Self-powered voltage sampling circuit

Abstract

A self-powered voltage sampling circuit, which includes at least a pair of half-wave rectifier circuits. One ends of the two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits are respectively connected to an input power supply, and the other ends of the two half-wave rectifier circuits are respectively connected to a sampling module and a power supply processing module. The power supply processing module is connected to a control unit to supply power to the control unit. The control unit is connected to the sampling module to perform voltage sampling. The current flows of the two half-wave rectifier circuits are opposite to each other, so that half of a cycle in an alternating current cycle of the input power supply is provided to the sampling module, and the other half of the cycle is provided to the power supply processing module. Through at least a pair of half-wave rectifier circuits with opposite current flows, the input power supply is rectified respectively, so that half of a cycle in at least one alternating current cycle of the input power supply is provided to the sampling module, and the other half of the cycle is provided to the power supply processing module, and there is no need to connect an additional power supply to supply power to the control unit.

Description

Technical Field

[0001] The present invention relates to the field of low-voltage electrical appliances, and particularly to a self-powered voltage sampling circuit. Background Art

[0002] Voltage sampling technology is often applied in fields such as voltage monitoring and voltage protection relay products. The voltage sampling circuit can achieve voltage sampling through a voltage transformer, a sampling resistor, or an optocoupler element. However, when the existing voltage sampling circuit samples the voltage, it still requires an additional power supply, and the voltage sampling circuit cannot supply power to itself. In addition, when using a voltage transformer for voltage sampling, there are also problems of large volume and high cost. When using an optocoupler element for voltage sampling, there are not only problems of poor linearity and temperature drift, but also problems of complex circuit and high cost. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a self-powered voltage sampling circuit with small volume, low cost, and high precision.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A self-powered voltage sampling circuit includes at least a pair of half-wave rectifier circuits. One ends of the two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits are respectively connected to an input power supply, and the other ends of the two half-wave rectifier circuits are respectively connected to a sampling module and a power supply processing module. The power supply processing module is connected to a control unit to supply power to the control unit, and the control unit is connected to the sampling module to perform voltage sampling. The current flow directions of the two half-wave rectifier circuits are opposite, so that half of a cycle in an alternating current cycle of the input power supply is provided to the sampling module, and the other half of the cycle is provided to the power supply processing module.

[0006] Preferably, the power supply processing module includes a power supply reverse circuit, and the output voltage of the power supply reverse circuit is opposite to the input voltage. The half-wave rectifier circuit connected to the power supply processing module supplies power to the control unit through the power supply reverse circuit.

[0007] Preferably, the two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits respectively include diodes, and the polarities of the ends of the two diodes of the two half-wave rectifier circuits connected to the input power supply are different.

[0008] Preferably, it further includes a current-limiting impedance, and the at least a pair of half-wave rectifier circuits are connected to the input power supply through the current-limiting impedance.

[0009] Preferably, it further includes a voltage-dividing resistor, and the half-wave rectifier circuit connected to the sampling module is connected to the current-limiting impedance through the voltage-dividing resistor

[0010] Preferably, the sampling module is resistor R7, the current-limiting impedance is resistor R1, and the effective value of the divided voltage of the sampling module where U D is the voltage drop of the diode of the half-wave rectifier circuit connected to the sampling module, and U L1 is the voltage of the input power supply.

[0011] Preferably, the power supply processing module further includes a zener diode V1. The half-wave rectifier circuit connected to the power supply processing module is connected to the ground terminal through the zener diode V1. The two input terminals of the power reverse circuit are respectively connected in parallel at both ends of the zener diode V1. The output terminal of the power reverse circuit is sequentially connected to the ground terminal through a current-limiting resistor R10 and a zener diode V2, and a voltage VCC for powering the control unit is formed between the current-limiting resistor R10 and the zener diode V2.

[0012] Preferably, it further includes a control circuit. A first power supply voltage is formed between the zener diode V1 and the half-wave rectifier circuit connected to the power supply processing module. A second power supply voltage is formed between the output terminal of the power reverse circuit and the current-limiting resistor R10. One of the first power supply voltage and the second power supply voltage powers the control circuit, and the other powers the power reverse circuit through the power supply processing module.

