JP3103347B2 - Rectifier and full-wave rectifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier and a full-wave rectifier, and more particularly, to a rectifier and a full-wave rectifier that cause less loss due to power consumed by components other than a load.

[0002]

2. Description of the Related Art In the case of obtaining a direct current by rectifying an alternating current, in order to suppress unnecessary power consumption by a rectifying element and to realize high-voltage rectification, a technique of intermittently rectifying a current path of a transistor. Is used. When rectification is performed using a transistor, the transistor detects the application of a voltage to be rectified or detects the inflow of current into a load, thereby turning on and off the timing of the current path of the transistor. Has been determined.

There is a method using a comparator or an operational amplifier to detect that a voltage to be rectified is applied. As a method for detecting the inflow of current into the load, there are a method using a current transformer and a method using a resistor. In the method using a current transformer, a primary winding of a current transformer is inserted into a current supply path to a load, and a signal having a magnitude proportional to a current flowing to the load is extracted from a secondary winding of the current transformer. In the method using a resistor, a resistor is inserted into a current supply path to a load, and a current flowing through the load is detected by measuring a voltage between both ends of the resistor.

[0004]

In any of the above-described methods, the comparator, the operational amplifier, the current transformer, or the resistor consumes power by itself, so that a loss occurs. Therefore, in order to keep this loss within a negligible range, it is necessary to sufficiently reduce the power consumption of the current transformer and the resistance value of the resistor.

However, in order to increase the sensitivity of the current transformer, it is necessary to increase the number of turns of the secondary winding of the current transformer. When the number of turns of the secondary winding of the current transformer increases, the power of the secondary transformer itself is reduced. Loss increases. Also, the voltage across the resistor inserted in the current supply path to the load is
It increases in proportion to the resistance value of this resistor. However, the loss due to this resistor also increases as the resistance value increases.

Further, since the current transformer acts as an inductive load from the viewpoint of the power supply, the phase of the voltage appearing on the secondary winding of the current transformer has a value different from the phase of the voltage supplied from the power supply. This phase shift changes depending on the impedance of the load and the frequency of the voltage supplied from the power supply. For this reason, it is extremely difficult to determine the ON and OFF timings of the rectifying transistor using the voltage appearing on the secondary winding of the current transformer.

The input terminal of the comparator or the operational amplifier is connected to the control terminal of the transistor (ie, the base of the bipolar transistor or the gate of the field effect transistor).
It is connected to the. The control end of the transistor has a low withstand voltage, and the voltage to be rectified instantaneously exceeds the withstand voltage rating of the transistor, and is easily destroyed.

When a bipolar transistor is used for rectification, a sufficient base current must be supplied to the base of the bipolar transistor in order to sufficiently reduce the value of the on-resistance of the current path (that is, between the emitter and the collector) of the bipolar transistor. Need to shed. However, as the base current increases, the loss due to the bipolar transistor itself also increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a rectifier and a full-wave rectifier having a small loss and a high withstand voltage.

[0010]

To achieve the above object, a rectifier according to a first aspect of the present invention has a current path, and when a voltage in a predetermined direction is applied across both ends of the current path, A rectifying element for flowing a forward current through the current path; a first load connected to the rectifying element; and a current path, and detecting a magnitude of a voltage drop generated between both ends of the first load. A first current path control element for intermittently controlling the current path according to the detected result; a second load connected in series to the current path of the first current path control element; A second current path control element for detecting the magnitude of a voltage drop generated between both ends of the second load, and intermittently controlling the current path according to the detected result;
A third load connected in series to the current path of the current path control element, and a current path, wherein the magnitude of a voltage drop generated between both ends of the third load is detected, and according to the detected result,
A third current path control element for intermittently controlling the current path thereof, a series circuit including the rectifier element and the first load, and a current path of the third current path control element. ,
Connected in parallel with each other, and the first, second and third
A voltage for supplying a current to the series circuit is applied between both ends of a series circuit including the current path of the first current path control element and the second load; When a voltage for flowing a forward current to the rectifier is applied between both ends of the current path of the third current path control element, a current flows in the current path of the third current path control element. It is characterized in that each current path is intermittently controlled.

According to such a rectifier, detection of the voltage to be rectified is performed by a voltage drop generated between both ends of the first load connected to the rectifier. Then, once the current path of the third current path control element is turned on, the first
No longer consumes substantially any power. When the current path of the third current path control element is off,
Substantially no current flows through the third load. Therefore, the loss of such a rectifier is small. Further, according to such a rectifier, detection of the voltage to be rectified is not performed by the comparator or the operational amplifier, but is performed by the first load including the rectifying element including a diode or the like having a high withstand voltage and the resistor. Therefore, the breakdown voltage is increased.

