JP5786390B2 - Rectifier circuit - Google Patents

Description

  The present invention relates to a rectifier circuit that is used for RFID (Radio Frequency IDentification) tags, microwave energy transmission, and the like, and converts input high-frequency power into DC power.

  Conventionally, the configuration shown in Non-Patent Document 1 (FIG. 1) has been used as a rectifier circuit used in high frequency, particularly in the microwave band. This is a rectifier circuit composed of a diode, a low-pass filter, and a DC-pass filter. FIG. 7A shows the current-voltage characteristics of the diode. In the figure, V is a voltage and I is a current. The diode is a non-linear element, and allows a current to flow for a forward voltage exceeding the ON voltage (Von) (ON state) and does not flow a reverse voltage lower than the ON voltage (OFF state).

  FIG. 7B and FIG. 7C show a voltage waveform and a current waveform when a sine wave voltage is applied to the diode, respectively. In the figure, t is time. A current flows through the diode while the amplitude of the sine wave voltage exceeds Von, and no current flows through the diode while it falls below Von. This current waveform is smoothed by a DC pass filter connected to the subsequent stage of the diode, and a DC current component is supplied to the load.

  Here, the lower the Von, the longer the time during which the current flows through the diode, and the higher the DC power smoothed by the DC pass filter. Therefore, the lower the ON voltage of the diode, the higher the rectification efficiency, which is the ratio between the high-frequency power input to the rectifier circuit and the DC power supplied to the load.

  Further, the higher the high-frequency power input to the rectifier circuit, the higher the rectification efficiency. When the high-frequency power input to the rectifier circuit is small, the diode is always in the OFF state when Von is high (state B in the figure), but the rectification operation is not performed. (State A in the figure) Rectification operation is performed. Therefore, the rectification efficiency becomes higher as the ON voltage of the diode is lower, particularly for a low-frequency high-frequency input.

T. Yoo and K. Chang, “Theoretical and experimental development of 10 and 35 GHz rectennas,” IEEE Trans. Microwave Theory Tech., Vol. 40, pp. 1259-1266, June 1992.

  As a diode used in the rectifier circuit, a Schottky diode using a junction between a metal and a semiconductor is generally used. Since the Schottky diode has an ON voltage as small as about 0.3 V, it can be rectified with high efficiency even for a relatively small power high-frequency input.

  However, when trying to reduce the size and cost by integrating the rectifier circuit including the diode by, for example, the Si process, a special process for joining the metal and the semiconductor is required when the Schottky diode is used. There is a problem that the cost cannot be reduced.

  As a diode that can be manufactured by a general Si process, there is a diode-connected MOS (Metal Oxide Semiconductor) transistor. This is obtained by connecting the gate terminal and the drain terminal of a MOS transistor, and exhibits a diode characteristic in which a forward current flows from the drain terminal to the source terminal and no current flows in the reverse direction.

  However, since the ON voltage of the diode-connected MOS transistor is about 0.7 V, which is higher than that of the Schottky diode, there is a problem that the rectification efficiency is low with respect to the high-frequency input with small power.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a rectifier circuit capable of performing high-efficiency operation in a wide input power range from low power.

A rectifier circuit according to the present invention includes:
A first filter that allows the input high frequency to pass therethrough and blocks direct current and harmonics of the high frequency ;
A transistor having a first terminal to which a periodic voltage having the same frequency as the high frequency is applied, a second terminal connected to the first filter, and a third terminal grounded, which rectifies the high frequency When,
A second filter connected to a connection point between the first filter and the second terminal, blocking the high frequency, and outputting a direct current rectified by the transistor;
It is characterized by comprising.

  According to the present invention, a high frequency input from the outside and converted into direct current is input to the transistor, and a high frequency for turning the transistor on and off is applied to the first terminal of the transistor. Even if the generated high frequency power is small, the rectification efficiency can be increased.

It is a block diagram which shows the rectifier circuit by Embodiment 1 of this invention. It is a figure which shows the relationship between high frequency input power and rectification efficiency. It is a block diagram which shows the rectifier circuit by Embodiment 2 of this invention. It is a block diagram which shows the modification of the rectifier circuit by Embodiment 2 of this invention. It is a block diagram which shows the modification of the rectifier circuit by Embodiment 2 of this invention. It is a block diagram which shows the rectifier circuit by Embodiment 3 of this invention. It is explanatory drawing explaining operation | movement of a prior art example.