[0013] Preferably, the power reverse circuit is a charge pump type polarity inversion circuit or a BUCK-BOOST switching power supply polarity inversion circuit.

[0014] Preferably, it includes one or more pairs of half-wave rectifier circuits corresponding to the number of phases of the input power supply.

[0015] The self-powered voltage sampling circuit of the present invention creates a rectification of the input power supply through at least one pair of half-wave rectifier circuits with opposite current flow directions, so that half of the cycle in at least one alternating current cycle of the input power supply is provided to the sampling module, and the other half of the cycle is provided to the power supply processing module. It does not require an additional power supply to power the control unit, and has the characteristics of simple circuit, small volume and cost savings.

[0016] In addition, the diode connected to the power supply processing module powers the control unit through the power reverse circuit. The working voltage provided by the power reverse circuit can have the same polarity as the sampling voltage of the control unit, thereby ensuring the smooth progress of the A / D sampling of the control unit. Description of the Drawings

[0017] Figure 1 is Embodiment 1 of the self-powered voltage sampling circuit of the present invention;

[0018] Figure 2 is Embodiment 2 of the self-powered voltage sampling circuit of the present invention;

[0019] Figure 3 This is the third embodiment of the self-powered voltage sampling circuit of the present invention;

[0020] Figure 4 This is the fourth embodiment of the self-powered voltage sampling circuit of the present invention;

[0021] Figure 5 This is the fifth embodiment of the self-powered voltage sampling circuit of the present invention;

[0022] Figure 6 This is the sixth embodiment of the self-powered voltage sampling circuit of the present invention. Specific embodiments

[0023] As Figure 1 shown, the self-powered voltage sampling circuit of the present invention includes at least a pair of half-wave rectifier circuits. One ends of the two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits are respectively connected to an input power supply, and the other ends of the two half-wave rectifier circuits are respectively connected to a sampling module and a power supply processing module. The power supply processing module is connected to a control unit to supply power to the control unit, and the control unit is connected to the sampling module to perform voltage sampling. The current flow directions of the two half-wave rectifier circuits are opposite, and the input power supply is rectified respectively, so that half of a cycle in an alternating current cycle of the input power supply is provided to the sampling module, and the other half cycle is provided to the power supply processing module. The power supply processing module can supply power to the control unit, and the control unit can perform voltage sampling on the sampling module.

[0024] The self-powered voltage sampling circuit of the present invention rectifies the input power supply respectively through at least a pair of half-wave rectifier circuits with opposite current flow directions, so that half of a cycle in at least one alternating current cycle of the input power supply is provided to the sampling module, and the other half cycle is provided to the power supply processing module, without connecting an additional power supply to supply power to the control unit, and has the characteristics of simple circuit, small volume and cost saving.

[0025] The following Figures 1 to 6 given embodiments are used to further illustrate the specific implementation manners of the self-powered voltage sampling circuit of the present invention. The self-powered voltage sampling circuit of the present invention is not limited to the descriptions of the following embodiments.

[0026] As Figure 1As shown, the self-powered voltage sampling circuit of the present invention includes at least a pair of half-wave rectifier circuits. One end of the two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits is respectively connected to the input power supply, and the other ends of the two half-wave rectifier circuits are respectively connected to the sampling module and the power supply processing module. The power supply processing module is connected to the control unit to supply power to the control unit. The control unit is connected to the sampling module to perform voltage sampling. The current flows of the two half-wave rectifier circuits are opposite. The two half-wave rectifier circuits respectively rectify the positive half-wave and the negative half-wave of the alternating current of the input power supply, so that half of a cycle in an alternating current cycle of the input power supply is provided to the sampling module, and the other half of the cycle is provided to the power supply processing module. The power supply processing module can supply power to the control unit, and the control unit can perform voltage sampling on the sampling module.