The first, second, and third current path control elements each include continuous control means for continuously changing the impedance of the current path according to the magnitude of the voltage drop detected by the first, second, and third current path control elements. The impedance of the second and third loads is between both ends of the current path of the third current path control element.
The size is such that each of the first, second, and third current path control elements is turned on in a non-saturated state when a voltage for flowing a predetermined amount of current is applied to the current path. has, first, each of said second and third current path control device
The continuous control means is configured such that, when the current flowing between both ends of the current path of the third current path control element increases, the impedance of the current path of the third current path control element decreases .
Each of the currents of the first, second and third current path control elements
Changing the impedance of the road may be a shall.
Accordingly, even when the current flowing in the current path of the third current path control element exceeds a predetermined amount, the current path of the third current path control element becomes closer to the saturated state, and the third current path An increase in loss due to the current path of the control element is prevented.

The first, second and third current path control elements
Each of the continuous control means has, for example, a control terminal, detects a voltage between any one end of the current path of the respective one and the control terminal, and, according to the detected result, sets the impedance of the current path of the respective one. It may be changed. In this case, for example, the first load is connected between one end of a current path of the first current path control element and a control terminal, and the second load is connected to the second load.
Is connected between one end of the current path of the second current path control element and the control end, and the third load is connected between one end of the current path of the third current path control element and the control end. What is necessary is just to be connected between.

At least one of the first to third current path control elements comprises, for example, a bipolar transistor having the control terminal composed of a base and the current path having both ends of an emitter and a collector. Is done.

At least one of the first to third current path control elements is, for example, a field effect transistor including the control terminal formed of a gate and the current path having a source and a drain at both ends. Be composed.

In order to achieve the above object, a second aspect of the present invention is provided.
The full-wave rectifier according to the aspect of
When a pair of AC voltages are supplied, these AC voltages are respectively subjected to half-wave rectification, and superposed voltages of substantially opposite phases obtained by the half-wave rectification are outputted, whereby the AC voltage is full-wave rectified. A rectifying full-wave rectifier, comprising a pair of rectifiers, each of which has a current path, and when a voltage in a predetermined direction is applied across both ends of the current path, the rectifier sequentially turns on the current path. A rectifying element for flowing a directional current, a first load connected to the rectifying element, and a current path, detecting a magnitude of a voltage drop generated between both ends of the first load, and according to the detected result. A first current path control element for intermittently controlling the current path of its own, a second load connected in series to the current path of the first current path control element, and a second current path. The magnitude of the voltage drop across the load Therefore, a second current path control element for intermittently controlling the current path of its own, a third load connected in series to the current path of the second current path control element, and a current path are provided. A third current path control element for detecting the magnitude of the voltage drop generated between both ends of the load of the third load and intermittently controlling the current path according to the detected result;
For each of the rectifiers, the rectifier and the first
And a current path of the third current path control element are connected in parallel with each other, and the first, second, and third current path control elements are connected to the first current path control element. A voltage for supplying a current to the series circuit is applied across the current path of the current path control element and the series circuit including the second load. When a voltage for flowing a forward current to the rectifying element is applied between both ends, each current path is intermittently controlled so that a current flows to the current path of the third current path control element. The rectifier includes a current path of the first current path control element of each of the rectifiers, and both ends of a series circuit including the second load.
The third current path control element of the rectifier forming a pair with the third current path control element is connected so that a voltage is applied to the other end of the current path of the third current path control element. One ends are connected to each other to form an output terminal, and a current flowing in the current path of the third current path control element of each rectifier is superimposed and flows to the output terminal.

According to such a full-wave rectifier, the detection of the voltage to be rectified is performed by the voltage drop generated between both ends of the first load connected to the rectifier element of each rectifier. Then, once the current path of the third current path control element of each rectifier is turned on, the first load does not substantially consume power. Also, when the current path of the third current path control element is off, substantially no current flows through the first to third loads. Therefore, the loss of such a rectifier is small. Further, according to such a full-wave rectifier, the voltage to be rectified is detected not by the comparator or the operational amplifier but by the rectifying element including a diode having a large withstand voltage and the resistor. Since it is performed using the load of 1, the withstand voltage also increases.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. (First Embodiment) FIG. 1 is a circuit diagram showing a configuration of a rectifier according to a first embodiment of the present invention. As shown, the rectifier includes transistors Q1 to Q3, a diode D, and resistors R1 to R5.

The transistors Q1 and Q3 are composed of NPN type bipolar transistors,
Are composed of PNP-type bipolar transistors, and each of the transistors Q1 to Q3 has a base, an emitter and a collector.

The base of transistor Q1 is connected to one end of resistor R5, the emitter of transistor Q1 is connected to the anode of diode D, and the collector of transistor Q1 is connected to the base of transistor Q2.

As described above, the base of the transistor Q2 is connected to the collector of the transistor Q1, and the emitter of the transistor Q2 is connected to the positive electrode of a driving voltage source for supplying a DC power supply voltage for driving the rectifier. The collector of the transistor Q2 is connected to the base of the transistor Q3. Note that the negative electrode of the drive voltage source is connected to the emitter of the transistor Q3.

