Active-feedback, speed-adjustable, low-power voltage regulator for high-voltage energy harvester

Abstract

The present disclosure relates to an active-feedback, speed-adjustable, low-power voltage regulator for a high-voltage energy harvester. According to one aspect of the present invention, the voltage regulator comprises: a comparator for comparing, to the reference voltage, a feedback voltage generated by stepping down the output voltage of the voltage regulator by a predetermined ratio; and a feedback circuit that outputs, according to the comparison result of the comparator, a feedback signal for adjusting the output voltage to a target voltage, wherein the comparator dynamically adjusts the comparison speed according to a voltage difference between the feedback voltage and the reference voltage and the feedback circuit adjusts the reference voltage according to the voltage difference.

Description

Active feedback rate control low-power voltage regulator for high-voltage energy harvesters

[0001] The following embodiments relate to an active feedback rate-adjustable low-power voltage regulator for a high-voltage energy harvester.

[0002] Recently, energy harvesting technology has been gaining attention. Energy harvesting devices can be described as new eco-friendly energy generation devices capable of converting and extracting mechanical energy generated from the surrounding environment, such as wind or vibrations, or human movement, into electrical energy. Since piezoelectric and triboelectric energy harvesters generate high voltages of tens of volts or more, a power conversion circuit is required to charge a battery with the energy generated from the harvester.

[0003] In particular, triboelectric nano generators (TENGs) are energy harvesters that generate energy by utilizing the motion and friction of objects. While they can improve upon the characteristics of conventional piezoelectric harvesters, which typically produce good output only within the resonant frequency range, they present difficulties in circuit implementation due to their output of very high voltage and very low current.

[0004] While the withstand voltage of the main switch for power conversion can be tens of volts or more, the control circuit that manages it typically uses a relatively low voltage of a few volts as the driving voltage. Consequently, a separate power conversion circuit must be constructed to generate the supply voltage for the control circuit; however, switching regulators utilizing capacitors or inductors also face the problem of having to secure the driving voltage for the control circuit that regulates the switching operation.

[0005] The aforementioned background technology is technical information that the inventor possessed for the derivation of the present invention or acquired during the process of deriving the present invention, and it cannot be considered as prior art disclosed to the general public prior to the filing of the present invention.

[0006] The invention provides a low-power voltage regulator capable of reducing current consumption by utilizing a comparator that actively adjusts the energy consumed in comparison.

[0007] Furthermore, the invention provides a method for generating a supply voltage for a control circuit of a power conversion circuit for charging harvester energy by utilizing the input voltage of the harvester energy. The problems to be solved by the present invention are not limited to those mentioned above, and other problems and advantages of the present invention not mentioned can be understood from the following description and will be more clearly understood by the embodiments of the present invention. In addition, it will be understood that the problems and advantages to be solved by the present invention can be realized by the means and combinations thereof set forth in the claims.

[0008] A voltage regulator according to one aspect comprises: a comparator that compares a reference voltage with a feedback voltage generated by reducing the output voltage of the voltage regulator by a predetermined ratio; and a feedback circuit that outputs a feedback signal to adjust the output voltage to a target voltage according to the comparison result of the comparator; wherein the comparator dynamically adjusts the comparison speed according to the voltage difference between the feedback voltage and the reference voltage, and the feedback circuit can adjust the reference voltage according to the voltage difference.

[0009] An energy harvesting circuit according to another aspect comprises: a DC-DC converter that converts an input voltage generated from an energy harvester into a battery charging voltage; a control circuit that controls the operation of the DC-DC converter; and a voltage regulator according to claim 1; wherein the voltage regulator can adjust the input voltage to a supply voltage of the control circuit and output it.

[0010] According to the means for solving the problem of the present disclosure described above, a voltage regulator that reduces unnecessary power consumption can be provided by using a CERO (Constant Energy-Per-Cycle Ring Oscillator) based comparator that dynamically adjusts the comparison speed.

