JP3103348B2 - Rectifier and power supply - 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 power supply, and more particularly, to a rectifier and a power supply 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 voltage having a magnitude proportional to a current flowing to the load is detected 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 voltage generated between both ends of the resistor and proportional to a current flowing through the resistor is detected.

The detection of the voltage between both ends of the secondary winding of the current transformer and the voltage between both ends of the resistor, and the determination of ON / OFF of the transistor are performed, for example, at each end of the secondary winding of the current transformer. This is performed by determining the difference between the above-mentioned voltage or the voltage at each end of the resistor and a predetermined reference voltage.

[0005]

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 as viewed from 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 in the current path of the bipolar transistor (that is, between the emitter and the collector). Need to shed. However, as the base current increases, the loss due to the bipolar transistor itself also increases.

Further, the higher the demand for the accuracy of detecting the current flowing through the load is,
The generated reference voltage is required to be stable. In addition, the device that determines the difference between the reference voltage and the voltage at each end of the secondary winding of the current transformer or the resistor is required to have higher accuracy in detecting the current flowing through the load. It is necessary to accurately detect the difference between the voltage at each end of the wire or the resistor and the reference voltage.

However, in general, the more stable the reference voltage source is, the more complicated the configuration becomes, and the greater the power consumption of the reference voltage source itself becomes. In addition, the device for determining the difference between the reference voltage and the voltage at each end of the secondary winding of the current transformer and the resistor is provided by using the voltage at each end of the secondary winding and the resistor of the current transformer and the reference voltage. The more accurately the difference is detected, the more complicated the configuration becomes, and the greater the power consumption of the device itself becomes.

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 power supply device having a simple structure that does not require a reference voltage source, having a small loss, and having a large withstand voltage.

[0013]

In order to achieve the above object, a rectifier according to a first aspect of the present invention includes a first control terminal and a first current path, and one end of the first current path. And a first current path control element for intermittently controlling the first current path in accordance with the detection result, and one end of the first current path is connected to the first current path. A first load connected to the other end; and a second current path, wherein the magnitude of a voltage drop generated between both ends of the first load is detected, and the second current is supplied in accordance with the detected result. A second current path control element for intermittently controlling a path, a second control end connected to one end of the second current path, and a third control end connected to the one end of the first current path. And a potential difference between the potential of the one end of the third current path and the potential of the second control terminal. And, according to the result detected, a third current path control device for intermittently controlling the third current path,
A second load connected between the one end of the second current path and the other end of the third current path, wherein the first control terminal is connected between both ends of the second load. The first current path control element is connected to the first current path control element when a voltage is applied across both ends of the third current path in a direction in which current flows in a predetermined direction. The first current path is intermittently controlled so as to substantially conduct the second and third current paths.
When a voltage is applied from the outside between the other end of the second current path and the other end of the third current path, and a current flows through the first current path, The second and third current paths are arranged to substantially conduct the third current path.
The current path is intermittently controlled.

According to such a rectifier, the potential at one end of the third current path to which the voltage to be rectified is applied at both ends, and the voltage between the other end of the third current path and the second control end. Is the second
The voltage to be rectified is detected by detecting the potential difference from the potential of the first control terminal representing the voltage divided by the load. For this reason, the ON / OFF timing of the third current path is determined without the need for the reference voltage source.
Also, when the third current path is off, substantially no current flows through the first load. Therefore, the loss of such a rectifier is small. According to such a rectifier,
Since the detection of the voltage to be rectified is performed using the first current path control element including a transistor with a high withstand voltage without using a comparator or an operational amplifier, the withstand voltage is also increased.

[0015] The first, second and third current path control device is provided with a continuous control means for continuously changing the impedance of the current path according to the magnitude of the voltage drop their senses, each of said successive control The means includes means for reducing the impedance of the current path of the third current path control element 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 . And third current path control element
The impedance of each current path of the child may be changed. Thus, even when the current flowing through the third current path increases, the third current path becomes closer to the saturation state, thereby preventing an increase in loss due to the third current path.

Before each of the first to third current path control elements
The continuous control means includes, for example, a control terminal, detects a voltage between any one end of a current path provided for each device and the control terminal, and, according to a detection result, determines an impedance of the current path provided for each device. It may be changed. In this case, for example, the first load may be connected between the other end of the second current path and the control end.

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.

[0018] At least one of the first to third current path control elements is, for example, 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. Be composed.

