Description:[001] This invention relates to the field of field of CMOS technology. More specifically, the invention pertains to a fast-switching voltage compensated 32nm CMOS rectifier for efficient energy harvesting.
BACKGROUND OF THE INVENTION
[002] The following description provides the information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] The fast expansion of the Web of Things (IoT) has prompted a phenomenal expansion in the number of associated gadgets, going from shrewd home apparatuses and modern sensors to wearable wellbeing screens and natural detecting hubs. These gadgets, by and large, alluded to as sensor hubs, assume a basic role in gathering and sending information, empowering shrewd navigation and computerization across different areas. Be that as it may, the far-reaching arrangement of sensor hubs presents huge difficulties, especially in terms of power supply and energy for the board. Customary battery-fuelled arrangements are frequently lacking because of their restricted life expectancy, natural effects, and support prerequisites.
[004] Energy harvesting includes catching and changing over-encompassing energy from the climate into usable electrical power. This approach uses different energy sources, including sun-oriented, wind, vibrational, and radio frequency (RF) energy, to supply a ceaseless and inexhaustible power [2]. Among these, RF energy gathering is especially appealing for IoT applications because of the pervasive presence of RF signals from remote correspondence organizations, like Wi-Fi, WiMAX, GSM, and Bluetooth. By saddling surrounding RF energy, sensor hubs can accomplish independence, diminishing dependence on regular batteries and empowering long haul, support-free activity.
[005] As shown in Figure 1 of the prior art, the reconciliation of energy collecting frameworks with sensor hubs includes a few key parts: the energy harvester, the rectifier unit, DC storage element, power management unit, and the sensor interface. For RF energy harvesting, this interaction commonly includes a receiving antenna to get RF signals, an impedance matching module to forward maximum power, and a rectifier. The storage unit directs and stores the collected energy, guaranteeing a steady power supply to the sensor hub. At last, the sensor interface associates the sensor to the energy gathering framework, working with proficient energy use and information transmission. Despite the promising possibilities of energy gathering for IoT sensor hubs, a few difficulties still need to be tended to. Central points of contention incorporate upgrading the energy change productivity, guaranteeing continuous power, and accomplishing consistent combinations with sensor interfaces. Also, the inconstancy of surrounding energy sources requires the advancement of versatile and strong energy collecting frameworks fit for working under assorted ecological circumstances.
[006] Accordingly, to overcome the prior art limitations based on aforesaid facts. The present invention provides AI-Powered Dynamic Code Optimization Framework for Real-Time Software Performance Enhancement. Therefore, it would be useful and desirable to have a system, and method to meet the above-mentioned needs.

