Abstract: A door unlocking and/or door opening mechanism may have an actuating device that may have at least one actuating element, a housing, and at least one detection unit. The detection unit may have a sensor, a trigger element and an evaluation unit. The detection unit may be arranged in the housing. The actuating element may be arranged for an actuation outside the housing and in a region that is accessible from the outside. The trigger element may be arranged at a distance from the sensor in a locked state of the door unlocking and/or door opening mechanism. When the actuating element is actuated in the direction of the housing, to the actuating element deforms the trigger element. The sensor detects a change in the distance between the trigger element and the sensor.

Abstract: An electronic faucet including a body, a capacitive sensor, a controller and a capacitive sensitivity adjustment device operably coupled to the controller to change the magnitude of an output signal of the capacitive sensor.

Abstract: In various aspects, the sensors include a substrate that is porous and non-conductive with nanoparticles deposited onto the substrate within pores of the substrate by an electrophoretic process to form a sensor element. The nanoparticles are electrically conductive. The sensor includes a detector in communication with the sensor element to measure a change in an electrical property of the sensor element. The change in the electrical property may result from alterations in quantum tunneling between nanoparticles within the sensor element, in various aspects.

Abstract: Circuits for measuring a leakage current of one or more capacitors coupled to a power supply line that powers an apparatus, such as a storage device, are disclosed. In one embodiment, the circuit includes first and second resistors between the power supply line, and first and second respective switches to ground. A controller may charge the voltage line to a first voltage. Thereafter, the controller discharges the first voltage to a second voltage via the first resistor during a first identified time. After recharging the voltage line, the controller then discharge the first voltage to the second voltage via at least the second resistor during a second identified time. The controller determines the parasitic resistance using the first and second identified times, and then the leakage current from the parasitic resistance.

Abstract: A cable compensation circuit compensates a voltage drop in a cable coupled between a power supply and a load. The cable compensation circuit includes: a node where a voltage that depends on an input voltage of the power supply during a turn-on period of a power switch of the power supply and depends on an output voltage of the power supply during a turn-off period of the power switch is generated; a sensing RC filter generating a sense voltage that depends on a diode current by filtering the voltage of the node; and an averaging RC filter generating an average voltage by averaging the sense voltage.

Abstract: The invention relates to an apparatus and method for tracking energy consumption. An energy tracking system comprises at least one switching element, at least one inductor and a control block to keep the output voltage at a pre-selected level. The switching elements are configured to apply the source of energy to the inductors. The control block compares the output voltage of the energy tracking system to a reference value and controls the switching of the switched elements in order to transfer energy for the primary voltage into a secondary voltage at the output of the energy tracking system. The electronic device further comprises an ON-time and OFF-time generator and an accumulator wherein the control block is coupled to receive a signal from the ON-time and OFF-time generator and generates switching signals for the at least one switching element in the form of ON-time pulses with a constant ON-time.

Abstract: Apparatus for monitoring and providing visual representations of the operating conditions of machine tool parameters, in particular for program-controlled turning, milling, and drilling machines, which have a machining unit displaceable in a plurality of coordinate axes, in which a work spindle for exchangeable receiving a machining tool and an electric motor for driving the work spindle are mounted. The machine tool includes a control unit and means for monitoring the operating state of the machine tool. The monitoring apparatus has at least one sensor for detecting at least one operating parameter of the machine tool. An evaluating unit is connected to both the sensor and the control unit and processes the measurement values detected by the sensor. An optical display is provided in the direct viewing range of the operator, which viewing range includes the machine operating spindle, tool holder, tool, and workplace.

Abstract: Aspects disclosed in the detailed description include an electrostatic discharge (ESD) protection circuit. In this regard, in one aspect, an ESD protection circuit is provided to protect an integrated circuit (IC) during fabrication and production. An ESD detection circuitry detects an ESD event by detecting a voltage spike between a supply rail and a ground rail exceeding an ESD threshold voltage. In response to detecting the ESD event, an ESD clamping circuitry is activated to discharge the ESD event, thus protecting the IC from being damaged by the ESD event. By detecting the ESD event based on the ESD threshold voltage, as opposed to detecting the ESD event based on rise time of the voltage spike, it is possible to prevent the ESD clamping circuitry from missing voltage spikes associated with a slow rise time or being falsely activated by a normal power-on voltage associated with a fast rise time.

