RF-DC rectifier

Abstract

The present invention relates to RF energy harvester technology, and more particularly, to an RF-DC rectifier that can be configured with a larger number of rectifier cells while maintaining the input resistance of the RF-DC rectifier at a certain level. According to one embodiment of the present invention, the RF energy harvester can have higher input sensitivity and can thus be used more efficiently in terms of wireless reception power in various wireless sensor networks such as remote monitoring, industrial and home IoT, wearable devices, etc.

Description

RF-DC rectifier

[0001] The present invention relates to an RF-DC rectifier, and more specifically, to an RF-DC rectifier that enables the rectifier to be configured with a larger number of rectifier cells while maintaining the input resistance of the rectifier at a constant level.

[0002]

[0003] With the recent advancements in wireless sensor network technology, RF energy harvesters are attracting significant attention as a key related technology. RF energy harvesters are devices that harvest energy from RF signals, store it, and supply it to a load. Systems utilizing RF energy harvesters have the advantage of eliminating the need for periodic battery replacement or charging, as they harvest energy directly from RF signals. Therefore, RF energy harvesters are expected to be used in various wireless sensor networks, including remote monitoring, industrial and home IoT, and wearable devices.

[0004] Typically, an RF energy harvester consists of an antenna, an impedance matching network, an RF-DC rectifier, a storage capacitor, and a power management circuit. Among them, the RF-DC rectifier plays a crucial role in generating a DC voltage from an RF signal. In order to generate a predetermined DC voltage from a very small RF signal, the RF-DC rectifier must be configured with a large number of rectifier cells while maintaining the input resistance of the RF-DC rectifier at a certain level. If the input resistance of the RF-DC rectifier is reduced, the passive voltage gain of the impedance matching network decreases, which lowers the overall input sensitivity of the RF energy harvester.

[0005]

[0006] The present invention relates to an RF-DC rectifier configured with a larger number of rectifier cells while maintaining the input resistance of the rectifier at a constant level.

[0007] In addition, the present invention relates to an RF-DC rectifier in which the input resistance value of a rectifier cell is increased by positioning a coupling capacitor for receiving an RF signal on a doped region formed within a P-type substrate instead of on a P-type substrate.

[0008] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0009]

[0010] According to one aspect of the present invention, an RF-DC rectifier is provided, which comprises a rectifier cell that receives an RF signal through a coupling capacitor positioned on a doped region formed in a P-type substrate.

[0011] An RF-DC rectifier according to one embodiment of the present invention may include a plurality of rectifier cells, wherein the rectifier cells may include a coupling capacitor for receiving an RF signal, two transistors connected in parallel, and a substrate on which the coupling capacitor and the transistor are located.

[0012]

[0013] According to one embodiment of the present invention, a rectifier cell constituting an RF-DC rectifier increases an input resistance value of the rectifier cell by receiving an RF signal through a coupling capacitor positioned on a doped region formed in a P-type substrate.

[0014] Additionally, according to one embodiment of the present invention, an RF energy harvester including an RF-DC rectifier can configure the RF-DC rectifier with a larger number of rectifier cells while maintaining an input resistance value at a constant level.

[0015] In addition, according to one embodiment of the present invention, an RF energy harvester including an RF-DC rectifier can have a higher input sensitivity, so it can harvest energy from lower RF power and supply it to various wireless sensor nodes such as remote monitoring, industrial and home IoT, and wearable devices.

[0016] The effects of the present invention are not limited to the above-described effects, and should be understood to include all effects that can be inferred from the composition of the invention described in the description or claims of the present invention.

[0017]

[0018] FIG. 1 is a drawing for explaining the structure of an RF energy harvester according to one embodiment of the present invention.

[0019] FIG. 2 is a drawing for explaining the structure of an RF-DC rectifier according to one embodiment of the present invention.

[0020] FIG. 3 is a drawing for explaining the structure of a rectifier cell according to one embodiment of the present invention.

[0021] FIG. 4 is a drawing for explaining the input resistance value of a rectifier cell in an equivalent model of a rectifier cell according to one embodiment of the present invention.

[0022] FIGS. 5 to 13 are drawings for explaining the position of a coupling capacitor of a rectifier cell according to one embodiment of the present invention.

[0023] FIGS. 14 and 15 are drawings for explaining the structure of a rectifier cell according to one embodiment of the present invention.

[0024]

[0025] The present invention is susceptible to various modifications and embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are determined to unnecessarily obscure the gist of the present invention. Furthermore, the terms "a," "an," and "the" used in this specification and claims should generally be construed to mean "one or more," unless otherwise specified.

[0026] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0027] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0029]

[0030] FIG. 1 is a drawing for explaining the structure of an RF energy harvester according to one embodiment of the present invention.

[0031] An RF energy harvester is a device that harvests energy from an RF signal, stores it, and supplies it to a load.

[0032] Referring to FIG. 1, the RF energy harvester includes an antenna (10), an impedance matching network (20), an RF-DC rectifier (30), a storage capacitor (40), and a power management circuit (50).

[0033] The antenna (10) receives RF signals from the surroundings.

