Abstract: A transient voltage suppressing (TVS) circuit with uni-directional blocking and symmetric bi-directional blocking capabilities integrated with an electromagnetic interference (EMI) filter supported on a semiconductor substrate of a first conductivity type. The TVS circuit integrated with the EMI filter further includes a ground terminal disposed on the surface for the symmetric bi-directional blocking structure and at the bottom of the semiconductor substrate for the uni-directional blocking structure and an input and an output terminal disposed on a top surface with at least a Zener diode and a plurality of capacitors disposed in the semiconductor substrate to couple the ground terminal to the input and output terminals with a direct capacitive coupling without an intermediate floating body region.

Abstract: A photocoupler includes a light emitting device, a drive circuit; a clamp circuit and a light receiving section. For an input voltage to the input terminal being within a range between a first voltage and a second voltage, the photocoupler is allowed to enter an operation mode in which the drive circuit, in response to the digital signal inputted thereto, drives the light emitting device to convert the digital signal to the optical signal, and the electrical signal is externally outputted from the light receiving section. For an input voltage to the input terminal being outside the range between the first voltage and the second voltage, the photocoupler is allowed to enter an inspection mode in which the drive circuit stops driving the light emitting device, the first transistor of the clamp circuit is turned on, and a current generally equal or proportional to a clamp current of the clamp circuit is supplied to the light emitting device so that characteristics of the light emitting device can be measured.

Abstract: A circuit and a method are provided for protecting sensitive circuitry from over voltage and over current during a double fault situation. The circuit may be used in a portable electronic device, and may include an over voltage protection component and an over current protection component. The over voltage protection component may be coupled across power supply inputs of a load of the portable electronic device. The over current protection component is configured in the circuit to provide over current protection to the load of the portable electronic device at least when the over current protection component provides over current protection to the over voltage protection component.

Abstract: A communication circuit for an electronic dimming ballast provides high-voltage miswire protection and improved rise and fall times of a transmitted digital signal. The electronic dimming ballast comprises a control circuit, which is coupled to a digital communication link, for example, a DALI communication link, via the communication circuit. The communication circuit comprises a receiving circuit for detecting when the digital ballast communication link is shorted and for providing a received digital message to the control circuit. The communication circuit also comprises a transmitting circuit for shorting the communication link in response to the control circuit. The communication circuit also includes a high-voltage fault protection circuit for protecting the circuitry of the communication circuit if the communication circuit high-voltage mains voltages. The communication circuit is operable to reliably transmit digital messages having improved rise and fall times.

Abstract: A communication circuit for an electronic dimming ballast provides high-voltage miswire protection and improved rise and fall times of a transmitted digital signal. The electronic dimming ballast comprises a control circuit, which is coupled to a digital communication link, for example, a DALI communication link, via the communication circuit. The communication circuit comprises a receiving circuit for detecting when the digital ballast communication link is shorted and for providing a received digital message to the control circuit. The communication circuit also comprises a transmitting circuit for shorting the communication link in response to the control circuit. The communication circuit also includes a high-voltage fault protection circuit for protecting the circuitry of the communication circuit if the communication circuit high-voltage mains voltages. The communication circuit is operable to reliably transmit digital messages having improved rise and fall times.

Abstract: A load drive circuit which can operate at high speed with low consumption current while performing the gate-to-source over voltage protection for its load driving field-effect transistor. A Zener function device is connected between the gate and the source of the load driving field-effect transistor, and an on/off-switch circuit to supply either on-potential or off-potential to the gate of the field effect transistor is provided. The current flowing through the Zener function device when the load driving field-effect transistor is conductive is limited by the on/off-switch circuit.

Abstract: The present invention provides an overpower-protection circuit and a power supply apparatus having the same. The power supply apparatus comprises a rectifier, a transformer and an overpower-protection circuit The overpower-protection circuit comprises a converter having a converter input electronically coupled to the rectifier and a converter output, a photo coupler having at least a first terminal coupled with the converter output, and having an output terminal, and a clipper electrically coupled across said terminals of the photo coupler for keeping the converter output below a predetermined voltage.

Abstract: An overvoltage protection element, provided as a component of a medical device (3) used on or in a human or animal body, reduces power absorption upon application of an external overvoltage signal having chronological rising and/or decay characteristic at an interface (15) of the medical device (3). The overvoltage protection element has reshaping means (17) which convert the external overvoltage signal at the interface (15) into an internal voltage pulse, and limiting means (19) which limit a voltage drop on at least one electronic component of the medical device to a predetermined limiting value.

