Abstract: A monitor control system and method for an electrical distribution system includes a trip unit of a circuit breaker. A sensor is associated with the electrical distribution system and coupled to the trip unit wherein the sensor is connected to one or more components of the electrical distribution system to detect whether the electrical distribution system is being serviced when a presence of a human being is also detected. A selector is coupled to the trip unit and configured to select maintenance mode parameters to define a mode of operation of the trip unit wherein in the maintenance mode arc flash reduction or tripping delay reduction is provided such that the trip unit operates based on the maintenance mode parameters.

Abstract: An overcurrent protection apparatus which, when a layer short or a dead short occurs in a load circuit, interrupts the circuit in accordance with respective situations, whereby the load circuit is protected is provided. The apparatus includes a first overcurrent detecting section for detecting a counter electromotive force generated in a power supply wiring, and a second overcurrent detecting section, disposed in each of the plural load circuits, for detecting that a load current ID becomes an overcurrent. The apparatus includes a delaying section for outputting a delay signal at a first delay time when an overcurrent is detected by the second overcurrent detecting section, and for outputting the delay signal at a second delay time which is shorter than the first delay time when an overcurrent is detected by both of the first overcurrent detecting section and the second overcurrent detecting section.

Abstract: A circuit breaker capable of microcontroller-based fault detection having a backup circuit for causing the circuit to trip in response to a microcontroller fault or a failure of a regulated power supply powering the microcontroller. The circuit breaker includes an RC circuit connected to an SCR. The resistor of the RC circuit is connected between the anode and gate of the SCR, and the capacitor is connected between the gate and cathode of the SCR. The microcontroller has a first pin coupled to the RC circuit, which is initially in a high input impedance state. In the event of a microcontroller fault or power supply failure, the capacitor will charge to a voltage sufficient to activate the SCR and trip the breaker. If the microcontroller startup routine is successful, the pin is configured as an output and is pulled low, shorting out the capacitor.

Abstract: A transmission delay line is introduced between the switch and the power output side of a power switching system so that sparking of the load is hidden from the switch by the time delay of the transmission line. This makes it possible to detect the load spark and actively protect the switch, typically by turning the switch off, before it actually knows that there has been a load fault spark. Alternatively, the delay of the transmission line is long enough so that the switch has already been turned off in normal pulse operation before the load fault current reaches the switch. Either way, the switch will be turned off under normal current flow and will not be subject to destructive over-current or over-voltage conditions.

Abstract: A circuit interrupter apparatus includes circuit interrupter and a device. The circuit interrupter includes separable contacts, an operating mechanism structured to open and close the separable contacts, and a trip mechanism cooperating with the operating mechanism to trip open the separable contacts. The trip mechanism includes a zone selective interlocking input and a zone selective interlocking output. The device includes a first input electrically interconnected with the zone selective interlocking input, a second input electrically interconnected with the zone selective interlocking output, and an indicator circuit structured to indicate that the zone selective interlocking input occurred at the first input or that the zone selective interlocking output occurred at the second input.

Abstract: An inrush current higher than a second anomaly threshold current ILfc passes through a power MOSFET 14, when a control signal S1 of low level is applied to a gate driver 28 so that the power MOSFET 14 and the like turn to a conductive state. A first forcing shutoff operation for the power MOSFET 14 is then prevented, because a first anomaly threshold current ILoc is set to an initial level higher than the inrush current. A fuse time counter 73 starts a count-up operation in response to the occurrence of the inrush current, and continues to increment its count value until a load current IL falls below the second anomaly threshold current ILfc. According to the count value, the first anomaly threshold current ILoc is decreased stepwise with time.

Abstract: A circuit for driving a transistor half bridge is disclosed that comprises a series circuit of a first and a second transistor both having intrinsic or external free-wheeling diodes coupled in parallel. The circuit for driving a transistor half bridge comprises: an over-current detection circuit that is configured to signal an over-current condition when a load current flowing through the first transistor exceeds a first threshold; a protection circuit that is coupled to the over-current detection circuit and that is configured to disable an activation of the first transistor in response to a detected over-current and to re-enable the activation of the first transistor after a first time interval has elapsed; an evaluation circuit that is coupled to the over-current detection circuit and that is configured to check whether a further over-current condition is detected within a second time interval that follows the first time interval.