Abstract: An embodiment apparatus comprises a secondary synchronous rectifier and a secondary gate drive controller coupled to a transformer winding. The secondary gate drive controller is configured to generate a forward gate drive signal for the forward switch and generate a freewheeling gate drive signal for the freewheeling switch, wherein the secondary gate drive controller generates a dead time between the forward gate drive signal and the freewheeling gate drive signal.

Abstract: A processing system comprises a sensor module and a determination module. The sensor module is configured to drive a modulated signal on to a sensor electrode to achieve a target voltage on the sensor electrode during a first portion of a sensing cycle, wherein the modulated signal comprises a first voltage that is beyond a level of the target voltage and which is driven for a first period of time and a second voltage that is at the target voltage and which is driven for a second period of time that follows the first period of time. The determination module is configured to determine an absolute capacitance of the sensor electrode during the first portion of the sensing cycle after driving the second voltage.

Abstract: A system and method for enabling a dual interface smart card reader to be able to determine if data should be read from a smart card using wireless technology or touch technology, even when the data can be accessed through wireless technology.

Abstract: An apparatus and method for determining characterizing attributes of an actuator is provided. An actuator may be moved to a maximum capacitance position. At the maximum capacitance position, an initial measurement of the actuator capacitance is made. The actuator is moved a predetermined increment toward a first extreme position, and the actuator capacitance is again measured. If the capacitance changed by a threshold amount, the signal preceding the signal that caused the actuator to move is recorded as an approximate response curve end point, or the first extreme position. The actuator is again moved a predetermined increment toward a second extreme position. After each move, the capacitance is measured. If it is determined the capacitance did change by a threshold amount from the previously measured capacitance, the signal related to the previously measured capacitance is recorded as an approximate response curve end point, or the second extreme position.

Abstract: A system and method for testing capacitance of a load circuit connected to an output pin of a driving circuit In one embodiment, the method may comprise driving a voltage at the output pin to a first voltage; a predetermined current to the output pin; comparing the voltage at the output pin to a reference voltage; and when the voltage at the output pin matches the reference voltage, generating an estimate of capacitance present at the output pin based on a number of clock cycles occurring between an onset of a timed voltage change period and a time at which the voltage at the output pin matches the reference voltage.

Abstract: A method for monitoring operation of a solenoid valve having an armature and a poppet coupled to the armature includes the steps of energizing a coil in the valve to generate a current signature reflecting current vs. time, detecting a first inflection point in the current signature, wherein the first inflection point occurs when the armature starts to move from one of the open and closed positions toward the other of the open and closed positions, and detecting a second inflection point in the current signature. The second inflection point occurs when the armature moves completely to the other of the open and closed positions. In one embodiment, the first inflection point indicates when the valve begins to open, making it possible to accurately determine the elapsed opening time of the valve.

Abstract: A proximity sensor interface device (PSID) for determining if a proximity sensor is in an acceptable position with respect to a target device is described. The PSID includes a frequency generator, a processing device, a memory associated with the processing device, a display, and an RC circuit. The processing device is programmed to route a signal generated by the frequency generator through the proximity sensor and the RC circuit for a prescribed period of time and the processing device is programmed to measure a discharge time of the RC circuit. The processing device is further programmed to cause the display to provide an indication of whether the relative position of the proximity sensor and the target device are within prescribed tolerances, based on the discharge time.

Abstract: A method and apparatus for determining an RC (resistive-capacitive) time constant is disclosed. In one embodiment, a method comprises determining a first period of oscillation when an oscillator is operating in a first configuration. The method further comprises determining a second period of oscillation when the oscillator is operating in a second configuration. A measurement circuit is configured to determine a resistive-capacitive (RC) time constant of the oscillator by determining a mean of the first and second periods.

Abstract: An emission spectrophotometer capable of inhibiting non-uniformity of spectral intensities of component elements is provided. The emission spectrophotometer generates pulse light emission by supplying an energy accumulated in an electricity accumulating and discharging unit to a gap between an electrode and a test material, and the emission spectrophotometer includes a detection unit, for detecting an energy charged to the electricity accumulating and discharging unit before the pulse light emission; and a detection unit, for detecting an energy remaining in the electricity accumulating and discharging unit after the pulse light emission. It is determined whether the detected light is emitted by fully using the energy accumulated in the electricity accumulating and discharging unit.