Abstract: A DC-DC converter for overvoltage protection is provided with a primary control circuit 12 which comprises an impedance controller 31 and a protective circuit 41 for ceasing operation of primary control circuit 12 when power source voltage VCC on primary control circuit 12 exceeds a predetermined voltage level. Impedance controller 31 comprises a potential detector 32 for picking out power source voltage VCC to primary control circuit 12 to produce a detection signal; and an impedance adjuster 33 for adjusting power input impedance Z in primary control circuit 12 in response to the detection signal from potential detector 32 to repress rapid rise in power source voltage on primary control circuit 12.

Abstract: In one embodiment, a protection device is used to protect a circuit. The protection device has a maximum rated power dissipation that is less than a maximum rated power dissipation of the circuit that is being protected.

Abstract: A safety PLC having duplex power supply circuits, includes: a first output-stage transistor; a first DC power supply that drives the first output-stage transistor; a second output-stage transistor; a second DC power supply that drives the second output-stage transistor; a signal transfer path that includes a resistor and connect the first output-stage transistor to the second output-stage transistor; and a pair of overvoltage protection units, each of which is disposed between a pair of output terminals of the corresponding one of the first and second DC power supplies and restricts the maximum value of an output potential difference between the pair of output terminals.

Abstract: A circuit and a method are provided for protecting sensitive circuitry from over voltage and over current during a double fault situation. The circuit may be used in a portable electronic device, and may include an over voltage protection component and an over current protection component. The over voltage protection component may be coupled across power supply inputs of a load of the portable electronic device. The over current protection component is configured in the circuit to provide over current protection to the load of the portable electronic device at least when the over current protection component provides over current protection to the over voltage protection component.

Abstract: A photocoupler includes a light emitting device, a drive circuit; a clamp circuit and a light receiving section. For an input voltage to the input terminal being within a range between a first voltage and a second voltage, the photocoupler is allowed to enter an operation mode in which the drive circuit, in response to the digital signal inputted thereto, drives the light emitting device to convert the digital signal to the optical signal, and the electrical signal is externally outputted from the light receiving section. For an input voltage to the input terminal being outside the range between the first voltage and the second voltage, the photocoupler is allowed to enter an inspection mode in which the drive circuit stops driving the light emitting device, the first transistor of the clamp circuit is turned on, and a current generally equal or proportional to a clamp current of the clamp circuit is supplied to the light emitting device so that characteristics of the light emitting device can be measured.

Abstract: A modular protection circuit can protect a first terminal and a second terminal of a first device. The circuit comprises a load device which has a third terminal and a fourth terminal with the third terminal for connection to a first voltage. A first diode is provided, with the first diode having a first cathode and a first anode with the first cathode connected to the fourth terminal and the first anode connected to the first terminal. A second diode is provided with the second diode having a second cathode and a second anode with the second cathode connected to the fourth terminal and the second anode connected to the second terminal. A third diode is provided with the third diode having a third cathode and a third anode with the third cathode connected to the first terminal and the third anode connected to a second voltage.

Abstract: The present invention is to provide a voltage detecting apparatus, which can downsize a circuit, reduce costs and detect a voltage with high accuracy, the voltage detecting apparatus to detect a voltage by using a flying capacitor. Furthermore, the voltage detecting apparatus does not halt whole functions. The first zener diode is connected to the first resistor R1, which divides a voltage stored with the capacitor as a flying capacitor into a detectable voltage at a microcomputer, in parallel. Furthermore, the voltage detecting apparatus prevents more than a zener voltage of the first zener diode from applying to the input of the microcomputer.

Abstract: A transient voltage suppressing (TVS) circuit with uni-directional blocking and symmetric bi-directional blocking capabilities integrated with an electromagnetic interference (EMI) filter supported on a semiconductor substrate of a first conductivity type. The TVS circuit integrated with the EMI filter further includes a ground terminal disposed on the surface for the symmetric bi-directional blocking structure and at the bottom of the semiconductor substrate for the uni-directional blocking structure and an input and an output terminal disposed on a top surface with at least a Zener diode and a plurality of capacitors disposed in the semiconductor substrate to couple the ground terminal to the input and output terminals with a direct capacitive coupling without an intermediate floating body region.