The base of the transistor Q3 is connected to the collector of the transistor Q2.
Form the anode of the rectifier, and the collector of transistor Q3 forms the cathode of the rectifier.

The diode D has an anode and a cathode. The anode of the diode D is connected to the emitter of the transistor Q1 as described above, and the cathode of the diode D is connected to the collector of the transistor Q3.

The resistor R1 is connected between the base and the emitter of the transistor Q1. The resistor R2 is connected between the base and the emitter of the transistor Q2. The resistor R3 is connected between the base and the emitter of the transistor Q3. The resistor R4 is connected between the emitter of the transistor Q2 and the base of the transistor Q1. The resistor R5 is connected between the emitter of the transistor Q3 and the base of the transistor Q1.

The resistance value of the resistor R1 is determined when a predetermined standard amount of current flows between the anode and the cathode of the rectifier.
Transistor Q to such an extent that transistor Q1 is not saturated
The voltage that turns on 1 is selected so that it is applied between the base and the emitter of the transistor Q1 according to the operation described later. The resistance value of the resistor R2 is such that when the above-mentioned standard amount of current flows between the anode and the cathode of the rectifier, a voltage enough to turn on the transistor Q2 so as not to saturate the transistor Q2, Are selected so as to be applied between the base and the emitter. The resistance value of the resistor R3 is
When the above-mentioned standard amount of current flows between the anode and the cathode of the rectifier, a voltage enough to turn on the transistor Q3 so as not to saturate the transistor Q3 is applied between the base and the emitter of the transistor Q3 according to an operation described later. Values are chosen.

The resistance value of the resistors R4 and R5 is
When substantially no current flows from the connection point of R4 and R5 to the resistor R1 and the diode D, the voltage between the base and the emitter of the transistor Q1 becomes slightly lower than the voltage at which the transistor Q1 turns on. It has been chosen to be.

Assuming that a power supply voltage is supplied from a drive voltage source in an initial state in which substantially no voltage is applied between the anode and the cathode of the rectifier, in this state,
No current substantially flows through the resistor R5, the base-emitter of the transistor Q1, and the diode D. Accordingly, the voltage between the base and the emitter of the transistor Q1 becomes slightly smaller than the transistor Q1 to turn on, and as a result, the transistor Q1 keeps turning off.

Therefore, substantially no current flows through the resistor R2, which forms a current path between the positive electrode of the drive voltage source and the transistor Q1, and a substantial voltage drop occurs across the resistor R2. Does not occur. As a result, the voltage between the base and the emitter of the transistor Q2 becomes almost 0 volt, and the transistor Q2 also keeps turning off.

When the transistor Q2 is off, substantially no current flows through the resistor R3 which forms a current path between the negative electrode of the driving voltage source and the transistor Q2, and the resistor R3
No substantial voltage drop occurs between both ends of the. As a result, the voltage between the base and the emitter of the transistor Q3 also becomes almost 0 volt, so that the transistor Q3 also keeps turning off.

Therefore, in a state where a voltage is not substantially applied between the anode and the cathode of the rectifier, the anode-cathode of the rectifier is substantially cut off even when the power supply voltage is supplied from the drive voltage source. to continue.

Next, it is assumed that the potential of the cathode of the rectifier is made higher than the potential of the anode while supplying the power supply voltage from the drive voltage source. In this state, the transistors Q1 to Q
3 are still off, and the diode D is reverse-biased, so that no current flows through the resistor R1. Therefore, the voltage at the connection point of the resistors R4 and R5 does not change when the potential of the emitter of the transistor Q1 is used as a reference, and the transistors Q1 to Q3 continue to be turned off.

Next, while supplying the power supply voltage from the driving voltage source, the potential of the cathode of the rectifier is made lower than the potential of the anode, and the above-mentioned standard amount of current flows between the anode and the cathode of the rectifier. Assume that a voltage is applied. In this state, since the diode D is forward-biased, a current flows from the anode of the rectifier to the cathode of the rectifier through the resistor R5, the resistor R1, and the diode D in this order.

As a result, a voltage drop occurs between both ends of the resistor R1 such that the polarity of the base with respect to the emitter of the transistor Q1 becomes positive. As a result, the voltage at the connection point of the resistors R4 and R5 with respect to the potential of the emitter of the transistor Q1 increases, and the transistor Q1 turns on.

Then, from the positive electrode of the driving voltage source, the resistor R
2. A current path is formed through the collector and emitter of the transistor Q1, the diode D, and the cathode of the rectifier in order, and the transistor Q2 is connected between both ends of the resistor R2.
A voltage drop occurs such that the polarity of the base with respect to the emitter becomes negative. Therefore, the transistor Q2
Also turns on.

When the transistor Q2 is turned on, a current path is formed from the positive electrode of the drive voltage source to the negative electrode of the drive voltage source through the emitter and collector of the transistor Q2 and the resistor R3 in order. As a result, a voltage drop occurs between both ends of the resistor R3 such that the polarity of the base with respect to the emitter of the transistor Q3 becomes positive. Therefore, the transistor Q3 turns on.