A power supply device according to a second aspect of the present invention is a power supply device for rectifying a single-phase AC voltage and outputting a rectified voltage, comprising a first control terminal and a first current path. ,
A first current path control element that detects a potential difference between one end of the first current path and a potential of the first control terminal, and controls the intermittent control of the first current path according to the detected result; Comprises a first load connected to the other end of the first current path, and a second current path having one end connected to the other end of the first load, between the both ends of the first load. The magnitude of the voltage drop that has occurred is detected, and the second
A second current path control element for intermittently controlling the current path, a second control end connected to the other end of the second current path, and one end connected to the other end of the first current path. A third current path, wherein a potential difference between the one end of the third current path and the potential of the second control terminal is detected, and the third current path is intermittently controlled in accordance with the detected result. A third current path control element, and a second load connected between the other end of the second current path and the other end of the third current path,
The first control terminal is coupled to a point between both ends of the second load, and the first current path control element is connected to the third load terminal.
The first current path is intermittently controlled so that the first current path is substantially made conductive when a voltage is applied across the current path in a direction in which a current flows in a predetermined direction. And the second and third current path control elements are configured to cause the second and third current paths to substantially conduct when the current flows through the first current path. And controlling intermittent control of a current path. When a single-phase AC voltage to be rectified is applied between the one end of the second current path and the one end of the third current path, the second A rectified voltage is output between the one end of the current path and the other end of the third current path.

According to such a power supply device, the potential at one end of the third current path to which the single-phase AC voltage to be rectified is applied, and the potential between the other end of the third current path and the second control end. Is detected by detecting a potential difference from a potential of the first control terminal representing a voltage obtained by dividing the voltage of the second load by the second load, thereby detecting a single-phase AC voltage to be rectified. For this reason, the ON / OFF timing of the third current path is determined without the need for the reference voltage source. Also, when the third current path is off, substantially no current flows through the first load. Therefore, the loss of such a rectifier is small. Further, according to such a rectifier, the detection of the single-phase AC voltage to be rectified is performed using the first current path control element including a transistor with a high withstand voltage, without using a comparator or an operational amplifier. Therefore, the withstand voltage also increases.

Further, a power supply device according to a third aspect of the present invention includes a first control terminal and a first current path, and
A first current path control element for intermittently controlling the first current path according to a detection result of detecting a potential difference between one end of the current path and the potential of the first control terminal; first a load connected to the other end of the first current path, a second current path having one end connected to the other end of the first load, and generated across said first load A second current path control element for detecting the magnitude of the voltage drop and intermittently controlling the second current path according to the detected result; and a second control connected to the other end of the second current path. An end, and a third current path having one end connected to the other end of the first current path;
A third current path control element that detects a potential difference between the potential of the one end of the third current path and the potential of the second control terminal, and controls the third current path according to the detection result; A second load connected between the other end of the second current path and the other end of the third current path;
An inductor connected to the one end of the current path, and the other end connected to the one end of the third current path. The first control end is connected to a point between both ends of the second load. Being coupled to each other, the first current path control element is configured to substantially cause the first current path to flow when a voltage is applied across both ends of the third current path in a direction in which current flows in a predetermined direction. The first current path is intermittently controlled so as to conduct the current,
The second and third current path control elements are configured to substantially conduct the third current path when current flows through the first current path. An external load is connected between the one end of the second current path and the other end of the third current path,
When an input voltage is applied across the third current path from an external voltage source, a current supplied from the voltage source to the inductor flows to the external load, and the application of the input voltage is stopped. The current flowing through the third current path is caused to flow to the external load by the self-induced electromotive force of the inductor.

According to such a power supply device, the potential at one end of the third current path to which the voltage generated by the electromotive force generated by the inductor is applied, and the other end of the third current path minus the second control terminal By detecting a potential difference from a potential at the first control terminal, which represents a voltage obtained by dividing the voltage between the first and second loads by a second load,
The detection of the electromotive force generated by the inductor is performed. For this reason, the ON / OFF timing of the third current path is determined without the need for the reference voltage source. Also, when the third current path is off, substantially no current flows through the first load. Therefore, the loss of such a rectifier is small. Further, according to such a rectifier, the detection of the electromotive force generated by the inductor is performed without using the comparator or the operational amplifier.
Since the process is performed using the first current path control element including a transistor or the like having a high withstand voltage, the withstand voltage also increases.

[0023]

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 and resistors R1 to R3.

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 the transistor Q1 is connected to the collector of the transistor Q2 and the transistor Q via a resistor R1.
3 connected to the base. Also, the transistor Q1
Is also connected to the emitter of the transistor Q3 via the resistor R2. The emitter of the transistor Q1 is connected to the base of the transistor Q2, and the collector of the transistor Q1 is connected to the collector of the transistor Q3.

As described above, the base of the transistor Q2 is connected to the emitter of the transistor Q1, and the emitter of the transistor Q2 is connected to the positive electrode of a drive 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 as described above, the emitter of the transistor Q3 forms the anode of the rectifier, and the collector of the transistor Q3 forms the cathode of the rectifier. I have.

The resistor R1 is connected to the transistor Q as described above.
1 and the base of the transistor Q3. The resistor R2 is connected between the base and the emitter of the transistor Q3. The resistor R3 is connected between the base and the emitter of the transistor Q2.

The resistance values of the resistors R1 and R2 are sufficient for the base of the transistor Q1 to saturate the emitter-collector of the transistor Q3 (that is, the state where the voltage between the emitter and the collector becomes almost 0 volt). When a substantially minimum current flows, the value is selected so that the emitter-collector of the transistor Q1 is turned on in an unsaturated state by the operation described later.