[0027] As Figure 1 Shown in Embodiment 1, the self-powered voltage sampling circuit includes one or more pairs of half-wave rectifier circuits corresponding to the number of phases of the input power supply. The input power supply in this embodiment is a three-phase alternating current power supply composed of L1 phase, L2 phase and L3 phase. The self-powered voltage sampling circuit includes three pairs of half-wave rectifier circuits, and the number of pairs of the half-wave rectifier circuits corresponds one by one to L1 phase, L2 phase and L3 phase. Each of the two half-wave rectifier circuits of the pair of half-wave rectifier circuits includes a diode. In this embodiment, the pair of half-wave rectifier circuits is a pair of diodes, that is, each half-wave rectifier circuit is respectively composed of a diode. The polarities of the ends of the two diodes of each pair of half-wave rectifier circuits connected to the input power supply are different. Through the diode for half-wave rectification, one diode rectifies the positive half-wave of the alternating current, and the other diode rectifies the negative half-wave of the alternating current. The current flows of the two half-wave rectifier circuits are different.

[0028] The self-powered voltage sampling circuit further includes current-limiting impedances corresponding one by one to L1 phase, L2 phase and L3 phase. The at least a pair of half-wave rectifier circuits are connected to the corresponding phases of the input power supply through the current-limiting impedances. The self-powered voltage sampling circuit further includes voltage-dividing resistors arranged corresponding to the at least a pair of half-wave rectifier circuits. The half-wave rectifier circuit connected to the sampling module is connected to the corresponding current-limiting impedance through the voltage-dividing resistor. The voltage-dividing resistor can make the sampling voltage lower than the control unit power supply voltage, so that the voltages VDD and VCC are greater than the peak voltages on resistors R7, R8 and R9, ensuring that the single-chip microcomputer MCU can perform A / D sampling within the range.

[0029] Now, taking phase L1 as an example for illustration, the sampling module is resistor R7, the current-limiting impedance is resistor R1, the voltage-dividing resistor is resistor R4, and the pair of diodes corresponding to L1 are diode D1 and diode D4 respectively. After the cathode of diode D4 is connected to the anode of diode D1 through resistor R4, it is then connected to the corresponding L1 phase through resistor R1. The cathode of diode D1 is connected to the power supply processing module, and the anode of diode D4 is connected to the ground terminal through resistor R7 serving as the sampling module. The sampling input terminal of the control unit is connected between the anode of diode D4 and resistor R7. The control unit performs voltage sampling based on the effective value of the voltage division of resistor R7, and the effective value of the voltage division of resistor R7 is V L1 :

[0030]

[0031] Among them, U L1 is the voltage of phase L1, and U D is the voltage drop of diode D4. It can be understood that the voltage-dividing resistor may not be set. For example, Figure 6 shown in Embodiment 1, that is, resistor R4 is not set, R4 = 0, which also belongs to the protection scope of the present invention. At this time, Equation (1) is changed to:

[0032]

[0033] The principles of the other two phases are the same as that of phase L1:

[0034] The pair of diodes corresponding to L2 are diode D2 and diode D5 respectively. After the cathode of diode D5 is connected to the anode of diode D2 through resistor R5, it is then connected to the corresponding L1 phase through resistor R2. The cathode of diode D2 is connected to the power supply processing module, and the anode of diode D5 is connected to the ground terminal through resistor R8 serving as the sampling module. The sampling input terminal of the control unit is connected between the anode of diode D5 and resistor R8. The control unit performs half-wave sampling based on the effective value of the voltage division of resistor R8. The calculation formula for the effective value of the voltage division of resistor R8 is the same as Equation (1). Resistor R5 may not be set, that is, R5 is deleted from the formula, U L1 is changed to the voltage corresponding to phase L2, and U D is changed to the voltage drop of diode D5. The resistance values of resistor R1, resistor R4, and resistor R7 are respectively changed to the resistance values of resistor R2, resistor R5, and resistor R8.