[0011] The effects of the embodiments are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description of the present invention.

[0012] FIG. 1 is an exemplary diagram illustrating a conventional energy harvesting circuit that utilizes battery power to supply a control voltage to a control circuit.

[0013] Figure 2 is an exemplary diagram illustrating an energy harvesting circuit that supplies voltage to a control circuit by utilizing the output power of an energy harvester.

[0014] Figure 3 is a diagram showing a typical voltage regulator including a current mirror circuit and a Zener diode.

[0015] FIG. 4 is a diagram illustrating a partial configuration of a voltage regulator according to one embodiment.

[0016] FIG. 5 is a configuration diagram for explaining a CERO comparator according to one embodiment.

[0017] Figure 6 is a configuration diagram to explain a conventional EPC comparator.

[0018] FIG. 7 is an exemplary drawing showing a voltage regulator including a CERO comparator according to one embodiment.

[0019] A voltage regulator according to one aspect comprises: a comparator that compares a reference voltage with a feedback voltage generated by reducing the output voltage of the voltage regulator by a predetermined ratio; and a feedback circuit that outputs a feedback signal to adjust the output voltage to a target voltage according to the comparison result of the comparator; wherein the comparator dynamically adjusts the comparison speed according to the voltage difference between the feedback voltage and the reference voltage, and the feedback circuit can adjust the reference voltage according to the voltage difference.

[0020] An energy harvesting circuit according to another aspect comprises: a DC-DC converter that converts an input voltage generated from an energy harvester into a battery charging voltage; a control circuit that controls the operation of the DC-DC converter; and a voltage regulator according to claim 1; wherein the voltage regulator can adjust the input voltage to a supply voltage of the control circuit and output it.

[0021] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but can be implemented in various different forms and should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0022] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0023] Some embodiments of the present disclosure may be represented by functional block configurations and various processing steps. Some or all of these functional blocks may be implemented by various numbers of hardware and / or software configurations that execute specific functions. For example, the functional blocks of the present disclosure may be implemented by one or more microprocessors or by circuit configurations for a specific function. Additionally, for example, the functional blocks of the present disclosure may be implemented in various programming or scripting languages. The functional blocks may be implemented as algorithms executed on one or more processors. Furthermore, the present disclosure may employ prior art for electronic configuration, signal processing, and / or data processing, etc. Terms such as "mechanism," "element," "means," and "configuration" may be used broadly and are not limited to mechanical and physical configurations.

[0024] Furthermore, the connecting lines or connecting members between the components depicted in the drawings are merely illustrative of functional connections and / or physical or circuit connections. In the actual device, connections between components may be represented by various alternative or added functional connections, physical connections, or circuit connections.

[0025] Piezoelectric and triboelectric energy harvesters generate high voltages of tens of volts or more. To effectively charge a battery with the energy harvester's energy, capacitor or inverter-based DC-DC converters are used to lower the harvester's output voltage and convert it into a voltage suitable for battery charging. Control circuits for utilizing these DC-DC converters are designed as semiconductor integrated circuits.

[0026] Although the voltage rating of a semiconductor device used as a main switch for a semiconductor integrated circuit can be approximately 70 to 100 volts, the driving voltage (control voltage) for controlling the semiconductor integrated circuit is approximately 5 volts; therefore, the output of the harvester cannot be used directly as the control voltage of the control circuit. Accordingly, conventional energy harvesting circuits utilize the voltage of a battery connected to the output side of a main converter as the control voltage of the control circuit. An energy harvesting circuit that utilizes the battery voltage as the control voltage of the control circuit is specifically explained in FIG. 1.

[0027] In this specification, an energy harvesting circuit refers to a circuit comprising a semiconductor integrated circuit for power management (control circuit), a main converter (e.g., a DC-DC converter), and a battery.