When a voltage is applied between the anode and the cathode of the rectifier, the potential difference between the base of the transistor Q1 and the potential of the anode of the rectifier becomes substantially equal to the magnitude of the voltage drop generated across the resistor R2. . The collector of the transistor Q1 is at substantially the same potential as the cathode of the rectifier. Further, the potential difference between the base of the transistor Q3 and the potential of the anode of the rectifier becomes substantially equal to the sum of the magnitudes of the voltage drops generated across the resistor R1 and across the resistor R2. The collector of the transistor Q3 has substantially the same potential as the cathode of the rectifier.

As described later, the transistor Q
When 1 and Q3 are in the off state, resistors R1 and R2
Does not substantially flow current. Therefore, when a voltage is applied between the anode and the cathode of the rectifier, when the transistors Q1 and Q3 are off, the bases of the transistors Q1 and Q3 become substantially equipotential with the anode of the rectifier. Q1 and Q3
Collector is substantially equipotential with the cathode of this rectifier.

When the power supply voltage is supplied from the drive voltage source, the voltage between the anode and the cathode of the rectifier causes (a) the emitter of the transistor Q1 to function as a collector, and the collector of the transistor Q1 to function as an emitter. In this case, the transistor Q1 is turned off, and (b) when the emitter of the transistor Q3 functions as a collector, and when the collector of the transistor Q3 functions as the emitter, the transistor Q3 is turned off. Suppose you have

More specifically, for example, when the transistors Q1 and Q3 are supplied with a power supply voltage from a drive voltage source, the voltage of their bases with respect to the potential of their collectors becomes 0.6 volts. It is assumed that it has a characteristic of turning on when it reaches. In this case, the anode voltage with respect to the cathode potential of the rectifier is set to 0.6.
It shall be kept below the bolt.

In this state, since the transistor Q1 is kept off, substantially no current flows through the resistor R3 which forms a current path between the positive electrode of the drive voltage source and the transistor Q1, 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 Q2 becomes almost 0 volt, and the transistor Q2 also keeps turning off.

When the transistor Q2 is turned off, a current path from the positive electrode of the driving voltage source to the base of the transistor Q3 via the emitter and the collector of the transistor Q2 is substantially cut off. In this state, the voltage between the base and the emitter of the transistor Q3 has a value that turns off the transistor Q3.
The transistor Q3 also keeps turning off.

Therefore, when the potential of the cathode of the rectifier is higher than the potential of the anode, the connection between the anode and the cathode of the rectifier continues to be substantially cut off even when the power supply voltage is supplied from the drive voltage source.

Note that the transistor Q2 is off,
Further, as a result of turning off both the transistors Q1 and Q3, substantially no base current flows through the bases of the transistors Q1 and Q3. Therefore, the current path for flowing the current through the resistors R1 and R2 is substantially interrupted,
No substantial voltage drop occurs between both ends of the resistor R1 and between both ends of the resistor R2.

Next, while the power supply voltage is supplied from the drive voltage source, the voltage between the anode and the cathode of the rectifier becomes
(C) It is assumed that a voltage is maintained such that the transistor Q1 is turned on when the emitter of the transistor Q1 functions as a collector and the collector of the transistor Q1 functions as an emitter.

More specifically, for example, when the transistors Q1 and Q3 are supplied with a power supply voltage from a drive voltage source, the voltage of their bases with respect to the potential of their collectors becomes 0.6 volts. In the case where the rectifier has a characteristic of turning on when it reaches the voltage, it is assumed that the anode voltage with respect to the cathode potential of the rectifier becomes 0.6 volt or more.

In this state, since the transistor Q1 is turned on, a current path is formed from the positive electrode of the driving voltage source to the cathode of the rectifier through the resistor R3, the emitter and the collector of the transistor Q1 in order, and both ends of the resistor R3. A voltage drop occurs in such a direction that the polarity of the base with respect to the emitter of the transistor Q2 becomes negative. 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 driving voltage source to the negative electrode of the driving voltage source via the emitter and collector of the transistor Q2, the base and the emitter of the transistor Q3, and the emitter. As a result, the base current flows into the base of the transistor Q3, and the transistor Q3 turns on. Therefore, current flows from the anode to the cathode of the rectifier.

When the transistor Q2 is turned on, a current path is also 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, the resistors R1 and R2 in that order. As a result, the potential at the base of the transistor Q1 has a magnitude obtained by subtracting the voltage drop generated across the resistor R1 from the potential at the base of the transistor Q3.

For this reason, the voltage at the base of the transistor Q1 depends on the voltage at the base of the transistor Q3. The transistor Q3 is connected to the base of the transistor Q1.
When a substantially minimum current flows to saturate the emitter-collector of the transistor Q1, the transistor Q1 turns on in a non-saturated state.

When the current flowing through the base of the transistor Q1 is negligible, the voltage at the base of the transistor Q1 is equal to the negative voltage of the base of the transistor Q3.
It can be regarded as a voltage obtained by dividing the voltage between the emitters by the resistors R1 and R2.