[0034] The impedance matching network (20) amplifies the voltage amplitude by conjugate-matching the input impedance of the RF-DC rectifier to the received RF signal.

[0035] The RF-DC rectifier (30) converts the amplified AC input voltage into a DC voltage. The RF-DC rectifier (30) plays an important role in generating a DC voltage from an RF signal. When the input resistance value of the RF-DC rectifier (30) drops below a certain level, the passive voltage gain of the impedance matching network (20) decreases, so the overall input sensitivity of the RF energy harvester decreases.

[0036] The storage capacitor (40) stores the converted DC voltage.

[0037] The power management circuit (50) manages the output of the stored DC voltage.

[0038]

[0039] FIG. 2 is a drawing for explaining the structure of an RF-DC rectifier according to one embodiment of the present invention.

[0040] Referring to FIG. 2, the RF-DC rectifier (30) may include N (N is a natural number) rectifier cells (100). The RF-DC rectifier (30) applies an applied RF signal to the rectifier cells in parallel. Accordingly, the input resistance of the RF-DC rectifier (30) is proportional to the input resistance of the rectifier cells constituting the RF-DC rectifier and inversely proportional to the number N of the rectifier cells (100). Additionally, the input sensitivity of the RF-DC rectifier (30) tends to be proportional to the number of rectifier cells (100) constituting the RF-DC rectifier. Therefore, in order to increase the input sensitivity of the RF-DC rectifier (30), it is necessary to simultaneously increase the input resistance of the rectifier cells (100) and the number N of the rectifier cells (100).

[0041]

[0042] FIG. 3 is a drawing for explaining the structure of a rectifier cell according to one embodiment of the present invention.

[0043] Referring to FIG. 3, the rectifier cell (100) may include one coupling capacitor (110) and two transistors (130).

[0044] The coupling capacitor (110) transmits the received RF signal to the transistor (130), and the transistor (130) rectifies the RF signal into DC.

[0045]

[0046] FIG. 4 is a diagram illustrating the input resistance value of a rectifier cell in an equivalent model of a rectifier cell according to one embodiment of the present invention.

[0047] Referring to FIG. 4, the main capacitor (C) is an equivalent model of the coupling capacitor (110). C ) as well as parasitic capacitors (C TOPand C BOT ) and parasitic resistance (R PAR ...includes ). Also, the rectifier cell includes a resistor (R) connected in parallel as an equivalent model of two connected transistors (130). MOS ) and capacitor (C MOS ) may be included. Here, the input resistance value of the rectifier cell (100) is approximately expressed as the mathematical formula below.

[0048] [Mathematical Formula 1]

[0049] Input resistance value of the rectifier cell R MOS || R PAR (1+Q 2 )

[0050] However, Q = 1 / {ω(C TOP +C BOT )R PAR}

[0051] Here, Q (Quality factor) is the quality factor and ω is the angular frequency.

[0052]

[0053] FIGS. 5 to 13 are drawings for explaining the location of a coupling capacitor of a rectifier cell according to an embodiment of the present invention.

[0054] Referring to FIG. 5, the coupling capacitor (110) of a rectifier cell according to one embodiment of the present invention may be located on a P-type substrate (120) when implemented as a semiconductor integrated circuit. Here, the coupling capacitor (110) has a relative parasitic resistance value (R PAR ) is located on a large P-type substrate (120). Referring to [Equation 1] described above in the equivalent model, the coupling capacitor (110) has a parasitic resistance value (R PAR Since the larger ) is, the smaller the Q value becomes, the parasitic resistance value (R PAR The larger the value, the smaller the input resistance value of the rectifier cell (100).

[0055]

[0056] Referring to FIGS. 6 through 13, the coupling capacitor (110) of the rectifier cell may be located on a doping region (140) formed within a P-type substrate (120) when implemented as a semiconductor integrated circuit. This is because the parasitic resistance value (R) in the doping region (140) formed within the P-type substrate (120) PAR ) is smaller than the P-type substrate (120), the input resistance value of the rectifier cell can become larger.

[0057] Specifically, referring to FIG. 6, the coupling capacitor (110) of the rectifier cell may be positioned on the P+ region, which is a doped region (140) formed in the P type substrate (120).

[0058] Referring to FIG. 7, the coupling capacitor (110) of the rectifier cell may be located on the N+ region, which is a doped region (140) formed in the P type substrate (120).

[0059] Referring to FIG. 8, the coupling capacitor (110) of the rectifier cell may be located on the N+ region, which is a doped region (140) formed in the N well within the P type substrate (120).

[0060] Referring to FIG. 9, the coupling capacitor (110) of the rectifier cell may be located on the P+ region, which is a doped region (140) formed in the N well within the P type substrate (120).

[0061] Referring to FIG. 10, the coupling capacitor (110) of the rectifier cell may be located on the P+ region, which is a doped region (140) formed in the P well within the P type substrate (120).

[0062] Referring to FIG. 11, the coupling capacitor (110) of the rectifier cell may be located on the N+ region, which is a doped region (140) formed in the P well within the P type substrate (120).

