Interrupt protection circuits, systems and methods for sensors and other components

Abstract

An interruption protection system (100) for a circuit, comprising: a power supply (Vs) that is designed to provide power to the circuit; a capacitor (130) designed to provide buffer energy; a charge pump (120) which is electrically coupled to the capacitor (130) to charge the capacitor (130) to a buffer voltage; a reference unit (116) configured to provide a reference signal; and a controller (114) coupled to the power supply and to the reference unit (116) and configured to receive the reference signal and selectively control a supply path from the power supply and from the capacitor (130) to supply power to the circuit based on a comparison of the reference signal and a voltage level (Vs) of the power supply, further comprising at least one storage pass-through element (124) coupled to the controller (114) and to the capacitor (130), wherein the controller (114) is configured to control the at least one storage pass-through element (124) in order to control a current flow from the capacitor (130) to a supplied load (128), wherein the controller (114) is configured to enable the at least one storage pass-through device (124) to provide the buffer energy to the circuit when the comparison indicates that the power supply level is lower than a threshold level of the reference signal, where the buffer energy complements the energy provided by the power supply, or where the buffer energy replaces energy provided by the power supply.

Description

TECHNICAL FIELD

[0001] The invention relates generally to interrupt protection circuits and, more particularly, to providing pump micro-interrupt protection to maintain sufficient voltage of the output signal from sensors and other devices during micro-interruptions and other interruptions. BACKGROUND

[0002] Sensors can be used for monitoring and control in a wide variety of applications. Such applications can include use in automotive safety systems. Here, the sensors can be used to detect environmental changes, such as collisions, and trigger deployment of an airbag system in a vehicle. The triggering event initiates communication between the sensor and the vehicle's electronic control unit. As a result, voltage deviations, such as a momentary reset of the supply voltage, can occur in the sensor supply networks of vehicles, and particularly in certain areas of the sensor supply network. For example, strong, jerky movements, such as impacts or vibrations of the vehicle, can cause momentary interruptions in one of the connector connections, resulting in momentary resets of the supply voltage of safety-relevant systems, such asof the airbag sensor. This power supply reset can generally be referred to as a micro-break.

[0003] Micro-interruption protection circuitry generally uses one or more buffer capacitors as secondary voltage sources to maintain a supply voltage in the event of momentary losses or interruptions. A conventional method used to maintain the supply voltage during the occurrence of a micro-interruption is to charge the buffer capacitors to the operating voltage by connecting the capacitor to the airbag sensor power supply. A disadvantage of this method is that a reduction in the operating voltage reduces the amount of charge available to the buffer capacitor, thereby disabling the capacitor's ability to bridge the micro-interruption.

[0004] Another conventional approach to overcome this disadvantage is the use of synchronization pulses to provide an increased charge voltage to the buffer capacitor. With this method, short, periodic pulses are applied to the input terminals of an airbag sensor to generate an increased supply voltage at the input. Consequently, this allows the buffer capacitor to store a larger charge and discharge a higher voltage than the operating voltage in the event of a micro-interruption. A disadvantage of this approach is that newer protocols that use synchronization pulses reduce the supply voltage value by applying negative synchronization pulses, which in turn are unable to provide the necessary charge voltage to the buffer capacitor.

[0005] Document DE 601 23 027 T2 describes a power converter comprising: a power output stage with a load capacitor and a switched capacitor, wherein the power output stage is configured to receive an input voltage from a power source and apply an output voltage via output terminals. The load capacitor is electrically coupled via the output terminals, wherein the power output stage is further configured to switch between a charge state and a discharge state, wherein the charge state includes the switched capacitor being electrically connected in parallel with the input voltage. The discharge state includes the switched capacitor being electrically coupled via the load capacitor.A dynamic controller is coupled to the power output stage and is configured to respond to the output voltage across the load capacitor and to a predetermined reference voltage, commanding switching from the charge state to the discharge state. The dynamic controller commands switching between the charge and discharge states at a predetermined rate of change. The switched capacitor comprises an ultracapacitor.

[0006] The document DE 10 2011 104 975 A1 discloses an integrated circuit for providing supply voltages, comprising a voltage source for generating a first supply voltage (VBAT), a charge storage device for generating a second supply voltage (VCAP), a first power consumption device, and a second power consumption device. The first power consumption device has a lower power consumption than the second power consumption device. If the first and second power consumption devices are operated simultaneously, the first supply voltage (VBAT) is provided for operating the second power consumption device, and the second supply voltage (VCAP) is provided for operating the first power consumption device.