Embodiment 1 FIG.
1 is a block diagram showing a rectifier circuit according to Embodiment 1 of the present invention. In each figure, the same numerals indicate the same or corresponding parts. In FIG. 1, 1 is an input terminal, 2 is a band-pass filter as a first filter, 3 is an inductor, 4 is a capacitor, 5 is a MOS (Metal Oxide Semiconductor) transistor, 6 is a signal source, and 7 is a first filter. 2 is a low-pass filter, 8 is an inductor, 9 is a capacitor, 10 is an output terminal, and 16 is a load resistance.

  A high frequency is input to the input terminal 1. The band pass filter 2 passes the high frequency input from the input terminal 1 and blocks the passage of waves of other frequencies. In FIG. 1, the band pass filter 2 is configured by a series resonator in which an inductor 3 and a capacitor 4 are connected in series, but other configurations may be used as long as equivalent characteristics are obtained. When the band-pass filter 2 shown in FIG. 1 is used, the values of the inductor 3 and the capacitor 4 are determined so as to resonate in series at the input high-frequency frequency, so that the high-frequency pass and other frequencies are cut off.

  The MOS transistor 5 is a non-linear element that has three terminals, a gate terminal as a first terminal, a drain terminal as a second terminal, and a source terminal as a third terminal, and rectifies a high-frequency waveform. A periodic voltage generated by the signal source 6 is applied to the gate terminal of the MOS transistor 5. The drain terminal of the MOS transistor 5 is connected to the band pass filter 2 at a connection point indicated by A in the figure. The source terminal of the MOS transistor 5 is grounded.

  The MOS transistor 5 shown in FIG. 1 is an N-channel MOS transistor. When a positive voltage exceeding the threshold voltage is applied to the gate terminal, a current flows between the drain and the source (ON state) and is applied to the gate terminal. When the voltage is lower than the threshold voltage, no current flows between the drain and source (OFF state). Therefore, the rectification operation can be performed in the same manner as the diode. The current waveform rectified by the MOS transistor 5 includes a direct current that is a direct current component, a high frequency component that is input, and a harmonic component thereof.

  The signal source 6 generates a sine wave periodic voltage of the same frequency synchronized with the high frequency input from the input terminal 1, and applies this periodic voltage to the gate terminal of the MOS transistor 5.

  The low-pass filter 7 is connected to a connection point (point A in the figure) between the band-pass filter 2 and the drain terminal of the MOS transistor 5. The low-pass filter 7 smoothes the current waveform rectified by the MOS transistor 5, outputs only the DC component to the output terminal 10, supplies it to the load resistor 16, and blocks the passage of high frequencies other than DC. In FIG. 1, the low-pass filter 7 is composed of an inductor 8 connected in series and a capacitor 9 connected in parallel, but other configurations may be used as long as equivalent characteristics are obtained. When the low-pass filter 7 as shown in FIG. 1 is used, the cutoff frequency is set lower than the high-frequency frequency input from the input terminal 1, so that cutoff of high frequencies other than direct current is realized.

Next, a more detailed operation will be described.
The high frequency input to the input terminal 1 passes through the band pass filter 2, and the voltage is applied to the drain terminal of the MOS transistor 5. Since the low-pass filter 7 has high impedance for high frequencies, the high-frequency is blocked by the low-pass filter 7 and does not pass through the load resistor 16.

  On the other hand, a sine wave periodic voltage having the same frequency synchronized with the high frequency input to the input terminal 1 is applied from the signal source 6 to the gate terminal of the MOS transistor 5. By applying this periodic voltage to the gate terminal with an amplitude exceeding the threshold voltage of the MOS transistor 5, the MOS transistor 5 is turned on in a substantially half-cycle time when the periodic voltage applied to the gate terminal exceeds the threshold voltage of the MOS transistor 5. The MOS transistor 5 is in an OFF state in a substantially half-cycle time below the threshold voltage.

  Here, the phase of the sine wave voltage applied from the signal source 6 to the gate terminal of the MOS transistor 5 is changed to the phase of the high frequency applied from the input terminal 1 to the drain terminal of the MOS transistor 5 through the band pass filter 2. And the voltage applied to the gate terminal exceeds the threshold voltage, and while the MOS transistor 5 is in the ON state, current flows from the drain terminal to the source terminal, and the MOS transistor 5 is in the OFF state. During this time, no current flows. Therefore, a current flows only for approximately half a period when the high frequency voltage applied to the drain terminal of the MOS transistor 5 is positive, and rectification can be performed.

