TW201010257A - Circuit for driving a direct current load - Google Patents

Abstract

A circuit for driving a direct current (DC) load is provided. The circuit includes a coil and an alternating current to direct current (AC-DC) converter. The coil forms an inductance. A first terminal of the coil receives an alternating current (AC). The coil limits a maximum current of the AC. The AC-DC converter is coupled between a second terminal of the coil and the DC load, and converters the AC to a DC to drive the DC load.

Description

201010257 f 28843twf.doc/e IX. Description of the Invention: TECHNICAL FIELD The present invention relates to a driving circuit, and more particularly to a driving circuit for driving a DC load. [Prior Art] A Light Emitting Diode (LED) is a semiconductor component. It is often used as an indicator light, a display panel, etc. at the beginning; it is also used as illumination with the appearance of a white light emitting diode. Until today, LEDs have become ubiquitous in people's living environment. It is worth mentioning that the impedance of the LED will vary with the ambient temperature. In general, the circuit generates heat when it is in operation, which in turn causes an increase in the ambient/BZL degree. When the ambient temperature rises, the impedance decreases, so the fine (iv) current also rises. The current through the LEDs and thus the LEDs is damaged. Conventional techniques (4) often use a combination of other components that are fabricated by semiconductor fabrication to limit the current through the LEDs. The pulse-width modulation controller

(Pulse Width Modulation Controller, referred to as PWM

Controller) is composed of components such as a plurality of transistors. ... Although the LED has a long life, the current limit (9) and the peripheral components are affected by the high temperature and the test is changed. #Limited chip or peripheral 2 pieces of damage, ?, LED is not bright due to no power supply or damaged due to excessive current blL. SUMMARY OF THE INVENTION The present invention provides a driving circuit that uses a coil to form an inductor, thereby limiting the maximum current of the alternating current by 5 201010257 28843 twf.doc/e, and converting the alternating current into a direct current by means of an alternating current to direct current circuit. Load, therefore, can reduce the cost of tilting electricity, and can also extend the life of the drive circuit. The ^ month sends a kind of drive circuit, suitable for driving DC = Γ = AC to DC circuit. The coil forms an inductance. The k current can limit the maximum current of the alternating current, and the second end of the alternating current f coil and the direct current is converted to direct current to drive the DC load. The decelerating circuit = the second middle 'driver circuit is more packet-domain circuit. _Filter, wave between, can be straight or organic light two 4 ^, in the DC load is the light-emitting diode drive == point of view. The present invention provides a drive circuit, suitable for ^ load. The driving circuit includes an nr circuit of a first core, a second core, and a second core, and a second inductor. The first region of the first coil forms a second sense of the first coil and is wound around the second end of the second core. In addition, the first end of the second coil of the crucible 4 is coupled to the first electric current of the first coil. The cross-coupling coil limits the maximum load of the alternating current to the second end of the second coil and the DC-DC load. The resistor 2 converts the parent current into a direct current, so as to drive the second end of the carrier and the 43: end and the second end are connected to the DC negative voltage. The second coil is wound around the second core of the first core. 201010257 28843twf. The doc/e area forms a third inductance. The first end of the third coil may be coupled to the first end of the resistor unit. The fourth coil is wound around the second region of the second core to form a fourth inductance. The first end and the second end of the fourth coil are respectively coupled to the second end of the third coil and the second end of the resistor unit. In an embodiment of the invention, the drive circuit further includes a subtractor. The subtractor is coupled to the first end of the resistance unit, the second end, the first end of the third coil, and the second end of the Q-coil to receive a preset first cross-over voltage and a second cross-pressure between the electric And according to the second end of the first-span. - 7 is pressed to the first end of the second coil and the fourth line = hair = - in the embodiment, the first - iron core is along the first time. The second end and the third coil: the mth through the first coil of the first coil in the clockwise direction, first. The second core is along the fourth line, the first end, the =: the first and second ends of the first coil and the first: the first end of the middle iron first coil to the second end to the second creep is the second winding end To the 坌? M counterclockwise wrapped around the 筮 _ ▼ 咏 的 的 的 的 的 的 弟 弟 弟 一端 一端 一端 一端 一端 一端 一端 一端 一端 一端 一端 一端 一端In the other - real d::: tangled two = circle: the first end to the first sand π k X counterclockwise square south key a U ^ the first wave of the second coil = the second to the second to the other In the second to the second direction of the second core = the direction of the winding, the winding direction of the second line is counterclockwise. Second, second:=: 7 201010257 V 28843twf.doc/e The hour hand is wound around the second core. In an embodiment of the invention, the first coil and the second coil have the same specifications. The third coil and the fourth coil have the same specifications. The first core has the same specifications as the second core. In another embodiment, when the first coil and the second coil are energized, the third coil induces a first voltage to cancel the second voltage induced by the fourth coil. In still another embodiment, the first core may induce a first magnetic flux when the third coil is energized, thereby changing the impedance of the first coil. When the fourth coil is energized, the second core can induce a second flux amount, thereby changing the impedance of the second coil. From another point of view, the present invention provides a drive circuit suitable for driving a DC load. The driving circuit comprises a first core, a second core, a fourth to fourth coil, an alternating current to direct current circuit, a first resistance unit and a second resistance unit. The first coil is wound around the first region of the first core to form a first inductance. The first end of the first coil can receive an alternating current. The second coil is wound around the first region of the second core to form a second inductance. The first end of the second coil is coupled to the second end of the first coil. The second coil can cooperate with the first coil to limit the maximum amount of current flowing. The AC-DC circuit is coupled between the second end of the second coil and the first end of the DC load to convert the AC power to DC power to drive the DC load. The first end of the first resistor unit is coupled to the first end of the DC load. The first end of the second resistor unit is coupled to the second end of the first resistor unit. The second end of the second resistor unit is coupled to the second end of the DC load and the reference voltage. The third coil is wound around the second region of the first core to form a third inductance. The first end of the third coil is coupled to the first end of the second resistor unit. The fourth coil is wound around the second region of the second core to form a fourth inductance. 8 201010257 28843twf.doc/e The first end and the second end of the fourth coil are respectively coupled to the second end of the third coil and the second end of the second resistor unit.