Abstract: The invention proposes a circuit arrangement for determination of a measuring capacitance (1), comprising a reference circuit portion for defined periodic charging and discharging of a predefined reference capacitance (1a), and a measuring circuit portion for defined periodic charging and discharging of the measuring capacitance (1) to be determined, and at least one circuit portion (4, 7; 4a, 7a) intended to determine at least one value (M2) characteristic of the charging time curve of the reference capacitance (1a) and for deriving at least one value (M1) characteristic of the charging time curve of the measuring capacitance (1), as well as a circuit portion (9) for comparing the at least one value (M2) characteristic of the charging time curve of the reference capacitance (1a) with the at least one value (M1) characteristic of the charging time curve of the measuring capacitance (1), and for deriving from that comparison the value of the measuring capacitance (1).

Abstract: Mechanically tuned radios and related methods are disclosed that utilize ratiometric time measurements to detect settings for mechanical adjustment mechanisms. The radio systems and methods disclosed make a first time measurement associated with a mechanically adjusted circuit, make a second time measurement associated with the mechanically adjusted circuit, determine a setting for the mechanical adjustment mechanism based upon a ratio associated with the first and second time measurements, and utilize the setting to select a tuning frequency for signals received by the radio. More generally, ratiometric time measurements can be used to determine a setting for a mechanical adjustment mechanism for a mechanically adjusted circuit, and this setting can be used to at least part control a desired operational feature of a device.

Abstract: Changes of the stray capacitances of a large number of sensing electrodes can be detected simultaneously. Further, even if a stray capacitance changes slightly, an input operation to a sensing electrode can be detected based on elapsed time until the electric potential of the sensing electrode becomes the same as a threshold potential. The stray capacitance of a sensing electrode and a resistor of the sensing electrode form a CR time constant circuit. Charge or discharge of the stray capacitance of the sensing electrode is controlled while a rest time in a predetermined time ratio is set. A stray capacitance that slightly increases in response to an input operation made near a sensing electrode can be detected by detecting the stray capacitance in extended elapsed time until the electric potential of the sensing electrode becomes the same as the threshold potential.

Abstract: A capacitance measurement circuit and method are provided. A storage capacitor is pre-charged. Charge transfer is performed between an under-test capacitor and the storage capacitor. The storage capacitor is discharged and charged according to a relationship between a voltage of the storage capacitor and a reference voltage. The capacitance of the under-test capacitor is measured according to the voltage on the storage capacitor.

Abstract: A method and apparatus for determining an RC (resistive-capacitive) time constant is disclosed. In one embodiment, a method comprises determining a first period of oscillation when an oscillator is operating in a first configuration. The method further the method further comprises determining a second period of oscillation when the oscillator is operating in a second configuration. A measurement circuit is configured to determine a resistive-capacitive (RC) time constant of the oscillator by determining a mean of the first and second periods.

Abstract: An analog front end circuit utilizes coherent detection within a capacitance measurement application. The analog front end circuit uses coherent detection to measure capacitance of a touch screen display. An analog excitation signal is modulated by a capacitor to be measured. The modulated signal is synchronously demodulated using a correlator, which includes an integrated mixing and integration circuit. The correlator includes a programmable impedance element that generates a time-varying conductance according to a controlling digitized waveform.

Abstract: A sync signal generator for a capacitive sensor includes a charge amplifier having an input for coupling to an inactive receive line in the capacitive sensor, a first comparator having a first input for receiving a first threshold voltage, a second input coupled to an output of the charge amplifier, and an output for providing a first sync signal, and a second comparator having a first input for receiving a second threshold voltage, a second input coupled to the output of the charge amplifier, and an output for providing a second sync signal. The charge amplifier includes an operational amplifier having a feedback circuit including a capacitor and a switch. The first threshold voltage is provided by a first digital-to-analog converter, and the second threshold voltage is provided by a second digital-to-analog converter.

Abstract: A configurable PSRO measurement circuit is used to measure the frequency dependent capacitance of a target through silicon via (TSV) or other conductive structure. Measurements of the target structure are aided by using adjustable resistors and a de-embedding structure to measure the effects of parasitic capacitance, CPAR. Current is measured to both the device under test (DUT) and the de-embedding structure. From these measurements, the frequency dependent capacitance of the DUT is calculated.