  Alternatively, the phase of the sine wave applied from the signal source 6 to the gate terminal of the MOS transistor 5 is opposite to the high-frequency phase input from the input terminal 1 and applied to the drain terminal of the MOS transistor 5 via the band pass filter 2. You may synchronize so that it may become a phase. In this case, current flows from the source terminal to the drain terminal while the voltage applied to the gate terminal exceeds the threshold voltage, and the MOS transistor 5 is turned on, and no current flows while the MOS transistor 5 is turned off. . Therefore, a current flows only during a half-cycle period when the high-frequency voltage applied to the drain terminal of the MOS transistor 5 is negative, and rectification can be performed.

  In this way, the high frequency input to the input terminal 1 is rectified by the MOS transistor 5.

  The current waveform rectified by the MOS transistor 5 includes a direct current component, a high frequency component that is input, and a harmonic component thereof. Among these, the low-pass filter 7 passes only the DC component to the output terminal 10 and supplies the DC component power to the load resistor 16.

  Since this direct current component is blocked by the band pass filter 2, it does not return to the input terminal 1. It is also possible to use a high-pass filter instead of the band-pass filter 2 so that the input high-frequency component passes and the DC component is cut off. However, it is more desirable to use a band pass filter 2 that only blocks high-frequency components and blocks direct-current components and harmonic components in that the harmonic components are also blocked and not returned to the input terminal 1.

  FIG. 2 shows the relationship between high-frequency input power and rectification efficiency. The horizontal axis in FIG. 2 is the high frequency input power, and the vertical axis is the rectification efficiency of the rectifier circuit. In FIG. 2, the dotted line indicates the rectification efficiency curve when a diode-connected MOS transistor is used, and the solid line indicates the rectification efficiency curve when the configuration of FIG. 1 is used.

  When a MOS transistor is diode-connected and used as a diode, this is equivalent to switching the diode with a high-frequency voltage itself input from the input terminal 1. At this time, when the high-frequency input power is large and a voltage amplitude sufficient to switch the diode is applied, the rectification efficiency is relatively high because the time exceeding Von is long. However, as the high frequency input power decreases, the voltage amplitude applied to the diode decreases, and the time exceeding Von is shortened, so that the rectification efficiency decreases. Further, when the voltage amplitude of the high frequency is lower than Von, the diode does not perform the switching operation, and the rectification efficiency becomes zero.

  On the other hand, when the configuration of FIG. 1 of the present embodiment is used, the MOS transistor 5 has a sine wave periodic voltage applied to the gate terminal from the signal source 6 in a positive half cycle regardless of the value of the high-frequency input power. It becomes ON state at the time of, and becomes OFF state at the time of the negative half cycle. Therefore, even when the high frequency input power is low, the rectification operation occurs, and there is an advantage that the conversion efficiency from the high frequency power to the DC power, that is, the rectification efficiency is increased. For this reason, as shown by the solid line in FIG. 2, the rectification efficiency can be increased as compared with the case where a diode-connected MOS transistor is used, and the rectification efficiency can be increased particularly when the input power is small.

  1, the signal source 6 is required separately from the high-frequency input from the outside, but since the gate terminal of the MOS transistor 5 has a high impedance, the periodic voltage of the sine wave output from the signal source 6 Can be small, and the power consumption of the signal source 6 can be small.

  In FIG. 1, the sine wave is output from the signal source 6, but instead, a rectangular wave may be output as a periodic voltage. Since the rise time and fall time of the rectangular wave are shorter than those of the sine wave, the ON state and the OFF state of the MOS transistor 5 are instantaneously switched to approach the ideal rectification operation, so that the rectification efficiency is higher than that of the sine wave input. Has the advantage of becoming.

  In the present embodiment, the N-channel MOS transistor 5 is used as the nonlinear element. However, the present invention is not limited to this, and a P-channel MOS transistor may be used as the nonlinear element. In this case, when the periodic voltage applied to the gate terminal becomes lower than a certain threshold voltage, the transistor is turned on and a current flows between the drain terminal and the source terminal. Further, when the voltage applied to the gate terminal becomes higher than the threshold voltage, the transistor is turned off and current between the drain terminal and the source terminal does not flow. Therefore, even in this case, the rectification operation can be performed in the same manner, and the effect of the present embodiment that the rectification efficiency can be increased can be obtained.

