WO2015125333A1

WO2015125333A1 - Charging current control circuit and charging current control device

Info

Publication number: WO2015125333A1
Application number: PCT/JP2014/075821
Authority: WO
Inventors: 思洋陳; 池田　豊; 清文鳥井
Original assignee: 株式会社村田製作所
Priority date: 2014-02-20
Filing date: 2014-09-29
Publication date: 2015-08-27
Also published as: JPWO2015125333A1; JP6202186B2

Abstract

Disclosed is a charging current control circuit that controls the charging current of a smoothing capacitor which is charged by a rectifier circuit, wherein a first switching element (SCR1) is connected between a first node (N1) to which an output voltage of the rectifier circuit is applied, and a second node (N2) that is connected to a positive electrode of the smoothing capacitor. When the value of a conduction control signal (Sg), which is generated on the basis of the voltage of a first timing capacitor (C1) charged by the voltage of the first node (N1), becomes equal to or higher than a threshold voltage of a second switching element (SCR2), the second switching element and the first switching element successively change from a non-conducting state to a conducting state. Thus, in cases of switching the charging path of the smoothing capacitor at turn-on to a thyristor, there is no need for a gate-triggering transformer for controlling the conduction of the thyristor, and an increase in size of the power supply circuit is prevented.

Description

Charging current control circuit and charging current control device

The present invention relates to a charging current control circuit and a charging current control device, for example, a charging current control circuit for suppressing an inflow of an excessive charging current (so-called inrush current) into a smoothing capacitor when power is turned on, and charging current control Relates to the device.

Various power supply circuits having a function of suppressing an inrush current when an AC power supply is turned on have been proposed in a power supply circuit that rectifies an AC power supply with a rectifier circuit and generates a DC voltage in which a pulsating current is suppressed with a smoothing capacitor.

Patent Document 1 discloses a power supply circuit including a current-limiting resistor and a thyristor connected in parallel between a rectifier circuit and a smoothing capacitor, and a transistor for controlling the arc-phase of the thyristor. The timing for switching the path for applying the full-wave rectified voltage to the smoothing capacitor from the current limiting resistor to the thyristor is performed by a transistor that controls the arc-phase.

Patent Document 2 discloses a switching power supply circuit including a current limiting resistor and a thyristor connected in parallel between a rectifier circuit and a smoothing capacitor, and a capacitor for supplying a conduction voltage to the gate terminal of the thyristor.

Patent Document 3 discloses a switching power supply including a current limiting resistor and a thyristor connected in parallel between a rectifier diode and a smoothing capacitor, and a time limit circuit for controlling the gate voltage of the thyristor. The time limit circuit includes a voltage dividing resistor that divides the pulsating output voltage and a delay capacitor that forms a time limit circuit together with the voltage dividing resistor.

JP-A 63-224666 JP 2012-157221 A Utility Model Registration No. 2546843

The power circuits disclosed in Patent Document 1 and Patent Document 2 are both connected to a thyristor gate at the gate of the thyristor, and the thyristor is charged with power generated by a transformer so that the thyristor is turned on after the power is turned on. Is confused. For this reason, a transformer for isolating the gate point of the thyristor is necessary, which causes the power supply circuit to become complicated and large. In the switching power supply disclosed in Patent Document 3, a thyristor is lit by connecting a lone capacitor to the gate of the thyristor and charging the lone capacitor with an input voltage. As a result, the timing of the thyristor's point-to-point is affected by fluctuations in the input voltage, resulting in large variations. Further, when the circuit for suppressing the inrush current is modularized, the number of connection terminals increases, and the wiring of the main wiring board becomes complicated. Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

The present invention is a charging current control circuit for controlling a charging current of a smoothing capacitor charged by a rectifying circuit, and a second node connected to a first node to which an output voltage of the rectifying circuit is applied and a positive electrode of the smoothing capacitor. A first switching element connected to the first node and the second node, the third electrode is electrically connected to the first node, and the fourth electrode is connected to the first node and the second node, respectively; A second switching element connected to the first control electrode of the first switching element; a third electrode of the second switching element; and a second node connected to the second control electrode of the second switching element. A timing control circuit for outputting, wherein the timing control circuit discharges a first timing capacitor charged with a voltage applied to the first node and a charge accumulated in the first timing capacitor. A conduction control signal is generated based on the voltage of the first timing capacitor, and when the value of the conduction control signal is equal to or higher than the threshold voltage of the second switching element, The one switching element sequentially changes from the non-conduction state to the conduction state, and when the value of the conduction control signal becomes less than the threshold voltage of the second switching element, the second switching element and the first switching element are changed from the conduction state. It is a charging current control circuit which changes to a non-conduction state.