In an embodiment of the invention, the drive circuit further includes a subtractor. The subtractor is coupled to the first end of the second resistance unit, the second end, the first end of the third coil, and the second end of the fourth coil, and can receive the preset first voltage across the first resistor and the second resistor unit a second cross-pressure between the end and the second end, and providing a third cross-pressure between the first end of the third coil and the second end of the fourth coil according to the first cross-pressure and the second cross-pressure. Since the drive circuit of the present invention forms an inductance by using a coil, it is possible to limit the maximum amount of current of the alternating current. In addition, the AC to DC circuit is used to convert the AC power to DC power to drive the DC load. In this way, not only can the DC load be effectively driven, but also the DC load can be protected, the cost of the drive circuit can be saved, and the life of the drive circuit can be extended. The above described features and advantages of the present invention will be more apparent from the following description. [Embodiment]

- The conventional limited chip and its peripheral components are not only costly but also damaged by the influence of the valley. In view of this, the driving circuit of the present invention is used to form the inductance 'and the coil to limit the maximum amount of alternating current. So - to '* but can be modified to limit the chip hardware 2 and the coil is a passive component is not easy to damage, so it can extend the drive. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 』^号 28843twf.doc/e

Referring to 201010257, FIG. 1 is a schematic diagram showing a driving circuit of a first embodiment of the present invention. Referring to FIG. 1', in the present embodiment, the driving circuit 10 includes a coil 20 and a parental flow m path 3A.秘 Secret AC power and AC to direct «· Circuit 30 between the parent flow DC circuit 3Q face between the coil and the straight load 50. In the above, the drive circuit 10 can be used to drive the DC load 50. The DC load 5G of the present embodiment is described by taking two light-emitting diodes 51 as an example, but the invention is not limited thereto. In other solid wipes, the direct current load of 50 VDC for various surfaces may be, for example, an organic light-emitting diode. Biting Figure 2 is a schematic diagram showing the voltage wave of the circuit shown in Figure 1. ; and with reference to Figs. 1 and 2, in the embodiment of the invention, the coil 20 can form a maximum amount of current that can be used for _ alternating current. More specifically, when ϊn passes through the coil 2', as the inductance value of the coil 2 turns, the larger the value of the NVC 61 = and the larger the resistance is, the smaller the AC power is reduced when it passes through the coil 20. Therefore, the present embodiment utilizes a coil 20-stage AC and 瑕t flow. The advantage of this is that the coil 2 is a passive element = ^ which has the characteristics of high temperature resistance and non-damage. Further, since the coil and the cost are low, the hardware of the drive circuit W can be effectively reduced, and the present invention is not limited to (10). In Wei Shibu, the AC circuit 3G can also be implemented by various types of circuits, for example, P "bridge rectifier circuit. In addition, the chopper power 28843twf.doc/e 201010257^ in this embodiment The capacitor is taken as an example for description. However, in other embodiments, other types of filter circuits may be used according to the needs of those skilled in the art, or may be directly output without using a filter circuit. According to the above, the coil 20 can receive