[0007] Document GB 2 262 003 A describes a circuit in which a supply voltage at an input terminal is applied to an output terminal via a Schottky diode and a capacitor. A voltage booster circuit charges the capacitor to a voltage greater than the supply voltage. The capacitor is connected to an output terminal via an FET when a circuit detects that the voltage at the input terminal is below a predetermined level. The voltage booster circuit includes a charge pump circuit, a voltage regulator, and a current limiting circuit. The charge pump circuit charges two capacitors to two and three times the input voltage, respectively. The input of the regulator is connected to a first capacitor, and the second capacitor provides a bias voltage for the FET. SUMMARY

[0008] There is a need to provide an improved concept for an interruption protection system for a circuit and a method for providing buffer energy to a circuit.

[0009] Such a need may be satisfied by the subject matter of any of the claims.

[0010] Embodiments relate to interrupt protection circuits for providing pump micro-interrupt protection to maintain sufficient voltage of the output signal from sensors and other devices during micro-interruptions and other interruptions.

[0011] In one embodiment, an interruption protection system for a circuit includes a power supply configured to provide power to the circuit; a capacitor configured to provide buffer energy; a charge pump electrically coupled to the capacitor to charge the capacitor to a buffer voltage; a reference unit configured to provide a reference signal; and a controller coupled to the power supply and to the reference unit and configured to receive the reference signal and selectively control a supply path from the power supply and from the capacitor to supply power to the circuit based on a comparison of the reference signal and a voltage level of the power supply.

[0012] Optionally, the buffer voltage is greater than a power supply voltage under normal operating conditions.

[0013] Again optionally, the charge pump has at least one pumping stage.

[0014] Optionally, the at least one pump stage has at least one switch.

[0015] The system further comprises at least one storage pass-through device coupled to the controller and to the capacitor, wherein the controller is configured to control the at least one storage pass-through device to control a current flow from the capacitor to a powered load.

[0016] The controller is configured to enable the at least one storage pass device to provide the buffer energy to the circuit when the comparison indicates that the level of power of the power supply is lower than a threshold level of the reference signal.

[0017] The buffer energy supplements the energy provided by the power supply or the buffer energy replaces energy provided by the power supply.

[0018] Again optionally, the system further comprises at least one input pass-through device coupled to the controller, wherein the controller is configured to control the at least one input pass-through device to provide power from the power supply to the circuit.

[0019] Optionally, the charge pump is designed to coordinate the charging of the capacitor with a circuit event.

[0020] Again optionally, the event is either a data signal transmission or a synchronization signal transmission.

[0021] Some embodiments relate to a method for providing buffer energy to a circuit, comprising enabling a charge pump to charge at least one buffer capacitor; receiving a power supply signal characterizing an event of a circuit; evaluating the power supply signal; and selectively using the at least one buffer capacitor to provide energy to the circuit based on the evaluation.

[0022] Optionally, enabling further comprises selectively switching the charge pump to enable or disable charging of the at least one buffer capacitor.

[0023] Again optionally, the evaluating further comprises comparing the power supply signal to a reference signal, and the selectively using further comprises using the at least one buffer capacitor to provide energy to the circuit when the power supply signal is lower than the reference signal.

[0024] Optionally, the selectively using further comprises activating a pass device to enable the buffer capacitor to provide energy to the circuit.

[0025] The selectively using further comprises providing energy to the circuit through the at least one buffer capacitor to supplement energy provided by a power supply, or the selectively using further comprises providing power to the circuit through the at least one buffer capacitor to replace power provided by a power supply.

[0026] Again optionally, the method further comprises coordinating the enabling with an event of the switching.

[0027] Optionally, coordinating further comprises enabling the charge pump to charge the at least one buffer capacitor during a data signal transmission through the circuit.

[0028] Again optionally, coordinating further comprises enabling the charge pump to charge the at least one buffer capacitor by an external supply during a synchronization signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be better understood by considering the following detailed description of various embodiments of the invention in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic diagram of a sensor integrated circuit according to one embodiment. Fig. 2 is a schematic diagram of a charge pump circuit and a storage capacitor according to an embodiment. Fig. 3A is a timing diagram of an output signal of the charge pump circuit according to an embodiment. Fig. 3B is a timing diagram of an output signal of the charge pump circuit according to an embodiment.

