Abstract: A switching regulator utilizing on/off control that reduces audio noise at light loads by adjusting the current limit of the switching regulator. In one embodiment, a switching regulator includes a state machine that adjusts the current limit of the switching regulator based on a pattern of feedback signal values from the output of the power supply for a preceding N cycles of the drive signal. The state machine adjusts the current limit lower at light loads such that cycles are not skipped to reduce the operating frequency of the switching regulator into the audio frequency range until the flux density through the transformer is sufficiently low to reduce the generation of audio noise.

Abstract: A linear voltage regulator, such as a low-dropout regulator, supplies power to one or more digital circuits within a computer system. The low-dropout regulator provides a substantially constant output voltage independent of loading conditions. The low-dropout regulator is biased at a relatively low operating current for steady-state operation to improve power efficiency of the low-dropout regulator. During a loading condition change, an adaptive biasing circuit senses the loading condition change and provides additional biasing current to momentarily increase the operating current of the low-dropout regulator to improve transient response.

Abstract: A circuit for regulating current is disclosed. The circuit includes a current sensor, a controller, and a current limiter. The current sensor is formed from resistance inherent to the current limiter. The controller receives a signal from the current sensor and sends a control signal to the current limiter. The current limiter responds to the control signal by limiting current, if necessary, through the circuit.

Abstract: An over-current protection circuit for a power regulation circuit includes a reference generator that provides a reference level that is related to the level of the power source output that is controlled by the power regulation circuit in providing a regulated output. During normal operating conditions, the over-current protection circuit is isolated from the control signal provided to the pass element by other circuitry of the power regulation circuit. When the output current exceeds a predetermined level, the over-current protection circuit alters the control signal to the pass element to reduce the output current to a level below the predetermined value. If the over-current condition is removed, the over-current protection circuit detects this condition and again isolates itself from the control signal.

Abstract: In the regulated power supply circuit, an overcurrent detection circuit detects the flow of an overcurrent through a transistor acting as an output control element and supplies a result of the detection to a cut-off operation prohibition circuit. During non-startup time of the regulated power supply circuit, the cut-off operation prohibition circuit simply relays a result of the overcurrent detection circuit detecting an overcurrent to a cut-off circuit without introducing any changes to the result. The cut-off circuit increases a base potential of the transistor according to the result of the detection of an overcurrent to cut off the output of the transistor. It is ensured that the output voltage rises even if the overcurrent detection circuit has activated the cut-off circuit upon detection of the overcurrent temporarily passing through the transistor during a startup.

Abstract: A power booster and current measuring circuit provides a quiet, accurate voltage to a load (such as a transistor during parametric testing) with a load current of up to 1 ampere, and can measure that load current to an accuracy of ±0.1 % over a range of currents extending nine orders of magnitude (e.g., 1 ampere to 10−9 amperes). The load voltage is supplied by a sense driver, a bypass driver, or both. The bypass driver comprises a high-current operational amplifier with a direct feedback loop (e.g., a voltage follower). The sense driver comprises a high-impedance operational amplifier having a feedback loop comprising a high-current operational amplifier connected as a voltage follower and one of a series of sense resistors having different values.

Abstract: These sources are so designed that the amount of power required at turn-on of the DC voltage source is greater than during normal operation, taht the power supply for the evaluation electronics is independent of the measured value, and that the so-called HART protocol can be trans-mitted over the two wires. A first variant of the sources has a first current path, which goes from terminal (P1) via diode (D), the emitter-collector path of transistor (T1), grounded voltage regulator (SR), and grounded current-sensing resistor (Rm) to terminal (P2) of the DC voltage source, and a second current path, which goes from terminal (P1) via diode (D), the emitter-base path of transistor (T1), resistor (R1), the collector-emitter path of transistor (T2), resistor (R2), and resistor (Rm) to terminal (P2). Feedback resistor (Rr) connects terminal (P2) to one of the inputs of operational amplifier (OP) fed by a control signal and the output of which being connected to the base of transistor (T2).

Abstract: A circuit for regulating a current provided by a power supply to drive a load in response to an input signal, is provided. The circuit contains a current source that has a specified current value and is coupled to the power supply. In addition, the circuit also comprises a controller that generates a reference voltage and is coupled to the current source. Furthermore, the circuit also includes a comparator that compares the reference voltage and a voltage at a node. To this node, controller is coupled. In addition, the load is coupled between the node and the power supply. In response to the input signal, the controller regulates the current to drive the load. This current has a first current-value that is proportional to the specified current value of the current source when the voltage at the node is greater than the reference voltage and a second current value that is based on the power supply when the voltage at the node is less than the reference voltage.