Thus, while the anode of the rectifier is positive with respect to the cathode of the rectifier, a standard amount of current flows from the anode of the rectifier to the cathode.

When the current flowing from the anode to the cathode of the rectifier is larger than the standard amount, the amount of voltage drop between the collector and the emitter of the transistor Q3 is increased. That is, the amount of loss generated by the rectifier increases.

On the other hand, when the current flowing from the anode to the cathode of the rectifier increases, the current from the anode of the rectifier to the cathode of the rectifier through the resistor R5, the resistor R1, and the diode D in order increases. I do. As a result, the voltage at the connection point of the resistors R4 and R5 with respect to the potential of the emitter of the transistor Q1 increases,
The voltage between the base and the emitter of transistor Q1 increases. That is, the forward bias to the transistor Q1 becomes deeper. Therefore, the impedance between the collector and the emitter of the transistor Q1 decreases, and the current flowing between the collector and the emitter of the transistor Q1 increases.

Then, the magnitude of the voltage drop between both ends of the resistor R2 increases, and the forward bias to the transistor Q2 becomes deeper. Therefore, the current flowing between the collector and the emitter of the transistor Q2 increases. Further, the magnitude of the voltage drop across the resistor R3 increases due to the increase in the current between the collector and the emitter of the transistor Q2,
As a result, the forward bias to the transistor Q3 becomes deeper. Therefore, the impedance between the collector and the emitter of the transistor Q3 decreases, and the magnitude of the voltage drop between the collector and the emitter of the transistor Q3 also decreases. Therefore, the amount of loss generated by this rectifier is reduced.

By the operation described above, this rectifier performs rectification. When this rectifier is off (ie,
When the transistor Q3 is off), the transistors Q1 and Q2 are also off, and no current flows through the diode D, so that the transistors Q1 to Q3, the diode D and the resistors R1 to R3 do not consume power. Further, once the transistor Q3 is turned on, the impedance between the emitter and the collector of the transistor Q3 becomes sufficiently small, and the voltage drop between the two becomes sufficiently low. Then, almost all the current flowing between the anode and the cathode of the rectifier flows between the emitter and the collector of the transistor Q3.
Therefore, the resistors R1 and R5 do not substantially consume the power to be rectified.

On the other hand, the resistors R4 and R5 consume power by passing a current from the positive electrode of the drive voltage source to the negative electrode of the drive voltage source via the resistors R4 and R5. However, the resistance value of the resistor R4 only needs to be low enough to cause a base current sufficient to turn on the transistor Q1.
The resistance value of the resistor R5 only needs to be low enough to generate a voltage large enough to turn on the transistor Q1 at the connection point between the resistors R4 and R5.

Accordingly, if the current amplification factor of the transistor Q1 is made sufficiently large and the resistance value of the resistor R3 is made sufficiently large, the resistance values of the resistors R4 and R5 will be reduced by the power consumption of the resistors R4 and R5. Can be made large enough to be negligible.

The structure of the rectifier is not limited to the above. For example, as shown in FIG. 2, the transistors Q1 and Q3 may be composed of PNP bipolar transistors, and the transistor Q2 may be composed of NPN bipolar transistors.

In this case, as shown in FIG. 2, the negative electrode of the drive voltage source is connected to the portion where the positive electrode of the drive voltage source is connected in the configuration of FIG. The positive electrode of the drive voltage source is connected to the point where the negative electrode is connected. Also, in the configuration of FIG. 1, the cathode of the diode D is connected to the place where the anode of the diode D is connected, and the anode is connected to the place where the cathode is connected. The collector of the transistor Q3 is shown in FIG.
And the emitter of transistor Q3 forms the cathode of the rectifier of FIG.

The operation of the rectifier of FIG. 2 is substantially the same as the operation of the configuration of FIG. 1 except that the direction of the current flowing through each part of the rectifier is opposite.

That is, when the power supply voltage is supplied from the drive voltage source in the initial state, the diode D and the resistor R1 have
Since substantially no current flows in either case, the transistor Q
The base-emitter voltage of 1 is slightly below the value that the transistor Q1 turns on, so that the transistor Q1 keeps turning off. Therefore, the resistor R2
, No substantial voltage drop occurs, and therefore the transistor Q2 also keeps turning off. Therefore, substantially no voltage drop occurs between both ends of the resistor R3, and the transistor Q3 continues to be turned off. Accordingly, the anode-cathode portion of the rectifier of FIG.

Next, when the potential of the cathode of the rectifier is made higher than the potential of the anode while supplying the power supply voltage from the drive voltage source, all of the transistors Q1 to Q3 are continuously turned off, and the diode D is inverted. Be biased. For this reason, the voltage at the connection point of the resistors R4 and R5 does not change with reference to the potential of the emitter of the transistor Q1, and the voltage between the anode and the cathode of the rectifier in FIG.