[0030] While the invention is susceptible to various modifications and alternative forms, details thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the invention is not intended to limit the invention to the specific embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0031] Embodiments relate to circuits, systems, and methods for providing interrupt protection for sensors and other devices. One embodiment includes an interrupt protection circuit configured to maintain sufficient voltage for output signals from sensors or other devices during micro-interruptions or other interruptions.

[0032] In embodiments, a sensor circuit includes an open-circuit protection circuit. In one embodiment, the open-circuit protection circuit may include at least one buffer capacitor and at least one charge pump. The charge pump may be coupled to the buffer capacitor to charge the capacitor such that the charge pump increases the amount of potential available to the sensor circuit across the capacitor by acting as a voltage multiplier. In embodiments, the charge pump is coupled to a supply source, such as a current source or a voltage source. In one embodiment, the supply source may refer to a synchronization pulse transmitted, received, or otherwise used by the sensor circuit.The charge pump may comprise at least one pump stage, wherein the pump stage may comprise at least one switch and at least one capacitor and uses at least one clock signal.

[0033] In operation, e.g. when the charge pump is activated, the clock signal goes to a logic high state and a first switch is activated. Activation of the first switch couples the capacitor to the charge pump such that the capacitor can be charged to the input voltage. The clock signal then goes to a logic low state after the capacitor is charged to the input voltage, which deactivates the first switch and activates a second switch. Activation of the second switch provides additional charge to the capacitor, allowing e.g. the bottom plate of the capacitor to also be charged to the input voltage, thereby increasing the amount of voltage available across the capacitor to a higher level than the input voltage of the charge pump.In another embodiment, the output voltage of the charge pump is supplied to the buffer capacitor, thereby providing a higher voltage than the supply voltage across the buffer capacitor and increasing the available potential. The desired output voltage of the charge pump can vary based on the number of pump stages used and the size of the buffer capacitor. Increasing the potential of the buffer capacitor allows an additional supply voltage to be set such that the voltage of the capacitor is higher than the operating voltage. In embodiments, the energy stored in the buffer capacitor can be used to provide a supply signal or an additional supply signal to the open circuit protection circuit.Charging the buffer capacitor to a voltage higher than the operating voltage and above the critical threshold provides the capacitor with sufficient stored energy to maintain a high supply voltage during micro-interruptions and other interruptions.

[0034] In another embodiment, a sensor circuit further comprises a processing unit, a pulse detection element, and a load. In embodiments, an output signal of the sensor circuit is provided to the load, wherein the load may be located internally or externally of the sensor circuit. Furthermore, the pulse detection element is configured to detect the presence of a pulse at the input, such as a synchronization pulse, and provides this information to the load, e.g., to indicate that the load should synchronize with other external circuitry to transmit data to a control unit.

[0035] In embodiments, the load provided by the externally supplied supply voltage or by the buffer capacitor during the occurrence of a micro-interruption or other interruption is the sensor itself and all of its associated processing circuitry, such as analog-to-digital converters, filters, clock and reset generators, microcontrollers and protocol generators, etc.

[0036] In embodiments, the processing unit comprises at least one controller, at least one reference unit, and at least one pass device circuit controlled by the controller. The reference unit is configured to provide a reference signal and information about an input signal. The controller is configured to receive an input signal, the reference signal, and an output signal. Consequently, the controller compares the input signal and the output signal with the reference signal, wherein the reference signal is used to provide the controller with a threshold range for the input signal and output signal. By evaluating the input signal, for example, the controller can determine whether the value of the input signal is high enough to maintain a sufficient voltage of the output signal.Based on the values ​​of the input signal, the controller manages the operation of a first pass device circuit and a second pass device circuit connected to the output of the controller.

[0037] In embodiments, the first pass device circuit is configured to receive the input signal and is activated by the controller when the input signal is above the reference signal. The second pass device circuit is configured to receive the supply signal or an additional supply signal and is activated by the controller when the input signal is slightly above or below the reference signal. Once the first pass device circuit is activated, the controller verifies the output signal to ensure that the input signal is sufficient to maintain the fixed voltage of the output signal. Otherwise, if the input signal is too low to maintain the fixed voltage of the output, such asIf it is slightly above the reference signal, the controller activates the second pass device circuit to provide an additional supply signal via the open-circuit protection circuit. In this case, both pass device circuits are activated, and the controller regulates the amount of the additional supply signal added to the input signal to maintain the fixed output voltage.