Abstract: A driver for producing a desired pulse width modulated current through a load has a driver control for storing diagnostics codes in a diagnostic register responsive to detection of at least one electrical fault condition in a circuit including the load. A short circuit detection signal is generated in response a sensed current exceeding a programmed load current range for the driver, whereupon the driver control disables the load current and generates an interrupt signal to a microprocessor. Open circuits and shorts across the load are distinguished by way of a minimum current signal representative of a sensed current flowing through the load exceeding a predetermined minimum.

Abstract: The present invention is directed to an apparatus and method for providing a regulated DC output voltage suitable for high power (e.g., high current), high transmission rate systems in a relatively straightforward, cost efficient manner. Exemplary embodiments of the present invention can provide stable DC voltage outputs possessing essentially no AC component over the desired operating voltage range (e.g., at a 5 volt DC output, virtually no AC component over one millivolt range peak-to-peak is present), and possesses a high current capability (e.g., at a 5 volt DC output exemplary embodiments can accommodate currents in excess of 0.5 amps (A) up to 7 A or greater). The ability to provide a very stable, high current capability voltage regulator is especially desirable for communication systems, and in particular, wireless communication systems, wherein transmission rates are on the order of 125 Mb/s or higher, and transmission power is on the order of 0.5 to 2 watts (W) or higher.

Abstract: During transient operation of a voltage regulator, the gate of p-channel MOS pass transistor may be pulled down during the transient period to cause excessive surge current. The surge current is limited by using the pass transistor as a current mirror during the transient period. After the transient period, the pass transistor resumes its role as an element together with a differential amplifier and a reference voltage in a feedback loop to regulate the output voltage.

Abstract: The present invention relates to an electronic control circuit that detects a short-circuit or excess current condition and, in response thereto, cuts off the output current from the system power supply. The circuit is disposed between a system power supply and a load device. An output transistor is connected between the system power supply and the load device to control the level of current supplied to the load device, including cutting off the current supply entirely in case of a short-circuit or excess current condition. The output transistor is controlled by a pre-drive transistor which, in combination with pre-drive resistors, provides a control signal to the output transistor to control the level of output current supplied to the load device. The control signal produced by the pre-drive transistor is dependent upon the output of an operational amplifier that compares the output potential to a pre-determined reference voltage to determine if the output potential has reached a stable level.

Abstract: A current detection resistance such as a metal resistance is formed in series with a power transistor, and in response to an output voltage of the current detection resistance, an overcurrent protective circuit performs an overcurrent suppressing operation with high accuracy without being affected by irregularity of a current multiplication factor, etc.; thus, it is possible to realize a smaller chip area so as to reduce the cost. Furthermore, a short-circuit protective circuit returns a terminal voltage of a referenced resistance, that appears in accordance with a partial pressure value of an output voltage, at the transistor, a partial pressure resistance, and a current mirror circuit. And the short-circuit protective circuit controls a potential of a base resistance and suppresses a base current. Hence, it is not necessary to dispose the transistor for suppressing a current between base lines, so that a low-voltage operation can be realized.

Abstract: An LDO voltage regulator includes an error amplifier having a first input coupled to a first reference voltage, a second input receiving a feedback signal, and an output producing a first control signal. An output transistor has a gate, a drain coupled to an unregulated input voltage, and a source coupled to produce a regulated output voltage on an output conductor. A feedback circuit is coupled between the output conductor and a second reference voltage. An overvoltage comparator has a first input coupled to receive the first reference voltage and a second input coupled to respond to the feedback signal to produce a discharge control signal indicating occurrence of an output overvoltage of at least a predetermined magnitude to control a discharge transistor coupled between the output conductor and the second reference voltage. An output current sensing circuit produces a control current representative of the drain current of the output transistor.

Abstract: There is disclosed a current control circuit, disposed between a primary terminal and a secondary terminal, for controlling a current flowing from the primary terminal to the secondary terminal. An overcurrent flowing through a resistance R1 is detected by a PNP transistor. A maximum value of a current flowing through a MOSFET is determined by a voltage dropped by a voltage drop correspondence by a diode from a voltage of the collector of the PNP transistor.