Abstract: A device for determining a position of a proximity sensor with respect to a target mechanism is described. The device includes a frequency generator, a processing device, and an RC circuit. An output of the frequency generator is operable for application to a proximity sensor whose position relative to a target is to be verified. The RC circuit is chargeable via voltage applied to the proximity sensor by the frequency generator. The processing device is programmed to turn off the output of the frequency generator after a prescribed amount of time, and further programmed to measure a discharge time of the RC circuit after turning off the output of the frequency generator. The discharge time of the RC circuit is directly proportional to a perceived gap between a face of the proximity sensor and the target mechanism.

Abstract: Changes of the stray capacitances of a large number of sensing electrodes can be detected simultaneously. Further, even if a stray capacitance changes slightly, an input operation to a sensing electrode can be detected based on elapsed time until the electric potential of the sensing electrode becomes the same as a threshold potential. The stray capacitance of a sensing electrode and a resistor of the sensing electrode form a CR time constant circuit. Charge or discharge of the stray capacitance of the sensing electrode is controlled while a rest time in a predetermined time ratio is set. A stray capacitance that slightly increases in response to an input operation made near a sensing electrode can be detected by detecting the stray capacitance in extended elapsed time until the electric potential of the sensing electrode becomes the same as the threshold potential.

Abstract: Disclosed is an arrangement for monitoring changes in an object's surrounding field, including a sensor-active region(s), a measurement path(s) with a driver for applying a variable, a receiver(s) detecting a variable, a circuit connected downstream of the receiver for determining changes in a surrounding field and generating a control and/or measurement signal, a further measurement path(s) or reference section(s) with a driver to detect changes in the variable and the measurement path(s), a clock circuit switched on at time intervals of the measurement path and the reference path a regulating device for the variable(s) introduced by the drivers in response to changes in the variable in the field, with the result that at the receiver average the same amplitude of the variable passes from the drivers and the sensor-active region to the receiver from the measurement paths the sensor-active region being coupled with high resistance to the drivers.

Abstract: A method of estimating an inductance delay includes determining a resistance-capacitance (RC) delay with resistances and capacitances of a network and estimating an inductance delay of the network by determining a propagation delay of an electromagnetic (EM) field across wires of the network. Additionally, the method includes determining if the RC delay is below a specified threshold and adding the estimated inductance delay to the RC delay to determine a total time to propagate voltage swings through the network if the RC delay is below the specified threshold.

Abstract: A method for controlling brake resistors and a brake chopper, the number of brake resistors being two or more and the brake resistors being connected in series with switches to be controlled, the series connection being connected between a positive and a negative rail of a DC voltage intermediate circuit, the method comprising the step of determining a magnitude for a voltage of the DC intermediate circuit; and determining a first voltage limit and a second voltage limit. The method further comprises the steps of switching brake resistors to the intermediate circuit in a periodically alternating manner, each switch being switched during a switching period and the on-period of each switch in a switching period being responsive to the magnitude of the voltage in the DC voltage intermediate circuit when the voltage is above the first predetermined limit and below the second predetermined limit.

Abstract: Subsystems and methods for use in patch clamp systems are provided. For example, in certain embodiments, compensation circuitry is used to compensate for non-idealities present in the patch clamp system. The accuracy of this compensation may be verified by employing, for example, circuitry that models the patch clamp system.

Abstract: A circuit arrangement is described for detecting the capacitance or change of capacitance of a capacitive circuit element or of a component, specifically of a sensor capacitor (1), with a control unit (2) ,with a monostable multivibrator (3) triggered by the control unit (2), and with an evaluation unit (4), the monostable multivibrator (3) having a first input (5) which is connected to the control unit (2), a second input (6)which is connected to the sensor capacitor (1), and one output (7), of the monostable multivibrator (3) is triggered by the control unit (2) at the output (7) of the monostable multivibrator (3) an output signal or output signals appearing, with a time duration which is proportional to the capacitance of the sensor capacitor (1), the output signal or output signals of the monostable multivibrator (3)being converted into a signal voltage proportional to its or their duration, and in the evaluation unit (4) a detection value corresponding to the capacitance or change of capacitance of the

Abstract: The invention relates to a method for producing a time base for a microcontroller and a simple circuit arrangement therefor, which comprises an RC-element having a specific time constant, said element being connected to a connection of the microcontroller. According to said method, the capacitor of the RC element is charged to an initial voltage in a first step, then in a second step, the number of timed impulses is counted until the voltage on the capacitor falls below the initial voltage to a determined percentage of the initial voltage or a voltage threshold value, and then in a third step, the counted number of timed impulses is used as a time base.