  In the present embodiment, the source terminal of the MOS transistor 5 is grounded and the high frequency power is applied to the drain terminal side. However, the source terminal and the drain terminal may be connected in reverse. The terminal and the third terminal may be interchanged. Also in this case, the switching operation is performed in the same manner, and the effect of the present embodiment can be obtained.

  In addition, in the present embodiment, the MOS transistor 5 which is a kind of field effect transistor (FET) is used as the nonlinear element. However, the present invention is not limited to this, and other types of field effect transistors can be used. Either of the P channels can be used. Further, a bipolar transistor can be used instead of a field effect transistor. In any type of transistor, it is more desirable to use a transistor that can be integrated with another circuit by a Si process, but the present invention is not limited to this. Note that when a bipolar transistor is used, a base terminal, a collector terminal, and an emitter terminal may be used as terminals corresponding to the gate terminal, the drain terminal, and the source terminal, and the connection between the collector terminal and the emitter terminal may be switched. . As the bipolar transistor, either an NPN type or a PNP type can be used, and the effects of the present embodiment can be obtained similarly.

  Furthermore, in the present embodiment, the configuration in which the periodic voltage applied to the gate terminal of the MOS transistor 5 is generated using the signal source 6 is shown. However, the present invention is not limited to this, and is input to the input terminal 1. A periodic voltage having the same frequency synchronized with the high frequency may be applied to the gate terminal of the transistor, and the signal source 6 is not necessarily provided. For example, the frequency information and phase information of the periodic voltage applied to the gate terminal can be supplied from a device (not shown) that generates a high frequency to be input to the input terminal 1.

  As described above, the rectifier circuit shown in the present embodiment has an effect that the rectification efficiency can be increased, and the cost can be further reduced if the Si process is used.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing a rectifier circuit according to Embodiment 2 of the present invention. In this configuration, the MOS transistor 5 is switched using a part of the high-frequency input instead of using the signal source 6. In FIG. 3, the same reference numerals as those in FIG. Reference numeral 11 denotes a power distributor as distribution means, reference numeral 12 denotes a transformer as boosting means, and reference numeral 13 denotes a phase shifter as phase shift means.

  In FIG. 3, the power distributor 11 distributes the high-frequency power input from the input terminal 1 and transmitted via the band-pass filter 2 into the first high frequency and the second high frequency. The first high frequency passes through point A in the figure and is applied to the drain terminal of the MOS transistor 5. The second high frequency is input to the transformer 12. The transformer 12 boosts the second high-frequency voltage output from the power distributor 11. The phase shifter 13 shifts the phase of the high-frequency voltage output from the transformer 12 and applies it to the gate terminal of the MOS transistor 5 as a periodic voltage.

Next, the operation will be described.
The high frequency power input from the input terminal 1 and transmitted through the band pass filter 2 is distributed into two by the power distributor 11. The voltage of the first high frequency distributed by the power distributor 11 is applied to the drain terminal of the MOS transistor 5. The high-frequency power does not pass through the output terminal 10 or the load resistor 16 because the low-pass filter 7 has high impedance for high frequencies.

  The second high frequency output distributed by the power distributor 11 is input to the transformer 12. This high frequency is boosted by the transformer 12 and applied to the gate terminal of the MOS transistor 5 via the phase shifter 13.

  When the boosted high-frequency voltage amplitude exceeds the threshold voltage of the MOS transistor 5, the MOS transistor 5 performs a switching operation. That is, the MOS transistor 5 is turned on during the positive half-cycle time when the sine wave voltage exceeds the threshold value of the MOS transistor 5, and the MOS transistor 5 is turned off during the negative half-cycle time when the sine wave voltage falls below the threshold value of the MOS transistor 5. It will be in the OFF state.

  When there is no phase difference between the two outputs of the power distributor 11 and there is no phase change due to passing through the transformer 12, the voltage applied to the drain terminal and the gate terminal of the MOS transistor 5 is in phase, that is, the level. The phase difference is 0 degree. Therefore, when the MOS transistor 5 is in the ON state, a positive half-cycle voltage of a high frequency input is applied to the drain terminal, and a current flows from the drain terminal to the source terminal. When the MOS transistor 5 is in the OFF state, a negative half-cycle voltage of the high-frequency input is applied to the drain terminal, but no current flows between the drain terminal and the source terminal.