Abstract: A module hot swap circuit includes a low voltage-drop rectifier adapted to receive either positive or negative voltages of different absolute values. The rectifier is coupled to a power manager that provides dual startup/shutdown voltage thresholds and inrush current limiting. A detector prevents reverse current flow allowing the module to hold up during input voltage drop-outs.

Abstract: An arrangement having DC power supply units connection parallel, wherein, the power supplies of the DC power supply units each generate a partial output current for supplying a load with a total output current. In accordance with the invention, an overload of power supply units when the power supply units are switched on and/or during their restart is largely avoided.

Abstract: A circuit protection device suitable for use with a photovoltaic power generation system. The circuit protection device includes an electronic control unit and a dual path fuse. The dual path fuse has a first current path defined by a main conductor and a second current path defined by a fuse element. In response to an overcurrent condition, the control unit activates the dual path fuse to open the first current path, thereby shunting current to the second current path. Residual follow-on current flows through the fuse element via the second current path until the fuse element melts. The control unit is programmable with multiple threshold current levels and associated time delays in order to provide different activation response times that are dependent upon the detected current level.

Abstract: A power supply (200) is provided having a plurality of independent current limiting circuits. A first current limiting circuit (6) provides protection against a short circuit or other extraneous load conditions, while a second current limiting circuit, using a trace on a PCB as a sensing element, is programmable on the basis of a time constant and a current level.

Abstract: Provided is a display device which enables the automatic return of a power source circuit after the power source circuit is protected from an overcurrent, at low cost. The display device includes: an output transistor having a base to which a drive voltage signal is inputted and outputting a drive voltage from an emitter; a first transistor being turned on when an overcurrent flows into the output transistor; and a second transistor being turned on and turning off the output transistor when the first transistor is turned on, the first and second transistors are repeatedly turned on and off so as to make the output transistor intermittently operate within an overcurrent operation period, and the first and second transistors are turned off and the output transistor automatically returns to a normal operation when an operation period is shifted from the overcurrent operation period to a normal operation period.

Abstract: When a battery pack, comprising an overcurrent protection section for stopping, when a current greater than a first threshold value passes, a current supply, is connected to a power supply terminal of an information processing apparatus, the information processing apparatus draws a current greater than the first threshold value. Thereafter, an output current and output voltage of the battery pack are detected, thereby measuring a time period from when a current drawing section draws the current greater than the first threshold value to when the battery pack stops the current supply. When the measured time period is within a first predetermined time range, the battery pack is permitted to supply an electric power. On the other hand, when the measured time period is not in the first predetermined time range, the battery pack is prohibited from supplying the electric power.

Abstract: A short circuit protection circuit which readily recovers a relay drive circuit to an output operation state after a short circuit is cancelled while preventing the relay drive circuit from being damaged by a short circuit. The relay drive circuit outputs a drive current to a load in accordance with a first control signal. A short circuit detection circuit detects the occurrence of a short circuit at an output side of the relay drive circuit and suspends output operation of the relay drive circuit when a short circuit occurs. Further, the short circuit detection circuit intermittently transmits a recovery signal to the relay drive circuit in a certain time interval after a predetermined time elapses from when the short circuit occurs to recover the output operation of the relay drive circuit. The time interval is gradually increased whenever the recovery signal is transmitted.

Abstract: A gate driver 28 performs a normal charging operation for a power MOSFET 14 by driving a charge pump 90 solely, when a low-level control signal S1 (ON signal) is received during a normal state. On the other hand, if a low-level control signal S1 (ON signal) is received during a load anomaly state, an urgent charge FET 92, as well as the charge pump 90, is turned on when a load current IL exceeds a second anomaly threshold current ILfc, so that a rapid charging operation is performed.

Abstract: A load driving and diagnosis system controls the feed and block of a load current flowing into an inductor such as a solenoid. The load driving and diagnosis system holds a counter-electromotive force, which is developed when the load current is blocked, at a voltage higher than a supply voltage so that the load current will decay for a short time. When an overcurrent condition is established in the load driving and diagnosis system because of a short circuit to a power supply, a malfunction of a circuit or destruction thereof may take place. In addition to a voltage holding means that holds a switching circuit output voltage at a predetermined voltage, a voltage holding means having a different predetermined voltage set therein is included. Moreover, a selection switch that switches the predetermined voltages according to a detected overcurrent condition is included.