Abstract: A voltage source provides an input signal to a drive circuit for a power semiconductor. A protective circuit is connected between the drain and the source of the power semiconductor and is activated when excess current is present. The protective circuit provides an output signal that is received by a control circuit to limit the voltage at the gate of the power semiconductor. The control circuit is connected between the gate and the source. A controllable resistance including an enhancement MOSFET and an external capacitor in which the enhancement MOSFET has a gate, a source and an internal capacitance between the gate and the source is connected in parallel to the external capacitance. The controllable resistance carries the input signal from the voltage source to the power semiconductor. The controllable resistance is switched to high impedance when the protective circuit is activated and switched to low impedance when the protective circuit is deactivated.

Abstract: A current through a transistor having a drain and a source is sensed using a resistor, and first and second current sources. The resistor is responsive to the first current source to establish a reference voltage between a first terminal and a second terminal. The second terminal of the resistor is coupled to the source of the transistor. The second current source is current-controlled by the first current source and has a current gain inversely related to a voltage between the drain of the transistor and the first terminal of the resistor.

Abstract: A circuit for controlling the power to a load such as motor or incandescent lamp with reduced radio frequency interference employs a microcontroller to trigger a power transistor into a conductive state for supplying power to the load. The power transistor is switched on and off at a controlled slew rate through an integrator circuit coupled between the microcontroller and the power transistor. A zero current detector circuit detects when no current is passing through the load during each half cycle of the live voltage to switch the power transistor off by generating an interrupt request signal which is supplied to the microcontroller. After an operator selected time interval, the microcontroller generates a signal to switch the transistor to a conductive state.

Abstract: A linear type of voltage regulator, having at least one input terminal adapted to receive a supply voltage and one output terminal adapted to deliver a regulated output voltage, includes a power transistor and a driver circuit for the transistor. The driver circuit includes an operational amplifier having an input differential stage biased by a bias current which varies proportionally with the variations of the regulated output voltage at the output terminal of the regulator.

Abstract: A hybrid regulator in which a switching regulator and a series regulator are inter-connected in a desired manner. In the hybrid regulator, most of current required for a load is supplied from the switching regulator which has a poor regulation performance while having high efficiency. The hybrid regulator also includes a sensing unit for the rapid sensing of the current supplied to the load. Based on the operation of the sensing unit, the series regulator, which has a poor power efficiency while exhibiting a excellent regulation performance, supplies or absorbs only a small amount of ripple current. The series regulator serves as an independent voltage source whereas the switching regulator serves as a dependent current source. Accordingly, the hybrid regulator ensures a superior regulation performance while achieving high efficiency.

Abstract: A circuit for operation of a semiconductor light source having terminals for connecting a source of power and output terminals for connecting the semiconductor light source. The circuit is also provided with a controlled current generator and is also concerned with a signal head incorporating the circuit. The controlled current generator is controlled by the current flow through the semiconductor light source and the current supplied by the controlled current generator.

Abstract: A charging circuit for charging a battery is disclosed. The charging circuit includes a power transistor having a charging terminal for connection to a charger, and a battery terminal for connection to the battery. Further, the charging circuit includes a shunt transistor connected between the battery and a control terminal of the power transistor. The shunt transistor prevents saturation of the power transistor when the charging source is disconnected from the charging terminal and the battery is in a charged state. This prevents leakage of current from the battery through the power transistor. The charging circuit further includes a diode connected between the charging terminal and a shunt control input of the shunt transistor. The diode, along with a voltage divider which divides the charging voltage, maintains the shunt transistor in a non-conductive state when the charger is connected to the charging terminal.

Abstract: The present invention relates to a current limiting circuit for controlled semiconductor power components, in particular to a current limiting circuit for power transistors which is independent of its voltage supply. A current limiting circuit for controlled semiconductor power components, in particular for power transistors, with a sense resistor, which is connected in series with the main current path of the controlled semiconductor power component, generating a voltage drop proportional to the current through the controlled semiconductor power component. A current mirror circuit device has a first current source device for generating a first current between a first and a second reference-ground potential. A second current source device generates a second current between the control potential of the control terminal of the semiconductor power component and a third reference-ground potential.

Abstract: A current limiting circuit in which, when the input DC voltage is raised from zero volts to the reference voltage, an output DC flows through the connected load only when the value of the input DC voltage rises to a value above an undervoltage threshold value which is below the reference voltage.

Abstract: A trigger circuit for a field-effect-controlled power semiconductor component has a controllable gate resistor for the power semiconductor component, which has low impedance in a normal situation and is switched to high impedance in the event of a short circuit. As a result, the turn-on time in the normal situation is shortened, and limiting the gate-to-source voltage of the power semiconductor component in the short-circuit situation is made possible.