The present invention is a charging current control device comprising a first terminal, a second terminal, and a wiring board, wherein the wiring board has a first node to which an output voltage of a rectifier circuit is applied, a positive electrode of a smoothing capacitor, A first switching element to which the first electrode and the second electrode are connected to the second node to be connected, the first node and the second node, respectively, and a third electrode to be electrically connected to the first node; A second switching element connected to the first control electrode of the first switching element; a third electrode of the second switching element; and a second control electrode of the second switching element connected between the second node. A timing control circuit that outputs a conduction control signal to the first node, the timing control circuit discharging a charge stored in the first timing capacitor and a first timing capacitor charged with a voltage applied to the first node. A conduction control signal is generated based on the voltage of the first timing capacitor, and when the value of the conduction control signal is equal to or higher than the threshold voltage of the second switching element, The one switching element sequentially changes from the non-conduction state to the conduction state, and when the value of the conduction control signal becomes less than the threshold voltage of the second switching element, the second switching element and the first switching element are changed from the conduction state. The charging current control device is changed to a non-conduction state, and the first terminal and the second terminal are connected to the first node and the second node, respectively.

According to the embodiment, a charging current control circuit that does not require a transformer for the gate point of the thyristor after turning on the power and suppresses the influence of the fluctuation of the input voltage on the timing of the point of the thyristor, the main wiring board, Thus, it is possible to realize a charging current control device in which the number of connection terminals is minimized.

2 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit according to Embodiment 1. FIG. 5 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit according to Embodiment 2. FIG. 6 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit according to Embodiment 3. FIG. 6 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit according to Embodiment 4. FIG. FIG. 10 is a circuit diagram of an AC / DC conversion circuit including a charging current control circuit according to a fifth embodiment. FIG. 10 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit according to a sixth embodiment. FIG. 7 is a perspective view of a charging current control device equipped with a charging current control circuit according to any of Embodiments 1 to 6.

Hereinafter, embodiments will be described with reference to the drawings. In the description of the embodiment, reference to the number, amount, and the like is not necessarily limited to the number, amount, and the like unless otherwise specified. In the drawings of the embodiments, the same reference numerals and reference numerals represent the same or corresponding parts. Further, in the description of the embodiments, the overlapping description may not be repeated for the portions with the same reference numerals and the like.

<Embodiment 1>
FIG. 1 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit 100 according to the first embodiment.

The AC / DC conversion circuit includes a diode bridge Db that rectifies an input AC voltage Vin and outputs a DC voltage, a limiting resistor Rp, a smoothing capacitor Cs, and a charging current control circuit 100. The DC voltage output from the diode bridge Db is applied to one end of the smoothing capacitor Cs via the limiting resistor Rp. In the diode bridge Db, the ground voltage GND is applied to the side facing the side that outputs a DC voltage and the other end of the smoothing capacitor Cs. For example, a positive temperature coefficient thermistor (PTC) is applied to the limiting resistor Rp.

The charging current control circuit 100 includes a node N1, a node N2, a first switching element SCR1, a second switching element SCR2, a resistor R1, a resistor Rg, a capacitor C0, a timing control circuit 10, and a first voltage clamp element Znr1. The timing control circuit 10 includes a resistor Rc1, a first discharge resistor Rc2, a diode D1, and a first timing capacitor C1, and outputs a conduction control signal Sg that controls the conduction state of the second switching element SCR2. The first switching element SCR1 and the second switching element SCR2 are both thyristors (SCR), and the first voltage clamp element Znr1 is a Zener diode or a diac (DIAC).

The anode and cathode of the first switching element SCR1 are connected to the node N1 and the node N2, respectively. One end and the other end of the limiting resistor Rp are also connected to the node N1 and the node N2, respectively. The first switching element SCR1 and the limiting resistor Rp are connected in parallel. By connecting the capacitor C0 between the gate and the cathode of the first switching element SCR1, the noise resistance of the first switching element SCR1 is improved.