Abstract: The invention relates to an arrangement for protecting a component in a power supply circuit. The arrangement comprises determination of an electric quantity constituting a load on the component, which electric quantity constituting a load on the component is determined repeatedly while the component is exposed to the load. The arrangement also comprises estimation of instantaneous load capacity of the component, which estimation of instantaneous load capacity is performed using a limitation criterion set for the load capacity of the component. This limitation criterion indicates the longest possible operating time of the component under a given loading condition. For the limitation criterion, a representation with respect to the electric quantity constituting a load on the component is provided, and a limitation criterion corresponding to the defined electric quantity constituting a load on the component is derived repeatedly from the said representation while the component is exposed to the load.

Abstract: An electrical fault detection device for use in a branch of a power circuit that utilizes signals from an AC line current sensor coupled to an electrical distribution line having a primary and neutral lines, a line high-frequency sensor coupled to the electrical distribution line, a differential current sensor coupled to the primary and neutral lines, and a ground fault current sensor coupled to the primary and neutral lines. A signal conditioner receives the signals outputted by AC current line current sensor, the line high frequency sensor, the differential current sensor and the ground fault current sensor and generates a signal indicative of the load current associated with a branch of the power circuit. Output of the signal conditioner is sampled and processed by a processing resource. The processing resource has stored therein data representing a plurality of time-versus-current curves that define a plurality of regions in which tripping may or may not occur.

Abstract: A circuit breaker for a power controller integrated circuit is described where an analog timer and a digital timer are provided in parallel. The digital timer provides a fixed, on-chip maximum delay during an overcurrent condition to ensure the transistor will not be damaged. The analog timer allows the user to select an external capacitor or resistor to provide a delay time that is shorter than the time provided by the digital timer. Accordingly, the power controller retains all the flexibility of an analog timer but prevents the overcurrent exceeding a maximum time limit. An autoretry circuit is also included in the power controller which prevents the duty cycle from exceeding a maximum. The autoretry timer is a digital timer that uses the same oscillator as the digital timer for the circuit breaker so the ratio of the delay times is known and fixed.

Abstract: The disconnector of the present invention comprises: a current transformer that detects a current flowing through electric wires; a rectifying part that rectifies the current outputted from the current transformer; a charging part that charges the current outputted from the rectifying part; a switching part that disconnects the electric wires upon driving; and a trigger part that drives the switching part when the charge stored in the charging part becomes a predetermined drive area. In this regard, the drive area is set larger than the charge that can be stored in the charging part by a lightning surge current. The disconnector of the present invention and the overvoltage protectors may be combined to constitute the overvoltage protection device.

Abstract: An apparatus and system are disclosed for protecting a power distribution unit from an electrical fault. A fuse interrupts a flow of electrical current in response to the electrical current rising above a current rating of the fuse. A current sensor measures the amplitude of the electrical current and outputs a current amplitude signal. A relay interrupts the flow of electrical current in response to an OFF signal. A fault module receives the current amplitude signal and sends the OFF signal to the relay in response to the amplitude of the electrical current exceeding a threshold value. The relay, the fuse, and the threshold value are selected so that a switching time of the relay is less than an opening time of the fuse for an amplitude of the electrical current between the threshold value and a maximum fault current value, so that the relay prevents the fuse from opening.

Abstract: A semiconductor device with an over-current detection feature is disclosed. According to an example of the invention the device includes: a semiconductor chip including a load current path that conducts a load current in response to an input signal activating the load current flow. A current sensor arrangement provides a measurement signal representing the load current. An evaluation circuit is configured to compare the measurement signal with a first threshold and to signal an over-current when the measurement signal exceeds the first threshold after a delay time period starting from the activation of the load current flow has elapsed.

Abstract: The system, which provides a control signal, includes an over-current control unit, a time clock that provides a periodic time signal, and a clock generator unit that includes a first input terminal, a second input terminal, and an output terminal. The first input terminal is coupled to the time clock and the output terminal is coupled to the over-current control unit. The first input terminal of the clock generator unit receives the periodic time signal and the second input terminal of the clock generator unit receives a modification signal. The clock generator unit generates a clock signal based on the periodic time signal and the modification signal. The output terminal of the clock generator unit provides the clock signal to the over-current control unit, and the over-current control unit provides a control signal based on the clock signal.