[0038] Additionally, if the input voltage level is lower than the threshold, e.g., due to a micro-interruption or other interruptions, the controller activates the second pass-device circuit to provide a supply signal to maintain the fixed output voltage. Without such circuitry, an interruption (i.e., micro-interruption) could reset the sensor circuitry and cause a restart after the micro-interruption disappears, resulting in unavailability of sensor function unless initialization is completed. Therefore, embodiments disclosed herein provide an additional supply source to maintain a fixed output voltage in the event of such an interruption.

[0039] Referring to Fig. Figure 1 shows a schematic diagram of a sensor circuit 100 employing open-circuit protection according to one embodiment. According to one embodiment, the sensor circuit 100 includes an open-circuit protection circuit 200, a processing unit 101, a reference unit 116, a load 128, and a pulse detection element 126. An open-circuit protection circuit may include a charge pump 120 and a buffer capacitor 130.

[0040] In embodiments, the input signal Vs is supplied from the bus supply of an external circuit, such as an electronic control unit (in Fig. 1 not shown), and is the operating input voltage of the sensor circuit 100.

[0041] In embodiments, a reference unit 116 provides a reference signal Vref to the controller 114, wherein the reference signal Vref includes predetermined thresholds with respect to the input signal Vs. These thresholds may vary in embodiments, e.g., depending on the available voltages, application, sensor type, or other factor.

[0042] The reference unit 116 may vary in embodiments and may, for example, be configured as a bandgap voltage reference or a Zener voltage reference. In embodiments, the energy stored in the buffer capacitor 130 may be used as a supply signal or additional supply signal when the value of the input signal Vs falls below a preset or critical threshold, as defined by the reference signal Vref. As such, the use of an additional supply signal enables the output signal Vout to maintain a fixed output voltage to be supplied to the circuitry of the load 128. In operation, the load 128 may, for example, be configured to generate an output signal to a control unit, wherein the output signal may include sensor measurement data, sensor status, or initialization data.The transfer of data from load 128 to the control unit may result in an increase in the current consumed by load 128. However, to compensate for this current increase, controller 114 adjusts the control settings of pass devices 122 and 124. In embodiments, controller 114 controls which pass device circuit 122 or 128 is activated based on a comparison of input signal Vs and reference signal Vref. If the level of input signal Vs is greater in magnitude than reference signal Vref, controller 114 activates input pass device 122, allowing output signal Vout to be maintained by input signal Vs.In another embodiment, the controller 114 activates the storage pass device 124 when the input signal Vs is below the reference signal Vref, allowing the output signal Vout to be maintained by the additional supply signal of the buffer capacitor 130. The current sharing between the external supply Vs and the buffer capacitor, performed by the input control pass device 122 and the storage pass device 124, can be performed by a variety of circuit and control components. For example, the input pass device 122 and the storage pass device 124 can comprise bipolar transistors whose base terminals are connected to the output of the controller 114, thereby selectively drawing current from either the input signal Vs or the additional supply signal of the buffer capacitor 130.

[0043] In another embodiment, the controller 114 compares the input signal Vs and the output signal Vout with the reference signal Vref to control the current flow from the pass device elements 122 and 124. The controller 114 manages the input pass device 122 and the storage pass device 124 by regulating the portion of the input signal Vs and the portion of the auxiliary supply that contributes to the output signal Vout. For example, conduction through the pass devices can be performed either from the operating voltage (input signal Vs) to the auxiliary supply signal or from the auxiliary supply signal into the input signal Vs, allowing a portion of the output signal Vout to be provided by the auxiliary supply signal and a portion to be provided by the input signal.The percentage of the output signal Vout maintained by the input signal Vs, the supply signal of the buffer capacitor 130, or a combination of the input signal Vs and the additional supply signal of the buffer capacitor 130 is determined by the controller 114.

[0044] In one embodiment, a pulse detection element 126 may be implemented in sensor circuit 100 to detect pulses, such as synchronization pulses or other brief increases in a supply signal associated with communications or other circuit events, in the input signal Vs to provide signal information to the load 128. The signal information provided by the pulse detection element 126 may be used, for example, to synchronize the data transmission behavior of the load 128 to be supplied by further circuitry.

[0045] In another embodiment, a controller 114 may provide an additional information signal to the load 128, which may be used to warn the load 128 to reduce its power consumption when the input signal Vs falls below the critical threshold. Upon receiving this signal information, the load 128 may turn off excess power consumers. For example, a power consumer could be a current modulator in a pressure or other sensor that provides data transmission to an electronic control unit and thus has a higher power consumption than the sensor itself.