[0035] The pair of diodes correspondingly arranged with L3 are diode D3 and diode D6 respectively. After the cathode of diode D6 is connected to the anode of diode D3 through resistor R6, it is then connected to the corresponding L1 through resistor R3. The cathode of diode D3 is connected to the power supply processing module. The anode of diode D6 is connected to the ground terminal through resistor R9 serving as the sampling module. The sampling input terminal of the control unit is connected between the anode of diode D6 and resistor R9. The control unit performs half-wave sampling according to the effective value of the voltage division of resistor R9. The calculation formula for the effective value of the voltage division of resistor R9 is the same as formula (1) described above. It is also possible not to set resistor R6, that is, to delete R6 in the formula, U L1 Change it to the voltage corresponding to phase L3, U D Change it to the voltage drop of diode D6. The resistance values of resistor R1, resistor R4, and resistor R7 are respectively changed to the resistance values of resistor R3, resistor R6, and resistor R9. The sizes of resistor R7, resistor R8, and resistor R9 are equal. The sizes of resistor R1, resistor R2, and resistor R3 are equal. The sizes of resistor R4, resistor R5, and resistor R6 are equal.

[0036] In this embodiment, resistor R1, resistor R2, and resistor R3 respectively constitute the current-limiting impedances of each phase, and resistor R4, resistor R5, and resistor R6 constitute the voltage-dividing resistors of each phase. Of course, multiple series-connected resistors can also be used as the current-limiting impedance, or a single or multiple series-connected capacitors can be used as the current-limiting impedance, or a single or multiple series-connected inductors can be used as the current-limiting impedance, all of which fall within the protection scope of the present invention. In addition, the sampling modules of each phase in this embodiment are resistor R7, resistor R8, and resistor R9 respectively, but the sampling module can also use a step-down capacitor instead of a resistor. In addition, the control unit in this embodiment is a single-chip microcomputer MCU, and the control unit can also be other integrated circuits, etc., all of which fall within the protection scope of the present invention.

[0037] The self-powered voltage sampling circuit of the present invention can also be applicable to input power supplies with different numbers of phases, such as single-phase input power supplies and two-phase input power supplies.

[0038] The self-powered voltage sampling circuit of this embodiment converts the electrical energy of half a cycle into a power supply, and the half-cycle voltage is used for sampling, realizing voltage sampling without an additional power supply, simplifying the circuit and saving costs.

[0039] Such as Figure 2 Shown in Embodiment 2, the working principle of this embodiment is basically the same as that of Embodiment 1, but the input power supply of this embodiment is opposite to that of Embodiment 1. The input power supply of Embodiment 1 is forward, and the input power supply of this embodiment is reverse.

[0040] Combined with Figure 1 and Figure 2 Shown, this embodiment will Figure 1In the first embodiment shown, the polarities at both ends of each of the diodes D1, D2, D3, D4, D5, and D6 are reversed. The anode of diode D4 is connected to the corresponding L1, and the cathode is connected to resistor R7 of the sampling module for voltage sampling. The cathode of diode D1 is connected to the corresponding L1, and the anode is connected to the power supply processing module for power supply, and the formula (1) is changed to formula (2):

[0041]

[0042] In formula (2), a minus sign is added to the right side of the equal sign in the above formula (1), and the other parts are the same as formula (1). Of course, resistor R4 can also not be set, that is, R4 = 0. At this time, the above formula (2) is changed to:

[0043]

[0044] As Figure 3 shown in the third embodiment, the working principle of this embodiment is basically the same as that of the first embodiment, but the input power supply of this embodiment is a single-phase input power supply composed of the L phase and the N phase, which is equivalent to removing resistor R2, resistor R5, resistor R8, diode D2, and diode D5 corresponding to the L2 phase in the first embodiment, and resistor R3, resistor R6, resistor R9, diode D3, and diode D6 corresponding to the L3 phase, and then only retaining the components corresponding to L1. Of course, it is also possible to only retain other corresponding components connected to the L phase, and no specific limitation is made here.

[0045] As Figure 4 shown in the fourth embodiment, the working principle of this embodiment is basically the same as that of the third embodiment, but the input power supply of this embodiment is opposite to that of the third embodiment, which is equivalent to the relationship between the second embodiment and the first embodiment. The input power supply of the third embodiment is forward, and the input power supply of this embodiment is reverse.

[0046] It can be understood that the self-powered voltage sampling circuit of the present invention can also be applied to a two-phase input power supply. When the input power supply is two-phase, any corresponding components in the first embodiment can be removed. For example, resistor R2, resistor R5, resistor R8, diode D2, and diode D5 corresponding to the L2 phase can be removed, or the components corresponding to the L1 phase or the L3 phase can also be removed, and no specific limitation is made here. Of course, at this time, the components corresponding to the L3 phase can also be connected to the N phase for a single-phase input power supply, which all belong to the protection scope of the present invention.