Abstract: A switched mode power convertor with a switch, a switching control device, a coil for storing energy, and a load. The switch is coupled between an input of the power convertor and the coil, and the coil is further coupled to an output of the power convertor. The switching control device has a control input and controls the switch. The switched mode power convertor further has an input current estimator which estimates the input from a quotient of a measured output power and a measured input voltage, taking into account the efficiency of the power convertor. A signal proportional to the estimated input current is supplied to the control input.

Abstract: For use with a power converter having a current sensor that senses an output current of the converter and generates a proportional voltage and a controller having an overvoltage protection circuit associated therewith. The overvoltage protection circuit includes a voltage sense input coupled to an output of the converter and a first reference voltage input, an integrated protection circuit, method of providing current-limiting and short-circuit protection and power converter employing the same. In one embodiment, the integrated protection circuit includes an operation amplifier circuit, coupled between the current sensor and the controller, that generates a voltage signal and causes the controller to limit a current supplied by the converter to the output when the proportional voltage exceeds a second reference voltage.

Abstract: The circuit configuration captures the load current of a field effect-controllable power semiconductor component. The drain and gate terminals of a further field effect-controllable semiconductor component are connected to the drain and gate terminals, respectively, of the first semiconductor component. A fraction of the load current flows through the further semiconductor component. The load current of the further semiconductor component is set as a function of the drain-to-source voltage of the two semiconductor components. The load current flowing through the further semiconductor component is compared with a reference current and an output signal is generated if the load current falls below a set value.

Abstract: A power supply unit has an output transistor and two resistors connected in series between a power source line and a ground potential point. The output electrode of the output transistor is connected to an output terminal. Between the output terminal and the ground potential point, a capacitor is connected. When a starting switch is turned on, the output transistor starts conducting. A current limiting circuit is also provided to limit the current that flows through the output transistor when it starts conducting. The current limiting circuit bypasses part of the output current of a comparator to the ground potential point.

Abstract: A linear type of voltage regulator, having an input terminal adapted to receive a supply voltage thereon, and an output terminal adapted to deliver a regulated output voltage, includes a power transistor and a driving circuit therefor. The driving circuit includes an operational amplifier having a differential input stage biased by a bias current which varies proportionally with the output current of the regulator.

Abstract: A regulator includes a driver stage having an output port for providing an output voltage, a predriver coupled to the driver to control the output voltage provided by the driver stage, a comparator to compare the driver output voltage to a reference voltage, and a feedback element coupled between the driver output port and the comparator. The driver may include a high side transistor having a collector coupled to a collector of a low side transistor, and a current sensing transistor having a base coupled to a base of the low side transistor.

Abstract: A self-excitation type switch power supply unit with overcurrent protection. For adopting a simple and reliable current negative feedback protective circuit to coordinate with a complementary bridge circuit, a positive feedback circuit without DC biasing capacitive coupling, an oscillation-starting circuit of the AC power supply, etc., so that the self-excitation type switch power supply can become a practical power supply unit with simple circuitry, small size and low cost.

Abstract: A method and circuit (10) for limiting current (I.sub.COIL) in a load (16). The current limiting circuit (10) includes a sensing circuit (12) having a current indicator output terminal (20) connected to an inverting input of a comparator (11). A reference voltage node (24) of a reference voltage generator (13) is connected to the non-inverting input of the comparator (11). The comparator (11) generates an output signal in accordance with the current flowing in the load (16). If an overcurrent condition exists, the signal from the comparator (11) disables a control circuit (14) which turns off the sensing circuit (12). With the control circuit (14) disabled and sensing circuit (14) off, the current (I.sub.COIL) is prevented from flowing through the load (16).

Abstract: A charging apparatus having a power supply circuit that provides a DC output current via a sense resistor. A current detector amplifies, detects and provides a voltage across the sense resistor. A controller designates the output of the current detector as a determination signal when the DC output current is equal to a preset voltage. Responsive to the determination signal, the controller generates a control signal in order to control the DC output current of the power supply circuit. More particularly, the current detector includes a first differential amplifier that amplifies and output the voltage across the sense resistor, a second differential amplifier amplifies and supplies a differential voltage between the output of the first differential amplifier and a predetermined first reference voltage, and a first output circuit responsive to the output of the second differential amplifier delivers the determination signal.