Abstract: A system for determining the logic state of a resistive memory cell element, for example an MRAM resistive cell element. The system includes a controlled voltage supply, an electronic charge reservoir, a current source, and a pulse counter. The controlled voltage supply is connected to the resistive memory cell element to maintain a constant voltage across the resistive element. The charge reservoir is connected to the voltage supply to provide a current through the resistive element. The current source is connected to the charge reservoir to repeatedly supply a pulse of current to recharge the reservoir upon depletion of electronic charge from the reservoir, and the pulse counter provides a count of the number of pulses supplied by the current source over a predetermined time. The count represents a logic state of the memory cell element.

Abstract: A level shift IC (3b) of a power supply/shutoff section (3) is operable, when a shutoff signal (Sa) is input from a timer circuit (8) for a time T during an ON state of a discharge lamp (7), to turn off a MOSFET (3a) so as to shut off power supply to a smoothing capacitor (4). When a detection signal (Sb) of a capacitor voltage is lowered to a value less than a reference voltage Vr1 during input of the shutoff signal (Sa), an output of a comparator (10) is changed from an H level to an L level in an inverted manner. In conjunction with this change, respective outputs of an auxiliary control circuit (12) and a NOT element (12a, 12b) are changed from an L level to an H level in an inverted manner. As a result, a current flows from the NOT element (12a) to an LED (13b) through a resistor (13a) to turn on the LED (13b). Thus, a life end of the smoothing capacitor 4 is annunciated, and a main control circuit (6) is operable to suppress an output of an inverter main circuit (5).

Abstract: Subsystems and methods for use in patch clamp systems are provided. For example, in certain embodiments, compensation circuitry is used to compensate for non-idealities present in the patch clamp system. The accuracy of this compensation may be verified by employing, for example, circuitry that models the patch clamp system.

Abstract: A capacitive proximity sensor for use in object and position sensing and/or position control in respect of a swing arm of a medical imaging system. The sensor comprises, within a cover (18), an emitter electrode (10) and a sense electrode (9) both of which are formed by spraying or otherwise coating or painting a layer of conductive material on the inner surface of the cover (18). A carrier plate (30) is mounted within the cover (18), at a distance therefrom, on which are provided an active guard electrode (13) in respect of the sense electrode (9) and a grounded shield member (15) in respect of the emitter electrode (10). As there is virtually no gap between the sense electrode (9) and the cover (18), the sensor is less sensitive to the effects of material changes caused by environmental changes in temperature and/or humidity, for example.

Abstract: An arrangement serves the purpose of monitoring an object such as a door for changes in a field surrounding the object. A sensor-active region having a measurement area (11a) is associated with the object, and a driver (12, 13) applies a certain variable in the sensor-active region. A receiver (14) detects the variable applied by the drivers and changes in the variable in the field surrounding the object (10) in the sensor-active region (11). By means of a circuit which is connected downstream of the receiver (14), the changes in the field surrounding the object (10) are used to produce a control and/or measurement signal (?11a, ?11b).

Abstract: A system for determining the logic state of a resistive memory cell element, for example an MRAM resistive cell element. The system includes a controlled voltage supply, an electronic charge reservoir, a current source, and a pulse counter. The controlled voltage supply is connected to the resistive memory cell element to maintain a constant voltage across the resistive element. The charge reservoir is connected to the voltage supply to provide a current through the resistive element. The current source is connected to the charge reservoir to repeatedly supply a pulse of current to recharge the reservoir upon depletion of electronic charge from the reservoir, and the pulse counter provides a count of the number of pulses supplied by the current source over a predetermined time. The count represents a logic state of the memory cell element.

Abstract: A bias tee for connecting a measurement device to a DUT, where the measurement device has a guard output, includes a DC port; a HF port; and a measurement port. The HF input port is guarded with the guard output during operation of the bias tee.

Abstract: A method and apparatus for detecting an impedance across a pair of terminals. A sensing circuit is AC coupled to the terminals which produces an output related to a time constant associated with the impedance.