[0047] As Figure 1As shown, the power supply processing module includes a power supply reverse circuit. The output voltage of the power supply reverse circuit is opposite to the input voltage. The half-wave rectification circuit connected to the power supply processing module supplies power to the control circuit and the control unit respectively through the power supply reverse circuit. Through the operating voltage provided by the power supply reverse circuit, the polarity can be the same as that of the sampling voltage of the control unit, thereby ensuring the smooth progress of the A / D sampling of the control unit.

[0048] Specifically, the power supply processing module includes a voltage stabilizing diode V1, a capacitor C1, and a power supply reverse circuit. The two input ends of the capacitor C1 and the power supply reverse circuit are respectively connected in parallel across the two ends of the voltage stabilizing diode V1. The diode connected to the power supply processing module is respectively connected to the voltage stabilizing diode V1, and the polarities of the connected ends of the voltage stabilizing diode V1 and the diode connected to the power supply processing module are opposite. A first supply voltage is formed between the voltage stabilizing diode V1 and the half-wave rectification circuit connected to the power supply processing module. A second supply voltage is formed between the output end of the power supply reverse circuit and the current-limiting resistor R10. One of the first supply voltage and the second supply voltage supplies power to the control circuit, and the other supplies power to the power supply reverse circuit composed of a charge pump through the power supply processing module;

[0049] The output end of the power supply reverse circuit is sequentially connected to the ground terminal through the current-limiting resistor R10 and the voltage stabilizing diode V2. A second supply voltage is formed between the output end of the power supply reverse circuit and the current-limiting resistor R10, and a voltage VCC for supplying power to the control unit is formed between the current-limiting resistor R10 and the voltage stabilizing diode V2. A capacitor C2 is connected in parallel across the two ends of the voltage stabilizing diode V2. In this embodiment, the first supply voltage is the voltage VDD, and the voltage VDD supplies power to the control circuit. The second supply voltage is the voltage -VDD, and the voltage -VDD is converted into the output of the control unit after passing through the power supply reverse circuit composed of a charge pump. Refer to Figure 5 In the shown embodiment, the first supply voltage in this embodiment is the voltage -VDD, and the second supply voltage is the voltage VDD. That is, the positions of the voltage VDD and the voltage -VDD are interchanged, but the functions of the voltage VDD and the voltage -VDD remain unchanged. The voltage VDD supplies power to the control circuit, and the voltage -VDD supplies power to the power supply reverse circuit composed of a charge pump. It can be understood that the voltage stabilizing diode V1 and the voltage stabilizing diode V2 in this embodiment can also be other circuit elements with voltage stabilizing functions, and they all belong to the protection scope of the present invention.

[0050] Such as Figure 5Embodiment 5 of the embodiment is shown. The working principle of Embodiment 5 is basically the same as that of Embodiment 1. The control circuit of this embodiment includes a series-connected relay RLY1 and a triode Q1. The base of the triode Q1 is connected to the control unit. Through the cooperation of the control unit and the program, in case of faults such as phase sequence faults, open phase, over-voltage and under-voltage, the control unit can control the conduction and cut-off of the triode Q1, and then drive the relay RLY1 to disconnect the input power supply through the triode Q1, thereby realizing fault protection.

[0051] The power reverse circuit of this embodiment is a charge pump type polarity inversion circuit, which includes a charge pump U1 of model ICL7660. In this embodiment, a capacitor C3, a capacitor C4, a light-emitting diode VD1 and a light-emitting diode VD2 are added on the basis of Embodiment 1. The light-emitting diode VD1 and the light-emitting diode VD2 are respectively connected to the control unit, and indication and alarm can be carried out through the light-emitting diode VD1 and the light-emitting diode VD2. The sixth pin and the eighth pin of the charge pump U1 are used as two input terminals of the charge pump U1 and are connected in parallel at both ends of the zener diode V1. The fifth pin of the charge pump U1 forms a voltage VDD for supplying power to the control circuit, and the fifth pin of the charge pump U1 is respectively connected to one end of the capacitor C4 and one end of the resistor R10. The other end of the capacitor C4 is connected to the ground terminal. The other end of the resistor R10 is sequentially connected to one end of the capacitor C2, one end of the zener diode V2 and the control unit. A voltage VCC for supplying power to the control unit is formed between the zener diode V2 and the resistor R10. The other end of the capacitor C2 and the other end of the zener diode V2 are respectively grounded. The capacitor C3 is connected between the second pin and the fourth pin of the charge pump U1.