Abstract: A lighting system made up of a plurality of light fixtures which each produce a light beam, in which each of a plurality of varying devices, each having an input and an output, and each capable of varying at least one parameter of the light beam from at least one of the light fixtures, is responsive to a first value received at the input, where the first value corresponds to the desired adjustment of a parameter of the light beam. Each of the varying devices is also capable of generating a second value which represents status information, and transmitting the second value via the output. A controller produces the first value and sends it to an output which is coupled to the input of the varying device. A monitoring device has an input and is separate from the controller, and its input is coupled to the output of the varying device.

Abstract: A DC-to-DC converter includes a pulse width modulation circuit for modulating a switch to produce current pulses having at least a minimum pulse width to thereby control an output voltage to the load. The converter also includes a current limit determining circuit for determining when a desired peak current is no longer sufficient to maintain a desired output voltage thereby defining a current limit condition. In addition, the pulse width modulating circuit, when operating at the minimum pulse width, thereby defines a minimum pulse width condition. Accordingly, the converter preferably further includes an over-current determining circuit for determining an over-current condition responsive to the minimum pulse width condition being reached during a current limit condition. The converter may turn off the switch responsive to an over-current condition. A blanking signal may be used to clamp a comparator and established a minimum pulse width.

Abstract: A circuit for limitation of maximum current delivered by a power transistor comprises: a network for detection of the current delivered by the power transistor which generates a first electrical signal; a reference network for generating a reference current proportional to a resistor and self-limited, provided by means of a current generator circuit and a limiting circuit with current mirror; and an operational amplifier which compares the first electrical signal with the reference current and which tends to inhibit the power transistor if the current delivered exceeds a certain threshold value.

Abstract: A voltage regulator with a current limit circuit for limiting pass current in a pass transistor below a current limit threshold and a foldback circuit for lowering the current limit threshold when the voltage differential between the input and output terminals of the voltage regulator exceeds a foldback threshold, where the current limit threshold has a negative temperature coefficient, the current limit circuit comprising two transistors coupled to a sense resistor such that the difference in emitter-to-base voltages of the transistors is equal to the voltage drop of the sense resistor, where the collectors of the two transistors provides first and second currents to first and second resistors, respectively, where the first current is responsive to a pass current flowing through the sense resistor and decreases when the pass current increases, where the second current is independent of the pass current, and the foldback circuit provides a third current to the second resistor when the voltage differential bet

Abstract: A method of protecting an adjustable impedance element such as a transistor controlling the power supplied to an electric motor, in particular in a motor vehicle, wherein the control of said adjustable impedance element is modified when the current passing through it exceeds a given threshold, characterized in that said current threshold is an increasing function of the voltage U.sub.M across the terminals of the motor.

Abstract: A circuit for protecting from overload currents includes an electronic power device having at least first and second terminals and at least one control terminal. The circuit also includes at least one voltage-generating circuit for generating a reference voltage having a predetermined pattern. The voltage-generating circuit includes at least a first terminal connected to the first terminal of the power device and at least a second terminal coupled to the second terminal of the power device through a sensor. The circuit also preferably includes at least one comparator for comparing the reference voltage with a voltage present across the sensor. The comparator has at least one output terminal and at least first and second input terminals. The first and second input terminals are respectively connected to a third terminal of the voltage-generating circuit and the second terminal of the power device.

Abstract: A linear voltage regulator is operated by a temperature sensor and a current sensor. The temperature sensor is a thermistor in a voltage divider connected across the output of the regulator. The current sensor operates a voltage follower connected to adjust the voltage in the voltage divider. The regulator controls voltage supplied to a cooling fan in a power supply. The sensed temperature is the air temperature near the power supply enclosure. The sensed current is the output current of the power supply. When the ambient temperature increases and/or the power supply output current increases, the voltage regulator increases the fan speed by raising the voltage. The current sensor can also be used to sense other parameters, such as voltage.

Abstract: A reconfigurable integrated circuit chip includes an output terminal (42) which is connected to the output of an inverting amplifier (44). The integrated circuit chip (10) includes an output terminal (46) which is connected to one input of a comparator (22). The other end of comparator (22) is connected to an internal voltage reference device (48). The output of comparator (22) is connected to the input of the inverting amplifier (44). The integrated circuit chip (10) may be configured as a linear regulator when a transconductance device (14) is connected between a DC power supply (12) and a load and an integrator (24) is connected between terminal (42) and the control input of the transconductance device (14). The integrated circuit chip (10) is configured as a switching regulator when a gated switch (14) is connected between a DC power supply (12) and a switching node (65) wherein the gated switch (14) is gated by the signal output by the output terminal (42).

