Abstract: The present disclosure relates to circuitry comprising: amplifier circuitry configured to receive a variable supply voltage, wherein the supply voltage varies according to an output signal of the amplifier circuitry; monitoring circuitry configured to monitor one or more parameters of an output signal of the amplifier circuitry; and processing circuitry configured to receive an indication of the voltage of the variable supply voltage and an indication of the monitored parameters from the monitoring circuitry and to apply a correction to one or more of the monitored parameters to compensate for coupling between the variable supply voltage and the monitoring circuitry.

Abstract: In accordance with an embodiment, a method of operating a transistor includes: switching the transistor on and off based on a control signal; monitoring a voltage of a collector node of the transistor; detecting whether the voltage of the collector node of the transistor is above a first threshold; and after detecting the voltage of the collector node of the transistor above the first threshold, regulating a voltage across a load path of the transistor to a first target voltage.

Abstract: A power conversion circuit includes a voltage regulator circuit and a detection circuit. The voltage regulator circuit includes a first switch and a second switch. A first end of the first switch receives an input voltage, and a control end of the first switch receives a first drive signal. The second switch is coupled between a second end of the first switch and the ground, and is turned on or off based on a second drive signal. The first switch and the second switch regulate the input voltage to output an output voltage. The detection circuit is configured to determine whether the first switch is short-circuited or not based on a voltage level of at least one of the first end, the second end, or the control end of the first switch, and adjust the second drive signal when the first switch is short-circuited, to turn on the second switch.

Abstract: An electric power system includes an input bridge rectifier configured to convert an AC voltage to a DC voltage; a DC capacitor configured to charge to an DC output voltage based on the DC voltage; and a voltage controlled active semiconductor device coupled to the input bridge rectifier to control a current through at least one of the input bridge rectifier and the DC capacitor. The voltage controlled active semiconductor device includes a switching device including a control terminal that receives a control voltage such that the switching device conducts the current based on the control voltage; and a voltage controlled circuit coupled to the switching device along a path of the current and having a total effective resistance. The voltage controlled circuit is configured to regulate the current based on the total effective resistance, and change the total effective resistance based on a voltage feedback parameter.

Abstract: An input redundant circuit according to the present disclosure may include: a core power supply unit; a first input port connected to a first input voltage; a second input port connected to a second input voltage; a relay unit connected to the first input port and the second input port to supply one of the first input voltage and the second input voltage to the core power supply unit; and a surge current limiting unit coupled to the relay unit, configured to limit a surge current generated when the relay unit is switched between the first input voltage and the second input voltage.

Abstract: In accordance with an embodiment, a method of operating a control circuit includes generating a threshold value based on a drive signal of an external power transistor, and determining an overpower state of the external power transistor based on a voltage at a drain or a collector of the external power transistor and the threshold value.

Abstract: A circuit for protection against overvoltages includes an input side to which an input voltage can be applied, an output side at which an output voltage can be tapped, an overvoltage protection element which is connected in parallel with the input side and which is configured to, when an overvoltage pulse occurs at the input side, conduct at least part of the overvoltage pulse away via a first current path, and a protective transistor which is connected in parallel with the output side. When an overvoltage pulse occurs at the input side, the protective transistor changes from a closed mode into an open mode forming a second current path parallel to the first current path along the protective transistor so that substantially the rest of the overvoltage pulse can be conducted away via the second current path.

Abstract: Provided is a detection circuit configured to avoid erroneous detection that may occur immediately after a detection circuit is powered on. The detection circuit includes: an output transistor connected between a voltage input terminal and a voltage output terminal; and a load open-circuit detection circuit configured to detect an open circuit of a load connected to the voltage output terminal, in which an output circuit of the load open-circuit detection circuit includes a first transistor and a second transistor connected in series, the first transistor having a gate connected to the output transistor in common, the second transistor having a gate to which a signal indicating that the open-circuit of the load is detected, and in which the first transistor is in an off state when the output transistor is in an off state.