Next, while supplying the power supply voltage from the driving voltage source, the potential of the cathode of the rectifier is made lower than the potential of the anode, and the voltage for flowing a standard amount of current between the anode and the cathode of the rectifier is reduced. When applied, diode D is forward biased. Then, a current flows from the anode of the rectifier to the cathode of the rectifier through the diode D, the resistor R1, and the resistor R5 in this order.

Then, a voltage drop occurs between both ends of the resistor R1 such that the polarity of the base with respect to the emitter of the transistor Q1 becomes negative. As a result, the voltage at the connection point of the resistors R4 and R5 with respect to the potential of the emitter of the transistor Q1 drops, and the transistor Q1 turns on.

Thus, from the anode of the rectifier,
A current path is formed through the diode D, the emitter and the collector of the transistor Q1, the resistor R2, and the negative electrode of the driving voltage source in order. The both ends of the resistor R2 are connected to the base of the transistor Q2 with the positive polarity. A voltage drop occurs in the following direction. Therefore, the transistor Q2 is also turned on.

When the transistor Q2 is turned on, a current path is formed from the positive electrode of the drive voltage source to the negative electrode of the drive voltage source through the resistor R3, the emitter and the collector of the transistor Q2 in this order. As a result, between both ends of the resistor R3,
A voltage drop occurs such that the polarity of the base with respect to the emitter of the transistor Q3 becomes negative, and the transistor Q3 turns on. This causes a standard amount of current to flow from the anode to the cathode of the rectifier.

When the current flowing from the anode to the cathode of the rectifier increases beyond the standard amount, the amount of voltage drop between the collector and the emitter of transistor Q3 increases, and the amount of loss generated by the rectifier increases. . When the current flowing from the anode to the cathode of the rectifier increases, the current from the anode of the rectifier to the cathode of the rectifier through the diode D, the resistor R1, and the resistor R5 in order increases.

Then, the voltage at the connection point of the resistors R4 and R5 with reference to the potential of the emitter of the transistor Q1 drops, and the forward bias to the transistor Q1 becomes deeper. The current flowing through increases. As a result, the forward bias to the transistor Q2 becomes deeper, and the current flowing between the collector and the emitter of the transistor Q2 increases. As a result,
The magnitude of the voltage drop across the resistor R3 also increases, so that the forward bias on the transistor Q3 becomes deeper, and the collector-emitter impedance of the transistor Q3 decreases. Therefore, the voltage drop between the collector and the emitter of the transistor Q3 is small, and the amount of loss generated by the rectifier is reduced.

1 and 2, among the transistors Q1 to Q3, those constituted by NPN-type bipolar transistors are enhancement-type n-channel MOSFETs (Metal-Oxide-Silicon Field Effect).
Transistor). Also, PNP
A structure composed of a bipolar transistor may be replaced with an enhancement p-channel MOSFET.

When an enhancement-type MOSFET is used instead of the bipolar transistor, a MOSF is provided at a place where the base of the bipolar transistor is to be connected.
The gate of the ET is connected. In addition, a portion to which the emitter of the bipolar transistor is to be connected is M
The source of the OSFET is connected. Also, the drain of the MOSFET is connected to a place where the collector of the bipolar transistor is to be connected.

Therefore, in this rectifier, as shown in FIG. 3, for example, the transistors Q1 and Q3 may be composed of an enhancement type n-channel MOSFET, and the transistor Q2 may be composed of an enhancement type p-channel MOSFET.

In the rectifier shown in FIG. 3, resistors R1, R2
And the resistance value of R3, when a standard amount of current flows between the anode and cathode of the rectifier, the transistors Q1 and Q3
A voltage that turns on these transistors so as not to saturate 2 and Q3 is selected to be a value applied between the gate and source of each of these transistors.
The resistance value of the resistors R4 and R5 is equal to the voltage between the gate and source of the transistor Q1 when substantially no current flows from the connection point of the resistors R4 and R5 to the resistor R1 and the diode D. Is the transistor Q1
Are chosen to be slightly less than the voltage at which they turn on.

The operation of the rectifier of FIG. 3 is substantially the same as the configuration of FIG. That is, when the power supply voltage is supplied from the drive voltage source in the initial state, substantially no voltage drop occurs between both ends of the resistor R1, and the gate of the transistor Q1
The voltage between the sources is slightly less than the voltage at which the transistor turns on, and the transistor Q1 keeps turning off. Therefore, substantially no voltage drop occurs between both ends of the resistor R2. Therefore, the voltage between the gate and the source of the transistor Q2 becomes almost 0 volt, and the transistor Q2
Also keeps off. When the transistor Q2 is off,
No substantial voltage drop occurs between both ends of the resistor R3,
The voltage between the gate and the source of the transistor Q3 also becomes almost 0 volt, and thus the transistor Q3 also keeps turning off.