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

Then, the collector of the transistor Q1 connected to the cathode of this rectifier and the resistors R1 and R2
The potential difference from the base of transistor Q1 connected to the connection point increases. That is, when the emitter of the transistor Q1 functions as a collector and the collector of the transistor Q1 functions as an emitter, 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 R3 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 forward bias to the transistor Q3 becomes deeper due to the increase in the current between the collector and the emitter of the transistor Q2,
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. The voltage between the anode and the cathode of the rectifier is such that the increase in the voltage causes an increase in the collector current of the transistors Q1 and Q2, and the increase in the collector current of the transistor Q2 causes the decrease in the voltage between the anode and the cathode of the rectifier. By receiving the negative feedback that it brings about, it is controlled to be a constant value.

Therefore, the transistors Q1 and Q2 have
The minimum current necessary for the voltage between the emitter and the collector of the transistor Q3 to become a value converged by the negative feedback flows. Therefore, the power consumption of the resistors R1 and R2 is also minimized, as the voltage between the emitter and the collector of the transistor Q3 has a value converged by the negative feedback.

The configuration of the rectifier is not limited to the one described above. For example, transistors Q1-Q3 each
An emitter may be connected to a place where a collector is to be connected, and the collector may be connected to a place where the emitter is to be connected.

Further, as shown in FIG.
1 and Q3 may be constituted by PNP-type bipolar transistors, and transistor Q2 may be constituted by NPN-type 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. The collector of transistor Q3 forms the anode of the rectifier of FIG. 2, 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, the power supply voltage is supplied from the drive voltage source, and the voltage between the anode and cathode of the rectifier is
In a state where the conditions described above as (a) and (b) are satisfied, the transistor Q1 is turned off. Therefore, 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, the current path from the base of the transistor Q3 to the negative electrode of the drive voltage source via the collector and the emitter of the transistor Q2 is substantially cut off. As a result, the transistor Q3 also keeps turning off. That is, the connection between the anode and the cathode of the rectifier in FIG.

Next, while the power supply voltage is being supplied from the drive voltage source, the voltage between the anode and the cathode of the rectifier becomes (c).
Assuming that the above conditions were met,
A current flows from the cathode of this rectifier to the negative electrode of the drive voltage source via the collector and the emitter of the transistor Q1 and the resistor R3 in this 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 Q2 becomes positive, and the transistor Q2 also turns on.

When the transistor Q2 is turned on, a current flows from the positive electrode of the driving voltage source to the negative electrode of the driving voltage source via the emitter and base of the transistor Q3 and the collector and emitter of the transistor Q2.
A base current flows through the base of transistor 3, and transistor Q3 is turned on. Therefore, current flows from the anode to the cathode of the rectifier.

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 resistors R2 and R1, the collector and the emitter of the transistor Q2 in that order. As a result, the potential of the base of the transistor Q1 has a magnitude obtained by adding a voltage drop generated between both ends of the resistor R1 to the potential of the base of the transistor Q3. Thus, when a substantially minimum current flows through the base of the transistor Q1 to make the emitter-collector of the transistor Q3 saturate, the transistor Q1 turns on in a non-saturated state. .

When the current flowing from the anode to the cathode of the rectifier increases, 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. At this time, the voltage between the base and the collector of the transistor Q1 increases, and the current flowing between the collector and the emitter of the transistor Q1 increases.

As a result, the magnitude of the voltage drop across the resistor R3 also increases, the forward bias to the transistor Q2 becomes deeper, the current flowing between the collector and the emitter of the transistor Q2 increases, and the current flowing to the transistor Q3 increases. The forward bias becomes deeper, and the impedance between the collector and the emitter 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.

In the configuration shown in FIGS. 1 and 2, of the transistors Q2 and Q3, the one composed of an NPN type bipolar transistor is an enhancement type n-channel MOSFET (Metal-Oxide-Silicon Field Effe
ct Transistor). Also, PN
A device composed of a P-type bipolar transistor may be replaced with an enhancement-type p-channel MOSFET.

When an enhancement type MOSFET is used in place 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.

When the transistor Q3 is composed of a MOSFET, a voltage drop is generated between the base of the transistor Q1 and the source of the transistor Q3 between both ends of the resistor R2 in a direction to forward bias the transistor Q3. Then, the diode may be connected in such a direction as to bypass the current flowing through the resistor R2. Thereby, for example, the magnitude of the gate-source voltage required to turn on the transistor Q3
It is possible to avoid a situation where the collector current of the transistors Q1 and Q2 does not decrease despite the saturation of the transistor Q3 because the voltage is larger than the voltage between the base and the collector required to turn on the transistor 1.

Accordingly, in this rectifier, for example, as shown in FIG. 3, the transistor Q2 may be constituted by an enhancement type p-channel MOSFET, and the transistor Q3 may be constituted by an enhancement type n-channel MOSFET. Further, as shown in FIG. 3, a diode D having an anode connected to the base of the transistor Q1 and a cathode connected to the source of the transistor Q3 may be further provided.