Abstract: A circuit breaker includes separable contacts; a load conductor; a neutral conductor; and an operating mechanism structured to open and close the separable contacts. An arc fault trip circuit cooperates with the operating mechanism and trips open the separable contacts responsive to detection of an arc fault condition associated with current flowing through the separable contacts. A ground fault trip circuit cooperates with the operating mechanism and is structured to trip open the separable contacts responsive to detection of a ground fault condition associated with current flowing through the separable contacts, the load conductor and the neutral conductor. The arc fault trip circuit includes an integration capacitor, and the ground fault trip circuit includes an output to the integration capacitor.

Abstract: An automated AC line filter and surge suppression apparatus 100 having an inductive current sense loop (ICSL) circuit 10 for sensing inductive current at a load and controlling the application of AC line filter 112 to an AC power line to the load. Current sensor 12 in series with the input line senses inductive load current. A first bridge rectifier 14 rectifies the sensed load current to a proportionate DC voltage, which triggers a switch 24. The output of switch 24 is fed into an opto-isolator 26, which in turn controls second switch 28. Switch 28 connects or disconnects AC line filter 112 from the system according to a predetermined sensed inductive current at the load. MOVs 102 and capacitive elements 104 provide continuous surge suppression protection to the load.

Abstract: The switching control circuit comprises a switching control signal generation circuit that detects a change in ripples of the output voltage and-generates a switching control signal for the on/off control of the switching element to make the output voltage follow the target level; an overcurrent state detection circuit that generates a state signal indicating whether the output current is in an overcurrent state where the output current is equal to or greater than a predetermined current; and a delay circuit that delays the state signal for a same predetermined delay time at both of the times when the output current exceeds the predetermined current and when the output current falls below the predetermined current.

Abstract: A method and apparatus measures electrical power usage and quality, while mitigating the effects of noise on measured signals or parameters. Specifically, a digital electrical power and energy meter employs a method in which a processor averages a parameter, such as voltage or current, over a plurality of cycles of a time-varying signal, such as an AC electrical signal. The method employed by the meter samples a parameter over the plurality of cycles and computes the average of the samples corresponding to the same phase angle of the signal to produce an average signal.

Abstract: A transmission delay line is introduced between the switch and the power output side of a power switching system so that sparking of the load is hidden from the switch by the time delay of the transmission line. This makes it possible to detect the load spark and actively protect the switch, typically by turning the switch off, before it actually knows that there has been a load fault spark. Alternatively, the delay of the transmission line is long enough so that the switch has already been turned off in normal pulse operation before the load fault current reaches the switch. Either way, the switch will be turned off under normal current flow and will not be subject to destructive over-current or over-voltage conditions.

Abstract: A power supply providing current interruption based on the energy from the supply over a sliding window of time is disclosed. The output current from the supply is periodically reestablished.

Abstract: The invention achieves the objective of ensuring that a solar installation mounted on a unit such as, for example, a residential house, can be safely switched off cost-effectively, whereby the consumers are to be galvanically disconnected from the solar installation, and the feed lines leading to the consumers are to be de-energized in case the safety switchgear has triggered a switch-off. A safety switchgear for a solar installation is proposed, whereby the solar installation consists of at least one photovoltaic element, of two connections, each to a feed line leading to a consumer, and said safety switchgear has a bypass that is situated between the two connections and upstream from the feed lines and that has at least one switching mechanism to close the contact points, whereby at least one additional switching mechanism for purposes of opening the contact points is arranged in each of the two feed lines.

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: A resettable short-circuit protection circuit can terminate excessive fault currents automatically and quickly. The short-circuit protection circuit is switchable and has a low input impedance during normal operation so that there is not a significant voltage drop across the switching elements of the protection circuit. The short-circuit protection circuit allows a power source internal to a portable device to be safely connected to an external accessory where there exists the possibility that the connection could be shorted at the time power is first supplied to the external accessory or a short develops afterwards. After terminating a short-circuit condition, the protection circuit may be reset by cycling an enable signal. The fault termination and reset timing may be configured by selection of internal resistance and capacitance values.