Next, when the potential of the cathode of the rectifier is made higher than the potential of the anode while the power supply voltage is being supplied from the drive voltage source, all of the transistors Q1 to Q3 are continuously turned off, and the diode D is turned off. Be biased. Therefore, the voltage at the connection point of the resistors R4 and R5 does not change with reference to the potential of the source of the transistor Q1, and the voltage between the anode and the cathode of the rectifier in FIG.

Next, while supplying the power supply voltage from the drive voltage source, the potential of the cathode of the rectifier is made lower than the potential of the anode, and the above-mentioned standard amount of current flows between the anode and the cathode of the rectifier. Assume that a voltage is applied. In this case, the diode D is forward-biased, and a voltage drop occurs between both ends of the resistor R1 such that the polarity of the gate with respect to the source of the transistor Q1 becomes positive, and the transistor Q1 turns on.

Then, a voltage drop occurs between both ends of the resistor R2 in a direction in which the polarity of the gate with respect to the source of the transistor Q2 becomes negative, and the transistor Q2 also turns on. As a result, a voltage drop is generated between both ends of the resistor R3 such that the polarity of the gate with respect to the source of the transistor Q3 is positive, and the transistor Q3 is also turned on. This causes a standard amount of current to flow from the anode to the cathode of the rectifier.

When the current flowing from the anode to the cathode of the rectifier exceeds the standard amount, the resistor R1
, The forward bias to the transistor Q1 becomes deeper, and the current flowing between the collector and the emitter of the transistor Q1 increases.

Then, the magnitude of the voltage drop between both ends of the resistor R2 also increases, the forward bias to the transistor Q2 becomes deeper, and the current flowing between the collector and the emitter of the transistor Q2 increases. Further, the magnitude of the voltage drop between both ends of the resistor R3 also increases, and the transistor Q3
3 becomes deeper and the collector-emitter impedance of transistor Q3 decreases. This reduces the amount of loss that this rectifier generates.

(Second Embodiment) FIG. 4 shows a rectifier circuit according to a second embodiment of the present invention. This rectifier circuit includes rectifiers Ra and Rb and a transformer T as shown. Rectifiers Ra and Rb are shown in FIG.
As shown in (1), each has substantially the same configuration as the configuration of the rectifier of FIG. 2 in the first embodiment.

The anode of the rectifier Rb (that is, the collector of the transistor Q3 of the rectifier Rb) is connected to a portion of the rectifier Ra that should be connected to the negative electrode of the external drive voltage source. Also, of the rectifier Rb,
The anode of the rectifier Ra (that is, the collector of the transistor Q3 of the rectifier Ra) is connected to a portion to be connected to the negative electrode of the external drive voltage source.

The anodes of the rectifiers Ra and Rb are:
The transformer T is connected to both ends of a secondary winding described later on a one-to-one basis. The cathodes of the rectifiers Ra and Rb (that is, the emitters of the transistors Q3 of the rectifiers Ra and Rb) are connected to each other to form a positive electrode at a power output terminal.

The transformer T has a primary winding and a secondary winding which are inductively coupled to each other, and a midpoint tap is provided at a substantially middle point of the secondary winding. Both ends of the primary winding of the transformer T form both poles of the power input terminal of the rectifier circuit. As described above, both ends of the secondary winding of the transformer T are connected to the anode of the rectifier Ra and the anode of the rectifier Rb in a one-to-one manner.
The center tap of the secondary winding forms the negative pole of the power output terminal of the rectifier circuit.

It is assumed that an external load is connected between the positive electrode and the negative electrode of the power output terminal of the rectifier circuit, and a single-phase AC voltage to be rectified is applied between both electrodes of the power input terminal. In this case, a single-phase AC voltage having an amplitude substantially proportional to the single-phase AC voltage applied between the two poles of the power input terminal is generated at both ends of the secondary winding of the transformer T of the rectifier circuit, Each pole of the secondary winding alternately reverses the polarity with respect to the potential of the center tap of the secondary winding.

It is assumed that, of both ends of the secondary winding of the transformer T, the voltage connected to the anode of the rectifier Ra has a positive polarity with respect to the potential of the center tap of the secondary winding. . At this time, since the cathode of the rectifier Ra is connected to the midpoint tap of the secondary winding via the load, the anode of the rectifier Ra has a higher potential than the cathode of the rectifier Ra.

In the rectifier Ra, the portion of the secondary winding of the transformer T connected to the anode of the rectifier Rb is generated at the end connected to the anode of the rectifier Rb. A negative voltage is applied to the potential of the midpoint tap. This voltage is supplied to the rectifier Ra as a power supply voltage for driving the rectifier Ra.

Accordingly, the anode-cathode of the rectifier Ra conducts, and the anode and cathode of the rectifier Ra and the external load are connected from the end of the secondary winding of the transformer T which is connected to the anode of the rectifier Ra. , A current flows to the midpoint tap of the secondary winding of the transformer T in this order.