Abstract: An electrical barrier (10) for connecting a power supply to electrical equipment situated in a potentially explosive atmosphere comprises an input (12), output (13), a shunt Zener diode (14), a fuse (15), an output resistor (16) and the sensor resistor (11). The Zener diode (14) is operable to limit the output voltage of the barrier. In some embodiments multiple Zener diodes are used if desired or appropriate. The output resistor (16) acts to limit the maximum output current whilst the fuse (15) acts to prevent operation of the barrier in the event of an excessive input. The sensing resistor (11), being in series with the Zener diodes (14), allows the current flowing through the Zener diode (14) to be determined. The value of this current is then used to regulate the voltage input to the barrier (10). By using such a sensing resistor in series with the Zener diode (14), the voltage on the Zener diode (14) can be controlled so that the desired current flows.

Abstract: A communication circuit for an electronic dimming ballast provides high-voltage miswire protection and improved rise and fall times of a transmitted digital signal. The electronic dimming ballast comprises a control circuit, which is coupled to a digital communication link, for example, a DALI communication link, via the communication circuit. The communication circuit comprises a receiving circuit for detecting when the digital ballast communication link is shorted and for providing a received digital message to the control circuit. The communication circuit also comprises a transmitting circuit for shorting the communication link in response to the control circuit. The communication circuit also includes a high-voltage fault protection circuit for protecting the circuitry of the communication circuit if the communication circuit high-voltage mains voltages. The communication circuit is operable to reliably transmit digital messages having improved rise and fall times.

Abstract: An overvoltage protection circuit for protecting a pass element in a controlled voltage supply circuit electrically connected between a circuit power supply interconnection terminal region suited for electrical connection to a circuit power supply and an output terminal, the pass element being protected from voltage surges that may occur on the circuit power supply interconnection with respect to a voltage reference interconnection. A voltage reference is provided electrically connected in series with a voltage. The voltage divider and the voltage reference are connected in series with one another between the circuit power supply interconnection and the voltage reference interconnection. A threshold switch is electrically connected to a corresponding one of the voltage divider output and one of the voltage divider terminating regions terminating regions, and has an output coupled to the pass element control region.

Abstract: An electronic device formed as an integrated circuit (IC) wherein the electronic device further includes a transient voltage suppressing (TVS) circuit. The TVS circuit includes a triggering MOS transistor connected between an emitter and a collector of a first bipolar-junction transistor (BJT) coupled to a second BJT to form a SCR functioning as a main clamp circuit of the TVS circuit. The TVS circuit further includes a triggering circuit for generating a triggering signal for the triggering MOS transistor wherein the triggering circuit includes multiple stacked MOS transistors for turning into a conductive state by a transient voltage while maintaining a low leakage current.

Abstract: In an integrated circuit for electrically permanently program information in the integrated circuit a current is driven through an NPN-transistor. The integrated circuit has a first current feeding circuit having an output connected via a resistor to the NPN-transistor, a feeding point connectable to a feeding voltage, and a control input for controlling the programming of the NPN-transistor. The integrated circuit also has at least a second current feeding circuit having an output connected to the feeding point for the first current feeding circuit, a feeding point connectable to a feeding voltage, and a control input for controlling the programming of the NPN-transistor. Finally the integrated circuit has a first voltage level controller provided to split the voltage needed to program the NPN-transistor over the first and at least second current feeding circuit.

Abstract: A circuit arrangement includes a first semiconductor switch and at least one second semiconductor switch, each of them having a control terminal and a first and second load terminal, and with an overvoltage protection arrangement for the at least two semiconductor switches. The overvoltage protection arrangement comprises a voltage limiting unit with a first and a second terminal, whose first terminal is connected to a central circuit node, whose second terminal is connected to a terminal for a reference potential, and which is configured so that it conducts current when a threshold voltage is applied between the first and second load terminals. The central circuit node is coupled to the first load terminals of the semiconductor switches. The overvoltage protection arrangement further comprises a first actuating circuit for the first semiconductor switch and a second actuating circuit for the at least one second semiconductor switch.

Abstract: In one embodiment, an over-voltage protection circuit is configured to have two control circuits that respond at different values of the input voltage.

Abstract: A fault handling system for short circuit recovery in three-phase multiple-level inverter bridges, used to drive inductive loads, to assure a proper sequence for turning-off switches in the inverter bridge. Switches are selected for use in the inverter bridge so that outer switches toward the most positive and most negative bus voltage levels of the inverter bridge have lower transconductances than inner switches closest to an output phase of the inverter bridge. Additionally, driver cards driving outer switches utilize lower magnitude excitation control signals than driver cards driving inner switches. Driver cards driving outer switches, when detecting desaturation of an on-state switch, are set to automatically command the outer switch to an off-state, whereas driver cards driving inner switches wait for instructions from a controller before taking action.