AC power. The AC VAC with limited current is supplied to the AC to DC circuit 3. Then, the AC to DC circuit 30 converts the AC VAC into DC power and provides it to the filter circuit 40. The filter circuit 40 can generate DC power according to the DC power Vdci*. VdC2. It can be clearly seen from Fig. 2 that the AC-DC circuit 3〇 can convert the negative voltage into a positive voltage, and the wave circuit 4〇 can make the voltage fluctuations gradual. Thus, the DC load 50 can be compared. Stable DC power V〇C2 〇 It is worth mentioning that the drive circuit 10 not only has a relatively low hardware cost, but also has a coil 20 that is resistant to high temperatures and is not easily damaged. Therefore, even if the driving circuit 10 is applied in a south temperature environment, for example, in the sun, the coil 20 is not easily damaged, so that the DC load can be effectively protected 5 〇, and excessive current can be prevented from flowing through the DC load 50 to damage the DC load. Φ Although a possible type of driving circuit has been drawn in the above embodiments, those skilled in the art should know that each manufacturer has different design for the driving circuit. Therefore, the application of the present invention is not limited. In this possible type, in other words, 'as long as the drive circuit uses the coil to form the inductance' to limit the maximum current of the alternating current. In addition, the AC to DC circuit is used to convert the alternating current into direct current, thereby driving the DC load. The spirit of the present invention is as follows. Several embodiments will be exemplified below so that those skilled in the art can further develop the spirit of the present invention and implement the present invention. Figure 1. The drive circuit of the first embodiment is just an alternative embodiment. A technical person skilled in the art can change the architecture of the driving circuit according to his needs. For example, FIG. 3 is a schematic diagram showing a driving circuit of a second embodiment of the present invention. Referring to FIG. 3, in the embodiment, the driving circuit may include a coil 21. 〜24, AC to DC circuit 3〇, filter circuit 4〇, resistor unit 60, cores 71, 72 and subtractor 8 (this embodiment is similar to the first embodiment, _ 21, 22 _ has AC power I The function of the maximum current amount. It is worth noting that the present embodiment uses the resistor unit 60: the subtractor 80, the coils 23, 24 and the core 7 72 to form a wide: 21, 22 equivalent impedance, and then adjust the straight tank = say: In this way, the DC load can be further protected by the following. In the present embodiment, the cores of the same core are used in the cores 71 and 72, and the coils 23 and 2 are green. More specifically, the cores 71, 72 can be iron cores of the second phase. The coils 21 and 22 may be made of the same material, the soil material, and the coil of the same size. The coils 23, 24 have the same number of coils and the same thickness of the coil. (4) The number of materials, the same number of coils, and the above-mentioned coils 21 and 23 are respectively entangled to form inductors. _ 22, 71 of its - region, region, can be divided into _ face. More specifically, the coils 21 and 22 are simmered in the counterclockwise direction of the iron 12 28843 twf.doc/e 201010257. The coils 23 and 24 are clockwise 7 and 72. In the present embodiment, the coil 21 is followed by a boring tool, and the following is the case of the ferrules of the circumstance of the circumstance of the circumstance of the circumstance of the circumstance.屮 The same voltage. It is worth noting that the 'coils 23, 24 are connected by reverse string =, so when the alternating current vAG flows through _ 21, 22, _ 23,