The anode of the second switching element SCR2 is connected to the node N1 via the resistor R1. The value of the resistor R1 is selected so that the voltage applied to the anode of the second switching element SCR2 becomes an optimum value. The cathode and gate of second switching element SCR2 are connected to the gate of first switching element SCR1 and one end of resistor Rg, respectively.

The timing control circuit 10 is disposed between the anode of the second switching element SCR2 and the node N2. In the timing control circuit 10, one end and the other end of the resistor Rc1 are connected to the anode of the second switching element SCR2 and the anode of the diode D1, respectively. The anode of the diode D1 is connected to the other end of the resistor Rg, and the conduction control signal Sg is output from the connection node. A first timing capacitor C1 and a first discharge resistor Rc2 are connected in parallel between the cathode of the diode D1 and the node N2.

In the timing control circuit 10, the resistor Rc1 and the first timing capacitor C1 connected in series determine the timing at which the second switching element SCR2 changes from the non-conductive state to the conductive state, as will be described later. Further, the first timing capacitor C1 and the first discharge resistor Rc2 connected in parallel determine the timing at which the second switching element SCR2 changes from the conductive state to the non-conductive state.

The first voltage clamp element Znr1 is connected to limit the voltage applied to the timing control circuit 10 and to suppress fluctuations in the charging time of the first timing capacitor C1 due to fluctuations in the power supply voltage or the like.

The operation of the charging current control circuit 100 will be described with reference to FIG.
First, the operation of the charging current control circuit 100 when the power is turned on will be described.

When the AC voltage Vin is applied to the diode bridge Db, that is, when the AC / DC converter circuit is powered on, the diode bridge Db starts generating a DC voltage obtained by full-wave rectifying the AC voltage Vin. This DC voltage has a ripple whose maximum voltage value rises to the amplitude value of the AC voltage Vin. The DC voltage output from the diode bridge Db is applied to the smoothing capacitor Cs via the limiting resistor Rp, and charging of the smoothing capacitor Cs is started. The value of the limiting resistor Rp is set to a value that does not damage the AC / DC converter circuit of FIG. 1 due to the inrush current immediately after the power is turned on.

As the charging of the smoothing capacitor Cs proceeds, the charging current of the smoothing capacitor Cs decreases. Further, when no abnormality has occurred in the AC / DC converter circuit, the value of the limiting resistor Rp hardly changes until the smoothing capacitor Cs reaches the fully charged state. That is, the resistance value of the limiting resistor Rp having a positive thermistor characteristic does not increase even when absorbing a constant Joule heat. As a result, the peak value of the DC voltage applied to the smoothing capacitor Cs and the charging current of the smoothing capacitor Cs each converge to a constant value. On the other hand, a voltage generated at both ends of the limiting resistor Rp is applied between the node N1 and the node N2 of the charging current control circuit 100, and the timing control circuit 10 has the node N1 clamped by the first voltage clamp element Znr1. A voltage is applied.

When the voltage of the node N1 is applied to the timing control circuit 10, charging of the first timing capacitor C1 is started via the resistor R1 and the resistor Rc1. The charging time of the first timing capacitor C1 depends on the values of the resistor Rc1, the first discharge resistor Rc2, and the first timing capacitor C1 that determine the time constant of the charging voltage, and the voltage value applied to the timing control circuit 10. To do. During the charging period of the first timing capacitor C1, discharging of the first timing capacitor C1 due to voltage fluctuation at the node N1 is blocked by the diode D1.

When charging of the first timing capacitor C1 proceeds and the value of the conduction control signal Sg exceeds the threshold voltage of the second switching element SCR2, the second switching element SCR2 changes from the non-conduction state to the conduction state, and the first The gate voltage of the switching element SCR1 is increased. When the cathode voltage of the second switching element SCR2 exceeds the threshold voltage of the first switching element SCR1, the first switching element SCR1 changes to a conductive state, and the impedance between the node N1 and the node N2 is lower than the value of the limiting resistor Rp. Are connected by the first switching element SCR1 set to.