Abstract: This invention discloses an active electrical current filter including an N-channel FET controller coupled in series along a positive electrical line between an electrical power input and an electrical power output having voltages within a given range, apparatus for providing a driving voltage to the FET controller, the driving voltage being in excess of the voltages within said given range, and a differential voltage sensor, which senses the difference between the voltages at the filter input and output and whose output governs the driving voltage supplied to the FET controller, the active electrical filter exhibiting a voltage drop of less than one volt.

Abstract: A power controller (10) for supplying power to a power distribution network (N) in which power from a polyphase source (G) is routed to using equipment (E) connected to the network through the power controller. A plurality of solid-state power devices (82) switch each separate phase of the polyphase power to the equipment. A firing circuit (14) controls gating of the switches to route the power. Fuses (F) are connected between the switches and the using equipment to interrupt power flow to the equipment if excessive current begins to be drawn. A con, roller (20) controls a shutdown sequence employed by the controller to eliminate current spiking at shutdown. The various components are housed in an enclosure (22) which includes a mounting structure (56) for mounting the aforesaid components. A cooling system (26) employs a fan (88) for directing air flow through the mounting structure to cool the components.

Abstract: An alarm based upon the voltage across a linear regulator's pass transistor and the regulator's load current alerts operational circuitry which obtains power through the regulator when the voltage across the pass transistor may be insufficient for proper voltage regulation. The alarm's trigger voltage is adjusted in response to variations in the regulator's output current.

Abstract: A circuit providing start-up capability and foldback protection to a voltage regulator. A start-up circuit provides a start-up signal to initiate current flow to a load and also provides a foldback signal to set a current limit threshold under an over-load or short-circuit condition. A signal generator circuit operating on the regulated output voltage of the voltage regulator provides a current limit signal and a start-up control signal. The start-up circuit provides the start-up signal in response to the start-up control signal. The current limit signal sets the current limit threshold under normal operating conditions after start-up.

Abstract: In a circuit arrangement for regulating the load current of a power MOSFET, the drain-source voltage of the power MOSFET is imaged onto the input of a second MOSFET connected between a gate terminal and source terminal of the power MOSFET. When the input voltage exceeds the cut-off voltage, then the gate-source voltage at the power MOSFET is regulated back to a value that corresponds to the sum of the cut-off voltages of the second MOSFET and a third MOSFET. The gate terminals of third MOSFET and the power MOSFET are connected to one another.

Abstract: A bidirectional communication system for communicating signals between a master device (1) and a slave device (2) connected by a single wire (3), in which the master device (1) includes a voltage signal generator (4) for generating voltage signals to be transmitted to the slave device (2) over the wire (3), a current sensor (6) for sensing current consumed on the wire (3), and a received signal generator (14, 19) for generating received signals corresponding to the sensed current consumption. The slave device (2) includes a receiver (7) for receiving the voltage signals transmitted over the wire and producing received data therefrom, and a current consuming device (8) for consuming current from the wire (3) in correspondence with a signal to be transmitted to the master device (1).

Abstract: In a regulated power supply circuit, a "J characteristic curve" is obtained between an output current and an output voltage. Moreover, the output current is minimized in a grounded state in which the output terminal is grounded to minimize heat dissipation so as to facilitate circuit integration. Between the input and output terminals, there are connected an output-stage transistor and a current sense resistor in series. A voltage sense circuit senses voltage between an output terminal of the transistor and a ground terminal. The current sense circuit senses the output current by the current sense resistor. The transistor has a base terminal connected to output terminals of the voltage and current sense circuits, respectively. In this configuration, when the output terminal is grounded, the output current is set independently of a current value sensed at occurrence of an excess current. This consequently lowers the power consumption of the regulated voltage circuit in the grounded state.

Abstract: The present invention relates to a current limiting circuit for controlled semiconductor power components, in particular to a current limiting circuit for power transistors which is independent of its voltage supply. A current limiting circuit for controlled semiconductor power components, in particular for power transistors, with a sense resistor, which is connected in series with the main current path of the controlled semiconductor power component, generating a voltage drop proportional to the current through the controlled semiconductor power component. A current mirror circuit device has a first current source device for generating a first current between a first and a second reference-ground potential. A second current source device generates a second current between the control potential of the control terminal of the semiconductor power component and a third reference-ground potential.