[0063] Referring to FIG. 12, the coupling capacitor (110) of the rectifier cell can be positioned on the P+ region, which is a doping region (140) formed in the P-well within the N-well within the P-type substrate (120).

[0064] Referring to FIG. 13, the coupling capacitor (110) of the rectifier cell can be positioned on the N+ region, which is a doping region (140) formed in the P-well within the N-well within the P-type substrate (120).

[0065] Here, the doping concentrations of the P+ region and N+ region are relatively higher than the doping concentration of the P-type substrate, so the parasitic resistance values ​​(R) of the P+ region and N+ region PAR ) is the parasitic resistance value (R) of the P type substrate (120) PAR It is relatively smaller than ). This is because as the doping concentration increases, the number of charge carriers increases, and conductivity increases. Referring to the aforementioned [Equation 1], the parasitic resistance value (R PAR ) is smaller, the Q value increases, so the input resistance value of the rectifier cell increases.

[0066] Consequently, the coupling capacitor (110) of the rectifier cell according to one embodiment of the present invention is positioned on a doping region (140) formed within the P-type substrate (120) instead of being positioned on the P-type substrate (120), thereby the parasitic resistance value (R PAR ) becomes relatively smaller, and as a result, the effect of increasing the input resistance of the rectifier cell can be obtained. According to the input impedance measurement results of the RF-DC rectifier, by placing a Metal-Oxide-Metal (MOM) coupling capacitor using metal layers 4, 5, and 6 with a value of approximately 20fF on a doping region (140) formed within a P-type substrate (120), the parasitic resistance value (R) is lower than when the capacitor is placed on the P-type substrate (120). PAR) was reduced by approximately 68%, and as a result, the input resistance value of the rectifier cell was increased by approximately 2.9 times.

[0067] Therefore, as the input resistance value of the RF-DC rectifier cell according to an embodiment of the present invention increases, a larger number of rectifier cells can be configured while maintaining the input resistance value of the RF-DC rectifier at a certain level, and an RF energy harvester including the RF-DC rectifier according to the present invention can have higher input sensitivity.

[0068]

[0069] FIGS. 14 and 15 are drawings for explaining the structure of a rectifier cell according to one embodiment of the present invention.

[0070] Referring to FIGS. 14 and 15, the rectifier cell (100) may include a coupling capacitor (110) and a transistor (130) when implemented as a semiconductor integrated circuit. Specifically, the rectifier cell (100) may be configured as an integrated circuit with a coupling capacitor (110) and two transistors (130) as in the structure of FIG. 3.

[0071] The coupling capacitor (110) can be implemented as a Metal-Oxide-Metal (MOM) capacitor or a Metal-Insulator-Metal (MIM) capacitor.

[0072] The transistor (130) can be configured as an N-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) in which the source and drain regions are doped with N-type electrons on the substrate (120) or a P-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) in which the source and drain regions are doped with P-type holes.

[0073] The substrate (120) may be located below the coupling capacitor (110) and may include a doped region of various embodiments. Here, the doped region is formed within the substrate (120) and may include, for example, a P+ region formed within a P-type substrate, an N+ region formed within a P-type substrate, an N+ region formed within an N-well within a P-type substrate, a P+ region formed within an N-well within a P-type substrate, a P+ region formed within a P-well within a P-type substrate, an N+ region formed within a P-well within a P-type substrate, a P+ region formed within a P-well within a P-type substrate, or an N+ region formed within a P-well within a P-type substrate.

[0074]

[0075] The modes for carrying out the invention are described together in the best mode for carrying out the invention above.

[0076]

[0077] The present invention relates to an RF-DC rectifier, and more specifically, to an RF-DC rectifier that allows the rectifier to be configured with a larger number of rectifier cells while maintaining the input resistance of the rectifier at a constant level, and thus has industrial applicability as it can be used in various ways.

Claims

1. Containing one or more rectifier cells, The above rectifier cell is A coupling capacitor receiving an RF signal; and Includes a transistor that rectifies an input RF signal and outputs a DC voltage. The above coupling capacitor is an RF-DC rectifier located on top of a doped region within a substrate on which the above transistor is implemented as an integrated circuit.

2. In Paragraph 1, The above substrate is an RF-DC rectifier which is a P type substrate.

3. In paragraph 1, The doped region within the above substrate is P+ region inside P type substrate or RF-DC rectifier with N+ region inside P type substrate.

4. In paragraph 1, The doped region within the above substrate is N+ region formed in N well within P type substrate or RF-DC rectifier, which is a P+ region formed inside an N well within a P-type substrate.

5. In paragraph 1, The doped region within the above substrate is P+ region formed in a P well within a P type substrate or RF-DC rectifier, which is an N+ region formed in a P-well within a P-type substrate.

6. In paragraph 1, The doped region within the above substrate is An RF-DC rectifier in which a P+ region is formed in a P well formed in an N well in a P type substrate or an N+ region is formed in a P well formed in an N well in a P type substrate.

7. In Paragraph 1, The above coupling capacitor RF-DC rectifier implemented with MOM capacitors or MIM capacitors.

8. In paragraph 1, The above transistor RF-DC rectifier implemented with N-channel MOSFET or P-channel MOSFET.

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