The voltages induced by 24 will cancel each other out. Thus, when the AC Vac flows through the coils 21, 22, it does not affect the coils 23, 24. On the other hand, the resistor unit 6 of the present embodiment can be constituted, for example, by a series resistor. The resistor unit 60 can be thought of as a current sensor (Currem Sens〇r) that senses the current flowing through the DC load 50. Since the resistance value of the resistor unit 6 is a fixed value, the larger the current flowing through the DC load 5 ,, the higher the voltage across the resistor unit 60 vs. Conversely, as the current flowing through the DC load 50 is smaller, the voltage across the resistor unit 60 will also decrease. The advantage of using the resistance unit 60 to sense the current flowing through the DC load 50 is that the 'resistance unit 60 is not easily damaged, so that a highly reliable cross-over voltage VS] can be provided [to the subtractor 80. The subtractor 80 can receive the voltage across the voltage VF1 and the voltage across the voltage VS1, and accordingly provides a voltage across the voltage V01 to the coils 23, 24, wherein the voltage across the voltage V01 = the voltage across the voltage VFr is VS1, and the voltage across the voltage Vfi is constant. That is to say, as the cross-pressure VS1 is larger, the cross-pressure V〇i will decrease. Conversely, as the crossover pressure VS1 is smaller, the crossover voltage V01 will rise. When the voltage across the voltage V〇i rises, the cores 71, 72 respectively induce a reverse magnetic flux. It is worth noting that the magnetic flux of the cores 71, 72 will respectively affect the equivalent impedance of the coil 21 23 . For example, suppose that when the alternating current is conducting, the coils 21 and 22 respectively generate the magnetic flux t weeks of the core 7 W2 = when the coils 23, 24 receive the cross-over, the core ", respectively, the magnetic fluxes d3, d4. Since the magnetic flux d^ Di is the same direction, so the ί ίi week guide, the magnetic flux d3 will increase the magnetic flux dl', the impedance of the coil 21 will decrease. When the magnetic flux of the core 71 reaches the full state, the impedance of the '21 will approach zero. Saturated