SUMMARY OF THE PRESENT INVENTION
[007] The present invention provides comparator circuit which plays a crucial role in the proposed design and enhances switching time by dynamically adjusting the threshold voltage, amplifying input signals for quicker activation, conditioning the output signal for stability, and ensuring a longer on-state duration with minimal input. Figure 5 provides a visual representation of the proposed rectifier circuit. It shows the connection between the comparator circuit and the parallel stage Dickson charge pump, highlighting the feedback mechanism and the bias voltage generation.
[008] The comparator is responsible for generating a bias voltage in phase with the RF input signal. This in-phase bias voltage is then used to control the M1 and M2 devices in the parallel stage Dickson charge pump thereby ensuring that both devices are triggered at the right moments, leading to improved switching performance of the NMOS. The output of the charge pump is applied to the noninverting terminal of the comparator which adjust the bias voltage based on the output conditions. The other input (the inverting input) is connected to the ground. This configuration helps in maintaining the stability and accuracy of the comparator output.
[009] The advantage of the proposed design is that there is no requirement of external power supply for the comparator circuit, making it self-sustainable. This is a significant benefit for RF energy harvesting systems. The output of the comparator is not directly fed back to M1and M2 due to potential negative node voltage and leakage current issues. Instead, an RC circuit (C5 and R1) is used for conditioning the comparator's output signal and introduce a delay in the signal. The comparator's output voltage pre-bias a device near its threshold region.
[010] This pre-biasing means that the device requires a smaller increase in input signal to switch on, thereby reducing the time it takes for the device to activate and essentially affect the plan of more compelling RF energy harvesting frameworks that can be used in various applications, including IoT gadgets and remote sensor organizations.
[011] In this respect, before explaining at least one object of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the set of rules and to the arrangements of the various models set forth in the following description or illustrated in the drawings. The invention is capable of other objects and of being practiced and carried out in various ways, according to the need of that industry. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
[012] These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[013] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
[014] FIG. 1, illustrates an Efficient Energy Harvesting System, in accordance with an embodiment of the present invention.
[015] FIG. 2, depicts a block diagram of the Proposed Rectifier Circuit, in accordance with an embodiment of the present invention.
[016] FIG. 3, illustrates a Timing comparison between comparators output signal (Vc) and the input signal (Vin), in accordance with an embodiment of the present invention.
[017] FIG. 4, illustrates Proposed Rectifier DC Output Voltage, in accordance with an embodiment of the present invention.
[018] FIG. 5, illustrates an Output Voltage Variation Versus Channel Width, in accordance with an embodiment of the present invention.
[019] FIG. 6, illustrates an Output Voltage Variation Versus Channel Length, in accordance with an embodiment of the present invention.
[020] FIG. 7, illustrates an Output power vs load resistance, in accordance with an embodiment of the present invention.
[021] FIG. 8, illustrates an Efficiency vs load resistance, in accordance with an embodiment of the present invention.
[022] FIG. 9, illustrates a Frequency response plot, in accordance with an embodiment of the present invention.
[023] FIG. 10, illustrates a Rise time vs load resistance, in accordance with an embodiment of the present invention.
[024] FIG. 11, illustrates a Variation in Efficiency versus operational frequency, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[025] While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described and are not intended to represent the scale of the various components. Further, some components that may form a part of the invention may not be illustrated in certain figures, for ease of illustration, and such omissions do not limit the embodiments outlined in any way. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claims. As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one” and the word “plurality” means “one or more” unless otherwise mentioned. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters form part of the prior art base or are common general knowledge in the field relevant to the present invention.
[026] In this disclosure, whenever a composition or an element or a group of elements is preceded with the transitional phrase “comprising”, it is understood that we also contemplate the same composition, element or group of elements with transitional phrases “consisting of”, “consisting”, “selected from the group of consisting of, “including”, or “is” preceding the recitation of the composition, element or group of elements and vice versa.
[027] The present invention is described hereinafter by various embodiments with reference to the accompanying drawings, wherein reference numerals used in the accompanying drawing correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the following detailed description, numeric values and ranges are provided for various aspects of the implementations described. These values and ranges are to be treated as examples only and are not intended to limit the scope of the claims. In addition, a number of materials are identified as suitable for various facets of the implementations. These materials are to be treated as exemplary and are not intended to limit the scope of the invention.