[0052] It can be understood that the reverse circuit can also adopt a BUCK - BOOST switching power supply polarity inversion circuit. Of course, the light-emitting diodes VD1 and VD2 can also adopt other quantities, or other alarm devices such as buzzers, which all belong to the protection scope of the present invention.

[0053] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A self-powered voltage sampling circuit, characterized in that: It includes at least a pair of half-wave rectifier circuits. One ends of the two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits are respectively connected to an input power supply, and the other ends of the two half-wave rectifier circuits are respectively connected to a sampling module and a power supply processing module. The power supply processing module is connected to a control unit to supply power to the control unit. The control unit is connected to the sampling module to perform voltage sampling. The current directions of the two half-wave rectifier circuits are opposite, so that half of a cycle in an alternating current cycle of the input power supply is provided to the sampling module, and the other half of the cycle is provided to the power supply processing module.

2. The self-powered voltage sampling circuit according to claim 1, wherein: The power supply processing module includes a power supply reverse circuit. The output voltage of the power supply reverse circuit is opposite to the input voltage. The half-wave rectifier circuit connected to the power supply processing module supplies power to the control unit through the power supply reverse circuit.

3. The self-powered voltage sampling circuit according to claim 1 or 2, characterized in that: The two half-wave rectifier circuits of the at least a pair of half-wave rectifier circuits respectively include diodes, and the polarities of the ends of the two diodes of the two half-wave rectifier circuits connected to the input power supply are different.

4. The self-powered voltage sampling circuit according to claim 3, wherein: It further includes a current-limiting impedance. The at least a pair of half-wave rectifier circuits are connected to the input power supply through the current-limiting impedance.

5. The self-powered voltage sampling circuit according to claim 4, wherein: It further includes a voltage-dividing resistor. The half-wave rectifier circuit connected to the sampling module is connected to the current-limiting impedance through the voltage-dividing resistor.

6. The self-powered voltage sampling circuit according to claim 4, wherein: The sampling module is resistor R7, the current-limiting impedance is resistor R1, and the effective value of the divided voltage of the sampling module where U D is the voltage drop of the diode in the half-wave rectifier circuit connected to the sampling module, and U L1 is the voltage of the input power supply.

7. The self-powered voltage sampling circuit according to claim 2, wherein: The power supply processing module further includes a voltage-stabilizing diode V1. The half-wave rectifier circuit connected to the power supply processing module is connected to the ground terminal through the voltage-stabilizing diode V1. The two input terminals of the power supply reverse circuit are respectively connected in parallel at both ends of the voltage-stabilizing diode V1. The output terminal of the power supply reverse circuit is sequentially connected to the ground terminal through a current-limiting resistor R10 and a voltage-stabilizing diode V2, and a voltage VCC for supplying power to the control unit is formed between the current-limiting resistor R10 and the voltage-stabilizing diode V2.

8. The self-powered voltage sampling circuit according to claim 7, wherein: It further includes a control circuit. A first supply voltage is formed between the voltage-stabilizing diode V1 and the half-wave rectifier circuit connected to the power supply processing module. A second supply voltage is formed between the output terminal of the power supply reverse circuit and the current-limiting resistor R10. One of the first supply voltage and the second supply voltage supplies power to the control circuit, and the other supplies power to the power supply reverse circuit through the power supply processing module.

9. The self-powered voltage sampling circuit according to claim 2, wherein: The power supply reverse circuit is a charge pump type polarity inversion circuit or a BUCK-BOOST switching power supply polarity inversion circuit.

10. The self-powered voltage sampling circuit according to claim 1, wherein: It includes one or more pairs of half-wave rectifier circuits corresponding to the number of phases of the input power supply.

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