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: The present invention is directed to a method and a system for fault detection analysis in a power device which is operatively associated with a differential protection unit. The power device has one input side and one output side through which an input current and an output current flows into and out from it, respectively. Signals representative of the input and output currents are processed in order to verify if an occurring fault is external to the power device. Under a condition of an external fault, the differential protection unit is disabled for a determined interval of time.

Abstract: A self-excited DC-DC converter includes a switching element that chops an input voltage; a smoothing circuit that smoothes the chopped voltage to generate an output voltage; and a switching control circuit. The switching control circuit includes a switching control signal generation circuit that generates a switching control signal for the on/off control of the switching element by comparing a feedback voltage of the output voltage and a comparison voltage; an output correction circuit that adjusts the comparison voltage according to an error between the feedback voltage and the reference voltage and, when the output current is in the overcurrent state, reduces the level of the comparison voltage; an overcurrent protection signal generation circuit that, when the output current is in an overcurrent state, generates an overcurrent protection signal for turning off the switching element regardless of the switching control signal; and a delay circuit that delays the overcurrent protection signal.

Abstract: A circuit breaker capable of microcontroller-based fault detection having a backup circuit for causing the circuit to trip in response to a microcontroller fault or a failure of a regulated power supply powering the microcontroller. The circuit breaker includes an RC circuit connected to an SCR. The resistor of the RC circuit is connected between the anode and gate of the SCR, and the capacitor is connected between the gate and cathode of the SCR. The microcontroller has a first pin coupled to the RC circuit, which is initially in a high input impedance state. In the event of a microcontroller fault or power supply failure, the capacitor will charge to a voltage sufficient to activate the SCR and trip the breaker. If the microcontroller startup routine is successful, the pin is configured as an output and is pulled low, shorting out the capacitor.

Abstract: A circuit breaker capable of microcontroller-based fault detection having a backup circuit for causing the circuit breaker to trip in response to a microcontroller fault, including a timing circuit powered by a power supply and a microcontroller. The timing circuit is electrically coupled to an SCR that causes the circuit breaker to trip. The timing circuit includes a BJT coupled to the gate of the SCR. The microcontroller has a first output coupled to the timing circuit and a second output coupled to the SCR. The first output is coupled to a node between a resistor and a grounded capacitor in the timing circuit, and the node is coupled to a gate of the SCR and to a base of the transistor. A voltage develops at the node sufficient to cause the gate of the SCR to turn on unless the microcontroller pulls the first high-impedance output to a logic low state.

Abstract: An overcurrent protection apparatus which, when a layer short or a dead short occurs in a load circuit, interrupts the circuit in accordance with respective situations, whereby the load circuit is protected is provided. The apparatus includes a first overcurrent detecting section for detecting a counter electromotive force generated in a power supply wiring, and a second overcurrent detecting section, disposed in each of the plural load circuits, for detecting that a load current ID becomes an overcurrent. The apparatus includes a delaying section for outputting a delay signal at a first delay time when an overcurrent is detected by the second overcurrent detecting section, and for outputting the delay signal at a second delay time which is shorter than the first delay time when an overcurrent is detected by both of the first overcurrent detecting section and the second overcurrent detecting section.

Abstract: Device for protecting an integrated circuit, comprising a device for detecting a latch-up condition, and a supply voltage control device for controlling a supply voltage of the integrated circuit, to modify a parameter of the supply voltage of the integrated circuit in order to prevent the latch-up from becoming permanently established.

Abstract: An appliance includes a plurality of electrical loads and a load control circuit including at least a clock enable circuit and a full power timer. The clock enable circuit is configured and operatively connected to activate the full power timer when all of the loads are energized, and the full power timer is configured and operatively connected to de-energize at least one load selected from the plurality of loads on reaching a predetermined full power time limit.

Abstract: A current protection apparatus (200) and current protection method (1000) that may include programmable current protection characteristics has been disclosed. A current protection apparatus (200) may include a power distribution unit (230) with power distribution outlets (PDO-1 to PDO-8), each having a corresponding circuit breaker unit (CB1 to CB8). Each circuit breaker unit (CB1 to CB8) may operate in response to a processing unit (236) that can sample current values flowing between a respective power distribution outlet (PDO-1 to PDO-8) and a load device (LD1 to LD8). Processing unit 236 may operate under control of software stored on a memory (238) to control a switching circuit (320). Current protection characteristics for each circuit breaker unit may be independently programmed and/or altered by a user, for example by way of a computer (250).