Abstract: A circuit for controlling a load current through a coil is connected to an output port of a transistor H-bridge that includes two low side transistors and two high side transistors. A current sense circuit is coupled to the H-bridge and configured to provide a representation of the load current provided by the output port. A current regulator is configured to generate a modulated signal dependent on the representation of the load current and a current set-point. The modulated signal has a duty-cycle. A gate control logic drives the individual transistors of the H-bridge on and off in accordance with the modulated signal. A direction signal provides the load current to the coil. The direction signal determines the direction of the load current. An over current detection circuit is coupled to each individual transistor and is configured to signal an over-current by providing an active over-current failure signal when a transistor current through the respective transistor exceeds a respective maximum value.

Abstract: Representative implementations of devices and techniques control regulator output overshoot. An offset signal is provided to a component of the regulator during at least a portion of the regulator start-up.

Abstract: A voltage regulator includes a power device formed by an NMOS transistor having a drain terminal coupled to an input voltage, a source terminal providing an output voltage and a gate terminal receiving a gate drive signal; and an integrated AC/DC control loop configured to access the output voltage and to generate the gate drive signal based on a value of the output voltage in relation to a first reference voltage and a second reference voltage. The AC control portion generates a gate drive control signal which is AC coupled to the gate terminal of the power device as an AC component of the gate drive signal. The DC control portion controls a DC voltage level of the gate drive signal. The AC control portion is powered by the input voltage while the DC control portion is powered by a high supply voltage greater than the input voltage.

Abstract: A power extractor suitable for locations proximate to the sink of a signal channel is disclosed. The power extractor can generate power from the signal channel without substantially disturbing a quality of signals within the channel. In one embodiment, the power extraction circuit can include: a current source coupled to a sink side of a signal channel, where the signal channel is independent of any power supply signal, the current source being high impedance to maintain signal quality within the signal channel; a first regulator configured to generate a first regulated supply from a current derived from the signal channel using the current source; and a second regulator coupled to the first regulator, where the second regulator is configured to generate a second regulated supply from the first regulated supply.

Abstract: A fan system is electrically connected to a power source, and the fan system includes a power reverse protection apparatus, a voltage regulator, a driver, and a fan. The power reverse protection apparatus, electrically connected to the power source, includes a voltage regulator switch and an activating device. The voltage regulator switch receives an input signal and outputs a first output signal according to the input signal. The activating device is electrically connected to the power source and the voltage regulator switch for receiving the input signal and the first output signal, respectively. The activating device outputs a second output signal to the fan according to the first output signal. The voltage regulator is electrically connected to the power source for receiving the input signal from the power source and outputting a regulating signal according to the input signal.

Abstract: An over current protection circuit for low dropout regulator comprises a sense transistor, a sense resistor, an operational amplifier and a first transistor. The sense transistor senses the current flowing through the power transistor. The sense resistor is coupled to the sense transistor and shares the same current flowing through the sense transistor. The operational amplifier outputs a control signal according to the voltage across the sense resistor and a reference voltage. The first transistor controls the power transistor according to the control signal.

Abstract: An integrated circuit package (202) includes a voltage regulator (208) and a power-out pin (236) for coupling to a load circuit (210) via a connection (234) external to the integrated circuit package and for coupling to an output (230) of the voltage regulator via a connection (224, 228, 226 and 231) internal to the integrated circuit package. The internal connection has a series resistance that causes a voltage drop due to a load current. The voltage regulator compensates for the voltage drop in the internal connection using a current feedback circuit, in which the current fed back is proportional to the voltage drop caused by the series resistance of the internal connection.

Abstract: In one set of embodiments, a circuit may be implemented to deliver accurately ratioed currents to a remotely located semiconductor device that has a substantially non-linear input-output characteristic that varies with temperature and is subject to effects of electromagnetic interference (EMI). The circuit may be configured to use common mode rejection by establishing an identical impedance at each of the two terminals of the remotely located semiconductor device, in lieu of coupling shunting capacitor(s) across the terminals, in order to reject EMI signals while performing temperature measurements using the remotely located semiconductor device. This may facilitate maintaining fast sampling times when performing temperature measurements, while providing a more effective method for handling EMI induced currents that may lead to temperature measurement errors, thereby eliminating those errors.