Abstract: A circuit arrangement includes plural semiconductor switches, at least one overvoltage protection arrangement and a coupling circuit. Each of a first semiconductor switch and a second semiconductor switch has a control terminal and first and second load terminals. The at least one overvoltage protection arrangement provides overvoltage protection to the semiconductor switches. The coupling circuit is operable to selectively couple the control terminals of at least two of the at least two semiconductor switches.

Abstract: A device is for short-circuiting a first electric line with a second electric line in order to reduce a voltage differential. At least one first electronic switching device is provided between the first and second lines and at least one second electronic switching device is arranged anti-parallel to the first switching device. No mechanical switch is present for the direct short-circuiting operation.

Abstract: The present invention relates to a hard disk drive system having overvoltage protection circuits for various types of overvoltage conditions. For example, the system comprises one or more hard disk drive integrated circuit chips residing on a board and a hard disk drive power plug receptacle residing on the board having two different value power supply ports associated therewith. The receptacle is operable to receive a power plug therein, wherein when the power plug is inserted therein in a proper orientation the two different value voltages are properly supplied to the one or more hard disk drive integrated circuit chips, and wherein when the power plug is inserted therein in an improper orientation the two different value voltages are switched with respect to their intended values. The system comprises a reverse power plug orientation protection circuit coupled between the hard disk drive power plug receptacle and at least one of the one or more hard disk drive integrated circuit chips.

Abstract: An ignition system for an internal combustion engine is connected to an ignition coil and to a circuit for providing an ignition signal. The ignition system includes a switch circuit connected to the ignition coil that switches on or off current supplied to the ignition coil, a control circuit that controls the switch circuit based on the ignition signal and a protection circuit that includes a pair of back-to-back connected zener diodes connected between the input terminal of the control circuit and a ground.

Abstract: The present invention relates to a hard disk drive system having overvoltage protection circuits for various types of overvoltage conditions. For example, the system includes one or more hard disk drive integrated circuit chips residing on a board and a hard disk drive power plug receptacle residing on the board having two different value power supply ports associated therewith. The receptacle is operable to receive a power plug therein, wherein when the power plug is inserted therein in a proper orientation the two different value voltages are properly supplied to the one or more hard disk drive integrated circuit chips, and wherein when the power plug is inserted therein in an improper orientation the two different value voltages are switched with respect to their intended values.

Abstract: A protective circuit for limiting the voltage for a device to be protected, particularly a load with an upstream-connected voltage and current limiting device. The device to be protected is provided in an output circuit of the protective circuit and is separable by means of a switching element, a voltage detector being provided with an electronic switch on the one hand and a voltage sensor on the other. The control terminal of the electronic switch is in electrical operative connection with the voltage sensor. A microdevice with a control circuit is provided, the microdevice having the switching element and being designed with a high input resistance of the control circuit. The control circuit is galvanically separated from the output circuit and switchable by the control circuit. The output circuit in the opened state has a galvanic separation of its output terminals.

Abstract: A protection system for an integrated circuit is disclosed. A detection system detects an overvoltage condition and provides an overvoltage condition signal to indicate a condition in which overvoltage protection may be desired. In response to the overvoltage condition signal, one or more variable resistance devices in the system, such as power devices of associated driver circuitry, are controlled to limit the voltage across such devices.

Abstract: The present invention relates to a hard disk drive system having overvoltage protection circuits for various types of overvoltage conditions. For example, the system comprises one or more hard disk drive integrated circuit chips residing on a board and a hard disk drive power plug receptacle residing on the board having two different value power supply ports associated therewith. The receptacle is operable to receive a power plug therein, wherein when the power plug is inserted therein in a proper orientation the two different value voltages are properly supplied to the one or more hard disk drive integrated circuit chips, and wherein when the power plug is inserted therein in an improper orientation the two different value voltages are switched with respect to their intended values. The system comprises a reverse power plug orientation protection circuit coupled between the hard disk drive power plug receptacle and at least one of the one or more hard disk drive integrated circuit chips.

Abstract: An over-voltage protection module protects communications equipment against voltage surges, including periodic voltage disturbances. The protection module provides a steady state activation voltage threshold and a reduced activation voltage threshold less than the steady state value. Upon a receiving a periodic disturbance, the module activates initially upon receiving a voltage exceeding the steady state activation voltage threshold and activates for subsequent cycles of the disturbance upon receiving a voltage exceeding the reduced activation voltage threshold.

