voltage of the switching element Q51 for connection / cutoff are reduced. The increase will be very slow. As a result, the response delay time at turn-on becomes significantly long.

  On the other hand, in the embodiment of the present invention, the resistance element R54 for rapid discharge is connected to the output side (drain side) of the switching element Q51 for connection / disconnection, so that the switching device A is brought into the connected state. In the initial period in which the connection / disconnection switching element Q51 is still in the non-conductive state, no current flows through the rapid discharge resistance element R54. Therefore, the presence of the rapid discharge resistance element R54 is not present. Does not affect response delay time at turn-on. That is, the response delay time at the turn-on time of the switch device A of the embodiment of the present invention is not different from the response delay time at the turn-on time of the first conventional example shown in FIG. Further, the effect of suppressing the inrush current is not inferior.

  The present invention relates to a switching device for connecting / disconnecting a load circuit including a DC power source and a capacitive load, and a series circuit of a rapid discharge resistance element and a unidirectional energization element is connected to the switching element for connection / disconnection. The arrangement on the output side is useful as a technique for realizing an inrush current suppressing effect, maintaining a good rise characteristic, and shortening a response delay time at turn-off with a simple configuration.

51 Time constant circuit 52 Drive control circuit 53 Load circuit C51 Capacitance element for integration C53 Capacitive load D51 Unidirectional energization element (rectifier diode)
E51 DC power supply L51 Power supply line L52 Ground line Q51 Switching element for connection / cutoff (P-channel type MOS-FET)
Q52 Driving switching element (NPN type transistor)
R51 Resistive element R52 Resistive element R53 Resistive load R54 Rapid discharge resistive element Sc Switch control signal T1p High potential side input terminal T1n Low potential side input terminal T2p High potential side output terminal T2n Low potential side output terminal

Claims (4)

A power supply line connecting a high potential side input terminal to which a DC power source is connected and a high potential side output terminal to which a load circuit is connected;
A ground line connecting an input terminal on the low potential side to which the DC power supply is connected and an output terminal on the low potential side to which the load circuit is connected;
A connection / disconnection switching element inserted in the middle of the power supply line;
An integral for suppressing inrush current at the time of turn-on of the connection / cutoff switching element connected in parallel between the input side terminal and the control terminal in the current path of the connection / cutoff switching element . A capacitive element and a resistive element;
A switching device comprising a driving switching element connected between a connection point between the control terminal of the switching element for connection / cutoff, the capacitive element for integration and the resistance element, and the ground line, ,
A rapid discharge resistance element connected between an output side terminal and a control terminal in the current path of the connection / cutoff switching element for rapidly discharging the charge of the integration capacitor element and one-way Switch device provided with a series circuit of conductive elements.
  The switch device according to claim 1, wherein the unidirectional energization element is configured by a rectifier diode.   The switch device according to claim 1, wherein the connection / disconnection switching element is configured by a P-channel MOS-FET.   4. The switch device according to claim 1, wherein the switching element for driving is composed of a bipolar transistor. 5.

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