[0028] FIG. 1 is an exemplary diagram illustrating a conventional energy harvesting circuit that utilizes battery power to supply a control voltage to a control circuit.

[0029] Referring to FIG. 1, a conventional energy harvesting circuit has a battery (40), and an input voltage (VIN) from a harvester is used to charge the battery (V scIt includes an inductor-based DC-DC converter and a control circuit (30) that adjusts to ). The control circuit (30) includes a switch controller, a level shifter, a clock generator, and a Schottky diode. A conventional energy harvesting circuit utilizes a battery power source located at the output side of the converter to control the control voltage (20, V) of the control circuit (30). DDL ) generates. In this case, since the battery voltage cannot be utilized at the beginning of the energy harvesting circuit operation, that is, when the battery (40) is completely discharged, the switch of the control circuit (30) is opened to bypass the output of the harvester to the switch and inductor, thereby slowly generating the battery voltage (V sc Fill ) afterwards. Then, the battery voltage (V sc The minimum voltage (V) at which this control circuit (30) can be driven DD When filled up to Min), the switch is closed, and the control circuit (30) is activated to start harvesting. This type of energy harvesting circuit is used for the discharged battery voltage (V sc It takes a long time because it fills slowly through the bypass. Also, after closing the switch, the harvester's output voltage (10, V) IN ) is the maximum power point (V MPP Since it can be raised up to ), the harvesting efficiency becomes lower.

[0030] To solve this problem, the control voltage (V) for driving the control circuit DDL To supply the control voltage (V), a separate voltage regulator other than the main converter may be used. DDL An energy harvesting circuit including a voltage regulator for supplying ) is described in detail later in FIG. 2.

[0031] Figure 2 is an exemplary diagram illustrating an energy harvesting circuit that supplies voltage to a control circuit by utilizing the output power of an energy harvester.

[0032] Referring to FIG. 2, the control circuit (31) of the power management integrated circuit controls the control voltage (21, V DDL It further includes a separate voltage regulator (32) for supplying the battery (41) voltage (V). sc Instead of driving the control circuit (31) using ), the driving current (I) of the control circuit (31) is driven using the output of the harvester. DDL ) and control voltage (21, V DDL Because it generates ), even during initial operation, compared to the method utilizing battery voltage (Vsc), the control voltage (21, V) DDL It can rapidly supply ). In addition, from the start of operation, the input voltage (11, V) from the energy harvester can be supplied. IN ) is the maximum power point (V MPP It can be maintained as ).

[0033] Power consumption can be reduced by using a voltage regulator (32) that includes a Zener diode and a current mirror circuit, rather than a conventional DC-DC converter, as a configuration that separately generates the supply voltage of the control circuit (31). A detailed description of a voltage regulator according to one embodiment that includes a Zener diode and a current mirror circuit will be provided later in FIG. 4.

[0034] Figure 3 is a diagram showing a typical voltage regulator including a current mirror circuit and a Zener diode.

[0035] Referring to FIG. 3, a conventional voltage regulator (300) includes a comparator (310), and the comparator (310) constantly monitors the state of the output voltage of the voltage regulator (300). The comparator (310) has a reference voltage (V REF ) and current output voltage (V 출력 By comparing ), the current level of the voltage regulator (300) can be adjusted according to the comparison result. In the case of a conventional comparator (310), constant monitoring is performed, which results in unnecessary current consumption.

[0036] A voltage regulator according to an embodiment of the present invention can reduce unnecessary current consumption caused by a comparator by adjusting the operating speed of the comparator according to the difference in magnitude between the output voltage and the reference voltage, thereby minimizing the energy consumed in the comparison.

[0037]

[0038] FIG. 4 is a diagram illustrating a partial configuration of a voltage regulator according to one embodiment. FIG. 4 may represent an embodiment that can replace the comparator (320) of the voltage regulator illustrated in FIG. 3. That is, although a current mirror circuit and a Zener diode are not illustrated in FIG. 4, the configuration of FIG. 4 can be operated in connection with the current mirror circuit and Zener diode illustrated in FIG. 3.