Abstract: An integrated circuit having a first couple of components R and C, at least a second couple of components R1–R3 and C?1–C?2 and a calibration circuit. The couple of componets form an RC cell of which one component is adjustable, and the calibration circuit. The invention corrects the errors in the values of the components of RC cells of the same nature. The calibration circuit performs the adjustment of an RC cell and then applies the same correction to the components of the other RC cells of the same nature.

Abstract: A method for determining capacitance includes alternately charging a capacitor to a first voltage and discharging the capacitor to a second voltage, generating an output signal having a frequency that is a function of a time period, and determining the capacitance based on the frequency of the output signal. The time period is selected from at least one of: (a) a time period needed to charge the capacitor from the second voltage to the first voltage and (b) a time period needed to discharge the capacitor from the first voltage to the second voltage.

Abstract: An electrical circuit for determining a capacitance is described. The electrical circuit includes a first device, a rectifying circuit and a feedback circuit. The first device has a first terminal and a second terminal. The first device has a first unknown capacitance and the first terminal may be configured to receive a time-varying voltage signal. The rectifying circuit has an input terminal, an output terminal and a feedback terminal. The input terminal may be coupled to the second terminal and the output terminal may be configured for coupling to an output electrical circuit. The feedback circuit may selectively couple the output terminal to the input terminal using the feedback terminal such that the output terminal and the input terminal are substantially at a common voltage.

Abstract: A method and device for determining the ratio between the actual value of an RC time constant of an RC network embodied in an integrated circuit and a set value of the RC time constant includes first and second reference RC networks each having a resistor and a capacitor. The two RC networks may be oppositely connected in a circuit arrangement between first and second supply potentials, where the product of the resistance and capacitance values of the two RC networks may be equal. A normalized RC time constant may be defined for the two reference RC networks. Successive charge and discharge cycles are implemented during a predetermined evaluation period, the two capacitors being charged in a cycle during a charge time until the potential at a first node of the first reference RC network approximately corresponds to the potential at a second node of the second reference RC network. The two capacitors may be subsequently discharged for a discharge time.

Abstract: The apparatus for detecting the effects of interconnect resistance and capacitance (RC) in a logic circuit includes a first ring oscillator with the interconnect RC parasitics in a logic circuit and a minimum reference ring oscillator without the interconnect RC parasitic in a logic circuit multiplexed to have common stages to obtain delay with and without the parasitics of the interconnect RC. The frequency difference between the first ring oscillator frequency and the minimum reference ring oscillator frequency is determined to detect the effects of the interconnect RC in the logic circuit.

Abstract: A method of estimating delay which includes configuring a first signal path and second signal path such that the first signal path is a victim signal path and the second signal path is an aggressor signal path, calculating Miller factors between the victim signal path and the aggressor signal path for a plurality of edge combinations between a victim signal edge and an aggressor signal edge, and using the Miller factors to perform a timing analysis.

Abstract: A method and apparatus for providing information from a speed and direction sensor is disclosed. The method and apparatus detect the presence of a ferromagnetic object as it moves past a sensor. The sensor determines speed and direction information regarding the ferromagnetic object, and further provides information relating to the environment surrounding the sensor or object, such as the status of an air gap between the sensor and the moving object, and the temperature of the environment in which the sensor or object is disposed.

Abstract: A method is contemplated. According to the method, capacitances in a first resistance/capacitance (RC) extraction corresponding to a circuit are modified. Each capacitance is modified to estimate Miller effect on that capacitance. A ratio of a total capacitance on a first wire after the modification in the first RC extraction to a total capacitance on the first wire before the modification in the first RC extraction is calculated. Capacitances in a second RC extraction that are coupled to the first wire are modified according to the ratio. The second RC extraction is a reduced extraction as compared to the first RC extraction. A timing analysis is performed for the circuit using the second RC extraction with capacitances modified to estimate Miller effect.

Abstract: A method and apparatus is provided for clamping of an electrostatic discharge using multiple time-constants. A rise in a voltage level is detected. A first time-constant is provided to determine whether the rise in the voltage level is caused by an electrostatic event. A clamping function is provided to clamp the voltage level in response to a determination that the rise in the voltage level is caused by the electrostatic event. A second time-constant is provided to provide a time period for maintaining the clamping function for a period of time to substantially extinguish the electrostatic event.