Abstract: Apparatus (100) for controlling inrush current from a power supply (250) to a load (255), the apparatus comprising a first (105a) and a second (105b) power supply input and a first (110a) and a second (110b) load output, a semiconductor device (115) coupled between the first power supply input (105a) and the first load output (110a), a control circuit (120) having a control circuit input (125) coupled to the first load output (110a) and a control circuit output (130) coupled to a conductance control node (135) of the semiconductor device (115), wherein, in use, when a load (255) is connected across the first load output (110a) and the second load output (110b), the control circuit (120) provides a control signal to the conductance control node (130) to thereby progressively vary the conductance of the semiconductor device (115) from a low conductance state to a high conductance state in response to a load signal being provided to the control circuit input (125) indicating that a load current (Isd) flowing thr

Abstract: An over current protection circuit provides over current protection (O.C.P) and short current protection (S.C.P) and can selectively operate in auto recover mode or latch off mode by replacing certain elements therein. Hence, the present invention can be designed easily and is cheaper than the prior art.

Abstract: A method for identifying a cause for insufficiency of an output voltage reduced to or below an undervoltage set value comprises a first comparison step for comparing the output voltage to a fixed first undervoltage set value and a second comparison step for comparing the output voltage to a second undervoltage set value that follows up the output voltage with a time lag, wherein the cause for the output voltage insufficiency is identified based on the steps and notified as a warning. As a preferable mode, the first undervoltage set value is set by means of a reverse conducting voltage of a voltage regulating diode D1 and the second undervoltage set value is set by means of a charging voltage of a capacitor C1 for directly or indirectly charging the output voltage.

Abstract: A protective circuit for a secondary battery pack advantageously having a simple circuit configuration while maintaining the safety of banks in the circuit. Each protective circuit has banks adapted to be charged or to discharge voltage, each bank being coupled to a controller that senses the charging or discharging voltage of the bank and outputs a predetermined value if overcharging or over-discharging is sensed. A level shifter is adapted to shift the voltage output from the controller to an adjusted voltage approximately equal to the voltage output from one of the other controllers. A switching means controls the stopping of charging or discharging of the banks.

Abstract: A time delay fault device includes an integrated circuit (IC) having an electronic circuit having a fault indicator signal output and a time delay circuit having an input connected to the fault indicator signal output and an output to provide a delayed fault indicator signal output, the time delay circuit being responsive to an external voltage from a resistor capacitor network coupled to the delayed fault indicator signal output to set the time delay of the delayed fault indicator signal.

Abstract: A load driving and diagnosis system controls the feed and block of a load current flowing into an inductor such as a solenoid. The load driving and diagnosis system holds a counter-electromotive force, which is developed when the load current is blocked, at a voltage higher than a supply voltage so that the load current will decay for a short time. When an overcurrent condition is established in the load driving and diagnosis system because of a short circuit to a power supply, a malfunction of a circuit or destruction thereof may take place. In addition to a voltage holding means that holds a switching circuit output voltage at a predetermined voltage, a voltage holding means having a different predetermined voltage set therein is included. Moreover, a selection switch that switches the predetermined voltages according to a detected overcurrent condition is included.

Abstract: A driver circuit for an electronic switch, the driver circuit having a first input for receiving a first control signal, and a second input for receiving a signal from a current sensor, the driver circuit further including a shut-off circuit for operating the electronic switch to cause an interruption to current flow in the event of a fault condition arising, such as current through the electronic switch exceeding a predetermined threshold, wherein operation of the shut-off circuit can be invoked by a predetermined event at the first input.

Abstract: An overcurrent detection circuit that detects an overcurrent state of a transistor that outputs a current to a load is provided with a start-up monitoring portion that distinguishes between a start-up state and a steady state, an overcurrent monitoring portion that monitors an overcurrent state of the transistor, and an output voltage monitoring portion that detects whether the output voltage to the load is normal or abnormal. The overcurrent monitoring portion changes an overcurrent detection level while referring to information from the start-up monitoring portion and the overcurrent monitoring portion.

Abstract: A method for diagnosing control circuits having at least one actuator, in particular of a fuel injection device, is provided. Before operation of a given control circuit, this control circuit and the at least one actuator are tested for short-circuits, and an error response is initiated if a short-circuit is present.