[0039] Referring to FIG. 4, a voltage regulator according to one embodiment may include a comparator (441) that compares an output voltage and a feedback voltage, and a feedback circuit that outputs a feedback signal to adjust the output voltage to a target voltage according to the comparison result of the comparator (441). In this case, the comparator (441) may be a CERO (Constant Energy-Per-Cycle Ring Oscillator) based comparator (hereinafter referred to as a CERO comparator) that dynamically adjusts the comparison speed according to the voltage difference between the feedback voltage and the reference voltage.

[0040] According to one embodiment, the feedback circuit may include a current control unit (443) that controls the ON / OFF of a MOSFET array supplying current to a comparator.

[0041] For example, the current control unit (443) can control the ON / OFF of a MOSFET array that supplies current in a current mirror manner. Here, the MOSFET array may include a plurality of P-type MOSFETs (PMOS). The current control unit (443) can control the current flowing through the current mirror circuit by controlling the number of ON / OFF MOSFETs included in the MOSFET array.

[0042] Alternatively, the current control unit (443) can adjust the BIASN voltage through a control block composed of an up / down counter and a D flip-flop according to the generation cycle of the comparator's comparison completion signal (CMP_OUT). The adjusted BIASN voltage is applied to a MOSFET array to determine the magnitude of the current supplied to the delay cell of the CERO comparator, and accordingly, the operating speed and current consumption of the comparator can be dynamically controlled.

[0043] According to one embodiment, the voltage regulator may further include a current source supplying a reference current, an input terminal and a current mirror circuit connected to the current source and generating at least one duplicate current based on the reference current from the input voltage of the input terminal, a Zener diode connected to the current mirror circuit, and an output terminal connected to the current mirror circuit and a load and supplying an output voltage to the load.

[0044] The feedback circuit can output a feedback signal to the current mirror circuit to maintain the output voltage at the target voltage of the voltage regulator. For example, the current control unit (443) can control the current flowing through the current mirror circuit.

[0045] A Zener diode can pass excess current in response to the input voltage exceeding a threshold voltage and the sum of at least one replication current exceeding the load's consumption current. The excess current refers to a current corresponding to the difference between the sum of the replication currents and the consumption current.

[0046] In one embodiment, the feedback circuit may further include a capacitor (445) that stores the charge leaked during the operation of the comparator. And, the current control unit (443) can optimize the operation speed of the comparator by controlling the ON / OFF state of the MOSFET array and the bias voltage according to the feedback signal. The capacitor (445) stores the charge leaked during the operation of the comparator, and the current control unit (443) can generate a bias voltage using this amount of charge, and accordingly, the energy of the comparison operation can be optimized as the current consumption of the comparator (441) is reduced.

[0047] The CERO comparator (441) can adjust the bias voltage through the current control unit (443) to adjust the comparison speed according to the comparison voltage difference, and accordingly, the comparison sensitivity of the comparator (441) can be dynamically adjusted. That is, an adjustment process to optimize the operating speed of the comparator within the feedback loop may be included. The specific configuration of the CERO comparator will be described later in FIGS. 5 and FIGS. 7.

[0048]

[0049]

[0050] FIG. 5 is a configuration diagram for explaining a CERO comparator according to one embodiment.

[0051] Referring to FIG. 5, the CERO comparator (500) includes a plurality of unit delay cells (510), and a reference voltage (V) which is a voltage to be compared. REF ) and feedback voltage (V FB It can be designed so that the delay and oscillation speed during voltage comparison can be adjusted according to the difference of ).

[0052] Here, the feedback voltage (V FB ) is a voltage generated by dividing the output voltage of a voltage regulator by a predetermined ratio, and is applied as an input to a comparator (500) to form a reference voltage (V REFIt is compared with ). For example, if the target voltage of a voltage regulator is 5V and the reference voltage is set to 2.5V, which is half the target voltage, the feedback voltage must also be divided by half the output voltage.

