Abstract: One example includes a power supply system. The system includes a voltage-limit power regulator to generate an output voltage and an instantaneous overvoltage sensor configured to detect an overvoltage condition associated with the output voltage. The system further includes an overvoltage latch-off timer system configured to initiate a latch-off timer in response to detecting the overvoltage condition. The latch-off timer can be uninterrupted by an amplitude of the output voltage. The overvoltage latch-off timer system can further be configured to detect a persistent overvoltage fault in response to detecting the overvoltage condition after expiration of the latch-off timer. The overvoltage latch-off timer system can be configured to generate a fault signal to disable the voltage-limit power regulator in response to detecting the persistent overvoltage fault.

Abstract: A system topology may use intentional signal injection to monitor one or more power supply circuits that may supply electrical power to components of the system. The system topology may include voltage monitoring circuitry to monitor the output of the power supply. In some examples, a power supply rail fault may happen either inside or outside of the power supply circuit, but not be detectable by the voltage monitoring circuitry. Injecting a check signal in the presence of an actual fault, may cause oscillations at the output node of the power supply detectable by the voltage monitoring circuitry. Once the check signal, combined with the fault signal, at the output node reaches the monitoring threshold detectable by the voltage monitoring circuitry, the voltage monitoring circuitry may output an indication of the fault to processing circuitry of the system.

Abstract: A current generation circuit includes a metal-oxide-semiconductor (MOS) transistor having a source terminal coupled to one line of a power supply line and a ground line, a voltage generation circuit configured to generate a first voltage corresponding to a resistance value of wiring between the one line and the source terminal, and a control circuit configured to cause the MOS transistor to generate a predetermined current based on the first voltage.

Abstract: A power converter monitor having built-in fault tolerance and containment including a plurality of voltage inputs operatively connected to a pulse timing device, a respective comparator electrically connected to each of the voltage inputs, an and-gate electrically connected in series to each of the comparators and wherein the pulse timing device is operatively connected by the and-gate and a-not gate to each of the voltage inputs configured to reset a detected voltage output fault and provide a converter inhibit pulse if the voltage output fault is detected.

Abstract: An LED lamp power supply includes a power conversion module, an AC/DC control module, a dimming control module, and an auxiliary control module. The auxiliary control module further includes a sampling unit, a starting range value preset unit, a protection value preset unit, and a control unit. The sampling unit is configured to continuously collect the value of the output supply voltage. The control unit causes the dimming control module to be in a standby mode of operation when the value of the collected output supply voltage falls outside the normal stable operating voltage range and is greater than the highest voltage value. The control unit causes the dimming control module to be in a protection mode of operation when the value of the collected output supply voltage is less than or equal to the highest voltage value.

Abstract: A time delay through a voltage converter, including a transformer therein, must be known or estimated in order to optimally control the voltage converter. For example, power switches that control the input power to the voltage converter must use this time delay in order to, e.g., achieve zero-voltage switching (ZVS) with minimal dead-time. The time delays are typically considered as constants, and the power switch control is optimized for a limited operational range that corresponds to such constant time delays. Herein, variable time delays are determined based upon varying load conditions of the voltage converter. By more accurately determining the time delay for a given load condition and basing the voltage converter control on such accurate (load-dependent) time delays, the voltage converter may be more optimally controlled and achieve higher efficiency.

Abstract: A power conversion apparatus includes a DC/DC converter which transforms DC power input from a dispersion type power source into DC power, a capacitor which holds the DC power supplied from the DC/DC converter, an inverter which converts the DC power held by the capacitor to AC power and outputs the AC power to a power system, and a controller which controls, when the power system recovers from an instantaneous voltage drop, the inverter to lower an AC current output from the inverter to be smaller than a value before occurrence of the instantaneous voltage drop by an amount increasing with an increase in the amount of voltage drop during the instantaneous voltage drop and to raise the AC current from the inverter after the lowering.

Abstract: An output apparatus includes an output driving unit configured to drive a final output signal; an output compensating signal generation unit configured to generate a delayed output signal by delaying the output signal by a predetermined time, and generate an output compensating signal based on the delayed output signal and the output signal; and an output driving compensation unit configured to compensate for the final output signal to a level opposite to a level to which the final output signal is driven.