Further, since the magnetic flux mountain is reversed from 4, when the alternating current is half-passed, the magnetic flux d4 is resistant to the magnetic flux 4, so the impedance of the coil 22 rises. When the positive galvanic positive half cycle is turned on, the impedance of the coil 21 drops and the impedance of the coil 22 rises. However, the overall impedance portion of the coil 2b 22 is lowered. Similarly, when the negative half cycle of the alternating current is turned on, the impedance of the coil U rises, and the impedance of the coil 22 decreases. However, the overall impedance of the coils 21, 22 is reduced. e In the above case, when the voltage across the voltage V01 rises, the overall impedance of the coils 21, 22 decreases. At this age, as the voltage across the voltage VQ1 drops, the overall impedance of the coils 21, 22 rises. Based on the above negative feedback control mechanism, when the power flowing through the DC load is too large, the voltage Vsi will rise and the voltage across the voltage ν〇ι will decrease, and the overall impedance of the coils 22 22 will rise. The current through the DC load of 5 下降 drops. On the other hand, when the current flowing through the DC load 5 过 is too small, the voltage across the Vsi decreases, and the voltage across the pressure 乂 (1) rises, and the overall impedance of the coils 21 and 22 decreases, thereby increasing the current flowing through the DC load 50. Therefore, this embodiment can not only limit the maximum current of the alternating current VAC: by the coils 21, 22, but also maintain the current flowing through the direct current load 50 in a safe range through the negative feedback control mechanism. Extend the life of the DC load 50. It is worth mentioning that in the present embodiment, the iron cores 71 and 72 are made of the same size of the core. The coils 2 and 22 are coils of the same specification, and the coils 23 and 24 are also coils of the same specification, but they are only An alternative embodiment of the invention. In other embodiments, those skilled in the art can modify the specifications of the various components in accordance with the spirit of the present invention and in accordance with their needs. Referring again to FIG. 3', the second embodiment utilizes a resistor unit 60 to sense the current flowing through the DC load 50, thereby implementing a negative feedback control mechanism. In fact, the second embodiment is merely an optional embodiment of the present invention. Those skilled in the art may also adopt other embodiments to implement the negative feedback control mechanism according to their needs. For example, Fig. 4 is a schematic view showing a driving circuit of a third embodiment of the present invention. Please refer to FIG. 3 and FIG. 4 together. This embodiment is similar to the second embodiment. In a nutshell, the second embodiment is different from the second embodiment in that the second embodiment uses the resistance unit 60 to sense the current flowing through the DC negative 5 ;; in this embodiment, the resistor units 61 and 62 are used. The voltage across the DC load 50 is sensed. That is to say, the resistor unit 61 can be regarded as a voltage sensor. - Since the resistance values of the resistor units 61, 62 are all constant values. Based on the partial pressure, the resistance unit 6 can provide a voltage across the voltage, and Vs2 to the subtractor 8 〇. Alternatively, the subtractor 80 may be based on the cross-over voltage Vf2 and the cross-pressure v across the v-coils 23, 24', wherein the cross-over voltage v 〇 2, the pressure & cross-pressure ~, and ^ VFZ is a constant value. In this way, a negative feedback control mechanism can also be implemented, and up to 15 28843 twf.doc/e 201010257 Αί is similar to the above embodiment. Referring to FIG. 3 again, in the second embodiment, in the X direction, the coils 21 and 22 are respectively wound around the core in the counter-clockwise direction, and the coils 23 and 24 are wound around the core in the clockwise direction. 71, 72, but it is merely an embodiment of the invention. In other embodiments, those skilled in the art can employ different winding methods depending on their needs. For example, Fig. 5 is a schematic view showing a driving circuit of a fourth embodiment of the present invention. Referring to Fig. 3 and Fig. 5 in combination, this embodiment is similar to the second embodiment. In short, the present embodiment is different from the second embodiment in that the coils 21, 22 of the present embodiment are wound in the clockwise direction around the cores 71, 72, respectively, in the X direction, and the coils 23, 24 are respectively It is wound around the cores 71 and 72 in a counterclockwise direction. This also achieves similar effects to the second embodiment. Similarly, those skilled in the art can also change the winding manner of each coil in the third embodiment according to the needs thereof. In summary, the driving circuit of the present invention utilizes a coil to form an inductor to limit the maximum amount of current of the alternating current. In addition, the AC to DC line is used to convert the AC power to DC power to drive the DC load. Therefore, it is not necessary to improve the cost of the conventional current limiting chip and the peripheral component hardware, and the coil is a passive component that is not easily damaged, thereby prolonging the life of the driving circuit. In addition, the embodiments of the present invention have at least the following advantages: The I filter circuit can make the fluctuation of the voltage tend to be gentle. In this way, the DC load can obtain a relatively stable DC power. 2 Through the feedback control mechanism, the current flowing through the DC load can be kept within the safe range to avoid damage to the DC load. 28843twf.doc/e 201010257 ΥΥ 3. Using a resistor unit to implement a current sensor or voltage sensor not only saves cost, but the resistor unit is not easily damaged, providing reliable detection data for use in the back-end circuit. The present invention has been disclosed in several embodiments, and is not intended to limit the scope of the present invention. Any one of ordinary skill in the art can make a few changes and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a drive circuit of a first embodiment of the present invention. Fig. 2 is a schematic view showing a voltage waveform of the driving circuit shown in Fig. i. Fig. 3 is a schematic view showing a drive circuit of a second embodiment of the present invention. Fig. 4 is a schematic view showing a drive circuit of a third embodiment of the present invention. 5 is a schematic view showing a driving circuit of the fourth embodiment of the present invention. [Main component symbol description] 10: Driving circuit 20 to 24: Coil 30: AC to DC circuit 17 201010257 28843twf.doc/e 40 ··Filter circuit 50: DC load 51: Light-emitting diode 60~62: Resistor unit 7 Bu 72: Core 80: Subtracter 屯 ~ (14: Magnetic flux VAC: AC