[0053] In the CERO comparator (500), a plurality of unit delay cells (510) are connected in series, and each unit delay cell operates sequentially to form the oscillation cycle of the comparator. The unit delay cell (510) can be configured as a latch-based delay circuit using a MOS transistor, and for each unit delay cell (510), a comparison voltage (V REF , V FB ) is input alternately. The unit delay cell (510) is the input comparison voltage (V REF , V FB It can regulate the current flow by detecting the difference in ).

[0054] At this time, if the comparison voltage difference is small, the response speed of the unit delay cell (510) decreases, causing the operation speed of the comparator (500) to slow down, and if the comparison voltage difference is large, the response speed of the unit delay cell (510) increases, causing the operation speed of the comparator (500) to speed up. Through this, the current consumption of the comparator (500) can be efficiently controlled, and power consumption can be minimized by preventing the operation of the comparator (500) from proceeding faster than necessary.

[0055] Meanwhile, in the case of existing EPC comparators, the reference voltage is half of the supply voltage (V DD Since it is fixed at / 2), the common-mode voltage of the comparison signal is constant at a fixed reference voltage value. In contrast, the CERO comparator (500) of the present invention is a reference voltage (V) of the comparator. REF) is dynamically changed, and the common mode voltage of the reference voltage and the feedback voltage is adjusted. In addition, when the reference voltage is changed, the voltage division ratio of the feedback voltage is also adjusted accordingly.

[0056] For example, the output voltage (V) of a voltage regulator OUT If you want to adjust ) to a target voltage of 5V, the comparator's reference voltage (V REF If ) is set to 2.5V, the comparator's feedback voltage (V FB ) is generated by dividing the output voltage by half. If the reference voltage is lowered to 1V, which is 1 / 5 of the target voltage, the feedback voltage (V FB ) is generated at 1 / 5 of the output voltage.

[0057] When the reference voltage (VREF) is 2.5V, half of the difference between the output voltage and the target voltage becomes the comparison voltage difference of the comparator (500), and when the reference voltage is 1V, the comparison voltage difference becomes 1 / 5 of the difference between the output voltage and the target voltage. As described above, since the operating speed of the comparator (500) depends on the comparison voltage difference, if the reference voltage is set low, the comparison speed becomes slow.

[0058] In this way, the CERO comparator (500) slows down as the reference voltage decreases, but since the voltage division ratio of the feedback voltage also changes according to the ratio of the reference voltage to the target voltage, the stability of the comparison operation can be maintained even at a low reference voltage.

[0059] Therefore, the comparator of the present invention can reduce current consumption by increasing the reference voltage and increasing the comparison speed to quickly adjust the output voltage when the output voltage deviates significantly from the target voltage, and by decreasing the reference voltage and decreasing the comparison speed when the output voltage approaches the target voltage.

[0060] A detailed explanation of the adjustment method for the reference voltage (VREF) is provided later in Fig. 7.

[0061]

[0062] Figure 6 is a configuration diagram illustrating a conventional EPC (Edge-Pursuit Comparator).

[0063] Referring to FIG. 6, the EPC comparator (600) includes a plurality of unit delay cells (610) inside the comparator and can adjust the comparison speed according to the voltage difference. However, the EPC comparator has a reference voltage (V REF Since the reference voltage is fixed, it is possible to adjust the comparison speed, but there is a limitation in that additional optimization based on the reference voltage itself is difficult.

[0064] On the other hand, the CERO comparator (500) of the present invention uses a reference voltage (V through a feedback loop. REF It is configured to allow dynamic adjustment up to ).

[0065] The CERO comparator (500) of the present disclosure can dynamically adjust the reference voltage, so in addition to the function of adjusting the comparison speed according to the voltage difference, it can adjust the reference voltage itself to more finely optimize the current consumption of the comparator.