Abstract: A LED-based lamp apparatus includes a LED unit having multiple LEDs connected in series, a step-up circuit for stepping up a power supply voltage by a switching action of a switching element to supply an electric current to the LED unit, a sensing element for measuring a value of the current, and a controlling element connected in series with the LED unit to control the current based on the measured current value. When some of the LEDs of the LED unit are broken and short-circuited due to, for example, long-term use, the current increases instantaneously and an overcurrent condition occurs. In this case, the controlling element limits the current immediately to correct the overcurrent condition. Thus, the controlling element prevents the overcurrent condition from causing a secondary failure to normal LEDs of the LED unit.

Abstract: Circuit arrangement for controlling the current flow through a load in the case of detection of the current flow according to the current sense principle. The circuit arrangement has a load transistor and a plurality of auxiliary transistors of identical type, which have a control terminal which is connected or can be connected to the control terminal of the load transistor. In the case of the circuit arrangement according to the invention, provision is made of a switching mechanism by which the auxiliary transistors, optionally or depending on the load current or depending on a load path voltage dropped across the load path of the load transistor, can be connected in parallel individually or as a plurality.

Abstract: A current limiting technique for a voltage converter. A current through a reactive element in a voltage converter is limited. Current from a supply is switched through a reactive element in accordance with a switch control signal for forming a regulated output voltage in a feedback loop. A first signal that is representative of the input current is sensed. A voltage that is representative of the output voltage of the voltage converter is sensed. A second signal that is representative of a difference between the output voltage and a desired voltage is formed. A selected one of the first signal and the second signal is compared to a ramp signal for forming the switch control signal wherein the selected one of the first signal and the second signal is selected according to the relative magnitudes of the first and second signal.

Abstract: Low voltage current sources having a high effective output impedance over a wide voltage range, including when individual transistors exhibit low output impedance states at low voltages. The low voltage current source replicates its output current and compares the replicated current to the desired current. The error between the replicated current and the desired current is used as feedback to force the output current to equal the desired current.

Abstract: A computer monitor having a universal serial bus system comprises a primary power supply that supplies power to the associated circuits of the computer monitor, a hub power supply that supplies hub power through universal serial bus ports to peripheral devices, and a hub power controller that cuts off the hub power to the peripheral devices when the hub power exceeds a predetermined power level. The computer monitor includes an on-screen display controller that displays the status of hub power on a partial area of a computer monitor screen.

Abstract: An AC-DC adapter includes a power transformer to which an AC voltage is applied, a rectifier circuit for rectifying and smoothing an AC voltage developed across the secondary side of said power transformer, and DC voltage stabilizing member for stabilizing a DC voltage outputted by said the rectifier circuit.

Abstract: A power switching circuit includes a power switching NPN transistor (1) having its collector electrode coupled to a reference potential terminal (17) and its emitter electrode coupled to an output terminal (7). A driver circuit (5) is provided having an input coupled to a supply terminal (6) and a driving current output coupled to the base electrode of the power transistor (1). A PNP transistor(4) has its emitter electrode coupled to the output terminal(7), its base electrode coupled to a reference voltage terminal (9) for receiving, in operation, a voltage which is positive relative to the reference potential and its collector electrode coupled to the base electrode of an NPN transistor (2). The NPN transistor (2) has its collector electrode coupled to the collector electrode of the power transistor (1) and its emitter electrode coupled to the base electrode of the power transistor (1).

Abstract: A low-voltage drop current regulator regulates the current in a data interchange circuit. In one embodiment, the low-voltage drop current regulator couples a positive power supply voltage to the power supply pin of a driver integrated circuit. In another form of the invention, the low-voltage drop current regulator is placed in series with the individual output leads of a driver integrated circuit to couple the respective output signals to respective pins of the data interchange circuit.