VdCI, VdC2: DC

Vsi, Vs2, Vfi, Vf2, V〇i, V〇2. Cross-pressure X: direction

18

Claims (1)

201010257 28843twf.doc/e X. Patent application scope: 1. A circuit suitable for driving a DC load, the circuit comprising: a coil forming an inductor having a first end and a second end, the first of the coil Receiving an alternating current, the coil limiting the maximum current of the alternating current; and an alternating current to direct current circuit coupled between the second end of the coil and the direct current load, converting the alternating current into a direct current to drive the direct current load. 2. The circuit of claim 1, wherein the circuit further comprises: a filter circuit coupled between the AC-DC circuit and the DC load to filter the DC power. 3. A circuit for driving a DC load, the circuit comprising: a first core; a second core; a first coil wound around the first region of the first core to form a first inductor a first end and a second end, the first end of the first coil receives an alternating current; a second coil is wound around the first region of the second core to form a second inductor having a first end and a first end a second end, the first end of the second coil is coupled to the second end of the first coil, the second coil is coupled to the first coil to limit the maximum current of the alternating current; an alternating current to DC circuit coupled to the first Between the second end of the second coil and the first end of the DC load, the alternating current is converted into a constant current, and the DC load is driven by 19 ry 28843 tw/doc/e 201010257; The second end is connected to the first end of the DC load and a reference voltage, and the first electric coil is wound around the second region of the first core, forming a - and a second end, the third coil The first end is lightly connected to the first end of the resistor; And Lu fourth: winding in the second region of the second core, forming - ί4 = the first end and the second end, the fourth line _ the first end and the third line _ second end and the resistor The second and second parts of the unit are as claimed in claim 3, and further include: a subtractor's first end, a second end, the second end, the first end, and the fourth coil The second end receives a preset: ^ cross-voltage and an ith in-th cross-pressure between the first end and the second end of the resistive unit and the second cross-pressure providing - the third cross-pressure 'two One end is between the second end of the fourth coil. Heart and ring ^ heart along a first circuit 'where the first-iron two ends and the third coil S pass, the first end of the first coil, the second clockwise oblique direction sequentially; the end 'the second a core along a first end of the fourth coil, a first end of the second coil, and a second end, and the circuit of claim 4, wherein the first 20 28843 twf.doc/e 201010257 _____- . v第,, :铁二的第一端的第一端至第一====二Ξ:: The first to second ends of the coil are reversed. 8. The circuit of claim 5, Wherein the first coil=the first end to the second end are wound in the counterclockwise direction to the material_4 heart The first end to the second end of the second coil are in a counterclockwise direction: a core: the first end to the second end of the third coil are wound in the clockwise direction of the Chuanbei === the first end of the fourth coil to The second end is wound in the clockwise direction on the second core. 9. The circuit of claim 5, wherein a coil and a second coil are of the same size, the third coil is of the same size as the fourth coil, and the first core and the second core are in specifications the same. 10. The circuit of claim 3, wherein when the first coil and the second coil are energized, the third coil induces a voltage of the third coil, thereby canceling and the fourth coil is induced. a second voltage. 11. The circuit of claim 3, wherein when the third coil is energized, the first core induces a first magnetic flux, thereby changing the first line_impedance when the fourth coil is energized. The first: the core induces a second magnetic flux to change the impedance of the second coil. 12. The circuit of claim 3, wherein the electrical connection in A further comprises: ^ - a filter circuit is formed between the AC-DC circuit and the DC load 21 28843 twf.doc/e 201010257 v, The DC power is filtered. 