[0066]

[0067] FIG. 7 is an exemplary drawing showing a voltage regulator including a CERO comparator according to one embodiment.

[0068] Referring to FIG. 7, a voltage regulator (70) according to one embodiment may include an adaptive on / off control unit (Adaptive On / Off Cont., 71) that optimizes current consumption by controlling the operating speed and current supply of a comparator (700) according to the state of the output voltage (VOUT).

[0069] The adaptive on / off control unit (71) may include a CERO comparator (700), a comparator start detection unit (Rising Edge Detector, 715), a comparator completion detection unit (Done Detector, 720), a reference voltage control unit (725), a feedback voltage generation unit (730), and a current control unit (735).

[0070] The CERO comparator (700) is the output voltage (V) of the voltage regulator (70). OUT The feedback voltage (V) generated by dividing the ) by a predetermined ratio FB ) and reference voltage (V REF Compares ). The comparator (700) includes a plurality of unit delay cells (710), each cell being configured with a MOS transistor-based latch structure. Each unit delay cell (710) has V REF and V FB It is input cross-linked to regulate current flow and oscillation cycle according to the voltage difference.

[0071] When the difference between the feedback voltage and the reference voltage is small, the response speed of the unit delay cell (710) slows down and the oscillation period increases, thereby decreasing the comparison speed; conversely, when the difference is large, the comparison speed increases. Accordingly, the current consumption of the comparator (700) can be dynamically controlled.

[0072] The comparator start detection unit (715) detects the start of the comparison operation, and the comparator completion detection unit (720) detects the CMP_OUT signal to recognize the end time.

[0073] If the generation cycle of the CMP_OUT signal is slow, that is, if the output voltage approaches the target voltage and the comparison operation time becomes long, the reference voltage adjustment unit (725) V REF The value is adjusted to a low value, and the feedback voltage generation unit (730) generates a feedback voltage by setting a corresponding voltage division ratio. As a result, the comparison speed is slowed down and the current consumption is reduced.

[0074] Conversely, if the generation cycle of the CMP_OUT signal is fast, the reference voltage is set high, and accordingly, the difference between the two voltages input to the comparator increases, thereby speeding up the comparison.

[0075] The CMP_OUT signal is also transmitted to the current regulator (735). In one embodiment, the current regulator (735) may include a D flip-flop and an up-down counter (e.g., 8b UPDN Counter) to regulate the BIASN voltage and thereby control the current supply of the PMOS array.

[0076] In one embodiment, the reference voltage adjustment unit (725) is the reference voltage (V) of the comparator. REF ) can be selected and adjusted to one of a plurality of preset voltage values. FIG. 7 illustrates an example in which a plurality of voltage values ​​that can be set as a reference voltage are 2.0V and 1.2V, but is not limited thereto.

[0077] The feedback voltage generation unit (730) outputs the voltage (V OUT It may be a voltage divider that generates a feedback voltage by dividing the voltage of the target voltage by a predetermined ratio. In this case, the ratio of the magnitude of the output voltage to the magnitude of the feedback voltage may be the same as the ratio of the magnitude of the target voltage to the magnitude of the reference voltage. That is, the voltage division ratio of the feedback voltage may vary depending on the setting of the reference voltage.

[0078] The feedback voltage generation unit (730) outputs the voltage (V OUT ) is divided by pressure at a predetermined ratio to V FB It generates. In this case, the voltage divider ratio is set to be equal to the ratio between the reference voltage and the target voltage; for example, if the target voltage is 5V and the reference voltage is 2.0V, then V FB is V OUT If it is set to 0.4 times, and the reference voltage is 1.2V, then V FB is V OUT It is set to 0.24 times.

[0079] In this way, when the magnitude of the reference voltage changes, the voltage division ratio of the corresponding feedback voltage changes accordingly, and as a result, the operating speed and current consumption can be optimized while maintaining the performance of the comparator.