  Even if there is a phase difference between the two outputs of the power distributor 11, if the phase change caused by passing through the transformer 12 cancels this, similarly, the drain terminal and the gate of the MOS transistor 5 The phase difference of the voltage applied to the terminal is 0 degree. In any case, the rectification operation by the MOS transistor 5 is performed.

  On the other hand, a phase difference occurs between the two outputs of the power distributor 11 and the phase of the high frequency passing through the transformer 12 changes, so that the voltages applied to the drain terminal and the gate terminal of the MOS transistor 5 are out of phase. That is, when the phase difference is 180 degrees, a negative half-cycle voltage of a high frequency input is applied to the drain terminal when the MOS transistor 5 is in the ON state, and a current flows from the source terminal to the drain terminal. No current flows when the MOS transistor 5 is in the OFF state.

  In this way, the high frequency input to the input terminal 1 is rectified by the MOS transistor 5.

  The waveform rectified by the MOS transistor 5 includes a direct current component, a high frequency component input thereto, and a harmonic component thereof. Among these, the low-pass filter 7 passes only the DC component and supplies it to the output terminal 10 and the load resistor 16.

  In the configuration of FIG. 3, even when the high-frequency power input from the input terminal 1 is small, the high-frequency voltage is boosted by the transformer 12, so that by applying this voltage to the gate terminal of the MOS transistor 5, The MOS transistor 5 performs a switching operation and a rectifying operation occurs. Therefore, even when the high frequency input power is low, there is an advantage that the conversion efficiency from the high frequency power to the DC power is increased.

  Moreover, since the high frequency input to the input terminal 1 is distributed by the power distributor 11 to obtain a periodic voltage, there is an advantage that a periodic voltage having the same frequency synchronized with the input high frequency can be easily created.

  Therefore, with the configuration shown in FIG. 3, rectification operation can be performed with high rectification efficiency in a wide input power range without using the signal source 6.

  There is a phase difference between the two outputs of the power distributor 11 or a phase change caused by passing through the transformer 12, and the voltage applied to the drain terminal and the gate terminal of the MOS transistor 5 is 0 degrees or 180 degrees. When a phase shift other than the above occurs, the current flows from the drain terminal to the source terminal for a part of the time when the MOS transistor 5 is turned on, but the current flows from the source terminal to the drain terminal for the remaining time. Become. For this reason, the value of the direct current component smoothed by the direct current pass filter 7 and supplied to the load resistor 16 is lowered, and the rectification efficiency is deteriorated.

  Therefore, as shown in FIG. 3, a phase shifter 13 is inserted between the transformer 12 and the drain terminal of the MOS transistor 5, and the phase of the high frequency is shifted by the phase shifter 13 so that the drain terminal of the MOS transistor 5 By making the periodic voltage applied to the gate terminal in phase or in reverse phase, current always flows from the drain terminal to the source terminal or from the source terminal to the drain terminal while the MOS transistor 5 is in the ON state. be able to. Therefore, deterioration of rectification efficiency can be suppressed, and a rectification circuit with higher conversion efficiency can be obtained.

  The transformer 12 can be composed of various circuits such as a transformer using a coil. In FIG. 3, the voltage is boosted using the transformer 12, but may be boosted using an amplifier or the like instead.

  In FIG. 3, the power distributor 11 is inserted between the band pass filter 2 and the connection point A, but the power distributor 11 may be inserted between the input terminal 1 and the band pass filter 2. Good.

  Further, in FIG. 3, the phase shifter 13 is connected between the transformer 12 and the gate terminal of the MOS transistor 5, but it is connected between the power distributor 11 and the connection point A in the figure as shown in FIG. Alternatively, as shown in FIG. 5, it may be connected between the connection point A in the drawing and the drain terminal of the MOS transistor 5. Further, the phase shifter 13 can be connected between the distributor 11 and the transformer 12, and in either case, the phase difference between the high frequency applied to the drain terminal and the periodic voltage applied to the gate terminal is adjusted. Therefore, the effect of this embodiment can be obtained.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing a rectifier circuit according to Embodiment 3 of the present invention. In FIG. 6, the same reference numerals as those in FIGS. Reference numeral 14 denotes a DC power source as DC voltage application means, and 15 denotes a capacitor. The DC power supply 14 applies a predetermined voltage to the gate terminal of the MOS transistor 5. The capacitor 15 is DC cut so that the voltage of the DC power supply 14 is not applied to the phase shifter 13.