[028] In the present system, within the turn-on process, the rise time directly affects how quickly the rectifier can reach its full conduction state after the initial threshold voltage is reached. A shorter rise time ensures that the rectifier transitions more swiftly to its full operating state, reducing the time spent in inefficient intermediate states where the device is neither fully on nor fully off. A faster rise time leads to better power conversion efficiency, improved high-frequency performance, and more stable output voltage, which are essential characteristics for effective energy harvesting and power management in modern electronic systems.
[029] In accordance with an embodiment of the present invention, once the turn on time ?(t?_on) of MOSFET is given by the equation:
t_on=t_d+t_r (9)
where, t_d is the delay time and t_r is the rise time.
The time taken by the gate voltage to rise from 0 to the threshold voltage is known as delay time, which is given as:
t_d˜R_g×C_gs×ln (V_(gs(on))/(V_(gs(on))-V_th )) (10)
where, R_g is the gate resistance, C_gs is the gate-source capacitance, and V_(gs(on)) is the gate-source voltage applied by the gate driver.
The rise time is defined as the time taken by the gate voltage to rise from threshold voltage to the full turn-on gate voltage V_(gs(on)), during which the MOSFET transitions from the off state to the fully on state. It is represented by the equation given as:
t_r=R_g×Q_gd/I_g (11)
where, Q_gd is the gate drain charge and I_g is gate current which is calculated as:
I_g=V_(gs(on))/R_g (12)
On combining equation 5 and 6, the total turn-on-time can be calculated as:
t_on=R_g×(C_gs+C_gd )×V_(gs(on))/I_g (13)
where, C_gd is the gate-drain capacitance. Equation 13 represents the total turn-on time of the NMOS transistor. This equation highlights the importance of the rise time in determining the overall turn-on time of the device. It also represents that if rise time increases, the on-time of the device also increases. The comparator outputs a phase-aligned bias voltage averaging 741.28 mV to the drain gate terminal of the M1 transistor, which is conditioned and delayed by an RC circuit to prevent negative node voltage and leakage current. Figure 3 and Figure 4 shows the timing comparison between comparators output signal and the input signal. It also shows the DC output voltage of the proposed circuit at a load resistance of 6 K?. The comparator's output voltage allows the M1, M2 devices to enter saturation at lower RF input signal levels, significantly improving the switching time and on-state duration compared to traditional configurations.
[030] In accordance with another embodiment of the present invention, the RMS value of the output current of the comparator is measured to be 3.956 mA. The threshold voltage of the M1, M2 devices is 422 mV. In a traditional Dickson charge pump, the RF signal must reach this threshold voltage to turn the device on. When the comparator output voltage reaches 712 mV, the RF signal value to the comparator output voltage is approximately 189.543 mV. At this point, the overall voltage exceeds the threshold voltage, turning the device on. The device remains in the on-state until the RF input value reaches 97.370 mV. This extended on-state duration enhances the switching time and overall performance of the rectifier circuit. The first parameter to be examined is the transistor width. This parameter affects the current-carrying capability and overall efficiency of the rectifier. The proposed work is based on the receiving of RF signal by an antenna from the ambient environment or dedicated RF sources like GSM, Wi-Fi, WiMAX, and Bluetooth etc. whose energy band ranges from 900 MHz to 5 GHz. The proposed circuit achieves maximum output voltage from 500 MHz to 8 GHz as shown in Figure 12 which covers the desired ambient RF energy range i.e 900 MHz to 5 GHz. Hence, the source of RF energy is ambient environment. The same source has been simulated through a voltage source as shown in Figure 5.
[031] In accordance with another embodiment of the present invention, Figure 8 shows the change in output voltage, during the variation in channel width from 70 nm to 5000 nm. This wide range helps in identifying the optimal width for maximum efficiency. This suggests that there is an optimal width, beyond which the performance decreases. The second parameter that need to be analysed for the RF rectifier design is the device length. This is a critical factor as it directly influences the performance and efficiency of the rectifier. Figure 9 illustrates the simulated output voltage variation when the transistor length is varied from 32 nm to 400 nm. This range was chosen to understand the impact of different lengths on the rectifier's output voltage. It is observed that after 40nm, the output voltage of the rectifier starts to degrade. This indicates that there is an optimal length similar to the width beyond which the performance of the rectifier diminishes. From the observations of Figures 8 and 9, the aspect ratio of the devices is chosen, which is 15 in this case. The aspect ratio is a crucial design parameter that balances the length and width to achieve optimal performance. Figure 10 illustrates the relationship between load resistance and output power and Figure 11 shows the variation in PCE with respect to load resistance. The load resistance of the rectifier is varied from 500 ohms to 40 Kilo ohms, revealing that a 6 Kilo ohm load resistor delivers maximum power, and efficiency i.e 50.66% and with an input power of 3.56 dBm calculated at this optimal load. This indicates an optimal point for power transfer in the system.