Abstract: A power circuit part, a power control method and a display apparatus having the same control an output DC voltage supplied as operating power to elements such as a display to be variably output at different levels according to a voltage level of input AC power. The power circuit part includes a rectifier configured to rectify a current of an input alternating current (AC) power into a direct current (DC); and a power factor corrector configured to output a DC voltage output set at a DC voltage level corresponding to an AC voltage level of the input AC power, and supplies the DC voltage as operating power to the electronic apparatus, wherein the DC voltage level is selected from a plurality of target DC voltage levels each corresponding to at least one of a plurality of AC voltage level ranges.

Abstract: A circuit including a low drop-out regulator (LDO) has a current control loop configured and connected to detect whether an external capacitor is connected to the output of the LDO. The current control loop includes a differential amplifier, a current source capable to output different reference currents and a small MOS transistor. The circuit may be operated in an output capacitor detection mode when started and in a regulated voltage source mode otherwise. In the output capacitor detection mode, the small MOS transistor is driven by the differential amplifier and drives the LDO's power MOS transistor depending on a difference between a current through the small MOS transistor and the reference current output by the current source. Components of the current control loop may be used during regulated voltage source mode for short circuit protection.

Abstract: A method for operating a brushless electric motor, the windings being energized by an inverter with the aid of six switches. A detection unit for detecting defective switches, a unit for measuring voltage at the outputs of the inverter, and a microcontroller for controlling the switch and for generating a pulse width modulated voltage supply for the windings are provided. A short-circuited switch causes a torque in the electric motor opposite the actuating direction of the electric motor. The method proposes that after detecting a short-circuited switch, the windings (U. V. W) are energized to generate a motor torque that is, on the whole, positive. An actuating period of the electric motor is divided into a plurality of sectors, wherein, in accordance with the defective switch, individual sectors are deactivated for the actuation of the windings (U, V, W), while other sectors are used to actuate the windings (V, W).

Abstract: A multi-phase voltage regulator module system includes a VRM and a phase control circuit. The VRM is capable of outputting a load detecting voltage which is direct proportion to the load of the CPU. The phase control circuit outputs a first level phase switching signal to the VRM, and a core voltage outputted by the VRM to the CPU is changed from N phases to M phases when the load detecting voltage increases to a first voltage. The phase control circuit a second level phase switching signal to the VRM, and the core voltage outputted by the VRM to the CPU from M phases to N phases when the load detecting voltage decreases to a second voltage. The first voltage is higher than the second voltage. M is larger than N.

Abstract: A system for supplying an electrical system with direct current, the system including at least two direct current power supply devices each having means of electrical connection to an alternating current power supply source and an AC/DC converter of alternating current into direct current, a module for managing the power supply of the electrical system which, after reception of an information of failure of a first active power supply device, transmits a command to start up a second inactive power supply device and a back up electrical energy storage device electrically by-pass connected between the power supply devices and the electrical system. The management module also receives the information of failure from the back up device and/or from the electrical system and transmits the command to start up the second power supply device during a discharge phase of the back up device.

Abstract: In a semiconductor device, a surge voltage is lowered on turning OFF of a switching element, and output current is reduced on turning ON of the switching element in a non-saturated condition to achieve a reduced amount of self-heating. The semiconductor device can comprise a semiconductor switching element, an overvoltage protection circuit, and a resistance circuit to transmit a control signal for turning the switching element ON and OFF to a control terminal of the switching element. The semiconductor device can further comprise a voltage detecting switch that receives a signal corresponding to a voltage appearing at the output terminal of the switching element on turning OFF of the switching element, and a gate resistor change-over switch that operates according to a voltage of a timing capacitor connected to the output side of the voltage detecting switch to increase a resistance value of the resistance circuit.

Abstract: A system comprises an AC/DC adapter having a connector. The system also comprises a portable computer that receives said connector. The portable computer comprising a delay circuit coupled to a power transistor that is coupled in parallel with a resistor. The delay circuit causes the power transistor to activate following a time delay after current from the adapter begins to flow through the resistor. As a result of a user beginning to remove the connector from the portable computer, a control transistor is activated to reset the delay circuit.

Abstract: An overvoltage protection method and circuit includes a positive supply input node, an output node, and a negative supply node. The overvoltage protection circuit further includes a first functional circuit configured to turn ON a MOSFET and maintain it in a low resistance state. A second functional circuit is configured to detect an overvoltage and control the gate of the MOSFET to regulate a voltage at the output node. A third functional circuit is configured to provide a startup wherein the overvoltage protection circuit is not damaged and/or to regulate an operating voltage such that an overvoltage does not appear on the overvoltage protection circuit. The external components include the MOSFET, which has a gate coupled to the output of the charge pump of the overvoltage protection circuit.