[0046] Referring to Fig. Figure 2 shows a block diagram of an interrupt protection circuit 200 according to one embodiment. The interrupt protection circuit 200 includes a charge pump circuit 120 and a buffer capacitor 130 in some embodiments.

[0047] The charge pump circuit 120 includes pump stages 210 and 212, as shown, but may include more or fewer pump stages in other embodiments. The particular layout and design of the charge pump circuit 120 is purely exemplary and may vary in embodiments. For example, the charge pump circuit 120 may include one or more pump stages that are electrically coupled by connecting the output of one stage to the input of the next stage based on the desired output. Each pump stage may include a plurality of switching devices and capacitors to generate a boosted output voltage at each pump stage, with each switching device being alternately controlled by a clock signal CLK and CLK¯ is activated. In operation, e.g., when the clock signal CLK is low, the first switch is activated and current flows to a first capacitor within the initial pump stage, providing an increased potential and allowing the capacitor to be charged to the input voltage. The clock signal CLK then goes high and the first switch is deactivated. In this state, the second switch is activated and current flows from the output of the first capacitor to a second capacitor within the initial pump stage, allowing the second capacitor to be charged to a higher voltage than the input voltage. On the next cycle, the clock signal CLK goes low and CLK¯ goes high, the second switch is deactivated, and a third switch with a second pumping stage is activated, increasing the voltage of a third capacitor to a higher voltage than the first two preceding capacitors. Depending on the desired output, multiple pumping stages can be implemented to generate a high output voltage of the charge pump circuit 120. In embodiments, the output terminal of the charge pump circuit 120 is connected to the input terminal of the buffer capacitor 130; therefore, when the charge pump circuit is activated, the output voltage of the charge pump circuit 120 is supplied to the top plate of the buffer capacitor 130.

[0048] Referring to Fig. 3A and Fig. 3B, timing diagrams of a charge pump mode of operation are shown according to one embodiment. Curve 300 represents the input voltage of the sensor circuit 100 based on the synchronization period of the input signal Vs. Curve 301 represents the input current of the sensor circuit 100 based on the data transmission period of the input signal Vs. Curve 302 represents a charge pump mode 314 based on the synchronization period and data transmission period of the input signal Vs. In embodiments, the charge pump circuit 120 is activated when the input signal Vs enters transmission mode 312, thereby increasing the sensor's current consumption. In this state, the input signal is a pulsed, current-modulated signal, and upon the rising edge of the signal, the charge pump circuit 120 transitions to an active state and remains in an active state for the entire data transmission period.Therefore, although charge pump circuit 120 typically generates high power consumption, with such a configuration, the total power consumed by sensor circuit 100 is minimized. Power consumption remains completely unchanged during transmit mode 312 because charge pump circuit 120 only consumes a portion of the modulation current, which is already higher to accommodate data transmission. In this example, charge pump circuit 120 can operate independently of synchronization mode 310 and remains completely inactive while the input sensor is not in transmit mode 312, further reducing the amount of power consumed.

[0049] Referring to Fig. 3B, curves 303 and 304 correspond to input signal curves 300 and 301, as in Fig. 3A. Curve 305 represents a charge pump mode 320 based on the synchronization period of the input signal. In another embodiment, the charge pump circuit 120 is activated when the input signal enters synchronization mode 316, thereby minimizing the power consumed by the sensor circuit 100. Here, the input signal periodically generates a logic high voltage level at the input signal, thereby reducing the number of pumping stages that would be needed to generate the target output voltage of the charge pump circuit 120. Upon the rising edge of the signal, the charge pump circuit 120 activates and remains active for one synchronization period. In this example, the charge mode 320 is active only during the synchronization mode 316 and is deactivated while the input signal is in the transmit mode 318.

[0050] In another embodiment, the input signal is measured using a controlled voltage source (in Fig. 3 not shown) to manipulate the magnitude of the input voltage, where the input voltage would behave as a stable voltage source. In this example, the number of pump stages required to achieve a desired output voltage of charge pump circuit 120 would increase, in addition to the power consumption of charge pump circuit 120.

[0051] Embodiments thereby provide open-circuit protection circuits, systems, and methods that can be used with a variety of devices and in a variety of applications. Various applications may relate to automotive sensing, such as with pressure and other sensors. For example, airbag sensing systems often employ pressure sensors and are considered safety-critical applications where small power and other interruptions can pose significant problems. Incorporating embodiments of the open-circuit protection circuitry discussed herein into airbag sensing systems can thus provide operational protection against micro-open circuits and other interruptions that may occur in an automobile.Other applications may include other sensors and components in automotive applications, as well as in aerospace, medical, machining, and virtually any other situation where a brief interruption in power may be a significant or unpleasant disadvantage.