[032] In accordance with another embodiment of the present invention, the operating frequency of the proposed design is evaluated across a wide RF range (10 MHz to 14 GHz), with the results plotted in Figure 12 to illustrate the relationship between frequency and output voltage. This plot provides insights into the rectifier response across the frequency range. It is observed that the output of the rectifier remains constant after 600 MHz. Therefore, the bandwidth range of the circuit is from 500 MHz to 8 GHz. This range ensures optimal performance and efficiency. Figure 13 presents the frequency versus rise time. The graph indicates that as the operating frequency increases, the rise time degrades. For the traditional parallel stage Dickson Charge Pump, the rise time is measured to be 848.63056 ns at 600 MHz. This value serves as a benchmark for comparing the performance of the proposed circuit.
[033] In accordance with another embodiment of the present invention, the proposed design, the turn-on time at different operating frequencies is significantly improved. At 600 MHz, the turn-on time is approximately 712.05548 ns, and at 1 GHz, it is approximately 676.12041 ns. The effectiveness of the proposed design in reducing rise time and improving overall performance is demonstrated by these enhancements. Figure 14 shows the dependence of efficiency on operational frequency. It is observed that the Power Conversion Efficiency (PCE) of the rectifier is 50.66% at an operating frequency of 600 MHz. At a higher operating frequency of 2000 MHz, the PCE decreases to 32.3%. This degradation in PCE is a trade-off for achieving a lower rise time at higher frequencies. So, for higher frequencies rise time is optimised rather than PCE. That ensures the applicability in the broader sense. Table 1 provides a key extract of the optimized parameters for the proposed rectifier. These parameters include key design specifications and performance metrics that determine the rectifier circuit's efficiency and effectiveness. All the parameters have been evaluated and analysed using LTspice.
[034] Furthermore, it is observed that the device's threshold voltage and rise time have decreased from 422 mV to -189.543 mV, and 848.63056 ns to 712.05548 ns at 600 MHz respectively. In turn, the device's turn on duration has also increased. Table 2 summarize the parameters of various design techniques used in threshold compensated rectifiers. Compared to other designs the proposed rectifier achieves a lower threshold and better efficiency with a lesser switching period. The proposed rectifier design, implemented using 32 nm CMOS technology and LTspice, achieves self-sustainability by compensating for threshold voltage without external sources. It demonstrates a PCE of 50.66% at 3.56 dBm with a 6 Kilo ohm load. The average output voltage is 157.217 mV at 600 MHz and 154.978 mV at 1 GHz, with fast response times of 712.05548 ns and 676.12041 ns, respectively. The use of a comparator in the feedback path significantly improves the switching time and on-state duration of the devices. This improvement leads to better efficiency and performance of the rectifier circuit. The design is optimized for high-frequency applications, making it suitable for RF energy harvesting.
[035] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-discussed embodiments may be used in combination with each other. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description.
[036] The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the embodiments.
[037] While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.
, Claims:. A fast-switching voltage compensated CMOS rectifier, comprising:
a comparator circuit configured to dynamically adjust the threshold voltage for enhanced switching performance;
a parallel stage Dickson charge pump connected to the comparator for improved energy conversion efficiency;
a bias voltage generation module that generates in-phase bias voltage synchronized with the RF input signal to control NMOS devices;
an RC circuit for conditioning the output signal of the comparator and introducing a delay to ensure stability;
a self-sustaining configuration that eliminates the need for an external power supply for the comparator circuit.

2. The system as claimed in claim 1, wherein the comparator circuit amplifies input signals for quicker activation and improved switching performance.

3. The system as claimed in claim 1, wherein the bias voltage generation module ensures phase alignment with the RF input signal for optimal NMOS triggering.

4. The system as claimed in claim 1, wherein the RC circuit conditions the comparator's output signal to prevent negative node voltage and leakage current.

5. The system as claimed in claim 1, wherein the self-sustaining configuration enhances energy efficiency by eliminating the need for an external power supply for the comparator.

6. A method for efficient RF energy harvesting using a fast-switching CMOS rectifier**, the method comprising:
receiving an RF input signal and generating an in-phase bias voltage using a comparator circuit;
dynamically adjusting the threshold voltage of NMOS devices based on the in-phase bias voltage;
amplifying input signals for quicker activation and enhanced switching time;
conditioning the output signal of the comparator using an RC circuit to introduce a delay;
maintaining a longer on-state duration with minimal input for efficient energy conversion.

7. The method as claimed in claim 6, wherein the threshold voltage is dynamically adjusted to minimize switching delay and enhance power conversion efficiency.

8. The method as claimed in claim 6, wherein the RC circuit introduces a delay in the comparator output signal to stabilize the switching operation.