[0080]

[0081] The voltage regulator of the present disclosure may be included in an energy harvesting circuit. An energy harvesting circuit according to one embodiment may include a DC-DC converter that converts an input voltage generated from an energy harvester into a battery charging voltage, a control circuit that controls the operation of the DC-DC converter, and a voltage regulator, and the voltage regulator may adjust the input voltage to a supply voltage of the control circuit and output it.

[0082] A person skilled in the art related to the present embodiment will understand that it may be implemented in modified forms without departing from the essential characteristics of the description above. Therefore, the disclosed methods should be considered in an illustrative rather than a restrictive sense, and the scope of rights is defined in the claims rather than the description above, and should be interpreted to include all differences within the scope of equivalence.

Claims

1. A comparator that compares a feedback voltage generated by reducing the output voltage of a voltage regulator by a predetermined ratio with a reference voltage; and A feedback circuit that outputs a feedback signal for adjusting the output voltage to a target voltage according to the comparison result of the above comparator; The above comparator dynamically adjusts the comparison speed according to the voltage difference between the feedback voltage and the reference voltage, and The above feedback circuit is a voltage regulator that adjusts the reference voltage according to the voltage difference.

2. In Paragraph 1, The above comparator is, A voltage regulator designed such that the comparison speed decreases when the voltage difference is small and increases when the voltage difference is large.

3. In Paragraph 1 The voltage division ratio between the above output voltage and the above feedback voltage is A voltage regulator equal to the ratio between the magnitude of the target voltage and the magnitude of the reference voltage.

4. In Paragraph 1, The above comparator is, It includes multiple unit delay cells, and A voltage regulator configured such that when the above reference voltage decreases, the operating speed of the above unit delay cell decreases, thereby reducing the current consumption of the above comparator.

5. In Paragraph 1, The above voltage regulator is, A current source supplying a reference current; A current mirror circuit connected to an input terminal and the current source, and generating at least one duplicate current based on the reference current from the input voltage of the input terminal; A Zener diode connected to the above current mirror circuit; and It further includes an output terminal connected to the current mirror circuit and the load, and supplying the output voltage to the load. The above feedback circuit is a voltage regulator that outputs the feedback signal to the current mirror circuit.

6. In Paragraph 5, The above Zener diode is, In response to the above input voltage exceeding a threshold voltage and the sum of the at least one replication current exceeding the current consumed by the load, a surplus current is passed, and A voltage regulator, wherein the above excess current refers to a current corresponding to the difference between the sum of the above replication currents and the above consumption current.

7. In Paragraph 5, The above feedback circuit is, A voltage regulator comprising a current regulator that regulates the current flowing through the above-mentioned current mirror circuit.

8. In Paragraph 7, The above feedback circuit is, It further includes a capacitor that stores charge leaking while the above comparator is operating, and The above current control unit is, A voltage regulator that generates a bias voltage of a MOSFET array included in the current mirror circuit using the charge stored in the capacitor.

9. In Paragraph 8, The above MOSFET array is, A voltage regulator comprising a plurality of P-type MOSFETs (PMOS).

10. In Paragraph 1, The above feedback circuit is, A MOSFET array comprising a plurality of P-type MOSFETs that supply current to the above comparator; and A voltage regulator comprising: a current control unit that controls the operation of the above MOSFET array.

11. In Paragraph 10, The above current control unit is, A voltage regulator comprising: a control circuit that adjusts the bias voltage applied to the MOSFET array according to the generation period of the comparison completion signal of the comparator.

12. A DC-DC converter that converts the input voltage generated from an energy harvester into a battery charging voltage; A control circuit for controlling the operation of the above DC-DC converter; and A voltage regulator according to claim 1; comprising, The above voltage regulator is an energy harvesting circuit that adjusts the input voltage to the supply voltage of the control circuit and outputs it.

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