[0052] While various embodiments discussed herein relate to sensors or particular types or applications of sensors, these embodiments are in no way limiting with respect to the claims and are used herein as examples. Additionally, while some examples discuss specific signals, including certain signals that may be logic high or logic low, these are again only examples, and in other embodiments, other signals may be used, or the logic high and low triggers may be interchanged, or other signal communication and processing techniques may be used, without limitation with respect to the claims or other embodiments discussed or shown herein.

[0053] Various embodiments of systems, devices, and methods have been described herein. These embodiments are provided solely by way of example and are not intended to limit the scope of the invention. However, it should be appreciated that the various features of the embodiments described may be combined in various ways to produce numerous additional embodiments. Furthermore, while various materials, dimensions, shapes, configurations, locations, etc., have been described for use with disclosed embodiments, others than those disclosed may be used without exceeding the scope of the invention.

Claims

[1] An interruption protection system (100) for a circuit, comprising: a power supply (Vs) configured to provide power to the circuit; a capacitor (130) configured to provide buffer energy; a charge pump (120) electrically coupled to the capacitor (130) for charging the capacitor (130) to a buffer voltage; a reference unit (116) configured to provide a reference signal; and a controller (114) coupled to the power supply and to the reference unit (116) and configured to receive the reference signal and selectively control a supply path from the power supply and from the capacitor (130) to supply power to the circuit based on a comparison of the reference signal and a voltage level (Vs) of the power supply, further comprising at least one storage pass-through device (124) coupled to the controller (114) and to the capacitor (130), wherein the controller (114) is configured to control the at least one storage pass-through device (124) to control a current flow from the capacitor (130) to a supplied load (128), wherein the controller (114) is configured to enable the at least one storage pass device (124) to provide the buffer energy to the circuit when the comparison indicates that the level of power of the power supply is lower than a threshold level of the reference signal, where the buffer energy supplements the energy provided by the power supply, or where the buffer energy replaces energy provided by the power supply. [2] The system (100) of claim 1, wherein the buffer voltage is greater than a power supply voltage under normal operating conditions. [3] The system (100) according to claim 1 or 2, wherein the charge pump (120) has at least one pumping stage. [4] The system (100) of claim 3, wherein the at least one pumping stage comprises at least one switch. [5] The system (100) of any preceding claim, further comprising at least one input pass-through device (122) coupled to the controller (114), wherein the controller (114) is configured to control the at least one input pass-through device (122) to provide power from the power supply to the circuit. [6] The system (100) according to any one of the preceding claims, wherein the charge pump (120) is configured to coordinate the charging of the capacitor (130) with an event of the circuit. [7] The system (100) of claim 6, wherein the event is either a data signal transmission or a synchronization signal transmission. [8] A method for providing buffer energy to a circuit, comprising: enabling a charge pump (120) to charge at least one buffer capacitor (130); Receiving a power supply signal characterizing a circuit event; evaluating the power supply signal; and Selectively using the at least one buffer capacitor (130) to provide energy to the circuit based on the evaluation, wherein the selectively using further comprises providing energy to the circuit through the at least one buffer capacitor (130) to supplement energy provided by a power supply, or wherein said selectively using further comprises providing power to the circuit through the at least one buffer capacitor (130) to replace power provided by a power supply. [9] The method of claim 8, wherein enabling further comprises selectively switching the charge pump (120) to enable or disable charging of the at least one buffer capacitor (140). [10] The method of claim 8 or 9, wherein evaluating further comprises comparing the power supply signal to a reference signal, and selectively using further comprises using the at least one buffer capacitor (130) to provide energy to the circuit when the power supply signal is lower than the reference signal. [11] The method of any one of claims 8 to 10, wherein said selectively using further comprises activating a pass device (124) to enable said buffer capacitor (130) to provide power to said circuit. [12] The method of any one of claims 8 to 11, further comprising coordinating the enabling with an event of the circuit. [13] The method of claim 12, wherein coordinating further comprises enabling the charge pump (120) to charge the at least one buffer capacitor (130) during a data signal transmission through the circuit. [14] The method of claim 12 or 13, wherein coordinating further comprises enabling the charge pump (120) to charge the at least one buffer capacitor (130) during a synchronization signal transmission by an external supply.

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