However, in the rectifier shown in FIG.
And the resistance of R2 is such that when the voltage at the gate of transistor Q3 is substantially the lowest voltage sufficient to saturate the source-drain of transistor Q3, the collector-emitter of transistor Q1 becomes non-saturated. Is selected to turn on.

In the rectifier shown in FIG. 3, when a power supply voltage is supplied from a drive voltage source and the voltage between the anode and the cathode of the rectifier satisfies the conditions (a) and (b), the transistor Q1 is turned off. And therefore the transistor Q
The voltage between the gate and source of the transistor 2 becomes almost 0 volt, and the transistor Q2 is also turned off. When the transistor Q2 is off, the voltage at the gate of the transistor Q3 does not substantially fluctuate. Therefore, since the voltage between the anode and the cathode of the rectifier satisfies the condition (b) described above, the transistor Q3 also keeps turning off, and the connection between the anode and the cathode of the rectifier in FIG.

Next, when a power supply voltage is supplied from the drive voltage source and the voltage between the anode and the cathode of the rectifier satisfies the above condition (c), a resistor R3 and a transistor Q1 are connected from the positive electrode of the drive voltage source. Current flows to the cathode of this rectifier through the drain and source of the transistor Q2 in sequence, and a voltage drop occurs between both ends of the resistor R3 in a direction in which the polarity of the gate with respect to the source of the transistor Q2 is negative, and the transistor Q2 is also turned on. I do.

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 via the source and drain of the transistor Q2 in order. As a result, the potential at the base of the transistor Q1 is equal to the potential at the gate of the transistor Q3 minus the voltage drop generated across the resistor R1. Thus, when the voltage at the base of the transistor Q1 becomes substantially the lowest voltage enough to saturate the source-drain of the transistor Q3, the emitter-collector of the transistor Q1 is turned on in an unsaturated state. become.

When the current flowing from the anode to the cathode of the rectifier increases, the amount of voltage drop between the drain and source of the transistor Q3 increases, and the amount of loss generated by the rectifier increases. At this time, the voltage between the base and the collector of the transistor Q1 increases, and the current flowing between the emitter and the collector of the transistor Q1 increases.

As a result, the magnitude of the voltage drop between both ends of the resistor R3 also increases, the forward bias to the transistor Q2 becomes deeper, the current flowing between the source and the drain of the transistor Q2 increases, and the current flowing to the transistor Q3 increases. As the forward bias becomes deeper, the drain of transistor Q3
The impedance between the sources decreases. Therefore, the voltage drop between the drain and the source of the transistor Q3 is reduced, and the amount of loss generated by the rectifier is reduced.

(Second Embodiment) FIG. 4 shows a rectifier circuit according to a second embodiment of the present invention. This rectifier circuit includes an AC input terminal, an output terminal,
It comprises a rectifier Rect and a capacitor C. As shown in FIG. 4, the rectifier Rect has substantially the same configuration as that of the rectifier of FIG. 2 in the first embodiment.

The capacitor C is connected between one pole of the AC input terminal having a pair of poles and the cathode of the rectifier Rect. The anode of the rectifier Rect is connected to the pole of the AC input terminal to which the capacitor C is not connected.

The output terminal has a positive electrode and a negative electrode. The positive electrode is connected to the cathode of the rectifier Rect, and the negative electrode is connected to a connection point between the capacitor C and the AC input terminal. In the rectifier Rect, a portion to be connected to the negative electrode of the external drive voltage source is connected to the negative electrode of the output terminal.

It is assumed that an external load is connected between the positive electrode and the negative electrode at the output terminal of the rectifier circuit, and a single-phase AC voltage to be rectified is applied between the two electrodes at the AC input terminal. In this case, since the cathode of the rectifier Rect is connected via the load to the other of the AC input terminals that is not connected to the anode of the rectifier Rect, the voltage applied between the two electrodes of the AC input terminal Is applied between the anode and the cathode of the rectifier Rect.

The voltage generated at the pole of the rectifier Rect connected to the negative pole at the output end is applied to the portion of the rectifier Rect connected to the negative pole at the output end. You. This voltage has a negative polarity with respect to the potential of one of the two poles of the AC input terminal connected to the cathode of the rectifier Rect. Therefore, this voltage is applied to the rectifier Re.
The rectifier Rect is used as a power supply voltage for driving ct.
Supplied to

Therefore, assuming that the voltage between the anode and the cathode of the rectifier Rect satisfies the above condition (c), the anode-cathode of the rectifier Rect conducts. And the rectifier Re among the two poles of the AC input terminal
ct from the pole connected to the anode of the rectifier R
A current flows to the other pole of the AC input terminal via the anode and the cathode of ect, and then via the external load and the parallel circuit of the capacitor C.

On the other hand, if the voltage between the anode and the cathode of the rectifier Rect satisfies the above conditions (a) and (b), the connection between the anode and the cathode of the rectifier Rect is substantially cut off.