13. A circuit for driving a DC load, the circuit comprising: a first core; a second core; a first coil wound around the first region of the first core to form a first inductor, Having a first end and a second end, the first end of the first coil receives an alternating current; a second coil is wound around the first region of the second core to form a second inductor having a first end The second end of the second coil is coupled to the second end of the first coil, and the second coil is coupled to the first coil to limit the parent current of the parent current, and an AC to DC circuit is coupled. Between the second end of the second coil and the first end of the DC load, converting the alternating current into a direct current to drive the direct current load; a first resistor unit having a first end and a second end, The first end is coupled to the first end of the DC load; Φ a second resistor unit having a first end and a second end, the first end of which is coupled to the second end of the first resistor unit, the second resistor The second end of the unit is coupled to the first part of the DC load And a third coil, wound in the second region of the first core, forming a third inductor having a first end and a second end, the first end of the third coil being coupled to the second a first end of the resistor unit; and a fourth coil wound around the second region of the second core to form a fourth inductor having a first end and a second end, the first end of the fourth coil and 22 201010257 28843 twf, the second end of the oc/e is coupled to the second end of the third coil and the second end of the second resistor unit, respectively. 14. The circuit of claim 13, further comprising: a subtractor coupled to the first end, the second end of the second resistance unit, the first end of the third coil, and the fourth coil Receiving a first voltage across the first voltage and a second voltage between the first end and the second end of the second resistor unit, and providing a first cross voltage according to the first voltage and the second voltage The three spans are pressed between the first end of the third coil and the second end of the fourth coil. The circuit of claim 13, wherein the first core and the second core are annular cores. 16. The circuit of claim 15, wherein the first core sequentially passes through the first end of the first coil, the second end, and the second end of the third coil in a first clockwise direction. The first end, the second core sequentially passes through the first end and the second end of the second coil and the first end and the second end of the fourth coil in a second clockwise direction. 17. The circuit of claim 15, wherein the first end to the second end of the first 10 coil are wound in a clockwise direction to the first core, the first end of the second coil to the first The two ends are wound in the clockwise direction on the second core, and the first end to the second end of the third coil are wound in the counterclockwise direction on the first core, and the first end to the second end of the fourth coil The second core is wound in a counterclockwise direction. 18. The circuit of claim 15, wherein the first end to the second end of the first coil are wound in the counterclockwise direction to the first core, and the first end to the second end of the second coil The second core is wound in a counterclockwise direction at 23 201010257 28843twf.doc/e, and the first end to the second end of the third coil are wound in the clockwise direction on the first core, the fourth coil One end to the second end are wound in the clockwise direction to the second core. 19. The circuit of claim 15, wherein the first coil and the second coil are of the same size, the third coil is of the same size as the fourth coil, the first core and the second core The specifications are the same. 20. The circuit of claim 13 wherein when the first coil and the second coil are energized, the third coil induces a first electrical voltage to offset and the fourth coil A second voltage induced. 21. The circuit of claim 13, wherein the first core induces a first magnetic flux when the third coil is energized, thereby changing an impedance of the first coil, when the fourth coil is energized The second core induces a second magnetic flux to change the impedance of the second coil. 22. The circuit of claim 13, wherein the circuit further comprises: a filter circuit coupled between the AC-DC circuit and the DC load Φ to filter the DC power. twenty four