As described above, since the voltage between the node N1 and the node N2 decreases after the power is turned on, it is important to set the timing for switching the conduction path between the node N1 and the node N2 from the limiting resistor Rp to the first switching element SCR1. Become. That is, if the switching timing is too early, damage to the AC / DC converter circuit due to the inrush current via the first switching element SCR1 occurs, and if the switching timing is too late, the limiting resistor Rp generates heat or is limited by this heating. There is a concern that the system may be down due to an increase in the resistance value of the resistor Rp.

According to the timing control circuit 10, by appropriately setting the values of the resistor Rc1 and the first timing capacitor C1, the conduction path between the node N1 and the node N2 is smoothly switched from the limiting resistor Rp to the first switching element SCR1. It becomes possible. Further, the voltage applied to the timing control circuit 10 is clamped to a constant value by the first voltage clamp element Znr1, thereby minimizing the variation in the charging time of the first timing capacitor C1 due to the voltage variation at the node N1. It becomes possible to suppress.

Next, the operation of the charging current control circuit 100 when the power is turned off will be described.
In the AC / DC conversion circuit shown in FIG. 1, when the diode bridge Db is charging the smoothing capacitor Cs via the first switching element SCR1, the supply of the AC voltage Vin is temporarily interrupted. Over the cutoff time, the charge accumulated in the smoothing capacitor Cs decreases due to discharge to a load (not shown), and the voltage of the smoothing capacitor Cs decreases. After that, when the supply of the AC voltage Vin is resumed, if the first switching element SCR1 of the charging current control circuit 100 is maintained in the conductive state, the smoothing is performed from the diode bridge Db via the first switching element SCR1. Inrush current flows to the capacitor Cs. Therefore, when the diode bridge Db stops outputting the DC voltage, it is necessary to quickly set the first switching element SCR1 to the non-conductive state in preparation for the resumption of the supply of the AC voltage Vin thereafter.

In the charging current control circuit 100, the first timing capacitor C1 and the first discharge resistor Rc2 connected in parallel included in the timing control circuit 10 operate as a timing circuit that sets the second switching element SCR2 from the conductive state to the non-conductive state. . That is, when the diode bridge Db stops supplying the DC voltage to the timing control circuit 10, the charge accumulated in the first timing capacitor C1 is discharged via the first discharge resistor Rc2, and the voltage of the first timing capacitor C1 Declines rapidly. The discharge time of the first timing capacitor C1 depends on the values of the first discharge resistor Rc2 and the first timing capacitor C1 that determine the time constant of the discharge voltage. When the value of the conduction control signal Sg falls below the threshold voltage of the second switching element SCR2 due to the voltage drop of the first timing capacitor C1, the second switching element SCR2 changes from the conduction state to the non-conduction state. Furthermore, the first switching element SCR1 is also set to a non-conduction state.

Therefore, according to the timing control circuit 10, by appropriately setting the values of the first discharge resistor Rc2 and the first timing capacitor C1, the second switching element SCR2 and the first switching element SCR1 are within the assumed power-off time. Can be set from the conductive state to the non-conductive state.

The effect of the charging current control circuit 100 will be described.
Based on the conduction control signal Sg output from the timing control circuit 10, the charging current control circuit 100 provides a conduction path for supplying the DC voltage output from the diode bridge Db to the smoothing capacitor Cs from the limiting resistor Rp to the first switching element SCR1. Switch. The switching of the conduction path is performed based on a conduction control signal Sg that changes with a time constant determined by the values of resistance and capacitance. Instead of the conventional general configuration using an inductor having a complicated structure, the charging current control circuit can be reduced in size and price by being configured with small electronic components such as resistors and capacitors.

The timing control circuit 10 controls the conduction state of the first switching element SCR1 based on the conduction control signal Sg not only when the AC / DC converter circuit is turned on but also when the power is turned off. Specifically, when the power interruption occurs, the timing control circuit 10 quickly sets the first switching element SCR1 in the conductive state to the non-conductive state. As a result, the occurrence of inrush current is suppressed not only when the power is turned on but also when the power is restored.

The charging current control circuit 100 clamps the DC voltage output from the diode bridge Db with the first voltage clamp element Znr1, and applies it to the timing control circuit 10. Thereby, it is possible to reduce the influence of the conduction timing of the second switching element SCR2 due to fluctuations in the power supply voltage and the inrush phase. Further, since the maximum value of the power supply voltage applied to the timing control circuit 10 does not exceed the breakdown voltage of the first voltage clamp element Znr1, the withstand voltage of the electronic components constituting the timing control circuit 10 can be lowered. Electronic parts can be reduced in size and price.