Abstract: An information handling system (IHS) is disclosed providing a power supply operable to provide an output current to the IHS during power initiation. The IHS may also include a first power component associated with a first power stage wherein the first power stage may have a first current threshold. Furthermore, the IHS may include a power control logic coupled to the power supply and the first power component. As such, the power control logic may be operable to communicate the first power stage to the power supply, and if the output current does not exceed the first current threshold during the first power stage, the power control logic may be operable to communicate a second power stage having a second current threshold to the power supply.

Abstract: An early warning method for an abnormal state of a lithium battery and a recording medium applicable to a portable electronic device are provided. The method includes the following steps. A plurality of curves of voltage against electric quantity is obtained according to different predicted average current consumptions of the portable electronic device. An operating average current consumption and an operating electric quantity from a first voltage to a second voltage are obtained when the lithium battery at an operating test state in a unit time. One of the curves of voltage against electric quantity is searched, and a warning electric quantity is obtained in a range from the first voltage to the second voltage. The warning electric quantity is compared with the electric quantity, so as to provide an early warning of an abnormal state.

Abstract: A temperature sensor circuit is provided that facilitates preventing a too-high overshooting voltage from occurring at an output terminal when a power supply is connected to the temperature sensor circuit. The temperature sensor circuit includes a short-circuiting device, disposed in parallel to depletion mode NMOS, that short-circuits the drain and source of depletion mode NMOS when a power supply is connected; and delay device that transmits a signal for short-circuiting the drain and source of depletion mode NMOS for a certain period from the time point of power supply connection to short-circuiting device for preventing the voltage at output terminal of temperature sensor circuit from overshooting.

Abstract: A control device for controlling a recovery from a locking of a motor includes: a switching unit which supplies a motor current from a current supplying unit to the motor; and a driving control unit which supplies a PWM control signal to the switching unit to control a driving of the switching unit. The driving control unit supplies the PWM control signal with a low duty ratio lower than a regular duty ratio to the switching unit when the locking of the motor is detected depending on a variation in temperature of the switching unit. The driving control unit supplies the PWM control signal with the regular duty ratio to the switching unit when a cancel of the locking of the motor is detected depending on a variation in inter-terminal voltage of the motor.

Abstract: A motor-drive circuit comprising: a current-passage-control circuit to perform ON/OFF control of a drive transistor connected to a motor coil to pass current through the motor coil; an overcurrent-state-detection circuit to detect whether current passing through the drive transistor is in an overcurrent state where the current exceeds a predetermined threshold value; a charging and discharging circuit to start charging a capacitor in response to detecting the overcurrent state by the overcurrent-state-detection circuit and subsequently discharge the capacitor in response to not detecting the overcurrent state; and an overcurrent-protection-control circuit to stop the ON/OFF control to turn off the drive transistor, for an elapsed charging period for a charging voltage of the capacitor at a predetermined voltage to exceed a threshold voltage, and determine whether to perform such an overcurrent-protection-control as to turn off the drive transistor by detection of the overcurrent state, after the charging peri

Abstract: An Insulated Gate Bipolar Transistor (IGBT) fault protection system is provided. The fault protection system includes a GVPA, a gate voltage clamper, and a soft-off unit. The GVPA analyzes a gate voltage pattern of an IGBT to determine whether or not a fault has occurred. The gate voltage clamper prevents an increase in a gate voltage of the IGBT according to an output signal that the GVPA outputs when a fault has occurred. The soft-off unit softly turns off the IGBT according to an output signal that the GVPA outputs when a fault has occurred.

Abstract: An interface circuit for connecting with a universal serial bus (USB) data cable includes a USB connector for connecting with the USB data cable, an over voltage protection (OVP) circuit connected to the USB connector, and a time delay circuit connected to the USB connector and the OVP circuit to control the OVP circuit. The OVP circuit is switched off in a predetermined delay time of the time delay circuit when the USB data cable is connected to the USB connector, and is then switched on after the delay time of the time delay circuit.

Abstract: Provision is made for a switch-state monitoring device that not only monitors the state of a switch but also prevents a motor burnout. A switch-state monitoring device for a switch that opens and closes a main circuit by use of a motor is provided with an operating time measuring unit for detecting an operating time for the motor when the switch is opened or closed; a first determination unit for comparing an operating time for the motor detected by the operating time measuring unit with an continuous-operating-capable setting time for the motor and determining whether or not the operating time for the motor has exceeded the continuous-operating-capable setting time; a protection device for halting energization of the motor in the case where, based on an output of the first determination unit, it is determined that the operating time for the motor has exceeded the continuous-operating-capable setting time.