By repeating the above operation, the rectifier circuit of FIG. 4 performs half-wave rectification. Then, the capacitor C smoothes the half-wave rectified voltage generated between the two electrodes at the output terminal. In the rectifier circuit of FIG. 4, a voltage applied to an AC input terminal as a single-phase AC voltage to be rectified is supplied to a rectifier Re as a power supply voltage for driving the rectifier Rect.
ct. For this reason, the rectifier circuit of FIG. 4 operates without separately preparing a drive voltage source for driving the rectifier Rect.

The configuration of the rectifier circuit is not limited to the one described above. For example, the rectifier Rect of this rectifier circuit
May have substantially the same configuration as the rectifier of FIG. 1, for example, as shown in FIG.

In this case, however, as shown, the capacitor C is connected between one pole of the AC input terminal and the anode of the rectifier Rect. The cathode of the rectifier Rect is connected to the pole of the AC input terminal to which the capacitor C is not connected. The positive terminal of the output terminal is connected to a connection point between the capacitor C and the AC input terminal, and the negative terminal is connected to the anode of the rectifier Rect. In the rectifier Rect, a portion to be connected to the positive electrode of the external driving voltage source is connected to the positive electrode of the output terminal.

It is assumed that an external load is connected between the positive electrode and the negative electrode at the output terminal of the rectifier circuit in FIG. 5, and a single-phase AC voltage to be rectified is applied between the two electrodes at the AC input terminal. in this case,
Since the anode of the rectifier Rect is connected via a load to one of the AC input terminals that is not connected to the cathode of the rectifier Rect, the voltage applied between the two electrodes of the AC input terminal is equal to the rectifier Rect. Rect is applied between the anode and the cathode.

Further, the voltage generated at the pole of the rectifier Rect connected to the positive pole at the output end is applied to the part of the rectifier Rect connected to the positive pole at the output end. You. This voltage has a positive polarity with respect to the potential of the other pole of the AC input terminal that is connected to the anode of the rectifier Rect. Therefore, this voltage is applied to the rectifier Re.
The rectifier Rect is used as a power supply voltage for driving ct.
Supplied to

Accordingly, if the voltage between the anode and the cathode of the rectifier Rect satisfies the above condition (c), the anode-cathode of the rectifier Rect conducts. Then, of the two poles of the AC input terminal, from the one connected to the positive electrode of the output terminal, through a parallel circuit of a load and a capacitor, and then through the anode and cathode of the rectifier Rect, to the other pole of the AC input terminal. The current that flows reaches.

On the other hand, assuming that the voltage between the anode and the cathode of the rectifier Rect satisfies the above conditions (a) and (b), the connection between the anode and the cathode of the rectifier Rect is substantially cut off.

With the above operation, the rectifier circuit of FIG. 5 also performs half-wave rectification. Also in the rectifier circuit of FIG. 5, the voltage applied to the AC input terminal as a single-phase AC voltage to be rectified is
Since the power supply voltage for driving the rectifier Rect is supplied to the rectifier Rect, there is no need to separately prepare a drive voltage source.

(Third Embodiment) Next, a switching regulator according to a third embodiment of the present invention will be described. As shown in FIG. 6, the switching regulator includes a pulse input terminal, an output terminal, a rectifier Rect.
, A capacitor C, and a coil L. As shown in FIG. 6, the rectifier Rect has substantially the same configuration as the configuration of the rectifier of FIG. 1 in the first embodiment and the configuration of the rectifier Rect of FIG. 5 in the second embodiment.

The capacitor C is connected between both electrodes at the output terminal having a positive electrode and a negative electrode. The anode of the rectifier Rect is connected to a negative electrode at a pulse input terminal having a positive electrode and a negative electrode, and a negative electrode at an output terminal. The cathode of the rectifier Rect is connected to the positive electrode of the pulse input terminal. In the rectifier Rect, a portion to be connected to the positive electrode of the external driving voltage source is connected to the positive electrode of the output terminal. The coil L is connected between the positive terminal of the output terminal and the positive terminal of the pulse input terminal.

An external load is connected between the positive terminal and the negative terminal of the output terminal of this switching regulator, and the positive terminal of the pulse input terminal has a positive polarity with respect to the negative terminal of the pulse input terminal between both terminals of the pulse input terminal. Thus, it is assumed that a rectangular pulse is applied.

In this case, the cathode of the rectifier Rect is
The potential between the anode and the cathode of the rectifier Rect becomes higher than that of the anode of the rectifier Rect, so that the voltage between the anode and the cathode of the rectifier Rect satisfies the above-described conditions (a) and (b). Is done.

Further, from the positive electrode at the pulse input terminal, the coil L
Then, a current flows further through the parallel circuit of the load and the capacitor C and reaches the negative electrode of the pulse input terminal. As a result, a voltage having a positive polarity with respect to the potential of the negative electrode at the output terminal is generated at the positive electrode at the output terminal, and the capacitor C is charged by this voltage.