<Embodiment 2>
FIG. 2 is a circuit diagram of an AC / DC conversion circuit including the charging current control circuit 200 according to the second embodiment.

In FIG. 2, the same reference numerals as those in FIG. 1 have the same functions or configurations, and the duplicate description thereof is omitted. The charging current control circuit 200 shown in FIG. 2 has a configuration in which, in the charging current control circuit 100 shown in FIG. 1, the second switching element SCR2 is replaced with a field effect transistor FET and a second voltage clamp element Znr2 is added. Equivalent to. The second voltage clamp element Znr2 is, for example, a Zener diode or a diac.

In the charging current control circuit 200, the drain of the field effect transistor FET is connected to the node N1 via the resistor R1. The source of the field effect transistor FET is connected to the gate of the first switching element SCR1. The gate of the field effect transistor FET is connected to the anode of the diode D1 included in the timing control circuit 10 and the cathode of the second voltage clamp element Znr2, and the conduction control signal Sg is applied. The anode of the second voltage clamp element Znr2 is connected to the node N2. The second voltage clamp element Znr2 is a gate protection element for preventing gate breakdown of the field effect transistor FET due to high voltage.

The operation of the charging current control circuit 200 will be described.
The diode bridge Db to which the AC voltage Vin is applied starts charging the smoothing capacitor Cs via the limiting resistor Rp. A voltage generated at both ends of the limiting resistor Rp is applied between the node N1 and the node N2 of the timing control circuit 10, and the voltage of the node N1 clamped by the first voltage clamp element Znr1 is applied to the timing control circuit 10. Is done.

When the charging voltage of the first timing capacitor C1 in the timing control circuit 10 increases and the value of the conduction control signal Sg exceeds the threshold voltage of the field effect transistor FET, the first switching element SCR1 changes from the non-conduction state to the conduction state. Change. When the first switching element SCR1 changes to the conductive state, the conductive path between the node N1 and the node N2 is switched to the first switching element SCR1 set to a lower impedance state than the value of the limiting resistor Rp. Further, when the value of the conduction control signal Sg drops below the threshold voltage of the field effect transistor FET due to power shutdown, the field effect transistor FET becomes non-conductive, and as a result, the field effect transistor FET and the first switching element SCR1 It changes from the conductive state to the non-conductive state.

The effect of the charging current control circuit 200 will be described.
As the second switching element SCR2 of the charging current control circuit 100, by applying a field effect transistor FET whose switching speed is higher than that of the thyristor, the switching speed of the conduction state of the first switching element SCR1 can be further increased. It becomes.

<Embodiment 3>
FIG. 3 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit 300 according to the third embodiment.

In FIG. 3, components having the same reference numerals as those in FIG. 1 have the same functions or configurations, and redundant description thereof will be omitted. The charging current control circuit 300 shown in FIG. 3 corresponds to a configuration in which the second switching element SCR2 is replaced with an npn bipolar transistor TR1 in the charging current control circuit 100 shown in FIG.

In the charging current control circuit 300, the collector of the bipolar transistor TR1 is connected to the node N1 via the resistor R1. A conduction control signal Sg output from the timing control circuit 10 is applied to the base of the bipolar transistor TR1 via the resistor Rb. The emitter of the bipolar transistor TR1 is connected to the gate of the first switching element SCR1.

When the diode bridge Db starts charging the smoothing capacitor Cs and the charging voltage of the first timing capacitor C1 in the timing control circuit 10 increases, the value of the conduction control signal Sg also increases. When the value of the conduction control signal Sg exceeds the value of the forward voltage between the base and emitter of the bipolar transistor TR1, the bipolar transistor TR1 raises the gate voltage of the first switching element SCR1. When the first switching element SCR1 changes to the conductive state, the conductive path between the node N1 and the node N2 is switched to the first switching element SCR1 set to a lower impedance state than the value of the limiting resistor Rp.

Further, when the conduction control signal Sg cannot supply the necessary forward voltage between the base and emitter of the bipolar transistor TR1 due to the power interruption, the bipolar transistor TR1 becomes non-conductive, and as a result, the bipolar transistor TR1 and the second transistor TR1. 1 switching element SCR1 changes from a conductive state to a non-conductive state.

The effect of the charging current control circuit 300 will be described.
As the second switching element SCR2 of the charging current control circuit 100, by applying the bipolar transistor TR1 whose switching speed is higher than that of the thyristor, it is possible to further increase the switching speed of the conduction state of the first switching element SCR1. Become.

<Embodiment 4>
FIG. 4 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit 400 according to the fourth embodiment.

In FIG. 4, components having the same reference numerals as those in FIG. 1 have the same functions or configurations, and redundant description thereof will be omitted. The charging current control circuit 400 shown in FIG. 4 corresponds to a configuration in which the timing control circuit 10 is replaced with the timing control circuit 20 in the charging current control circuit 100 shown in FIG. The timing control circuit 20 improves the response speed of the timing control circuit 10.

As with the timing control circuit 10, the timing control circuit 20 includes a resistor Rc1, a diode D1, and a first timing capacitor C1 connected in series between the anode of the second switching element SCR2 and the node N2. The first discharge resistor Rc2 is connected in parallel with the first timing capacitor C1 via a pnp bipolar transistor TR2 (discharge switch). When the bipolar transistor TR2 is set to the conductive state, the first discharge resistor Rc2 is connected in parallel with the first timing capacitor C1 via the emitter and collector of the bipolar transistor TR2, and the bipolar transistor TR2 is set to the nonconductive state. When set, the parallel connection of the first discharge resistor Rc2 and the first timing capacitor C1 is released. That is, the bipolar transistor TR2 operates as a discharge switch that controls the discharge of the first timing capacitor C1 by the first discharge resistor Rc2.

The timing control circuit 20 is further connected in parallel with the resistor Rc3, the diode D2, the second timing capacitor C2, and the second timing capacitor C2 connected in series between the anode of the second switching element SCR2 and the node N2. And a second discharge resistor Rc4. A connection point between the cathode of the diode D2 and the second timing capacitor C2 is connected to the base of the bipolar transistor TR2. The resistor Rc3, the diode D2, the second timing capacitor C2, and the second discharge resistor Rc4 perform the same operation as the timing control circuit 10.

When the voltage at the node N1 rises, charging of the second timing capacitor C2 is started. The charging time depends on the values of the resistor Rc3, the second discharge resistor Rc4, and the second timing capacitor C2 that determine the time constant of the charging voltage. When the cathode voltage of the diode D2 rises and the bipolar transistor TR2 becomes non-conductive, the parallel connection between the first timing capacitor C1 and the first discharge resistor Rc2 is released. As a result, the first timing capacitor C1 is charged by all of the current supplied via the resistor Rc1 and the diode D1. When the first discharge resistor Rc2 is connected in parallel with the first timing capacitor C1, the charging current supplied to the first timing capacitor C1 is reduced by the amount diverted to the first discharge resistor Rc2.

Accordingly, by releasing the parallel connection of the first timing capacitor C1 and the first discharge resistor Rc2, the increasing speed of the conduction control signal Sg is improved, and the first switching element SCR1 is changed from the non-conduction state to the conduction state at a higher speed. The speed of switching the conduction path between the node N1 and the node N2 is increased.

When the voltage at the node N1 drops, the second timing capacitor C2 starts to be discharged. The discharge time depends on the values of the second discharge resistor Rc4 and the second timing capacitor C2 that determine the time constant of the discharge voltage. When the cathode voltage of the diode D2 drops and the bipolar transistor TR2 becomes conductive, the first timing capacitor C1 and the first discharge resistor Rc2 are connected in parallel. As a result, the discharge of the first timing capacitor C1 is also started, and the voltage of the conduction control signal Sg is also lowered. Since the value of the resistor Rc1 of the timing control circuit 20 can be set smaller than the value of the resistor Rc1 of the timing control circuit 10 shown in FIG. 1 and the like, the timing control circuit 20 compares the conduction control signal Sg with the timing control circuit 10. Can be reduced more quickly.

The effect of the charging current control circuit 400 will be described.
According to the timing control circuit 20 included in the charging current control circuit 400, when the voltage at the node N1 is increased, the conduction path between the node N1 and the node N2 is further transferred from the limiting resistor Rp to the first switching element SCR1. It becomes possible to switch quickly.

<Embodiment 5>
FIG. 5 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit 500 according to the fifth embodiment.

In FIG. 5, the same reference numerals as those in FIG. 2 have the same functions or configurations, and duplicate descriptions thereof are omitted. The charging current control circuit 400 shown in FIG. 5 corresponds to a configuration in which the timing control circuit 10 is replaced with the timing control circuit 20 in the charging current control circuit 200 shown in FIG. The timing control circuit 20 improves the response speed of the timing control circuit 10.

The configuration and operation of the timing control circuit 20 of FIG. 5 are the same as those of the timing control circuit 20 shown in FIG. According to the charging current control circuit 500, when the voltage at the node N1 is rising, the conduction path between the node N1 and the node N2 can be more quickly switched from the limiting resistor Rp to the first switching element SCR1. It becomes.

<Embodiment 6>
FIG. 6 is a circuit diagram of an AC / DC converter circuit including a charging current control circuit 600 according to the sixth embodiment.

In FIG. 6, components having the same reference numerals as those in FIG. 3 have the same functions or configurations, and redundant description thereof will be omitted. The charging current control circuit 600 shown in FIG. 6 corresponds to a configuration in which the timing control circuit 10 is replaced with the timing control circuit 20 in the charging current control circuit 300 shown in FIG. The timing control circuit 20 improves the response speed of the timing control circuit 10.

The configuration and operation of the timing control circuit 20 of FIG. 6 are the same as those of the timing control circuit 20 shown in FIG. According to the charging current control circuit 600, when the voltage at the node N1 is increasing, the conduction path between the node N1 and the node N2 can be more quickly switched from the limiting resistor Rp to the first switching element SCR1. It becomes.

<Embodiment 7>
FIG. 7 is a perspective view of a charging current control device equipped with the charging current control circuit according to any one of the first to sixth embodiments.

The charging current control device includes terminals T1, terminal T2, wiring board PCB, limiting resistor Rp, and electronic components constituting any of charging current limiting circuits 100 to 600 according to the first embodiment. In FIG. 7, the first switching element SCR1 is shown as an example of the electronic component.

As the wiring board PCB, a printed wiring board is applied as an example. On one surface of the wiring substrate PCB (the surface facing upward in FIG. 7), electronic components included in the charging current limiting circuit selected from the charging current limiting circuits 100 to 600 are mounted. Each electronic component is connected by wiring (not shown). For example, when the charging current limiting circuit 100 is mounted on the wiring board PCB, the node N1 and the node N2 are connected to the terminal T1 and the terminal T2, respectively. A limiting resistor Rp is mounted on the other surface of the wiring board PCB (the surface facing downward in FIG. 7).

As understood from FIG. 7, the charging current control device has an outer shape in which a pair of terminals T1 / T2 extend from the wiring board PCB. The terminals T1 and T2 are inserted into connection holes of another main wiring board (not shown) on which the diode bridge Db and the smoothing capacitor Cs provided in the AC / DC converter circuit shown in FIG. Electrically connect the boards. The limiting resistor Rp may be mounted on the main wiring board instead of the wiring board PCB. In that case, in the main wiring board, the connection holes into which the terminals T1 and T2 of the wiring board PCB are inserted are electrically connected to one terminal and the other terminal of the limiting resistor Rp, respectively.

By inserting the terminals T1 and T2 of the wiring board PCB into the connection holes of the main wiring board, the surface directions of the two wiring boards are set not perpendicular to each other but perpendicular to each other. That is, the wiring board PCB is mounted perpendicular to the surface of the main wiring board on which the limiting resistor Rp and the like are mounted. As a result, the heat dissipation performance of the wiring board PCB is sufficiently exhibited without deteriorating the heat dissipation characteristics of the main wiring board. Further, by arranging the main wiring board and the wiring board PCB in parallel, the height of the wiring board PCB can be suppressed low, and the power circuit can be reduced in height.