Abstract: A current sink includes an electronic component having a switched current path and a control terminal. The current path can be switched to a low-impedance condition by the control terminal to sink a current flowing into it. A component having a frequency-dependent passband is connected to the control terminal for passing signals of a predetermined frequency range.

Abstract: A self-correcting protective circuit for providing a reference voltage to a backplane bus wherein the circuit includes a primary transistor, current sensing resistor and diode connected between a supply voltage and the backplane. The combination of a current-limiting resistor and a control transistor is used to sense current flow to the board through the primary transistor and limit same when the backplane bus voltage fluctuates.

Abstract: A redundant power bus arrangement for electronic circuits controls the application of voltage from a power source to an active circuit card and a standby circuit card. Current limited switches are used to connect the power source to the active or standby circuits. A switch control circuit controls the conductive state of the current limited switches in response to a control signal generated by at least one of the controlled circuits. The maximum current permitted by each of the current limited switches is less than the maximum output current rating of the power source, thereby preventing a short on a power bus within one of the controlled circuits from affecting the voltage available for the other controlled circuit.

Abstract: An inrush current limiting circuit in accordance with the principles of the present invention limits initial current flow to a highly initially reactive power load. The current limiting circuit comprises a plug in connection to a power source and two conductor paths leading from the plug in connection. A power FET has a source element to drain element path in series with one of the conductor paths and has a gate connection. A bipolar transistor is connected to shunt the gate element of the power FET to the potential at its source element when the bipolar transistor is conducting, thereby to limit the current passing through the power FET. A sense resistor is in series with one of the conductor paths for controlling a base element of the bipolar transistor to cause it to conduct when current through the sense resistor exceeds a predetermined amount.

Abstract: An electronic device including a circuit element to which a pulse current is applied, and a device for limiting the time integration value of current flowing in the circuit element, the device being connected in series to the circuit element, to prevent the circuit element from being overheated.

Abstract: A method for limiting short circuit current flow in a Field Effect Transistor (FET) to limit the power dissipated therein includes sensing a rise in the drain-to-source voltage of the transistor and clamping the gate-to-source voltage to a predetermined adjustable value thereby reducing the magnitude of the short circuit current flow to within the safe operating characteristics of the device. A comparator switch circuit is responsive to the drain-to-source voltage of the FET exceeding a reference voltage value for clamping the gate-to-source voltage to a predetermined reduced voltage. A trimmable resistive network is connected between the gate and the source electrode of the transistor for adjusting the gate to source clamped voltage potential to compensate for variations in transistor transconductances from one transistor to the next that they may be used in conjunction with the electronic circuitry.

Abstract: A current limit circuit is provided which may be used to limit the current conducted by a pass transistor in a low dropout voltage regulator circuit having no ground terminal. The output current of the regulator is sensed by a low value resistor in the collector of the transistor. The voltage developed across the resistor is proportional to the output current of the regulator, and is used to vary a current ratio which sets the current limit value. The gain of the current limit loop is increased by providing positive feedback during current limiting. A foldback network is provided which reduces the current limit value at higher input/output voltage differentials. The feedback provided by the foldback network has a breakpoint which is sensitive to the operating temperature of the regulator circuit.

Abstract: To turn off an output transistor and generate an alarm whenever a load driven by the output transistor is shorted or opened, the abnormality detection alarm circuit comprises a short detection circuit; an open detection circuit; a delay circuit; an output transistor driving circuit; and an alarm circuit. The delay circuit generates a delayed abnormality signal after the short or open detection circuit has kept generating an abnormal signal beyond a predetermined time. Further, a latch circuit is incorporated, to automatically returning the output transistor driving circuit and the alarm circuit to the normal status immediately after the abnormality has been removed.