Abstract: Method, and apparatus for operating a power feed in a computing system. One exemplary embodiment includes monitoring the power feed to ensure the power level of the entire system never remains above a first power level and only remains above a second power level for a period of time determined by a timer level.

Abstract: A circuit and method for limiting the power supplied to a load are provided. The circuit and method prevent power supplied to the load from exceeding a power threshold for a programmable amount of time specified in a timer. The circuit includes a voltage controlled current source coupled to the load. A current multiplier divider is coupled to the voltage controlled current source and a timer is coupled to the load. A comparator with an adaptive threshold is coupled to the current multiplier divider and the input for controlling the timer to limit the power supplied to the load.

Abstract: A power supply controller includes detection circuits that are provided so as to correspond to a plurality of load circuits performing an operation by power output from a power supply circuit and that detect an overcurrent condition of load currents of the respective load circuits; and a control unit controlling a predetermined operation of the power supply circuit so as to change the amount of power output from the power supply circuit in accordance with detection outputs of the detection circuits.

Abstract: A battery protecting circuit is disclosed that includes a negative voltage terminal voltage detecting circuit that detects when a voltage of a negative voltage terminal decreases to less than a predetermined voltage; an abnormality detecting circuit that detects an abnormality in charge/discharge conditions of a battery; a switch that is connected between the battery and the negative voltage terminal, the switch being turned off when the negative voltage terminal voltage detecting circuit detects that the voltage of the negative voltage terminal has decreased to less than the predetermined voltage and when the abnormality detecting circuit detects the abnormality in the charge/discharge conditions of the battery; a delay time reducing circuit that reduces a time period from a time the abnormality in the charge/discharge conditions of the battery is detected to a time the switch is turned off when the voltage of the negative voltage terminal decreases to less than the predetermined voltage; and an output inval

Abstract: Disclosed is an inverter-circuit power supply circuit capable of redriving an inverter circuit upon temporary blackout without turning on a main power again An inverter-circuit power supply circuit according to the present invention cuts off a backlight driving signal from a microcomputer (11d2) with a Zener diode (18a), a first transistor (19a), and a second transistor (20a) when a power supply voltage from a main power supply circuit (12a) is lowered, by use of a power recovery circuit (12c3) to thereby cancel a protective function of a protective circuit (17).

Abstract: A power abnormal protection circuit includes a power detection unit, a voltage drop correction unit, a drop out detection unit, a delay unit and a delay masking unit. By detecting an input power average value of a power supply occurring of a brown out condition can be determined. The power supply includes a power factor correction unit which has an output capacitor. By detecting the voltage of the output capacitor a drop out condition can be determined. When a power abnormal condition occurs all units of the power supply can be set off sequentially according to a delay time to protect circuit elements and a connecting computer.

Abstract: A protective device for a controlling system of a sewage pump has a protective circuit to protect a start capacitor and to avoid the start capacitor from burnout when an overload is occurred by actuating power source (ON status) or a transient voltage is occurred by malfunction of a controlling circuit. Therefore, the start capacitor is certainly protected and significantly improved in lifespan.

Abstract: A battery protection IC using charging control pin, Cout, so as to reduce delay time during CP test or FT test for is disclosed. The battery protection IC has a delay time control circuit including a comparator and a delay signal selector. The comparator has a negative input terminal connected to VCC, a positive input terminal connected with the Cout pin and an output terminal connected to the delay signal selector. To perform foregoing test, a voltage source is added to activate the short delay time mode rather than a normal delay time one.

Abstract: A power abnormal protection circuit includes a power detection unit, a voltage drop correction unit, a drop out detection unit, a delay unit and a delay masking unit. By detecting an input power average value of a power supply occurring of a brown out condition can be determined. The power supply includes a power factor correction unit which has an output capacitor. By detecting the voltage of the output capacitor a drop out condition can be determined. When a power abnormal condition occurs all units of the power supply can be set off sequentially according to a delay time to protect circuit elements and a connecting computer.