Abstract: A protective relay is provided to protect circuitry against reverse battery polarity or load dump, wherein a relay coil is operatively connected to a contact switch and is fed by a reverse bias diode (which may be a Zener diode) such that the relay coil opens the switch contact when the diode is energized to protect the circuitry; wherein the protective relay optionally includes a positive temperature coefficient resistor or a current source to protect the relay coil from overheating.

Abstract: The specification describes a DMOS transistor that is fully integrated with an electrostatic protection diode (ESD). The ESD diode is isolated from the DMOS device by a trench. The trench is metallized to tie the guard ring of the ESD to the substrate thereby increasing the current handling capabilities of the ESD. The trench also provides a convenient buried contact to the RF ground.

Abstract: An over-voltage protection circuit is disclosed herein for protection against over-voltage of an energy storage device while charging. The circuit operates within the operational limits of a battery-operated device, such as a mobile or handheld device. The over-voltage protection circuit comprises an over-voltage protection device, and an over-voltage protection controller. The controller allows current to flow to the over-voltage protection device only when an energy storage device is experiencing over-voltage.

Abstract: A dc-to-dc converter is provided with overvoltage protection circuitry while still providing normal output voltage. Such overvoltage protection circuitry does not require resetting. The overvoltage protection circuitry includes a first switching device connected between the input bridge and a dc output voltage bus and further includes an overvoltage current path. The overvoltage current path includes a complementary switching device in series with Zener diode circuitry having a predetermined breakdown voltage, and further has a transition current path. The first switching device is closed for nominal input voltage and is open for overvoltages. When the input voltage exceeds the Zener diode breakdown voltage, the transition current path conducts current. When the threshold voltage of the complementary switching device is exceeded, the complementary switching device turns on and conducts current through the overvoltage current path.

Abstract: The present invention relates to a hard disk drive system having overvoltage protection circuits for various types of overvoltage conditions. For example, the system comprises one or more hard disk drive integrated circuit chips residing on a board and a hard disk drive power plug receptacle residing on the board having two different value power supply ports associated therewith. The receptacle is operable to receive a power plug therein, wherein when the power plug is inserted therein in a proper orientation the two different value voltages are properly supplied to the one or more hard disk drive integrated circuit chips, and wherein when the power plug is inserted therein in an improper orientation the two different value voltages are switched with respect to their intended values. The system comprises a reverse power plug orientation protection circuit coupled between the hard disk drive power plug receptacle and at least one of the one or more hard disk drive integrated circuit chips.

Abstract: A protective relay is provided to protect circuitry against reverse battery polarity or load dump, wherein a relay coil is operatively connected to a contact switch and is fed by a reverse bias diode (which may be a Zener diode) such that the relay coil opens the switch contact when the diode is energized to protect the circuitry; wherein the protective relay optionally includes a positive temperature coefficient resistor or a current source to protect the relay coil from overheating.

Abstract: There is provided a device in an accessory apparatus, which is connected with a main apparatus, for protecting a motor driver IC and a logic circuit in the accessory apparatus from the application of a voltage higher than the rated voltage for these circuits, when the connection between the main apparatus and the accessory apparatus (optional apparatus) which receives power from the main apparatus enters an abnormal state. Therefore, even when the power of the main apparatus is ON, the accessory apparatus can be attached to, or removed from, the main apparatus without damaging the circuits. The device comprises an inexpensive element, such as a rectifying diode or a Zener diode.

Abstract: The protection circuit for a power supply unit comprises a switching stage, at which at least two output voltages to be monitored are connected, these voltages being isolated from one another by means of resistors. Arranged here in the connection path of the output voltages is a diode, which turns on and thereby triggers the switching stage in the event of a fault, when there is a drop in one of the output voltages. In this way, the switching stage provides information which acts on a control loop of the power supply unit, so that the power supply unit switches off. The protection circuit also includes a passive network with a resistor and a capacitor, which prescribes a time constant, after which the protection circuit permits renewed starting of the power supply unit. The switching stage may be realized, for example, by a transistor stage, which provides the information signal for the event of a fault for the power supply unit when turning on occurs.

Abstract: An electrical circuit, which accepts an integrated circuit, which is supplied with operating voltages of different levels, and in which, between the supply voltages at their regular level, there is a diode function which is poled in the block direction. Such diode function preferably includes a Schottky diode between the circuit's terminals for the supply voltages at their regular levels, wherein the diode protects the circuit when the nominally low supply voltage has a higher voltage than the nominally high supply voltage.