Abstract: A constant current battery charger includes a bucking regulator comprising a power switch transistor, a diode, an inductor and a voltage sensitive switch with adjustable delay for controlling the power switch transistor. The hysteresis or delay is obtained with a Schmitt trigger and the effect is a stable pulse width modulator in which the duty cycle of the power switch transistor is varied. A temperature sensor adds resistance to change the sensitivity of the switch and reduce charging current when a predetermined battery temperature is reached. A speed up circuit consisting of a shorting transistor is connected across the base-emitter of the switch transistor.

Abstract: A self-protective driver circuit with automatic reset features is provided for a marine electric fuel pump (2, 102) energized by the boat battery (4, 104) as controlled by a series connected semiconductor switch (6, 106). A first stage protective subcircuit (28, 128) senses surge current through the semiconductor switch at initial turn on with the fuel pump at rest and causes the semiconductor switch to depart from saturated conduction and thus limit the current until the pump starts running and the current decreases to a safer level, to protect the semiconductor switch from excessive current.

Abstract: In an output driver semiconductor circuit, a protection circuit is used to protect the output NPN transistor from being destroyed. The protection circuit comprises an excessive current detector for detecting an excessive collector current of the output NPN transistor, an excessive temperature detector for detecting an excessive temperature of the output transistor, and an OR gate for taking a logical sum of output signals of the detectors. According to the output signal of the OR gate, a base current of the control NPN transistor is controlled, so that a base current of the output transistor is kept below a predetermined value.

Abstract: In a series-regulation transistor (T.sub.1), which is driven by a drive circuit (10), for generating a constant voltage across a load (R.sub.L) the occurrence of comparatively large substrate currents in the case of saturation of the series-regulation transistor (T.sub.1) is precluded by a limiting circuit comprising a resistor (R.sub.1) arranged in the base line of the series-regulation transistor (T.sub.1) and a second transistor (T.sub.2) whose base-emitter junction is arranged across the resistor (R.sub.1) and the base-collector junction of the series-regulation transistor (T.sub.1). The collector of the second transistor is connected to a control input (12) of the drive circuit.

Abstract: A power driver including a switch (17) that connects between a power input terminal (12) and a power output terminal (13). A current sense unit (22) provides an over current sense signal if an over current condition should exist with respect to the switch (17). A reference signal unit (23) utilizes a control signal as introduced at a contol signal input (11) to provide a threshold current level signal. A comparator (21) compares the latter two signals and provides an enabling signal to a second switch (19) to disable the switch (17) upon detecting an over current condition. The comparator (21) is enabled by the control signal.

Abstract: A voltage regulator having a series regulator operated by a shunt regulator.

Abstract: A semiconductor device comprising first and second transistors connected in series with one another to pass a primary current upon receipt of a control signal at the gate of the second transistor. The first transistor is coupled to receive a base current from a secondary power source. A third transistor is coupled to have a primary current path to shunt the base current away from the first transistor upon conduction of the third transistor. A capacitor is connected between the base of the third transistor and the base of the first transistor so that, at the moment the second transistor ceases conduction in response to the control signal, a voltage gradient is generated between the base of the first transistor and the base of the third transistor, causing the current from the secondary power source to charge the capacitor and thus render the third transistor conductive, thereby shunting the base current from the secondary power source away from the base of the first transistor.

Abstract: A semiconductor device comprising first and second transistors connected in series with one another to provide a path for a primary current upon receipt of a control signal at the gate of the second transistor. The first transistor is coupled to receive a base current from a secondary power source. A third transistor is coupled to have a current path which shunts the base current of the first transistor upon conduction of the third transistor. A zener diode is connected between the base of the third transistor and the common junction of the first and second transistors and is arranged to provide base current to the third transistor thereby causing the third transistor to be conductive upon turn-OFF of the second transistor, and as a consequence quickly turning OFF the first transistor.