The voltage of the positive terminal of the output terminal is applied to the portion of the rectifier Rect connected to the positive terminal of the output terminal. Since the voltage is positive with respect to the potential of the anode of the rectifier Rect connected to the negative electrode of the output terminal, the voltage is supplied to the rectifier Rect as a power supply voltage for driving the rectifier Rect. However, while the rectangular wave is applied to the pulse input terminal, the voltage between the anode and the cathode of the rectifier Rect satisfies the above-described conditions (a) and (b) as described above.
Is substantially shut off between the anode and the cathode.

Next, it is assumed that the application of the rectangular pulse is completed, and the positive electrode at the pulse input terminal of the switching regulator becomes lower than the potential of the negative electrode at the pulse input terminal. In this case, the cathode of the rectifier Rect has a lower potential than the anode of the rectifier Rect, and therefore, the voltage between the anode and the cathode of the rectifier Rect satisfies the above condition (c).

Then, a back electromotive force is generated at both ends of the coil L such that one end of the pulse input end connected to the positive electrode has a negative polarity with respect to the other end. Further, a voltage is generated at both ends of the capacitor C charged while the rectangular pulse is being applied to the pulse input terminal, such that the terminal connected to the positive terminal of the output terminal has a positive polarity.

For this reason, the portion of the rectifier Rect connected to the positive terminal of the output terminal continues to have the rectifier Re.
The voltage of the positive polarity is continuously applied to the potential of the anode of ct. Therefore, the rectifier Rect is driven by this voltage, and the rectifier Rect conducts between the anode and the cathode.

As a result, a current flows from the coil L to the coil L via the parallel circuit of the load and the capacitor C, the anode and the cathode of the rectifier Rect. As a result, a voltage having a positive polarity with respect to the potential of the negative electrode at the output terminal is continuously applied to the positive electrode at the output terminal.

By repeating the above operation, the switching regulator of FIG. 6 supplies power having a constant polarity to the load. In the switching regulator of FIG. 6, the back electromotive force generated by the coil L and the capacitor C
Is supplied to the rectifier Rect as a power supply voltage for driving the rectifier Rect.
For this reason, the switching regulator of FIG. 6 operates without separately preparing a drive voltage source for driving the rectifier Rect.

The configuration of the switching regulator is not limited to the one described above. For example, the rectifier Rect of this switching regulator may have substantially the same configuration as the rectifier of FIG. 2, for example, as shown in FIG. However, in this case, of the rectifier Rect,
The portion to be connected to the negative electrode of the external drive voltage source is connected to the negative electrode of the output terminal. The coil L is connected between the negative electrode at the output terminal and the negative electrode at the pulse input terminal.

An external load is connected between the positive terminal and the negative terminal of the output terminal of the switching regulator of FIG. 7, and the positive terminal of the pulse input terminal has a positive polarity with respect to the negative terminal of the pulse input terminal between the two terminals of the pulse input terminal. Assuming that a rectangular pulse is applied, the voltage between the anode and the cathode of the rectifier Rect satisfies the above-described conditions (a) and (b). Therefore, the connection between the anode and the cathode of the rectifier Rect is substantially shut off.

Further, from the positive electrode of the pulse input terminal, through the parallel circuit of the load and the capacitor C, further through the coil L,
A current flows to the negative electrode of the pulse input terminal. As a result, a voltage having a positive polarity with respect to the potential of the negative electrode at the output terminal is generated at the positive electrode at the output terminal, and the capacitor C is charged by this voltage.

Next, when the application of the rectangular pulse is completed and the positive electrode at the pulse input terminal of the switching regulator becomes lower than the potential of the negative electrode at the pulse input terminal, the rectifier Rect.
The voltage between the anode and the cathode satisfies the above condition (c). At both ends of the coil L, back electromotive force is generated such that the end connected to the negative electrode of the pulse input terminal has a positive polarity with respect to the other end. Further, a voltage is generated at both ends of the capacitor C such that the end connected to the positive terminal of the output terminal has a positive polarity.

For this reason, the portion of the rectifier Rect connected to the negative electrode of the output terminal continues to have the rectifier Re.
The voltage of the negative polarity is continuously applied to the potential of the cathode of ct. Therefore, the rectifier Rect is driven by this voltage, and the rectifier Rect conducts between the anode and the cathode.

Thus, the rectifier Rec from the coil L
A current flows to the coil L through the parallel circuit of the anode and the cathode t, the load, and the capacitor C in order. As a result, a voltage having a positive polarity with respect to the potential of the negative electrode at the output terminal is continuously applied to the positive electrode at the output terminal.

With the above operation, the switching regulator of FIG. 7 also supplies power having a constant polarity to the load without separately preparing a drive voltage source for driving the rectifier Rect.

[0103]

As described above, according to the present invention, a rectifier and a power supply device with a small loss and a high withstand voltage can be realized with a simple structure that does not require a reference voltage source.

[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.

FIG. 6 is a circuit diagram showing a configuration of a switching regulator according to a third embodiment of the present invention.