Next, the operation will be described.
The predetermined voltage supplied from the DC power supply 14 is a value close to the threshold voltage of the gate terminal of the MOS transistor 5. For this reason, by using the DC power supply 14 and the capacitor 15, a voltage close to the threshold voltage is always applied to the gate terminal of the MOS transistor 5. Therefore, the high-frequency periodic voltage applied from the input terminal 1 to the gate terminal via the band-pass filter 2, the power distributor 11, the transformer 12, and the phase shifter 13 is superimposed on the voltage supplied from the DC power supply 14. Applied to the gate terminal. Therefore, the ON voltage of the MOS transistor 5 is equivalent to a value close to 0 V for a high-frequency periodic voltage. Therefore, even if the high-frequency power boosted by the transformer 12 is small, the voltage at the gate terminal can be easily swung up and down the threshold voltage, and the MOS transistor 5 can be switched in an almost ideal state. It becomes possible.

  Therefore, even if the power distribution ratio of the power distributor 11 is changed to reduce the power output to the transformer 12 and increase the power output to the MOS transistor 5, the rectification operation can be performed. As a result, the high frequency power output from the power distributor 11 to the drain terminal of the MOS transistor 5 that is power directly related to the rectification efficiency can be increased, so that the rectification efficiency can be further increased.

  The voltage applied by the DC power supply 14 may be configured to supply a part of the threshold voltage to the gate terminal of the MOS transistor 5, or may be configured to supply a higher (lower) voltage that exceeds the threshold voltage. . Even in this case, the ON voltage of the MOS transistor 5 can be equivalent to a value having an absolute value lower than the original threshold voltage with respect to the high-frequency periodic voltage. Therefore, the rectification efficiency of the rectifier circuit can be increased similarly.

  Further, in the present embodiment, a configuration is shown in which a part of the high frequency input using the power distributor 11 is branched and applied to the gate terminal as a periodic voltage. However, the present invention is not limited to this, as in the first embodiment. A periodic voltage to be applied to the gate terminal may be generated by providing a signal source 6 for the gate terminal.

1 input terminal, 2 band pass filter, 3 inductor, 4 capacitor, 5 N channel MOS transistor, 6 signal source, 7 low pass filter, 8 inductor, 9 capacitor, 10 output terminal, 11 power divider, 12 transformer, 13 phase shifter, 14 DC power supply, 15 capacitor, 16 load resistance

Claims (9)

A first filter that allows the input high frequency to pass therethrough and blocks direct current and harmonics of the high frequency ;
A transistor having a first terminal to which a periodic voltage having the same frequency as the high frequency is applied, a second terminal connected to the first filter, and a third terminal grounded, which rectifies the high frequency When,
A second filter connected to a connection point between the first filter and the second terminal, blocking the high frequency, and outputting a direct current rectified by the transistor;
A rectifier circuit comprising:   The rectifier circuit according to claim 1, wherein the first terminal is a gate terminal or a base terminal of the transistor.   3. The rectifier circuit according to claim 1, wherein the first filter is a band-pass filter that cuts off a high-frequency harmonic component. 4. It said second filter rectifier circuit as claimed in any one of claims 3, characterized in that the low-pass filter. Rectifier circuit as claimed in any one of claims 4, characterized in that it comprises a direct current voltage applying means for applying a DC voltage to the first terminal. Distributing means for distributing the input high frequency to a first high frequency and a second high frequency, and outputting the first high frequency to the second terminal;
Boosting means for boosting the second high frequency voltage distributed by the distributing means,
Rectifier circuit as claimed in any one of claims 5, characterized in that for applying the second high-frequency boosted by said boosting means, to said first terminal as said periodic voltage.   7. The rectifier circuit according to claim 6, further comprising a phase shift unit configured to change a phase of either the first high frequency or the second high frequency distributed by the distribution unit. Rectifier circuit as claimed in any one of claims 5, characterized in that it comprises a signal source for generating the periodic voltage. The periodic voltage to said high frequency to be applied to the second terminal, claim 1, characterized in that it is synchronized to the same phase or reverse phase according to any one of claims 8 Rectifier circuit.

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