Abstract: The invention concerns a primary switched-mode power supply device with several electrically isolated secondary circuits, the output voltage of the secondary circuit being connected to an actual-value sensor with a regulator connected to the sensor output, with the output voltage being protected by a fuse connected in series with the filter capacitor. In accordance with the invention, the junction point of the filter capacitor and the fuse is connectable by an electrically controlled switch to the output terminal of the actual-value sensor as soon as the switch is turned on after the fuse has been tripped. Thus, a simple embodiment of an over-voltage protection is obtained for a primary switched-mode power supply unit with several electrically isolated secondary circuits, without additional monitoring of an in-phase output voltages A.sub.2 and A.sub.3 and a controlled secondary circuit being controlled in case of a fault to an output voltage that is lower than the normal operating controlled output voltage A.

Abstract: A thermal shutdown circuit for use with a high power transistor which incorporates a sense emitter. A differential amplifier is driven from the transistor base and the sense emitter and has an output that is coupled to the power transistor base. When the sense emitter potential exceeds the base potential, the amplifier output will pull the base down so as to limit the current in the power transistor. For a silicon transistor, the circuit will act to limit the hottest portion of the sense emitter to a maximum of about 250.degree. C. When there are no hot spots and the sense emitter is heated uniformly, heating of the transistor will be limited to about 200.degree. C.

Abstract: An intrinsically safe safety barrier includes an outgoing line, a return line, two switching transistors connected in the outgoing line, at least two control transistors having base-emitter circuits for controlling the switching transistors in order to regulate current when current increases in the outgoing line, and a single sensing resistor connected in the outgoing line in the base-emitter circuits of each of the control transistors.

Abstract: A three-terminal series regulator achieves high efficiency by using an enhancement mode P-channel or N-channel FET for the series regulating element, respectively, for positive or negative voltage regulation thereby eliminating the need for a boost voltage and also minimizing the input-to-output voltage differential at high power levels. Short circuit protection is provided using output voltage and current foldback.

Abstract: A power supply which includes terminals for connection to an electric power source, a storage capacitance, an electrical charging circuit and an operative arrangement for connecting storage capacitance in series with the charging circuit across the terminals. The power supply has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A first transistor, which has a collector-emitter path and a base-emitter path, is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.

Abstract: A battery charger which includes terminals for connection to an electric power source, an electrical charging circuit and an operative arrangement for connecting at least one rechargeable battery cell in series with the charging circuit across the terminals. The battery charger has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A first transistor, which has a collector-emitter path and a base-emitter path, is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.

Abstract: An electronic current interrupter included in a DC distribution system contains a transistorized power circuit (EK), a threshold circuit (JF), a time circuit (TK) and holding circuit (HK). In one embodiment, the power circuit comprises a power transistor (T1) connected in series with the load and with a resistor (R1) in the threshold circuit. There is a current-limiting path containing a transistor (T2) and a current-limiting resistor (R4) in parallel with a power transistor (T1). When the load current exceeds a given value, the threshold circuit sends a voltage blocking the power transistor (T1) simultaneously as the transistor (T2) in the current-limiting path becomes conductive. After a given time (t), determined by the time circuit (TK), the holding circuit sends a voltage which also blocks the transistor (t2) in the current-limiting path, and the power circuit (EK) becomes entirely non-conductive to the load current.

Abstract: A power supply which includes terminals for connection to an electric power source, a storage capacitance, an electrical charging circuit and an operative arrangement for connecting the storage capacitance in series with the charging circuit across the terminals. The power supply has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A control stage includes a first transistor, which has a collector-emitter path and a base-emitter path. The transistor is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.

Abstract: A battery charger which includes terminals for connection to an electric power source, an electrical charging circuit and an operative arrangement for connecting at least one rechargeable battery cell in series with the charging circuit across the terminals. The battery charger has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A first transistor, which has a collector-emitter path and a base-emitter path, is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.

Abstract: A power driver including a switch (17) that connects between a power input terminal (12) and a power output terminal (13). A current sense unit (22) provides an over current sense signal if an over current condition should exist with respect to the switch (17). A reference signal unit (23) utilizes a control signal as introduced at a control signal input (11) to provide a threshold current level signal. A comparator (21) compares the latter two signals and provides an enabling signal to a second switch (19) to disable the switch (17) upon detecting an over current condition. The comparator (21) is enabled by the control signal.