FIG. 7 is a circuit diagram showing a modification of the switching regulator of FIG. 6;

[Explanation of symbols]

 Q1 to Q3 Transistors R1 to R3 Resistor D Diode Rect Rectifier C Capacitor L Coil

Claims (7)

(57) [Claims] A first control terminal and a first current path, wherein a potential difference between one end of the first current path and a potential of the first control terminal is detected, and the potential difference is detected in accordance with a result of the detection. First
A first current path control element for intermittently controlling the current path of the first current path, a first load having one end connected to the other end of the first current path, and a second current path. The magnitude of the voltage drop that occurs between both ends of the
A second current path control element for intermittently controlling the second current path; a second control end connected to one end of the second current path;
A third current path having one end connected to the one end of the first current path, and detecting a potential difference between the potential of the one end of the third current path and the potential of the second control terminal; A third current path control element for intermittently controlling the third current path according to the detected result; and a third current path control element connected between the one end of the second current path and the other end of the third current path. A second load, wherein the first control end is coupled to a point between both ends of the second load, and wherein the first current path control element includes both ends of the third current path. The second current path is intermittently controlled so that the first current path is substantially conducted when a voltage for flowing a current in a predetermined direction is applied between the second and third current paths; A voltage is externally applied between the other end of the second current path and the other end of the third current path. And controlling the intermittent control of the second and third current paths so as to substantially conduct the third current path when a current flows in the first current path. . Wherein said first, second and third current path control device is provided with a continuous control means for continuously changing the impedance of the current path according to the magnitude of the voltage drop their senses, each of said The continuous control means is configured to reduce the impedance of the current path of the third current path control element so that the impedance of the current path of the third current path control element decreases when the current flowing between both ends of the current path of the third current path control element increases . Second and third current path control elements
The rectifier according to claim 1, wherein the impedance of each of the current paths of the child is changed . 3. Each of said first to third current path control elements .
The continuous control means includes a control terminal, detects a voltage between any one end of a current path included in each device and the control terminal, and changes an impedance of the current path included in each device according to a detected result. The rectifier according to claim 2, wherein the first load is connected between the other end of the second current path and a control end. 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. A power supply device for rectifying a single-phase AC voltage and outputting a rectified voltage, comprising a first control terminal and a first current path, wherein a potential at one end of the first current path and A first current path control element that detects a potential difference between the potentials of the first control terminal and controls the intermittent control of the first current path according to the detected result; one end connected to the other end of the first current path; A first load, and a second current path having one end connected to the other end of the first load, and detecting a magnitude of a voltage drop generated between both ends of the first load, A second current path control element for intermittently controlling the second current path in accordance with the detected result; a second control end connected to the other end of the second current path;
A third current path having one end connected to the other end of the first current path, and detecting a potential difference between the potential of the one end of the third current path and the potential of the second control terminal; A third current path control element for intermittently controlling the third current path according to the detected result; and a third current path control element connected between the other end of the second current path and the other end of the third current path. A second load, wherein the first control end is coupled to a point between both ends of the second load, and wherein the first current path control element is connected to the third current path. When a voltage for flowing a current in a predetermined direction is applied between both ends, the first current path is intermittently controlled so as to substantially conduct the first current path. The second and third current path control elements cause the third current path to substantially conduct when a current flows through the first current path. The second and third current paths are intermittently controlled, and a single-phase alternating current to be rectified between the one end of the second current path and the one end of the third current path. When a voltage is applied, a rectified voltage is output between the one end of the second current path and the other end of the third current path. A first control terminal and a first current path, wherein a potential difference between one end of the first current path and a potential of the first control terminal is detected, and the potential difference is detected according to a result of the detection. First
A first current path control element for intermittently controlling the current path, a first load having one end connected to the other end of the first current path, and one end connected to the other end of the first load. A second current path for detecting a magnitude of a voltage drop generated between both ends of the first load, and intermittently controlling the second current path according to the detected result. An element, a second control end connected to the other end of the second current path,
A third current path having one end connected to the other end of the first current path, and detecting a potential difference between the potential of the one end of the third current path and the potential of the second control terminal; A third current path control element for intermittently controlling the third current path according to the detected result; and a third current path control element connected between the other end of the second current path and the other end of the third current path. A second load, and an inductor having one end connected to the one end of the second current path and the other end connected to the one end of the third current path. Is coupled to a point between both ends of the second load, and the first current path control element is applied with a voltage for flowing a current in a predetermined direction between both ends of the third current path. The first current path is intermittently controlled so that the first current path is substantially conducted. The second and third current path control elements cause the second and third current paths to substantially conduct when the current flows through the first current path. An external load is connected between the one end of the second current path and the other end of the third current path, and an external load is connected to the third current path. When an input voltage is applied between both ends, a current supplied from the voltage source to the inductor flows to the external load, and when the application of the input voltage is stopped, the inductor is self-induced by an electromotive force. A power supply device, wherein a current flowing in the third current path flows to the external load.