Abstract: A power control system for use in an electronic device provided with a transforming module becoming self-contained upon connection with a power supply includes a switch module, a delay module, and a control module. The switch module turns on or off a power input route whereby the transforming module can supply power to the electronic device, and keeps the power input route at an off state while the transforming module remains unconnected to the power supply. The delay module performs a delay process and generates delay signals. The control module receives the delay signals generated and enables the switch module to turn on the power input route. The present invention prevents the stability of the electronic device from being deteriorated as a result of electric sparks induced by metallic friction and excessive instantaneous current while the electronic device is being connected to the power supply.

Abstract: A circuit for protecting a motherboard includes a first transistor (Q1), a second transistor (Q2), a third transistor (Q3), and a power control circuit (200). The power control circuit includes a power controller (10), and a power supply (20), and a fourth transistor (Q4) connected therebetween. The first transistor is supplied with a CPU power signal on the motherboard. The second and third transistors are jointly supplied with a sleep signal and turned on if the CPU power signal is at low level after the power supply is turned on, thereby turning off the fourth transistor and grounding a PWRBTN# pin of the power controller to turn off the power supply for protecting the motherboard from damage due to no CPU power-on voltage applied thereto after the power supply is turned on.

Abstract: A test device is provided for testing stability of a computer when the computer is started up or shut down. The test device includes a monolithic chip and a switch module. The monolithic chip includes an input port and an output port. The input port receives a high level or a low level signal from the computer. A test control module is disposed in the monolithic chip. The switch module includes an input pin coupled to the output port of the monolithic chip and a pair of output pins corresponding to the input pin. The pair of output pins is connected to the computer, for controlling the computer to be started up or shut down. The input port of the monolithic chip is connected to the computer for detecting a state of the computer.

Abstract: In a digital protection relay with a time sync function, the sampling timing of which is specified based on a reference timing transmitted from a time signal generator to a time sync unit, with a determination value. The time sync unit includes a reception circuit that receives a discrimination code and time data transmitted from the time signal generator, a code discrimination circuit that discriminates the reference timing on condition that the received discrimination code coincides with a desired code, a time calculation circuit that calculates the sampling timing on the basis of the discriminated reference timing and the time data, and a sampling sync circuit that specifies the sampling timing of a digital quantity of electricity on the basis of the calculated sampling timing.

Abstract: A drive control apparatus comprises a drive signal supply unit for generating, when a power-supply voltage is supplied to the drive control apparatus, a drive signal, which is used for driving a load from this power-supply voltage, and for supplying this generated drive signal to an output port of a microcomputer, a drive signal stop unit for stopping, when the power-supply voltage has a value that is equal to or less than a predetermined value, the drive signal supply unit from supplying the drive signal, and a drive signal delay unit for delaying the drive signal outputted by the drive signal supply unit.

Abstract: An electromechanical switching device can be tripped in a quick and reliable timed manner. The timed tripping circuit includes a voltage-sensitive switching element which separates an energy storage mechanism from the switching device when the supply voltage falls below a specific voltage limit which is higher than the withstand voltage of the switching device.

Abstract: A high precision, high efficiency controller for LED devices such as LED arrays includes a current limiter, driver and buffer.

Abstract: A waveform correction filter is connected into an alternating current power line to absorb and remove various forms of power pollution, including high-frequency spikes, surges and other forms of high-frequency oscillations, such as those which result from switching inductive loads on and off. The waveform correction filter of the invention includes a fuse and a coaxial amorphous toroidal inductor connected between a power line and neutral with a low-pass filter connected in series with the fuse and coaxial amorphous toroidal inductor. The filter includes a capacitor, a varistor connected in parallel with said capacitor, and a magnetic core inductor connected in series with each other and in parallel with the capacitor and said varistor. A lamp may be connected in series with the resistor and the magnetic core inductor or across the resistor. Various arrangements are shown for connecting a plurality of the waveform correction filters into single phase or three-phase Wine or delta circuits.

Abstract: A circuit is provided for selectively providing electric supply voltage from an input feed line with a neutral conductor, a phase conductor and optionally an earth conductor to individual or parallel-connected groups of connected terminals each comprising a phase core, a neutral core and optionally an earth core, to which electrical units using electricity, for instance light fittings, are or can be connected, which circuit includes: a neutral connection between the neutral conductor and each neutral core; optionally an earth connection between each earth conductor and each earth core; a phase connection between the phase conductor and each phase core, in which phase connection is arranged a current control element; and an overcurrent safety element, for instance a fuse, which is incorporated in each phase connection and which limits the current to the maximum value determined for the relevant phase connection.