On the other hand, of both ends of the secondary winding of the transformer T,
When the voltage connected to the anode of the rectifier Ra becomes positive with respect to the potential of the center tap of the secondary winding,
The other end of the secondary winding has a negative polarity with respect to the potential of the midpoint tap. Since the cathode of the rectifier Rb is connected to the midpoint tap of the secondary winding via the load, the anode of the rectifier Rb has a lower potential than the cathode of the rectifier Rb. Therefore, the connection between the anode and the cathode of the rectifier Rb is substantially shut off.

Conversely, of both ends of the secondary winding of the transformer T,
When the voltage connected to the anode of the rectifier Ra becomes negative with respect to the potential of the center tap of the secondary winding,
The anode of the rectifier Ra has a lower potential than the cathode of the rectifier Ra, and the anode of the rectifier Rb has a higher potential than the cathode of the rectifier Rb. The rectifier Rb of the rectifier Rb
A voltage having a negative polarity with respect to the potential of the midpoint tap is applied to the portion connected to the anode a, and the rectifier Rb is driven by this voltage.

Accordingly, conduction is established between the anode and cathode of the rectifier Rb, and the anode and cathode of the rectifier Rb and the external load are connected from the end of the secondary winding of the transformer T connected to the anode of the rectifier Rb. , A current flows to the midpoint tap of the secondary winding of the transformer T in this order. On the other hand, the connection between the anode and the cathode of the rectifier Ra is substantially shut off.

By repeating the above operation, the rectifier circuit of FIG. 4 performs full-wave rectification. In the rectifier circuit of FIG. 4, the voltage generated in the secondary winding of the transformer T as a result of the single-phase AC voltage to be rectified applied to the power supply input terminal is used as the power supply voltage for driving the rectifiers Ra and Rb. , Rectifiers Ra and Rb. For this reason, the rectifier circuit of FIG. 4 operates without separately preparing a drive voltage source for driving the rectifiers Ra and Rb.

The configuration of the rectifier circuit is not limited to the one described above. For example, the rectifiers Ra and Rb of this rectifier circuit may each have substantially the same configuration as the rectifier of FIG. 1, as shown in FIG. 5, for example.

In this case, the cathode of the rectifier Rb (that is, the collector of the transistor Q3 of the rectifier Rb) is connected to the portion of the rectifier Ra that should be connected to the positive electrode of the external drive voltage source. The rectifier Rb
Of these, the cathode of the rectifier Ra (that is, the collector of the transistor Q3 of the rectifier Ra) is connected to a portion to be connected to the positive electrode of the external drive voltage source.

The cathodes of the rectifiers Ra and Rb are:
It is assumed that one end is connected to both ends of a secondary winding of the transformer T, which will be described later. The anodes of the rectifiers Ra and Rb (that is, the emitters of the transistors Q3 of the rectifiers Ra and Rb) are connected to each other to form a positive electrode of a power supply output terminal. The rectifier circuit serves as a negative electrode of a power supply output terminal.

The operation of the rectifier circuit of FIG. 5 is substantially the same as the operation of the configuration of FIG. 4 except that the direction of the current flowing through each part of the rectifier circuit is different from that in the configuration of FIG. .

That is, when an external load is connected between both poles of the power supply output terminal and a single-phase AC voltage is applied between both poles of the power supply input terminal, of the two ends of the secondary winding of the transformer T,
When the voltage connected to the cathode of the rectifier Ra becomes negative with respect to the potential of the center tap of the secondary winding,
A voltage having a positive polarity with respect to the potential of the center tap is applied to a portion of the rectifier Ra connected to the cathode of the rectifier Rb.

As a result, the rectifier Ra is driven to conduct between the anode and the cathode of the rectifier Ra. Rectifier R of the next winding
A current flows to the end connected to the cathode of a. On the other hand, the anode of the rectifier Rb has a lower potential than the cathode of the rectifier Rb, and the connection between the anode and the cathode of the rectifier Rb is substantially cut off.

Conversely, when the voltage of the cathode of the rectifier Ra becomes positive with respect to the potential of the center tap of the secondary winding,
The anode of the rectifier Ra has a lower potential than the cathode of the rectifier Ra, and the anode of the rectifier Rb has a higher potential than the cathode of the rectifier Rb. The rectifier Rb of the rectifier Rb
A voltage having a positive polarity with respect to the potential of the center tap is applied to the portion connected to the cathode of a, and the rectifier Rb is driven by this voltage.

Therefore, conduction between the anode and cathode of the rectifier Rb is performed, and an external load,
A current flows through the anode and the cathode of the rectifier Rb in order, and reaches the end of the secondary winding of the transformer T connected to the cathode of the rectifier Rb. On the other hand, the connection between the anode and the cathode of the rectifier Ra is substantially shut off.

[0084]

As described above, according to the present invention, a rectifier and a full-wave rectifier having a small loss and a high withstand voltage can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a rectifier according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a modification of the rectifier of FIG.