In the AC / DC converter circuit, the charging current control circuit 100 connected in parallel with the limiting resistor Rp is mounted on a wiring board PCB different from the main wiring board, so that the output voltage of the diode bridge Db mounted on the main wiring board is obtained. It is easy to change to a charging current control circuit having necessary characteristics according to the maximum value of the output current, the temperature characteristic of the limiting resistor Rp, the capacitance value of the smoothing capacitor Cs, or the like.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

10, 20 timing control circuit, 100, 200, 300, 400, 500, 600 charging current control circuit, C0 capacity, C1 first timing capacity, C2 second timing capacity, Cs smoothing capacitor, D1, D2 diode, Db diode bridge , FET field effect transistor, GND ground voltage, HS radiator, N1, N2 node, PCB wiring board, R1, Rb, Rc1, Rc3, Rg resistance, Rc2 first discharge resistance, Rc4 second discharge resistance, Rp limiting resistance, SCR1, SCR2 switching element, Sg conduction control signal, T1, T2 terminal, TR1, bipolar transistor, TR2, bipolar transistor (discharge switch), Vin AC voltage, Znr1, Znr2 voltage clamping element.

Claims

A charging current control circuit for controlling a charging current of a smoothing capacitor charged by a rectifier circuit,
A first node to which an output voltage of the rectifier circuit is applied;
A second node connected to the positive electrode of the smoothing capacitor;
A first switching element having a first electrode and a second electrode connected to the first node and the second node, respectively;
A second switching element in which a third electrode is electrically connected to the first node, and a fourth electrode is connected to a first control electrode of the first switching element;
A timing control circuit connected between the third electrode of the second switching element and the second node and outputting a conduction control signal to the second control electrode of the second switching element;
With
The timing control circuit includes a first timing capacitor that is charged with a voltage applied to the first node, and a first discharge resistor that discharges a stored charge of the first timing capacitor, and the timing control circuit includes: Generating the conduction control signal based on the voltage;
When the value of the conduction control signal becomes equal to or higher than the threshold voltage of the second switching element, the second switching element and the first switching element sequentially change from a non-conduction state to a conduction state,
When the value of the conduction control signal becomes less than a threshold voltage of the second switching element, the second switching element and the first switching element change from a conduction state to a non-conduction state.
The timing control circuit further includes:
A discharge switch for controlling connection between the first discharge resistor and the second node;
A second timing capacitor charged with a voltage applied to the first node;
A second discharge resistor connected in parallel with the second timing capacitor and discharging the accumulated charge of the second timing capacitor;
When the voltage of the second timing capacitor becomes equal to or higher than a predetermined voltage, the discharge switch changes from a conductive state to a non-conductive state,
2. The charging current control circuit according to claim 1, wherein when the voltage of the second timing capacitor becomes less than the predetermined voltage, the discharge switch changes from a non-conductive state to a conductive state.
A voltage clamp element connected between the third electrode of the second switching element and the second node;
3. The charging current control circuit according to claim 1, wherein the voltage clamp element clamps a voltage between the third electrode of the second switching element and the second node to a predetermined voltage. 4.
The first switching element and the second switching element are thyristors,
The first electrode, the second electrode, and the first control electrode of the first switching element are an anode, a cathode, and a gate, respectively;
2. The charging current control circuit according to claim 1, wherein the third electrode, the fourth electrode, and the second control electrode of the second switching element are an anode, a cathode, and a gate, respectively.
The first switching element is a thyristor;
The second switching element is a field effect transistor;
The first electrode, the second electrode, and the first control electrode of the first switching element are an anode, a cathode, and a gate, respectively;
2. The charging current control circuit according to claim 1, wherein the third electrode, the fourth electrode, and the second control electrode of the second switching element are a drain, a source, and a gate, respectively.
The first switching element is a thyristor;
The second switching element is a bipolar transistor;
The first electrode, the second electrode, and the first control electrode of the first switching element are an anode, a cathode, and a gate, respectively;
2. The charging current control circuit according to claim 1, wherein the third electrode, the fourth electrode, and the second control electrode of the second switching element are a collector, an emitter, and a base, respectively.
A charging current control device comprising:
A first terminal, a second terminal, and a wiring board;
The wiring current board according to claim 1 is mounted on the wiring board,
The charging current control device, wherein the first terminal and the second terminal are connected to the first node and the second node, respectively.
The charging current control device according to claim 7, wherein a limiting resistor connected between the first terminal and the second terminal is further mounted on the wiring board.