Abstract: An IGBT gate driver circuit includes means for detecting when the collector-to-emitter voltage (Vce) of a turned-on IGBT, intended to be operated in the saturation region, increases above a preset level, indicative of a fault condition, such as a short circuit. In response to such an increase in the Vce of a turned on IGBT, the IGBT is turned-off in two steps. First, the turn-on gate drive is decreased to a level that is still above the threshold (turn-on) voltage of the IGBT in order to decrease the current flowing through the IGBT and hence, the peak power dissipation. This decrease in the current through the IGBT and the peak power dissipation increases the length of time the IGBT can withstand a fault condition such as a short circuit. Then, after decreasing the gate drive to the IGBT, the gate drive is gradually decreased until the IGBT is completely turned off.

Abstract: An electronic regulator for driving a power device connected to an output load having a first portion and a second protection portion, the first portion including a controlled switching element connected upstream of the power device and controlled by a timer adapted to be operated in a short circuit or overload situation of the device, such that the load current can flow in the power device in a pulsed state clocked by the timer.

Abstract: A sensing circuit 100 includes two resistors 11 and 12, two pnp transistors 13 and 14, and a current mirror 15 and 16. Resistors 11 and 12 convert the high voltages present in the bridge into a proportional current. The current mirror, mosfets 15 and 16, compares I.sub.1 and I.sub.2. If I.sub.2 is greater than I.sub.1 the voltage at point A is high. Otherwise this voltage is low. Resistor 12 is chosen smaller than 11 so that under normal operation, when FET 22 turns on, I.sub.2 is greater than I.sub.1 and the voltage at point A is high. During an overcurrent event, the drop across the FET 22, Von, is so great that I.sub.2 is less than I.sub.1 and the voltage a point A stays low.

Abstract: A constant voltage power supply includes one or more sense leads connected to a load and in a feedback control loop. The voltage at the load is fed back via the sense leads for comparison to a reference voltage in the loop to generate an error signal that adjusts the voltage output of the power supply to achieve and maintain the voltage delivered to the load constant at a desired value. The power supply further includes a continuity checking circuit for checking continuity status of the sense leads while the power supply is in a disable mode wherein it is isolated from the load. This allows any detected discontinuity to be repaired before the supply is connected to a load. The detected discontinuity informs the user that the voltage delivered to the load will not be accurately controlled because of the broken or disconnected sense lead.

Abstract: The system impedance ratio (SIR) is determined for the original zone 1 distance element reach of a protective relay. The reduction in the original zone 1 reach is then determined, using the SIR value and a known table of reduced values. When a fault is recognized the minimum reach to just detect the fault is determined. A trip signal is provided without any delay if the minimum reach is less than or equal to the reduced reach. The trip is delayed for a selected time if the minimum reach is greater than the reduced reach but not greater than the original reach.

Abstract: An electronically controlled micro-dispensing apparatus (10 or 210) is described. The apparatus includes a liquid storage container (12), a propellant container (16), a control circuit (34 or 42) and an ejector (28). In a second embodiment, the liquid and propellant are in the same container (212). The control circuits control the length of pulse and the time duration between each pulse. By controlling these factors, the apparatus dispenses a precise amount of liquid over a set time period. The ejector allows for controlled dispensing and allows the liquid to be sprayed a greater distance. In the preferred embodiment, the apparatus are used to dispense a pheromone in an outdoor setting, such as an orchard, to control insects.

Abstract: A display protection circuit includes a first OR gate which receives a first pulse at one input and a first clock signal at another input. A second OR gate receives the first pulse at one input and a second clock signal at another input. A first monostable multivibrator is coupled to the first OR gate and receives an output of the first OR gate and generates a second pulse in response thereto. A second monostable multivibrator is coupled to the second OR gate and receives an output of the second OR gate and generates a third pulse in response thereto. A first logic gate is coupled to the first and second monostable multivibrators and generate a fourth pulse which changes state in response to one of the first and second clock signals stopping transitioning for a first predetermined period of time.

Abstract: An integrated circuit includes protected circuit portions for being electrically connected to an electronic circuit via electrical conductors, and a multiple time constant transient clamping circuit for clamping a transient voltage based upon one of first and second time constants. The first time constant is preferably selected when the integrated circuit is electrically connected to the electronic circuit and is preferably relatively short to permit operation and while protecting the IC from a transient voltage, such as an electrostatic discharge (ESD) event. The longer second time constant is preferably selected when the IC is removed or not electrically connected to the electronic circuit. The longer second time constant is preferably sufficiently long to protect the IC from a transient voltage when the IC is not electrically connected to the circuit board.