FIG. 3 is a circuit diagram showing a modification of the rectifier of FIG.

FIG. 4 is a circuit diagram showing a configuration of a rectifier circuit according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram showing a modification of the rectifier circuit of FIG.

[Explanation of symbols]

 Q1-Q3 Transistor D Diode R1-R5 Resistor T Transformer

Claims (6)

(57) [Claims] A rectifying element for supplying a forward current to the current path when a voltage in a predetermined direction is applied between both ends of the current path; and a first rectifying element connected to the rectifying element. A first current path control element including a load, a current path, detecting a magnitude of a voltage drop generated between both ends of the first load, and intermittently controlling the current path according to the detected result; A second load connected in series to a current path of the first current path control element; and a current path, and detecting a magnitude of a voltage drop generated between both ends of the second load. A second current path control element for intermittently controlling the current path of the self, a third load connected in series to a current path of the second current path control element, and a current path, The magnitude of the voltage drop generated between both ends of the third load is detected, and the detected result is I, a series circuit including a third current path control device, wherein the rectifying element and the first load intermittently controlling the current path of the self,
The current paths of the third current path control element are connected in parallel with each other, and the first, second, and third current path control elements are connected to the first current path control element.
A voltage for supplying a current to the series circuit is applied across the current path of the current path control element and the series circuit including the second load. Intermittently controlling each current path so that current flows through the current path of the third current path control element when a voltage for flowing a forward current to the rectifying element is applied between both ends. A rectifier characterized by the following. 2. The first, second, and third current path control elements each include continuous control means for continuously changing the impedance of the current path according to the magnitude of a voltage drop detected by each element. The impedances of the first, second and third loads are set such that when a voltage for flowing a predetermined amount of current through the current path is applied between both ends of the current path of the third current path control element, Each of the first, second and third current path control elements has a size such that each of the current paths turns on in an unsaturated state, and each of the first, second and third current path control elements has Continuous
Control means, when the current flowing across the current path of said third current path control device is increased, so that the impedance of the current path of said third current path control device is decreased, the
The current path of each of the first, second and third current path control elements
Impedance Ru changing the rectifier of claim 1, wherein the. 3. The first, second, and third current path control elements.
Each of the continuous control means includes a control terminal, detects a voltage between any one end of the current path of the respective one and the control terminal, and changes the impedance of the current path of the respective one according to the detected result. Wherein the first load is connected between one end of a current path of the first current path control element and a control end, and the second load is connected to the second current path control element. The third load is connected between one end of a current path and a control end, and the third load is connected between one end of the current path of the third current path control element and the control end. The rectifier according to claim 2, wherein 4. At least one of the first to third current path control elements comprises a bipolar transistor having the control terminal composed of a base and the current path having both ends of an emitter and a collector. The rectifier according to claim 3, wherein: 5. At least one of the first to third current path control elements is formed of a field effect transistor including the control terminal composed of a gate and the current path having both ends of a source and a drain. The rectifier according to claim 3, wherein the rectifier is configured. 6. When a pair of AC voltages having phases substantially opposite to each other are supplied, these AC voltages are respectively subjected to half-wave rectification, and the voltages having phases substantially opposite to each other obtained by the half-wave rectification are converted. A full-wave rectifier for performing full-wave rectification of the AC voltage by superimposing and outputting the same, comprising a pair of rectifiers, each of the rectifiers including a current path, and a predetermined direction between both ends of the current path. A rectifying element that causes a forward current to flow through the current path when a voltage of ?? is applied; a first load connected to the rectifying element; and a current path, which is generated between both ends of the first load. A first current path control element for detecting the magnitude of the voltage drop and intermittently controlling the current path according to the detected result; and a first current path control element connected in series to the current path of the first current path control element. And a current path between the two ends of the second load. A second current path control element for detecting the magnitude of the pressure drop and intermittently controlling the current path according to the detected result; and a second current path control element connected in series to the current path of the second current path control element. A third current path control comprising a current path, a magnitude of a voltage drop generated between both ends of the third load, and intermittently controlling the current path according to the detected result. A rectifier element and the first rectifier.
And a current path of the third current path control element are connected in parallel with each other, and the first, second, and third current path control elements are connected to the first current path control element. A voltage for supplying a current to the series circuit is applied across the current path of the current path control element and the series circuit including the second load. When a voltage for flowing a forward current to the rectifying element is applied between both ends, each current path is intermittently controlled so that a current flows to the current path of the third current path control element. The rectifier includes a third current path control of the rectifier paired with itself between both ends of a series circuit including a current path of the first current path control element and the second load of each of the rectifiers. Each of the rectifiers is connected such that the voltage at the other end of the current path of the element is applied. One ends of the currents of the third current path control elements are connected to each other to form output terminals, and currents flowing in the current paths of the third current path control elements of the rectifiers are superimposed and flow to the output terminals. A full-wave rectifier, characterized in that: