Abstract: A protection circuit for protecting DCDC converter with a power MOS transistor from start-up in-rush current includes a coupling capacitor and a voltage clamping circuit. By using the coupling capacitor to turn-off the power MOS transistor, there is no current consumed during the normal operation of the circuit. Enable signal or leakage current circuit is used to discharge the capacitor so that the circuitry can work in another turning-on of power supply.

Abstract: It is an object of the present invention to provide a driving circuit which is adapted, for a semiconductor device which exhibits a diode characteristic of flowing an abrupt current if the gate-source voltage therein exceeds a predetermined voltage, to have the functions of reducing electric-power consumption in high-load state, reducing the loss in the driving circuit in low-load states, preventing excessive voltages, excessive currents and excessive electric-power consumption, and reducing the loss in the semiconductor device.

Abstract: This invention relates to a control method and a circuit for MOS-gated power semiconductor switching devices such as IGBTs or MOSFETs, which allows control and optimisition of the current and voltage commutation of a power semiconductor switching device and freewheel diode pair in the basic half-bridge circuit found in a wide range of equipment.

Abstract: A voltage regulator has a first error amplifier circuit that amplifies a difference between a first reference voltage and a voltage based on an output voltage of an output transistor, and an overcurrent protection circuit that detects an overcurrent flowing through the output transistor and limits a current of the output transistor.

Abstract: A current sensor having a pair of sense transistors is disclosed. The sense transistors sense a current conducted by a power transistor of a voltage regulator. The ratio in size between the power transistor and the sense transistors corresponds to a scaling factor M. Each sense transistor has an associated series connected sense resistor. The two sense resistors are unbalanced and provide a differential voltage based on the sensed current at the sense transistor to a transconductor. The transconductor has heavy emitter degeneration to provide an output current substantially proportional to the current conducted by the primary power transistor, the proportion determined by the scaling factor M and a ratio of the emitter degeneration and sense resistors.

Abstract: The invention discloses a voltage adjusting apparatus including a power adaptor, a first resistor, a current detecting module, a second resistor, and a voltage feedback controlling module. The power adaptor outputs a first current first. The first resistor is used to convert the first current to a first voltage. The current detecting module is used to convert the first voltage to a second current. The second resistor is used to convert the second current to a second voltage. The voltage feedback controlling module is used to convert the second voltage to a third voltage. The power adaptor is used to convert the third voltage to a fourth voltage and output the fourth voltage.

Abstract: A drive circuit supplies a drive current to a plurality of light emitting diodes. The drive circuit includes a voltage converter circuit having a particular topology and including at least one inductive element and at least one switching element. The drive circuit senses a current through one of the inductive and switching elements and generates a feedback signal from the sensed current. The feedback signal has a value indicating the drive current being supplied to the light emitting diodes and the drive circuit controls the operation of the voltage converter responsive to the feedback signal.

Abstract: A linear voltage regulator is provided which has a pair of complementary power transistors connected “back to back” in series between a voltage input and a voltage output. A current sense circuit including a current sense resistor is connected in parallel across one of the power transistors, such as the one connected to the voltage input. As long as the voltage drop in the current sense circuit remains small, i.e. less than app. 0.7V, the current flowing through the bulk diode of the power transistor remains negligible and the entire output current flows through the current sense circuit. For higher output currents the voltage drop across the current sense circuit is limited by the parallel bulk diode of the power transistor. The current sense resistor can be dimensioned to generate a relatively high voltage drop of e.g. 100 mV, and a high accuracy of open load detection is achieved without the requirement for a high precision comparator.

Abstract: A stabilized regulator circuit is provided A first Pch transistor (PTr) (P1) whose source is connected to a power supply line and whose drain is connected to an output terminal that outputs a load current, a PTr (P2) whose source and gate are respectively connected to the source and gate of the PTr (P1), resistor elements connected in series between the output terminal and ground, a resistor element (R3) connected between a drain of P2 and ground, and an amplifier which controls P1 and P2 based on a difference between potential of a connection point of the resistor elements and a reference. A comparator, with a differential amplifier input stage configured by an Nch transistor, compares potential difference between two ends of R3 and potential difference between the connection point of the resistor elements and ground, and when the former is larger, controls P1 so as to limit load current.

Abstract: A current-limiting circuit (100), which limits an electrical current from a voltage source to a consumer to a predetermined maximum current. A measuring resistor (110) is coupled into a current lead (103) between a circuit input (102) and a circuit output (104). A transistor (106) of the circuit is coupled into the current lead (103) with its collector-emitter path in series with the measuring resistor (110), and its base is connected to the current lead (103) through a series resistor (108). A shunt regulator (116) of the circuit has an anode, a reference input and a cathode, wherein the cathode is connected to the base of the transistor (106), and the anode and the reference input form a voltage tap across the measuring resistor (110).

Abstract: Provided is a voltage regulator capable of setting an accurate short-circuit current. Used as a circuit for determining a current value of a short-circuit current of an overcurrent protection circuit is not a resistor for converting current into voltage but a circuit for controlling in the form of current, that is, a circuit of an N-channel depletion type transistor including a gate and a drain that are connected to each other and operating in a non-saturated state. The N-channel depletion type transistor has process fluctuations that are linked with those of a detection transistor, and hence an accurate short-circuit current may be set without trimming.

Abstract: A voltage supply circuit includes an output transistor causing a first current to flow to an output terminal of the voltage supply circuit based on a control voltage applied from an error amplifier to a control terminal of the output transistor; and an overcurrent protection circuit including a reference transistor causing a second current to flow to the output terminal, the second current having an amount corresponding to an amount of the first current, the overcurrent protection circuit regulating a level of the control voltage based on comparison between a detection voltage caused based on the second current and a reference voltage.

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: A two-gain-stage linear error amplifier is provided with frequency compensation and independently selectable stage gains and a reasonably small compensation capacitor to promote stability with a reasonable phase margin over a wide load range so that the invention is useful as a low drop out (LDO) voltage regulator circuit device that is stable over a wide load range.

Abstract: An electronic circuit. The electronic circuit includes a pass transistor having a channel coupled between an input node and an output node. An error circuit is coupled thereto and configured to control the amount of current flowing through the pass transistor. The electronic circuit may further include a feedback node. A current limiting circuit is coupled to both the feedback node and the error circuit. The current limiting circuit is configured to limit an amount of current provided to the pass transistor by the error circuit based on a on a feedback voltage present on the feedback node and a current through a current mirror circuit, and therefore limits the output current provided by the electronic circuit.

Abstract: The present invention discloses a current regulation module for providing a predetermined current. The current regulation module comprises a linear power conversion circuit, a switching power conversion circuit, a current detector, and a controller. The current detector is used to detect the output current of the current regulation module and output a detected current value. The controller control the switches in the linear power conversion circuit and the switching power conversion circuit in accordance with the detected current value, to strengthen the dynamic response ability to the sudden change in the output current.

Abstract: Aspects of a method and system for a power switch with a slow in-rush current are presented. Aspects of the system may include at least one resistive component, which is coupled between an input control signal and an output stage circuit of a power switch circuit, so as to limit a peak transient current level, which may result from in-rush current delivered by the power switch circuit to a load impedance circuit during a transient time interval during which a voltage level across the load impedance circuit may rise or fall from an initial voltage level to a quiescent voltage level.

Abstract: A dimmable, light-emitting diode (LED) power supply adapted to provide a direct current (DC), constant current (“constant current source”) from a conventional, phase-controlled 120 VAC, 60 Hz power source is disclosed. The constant current source of the present invention utilizes two processes to control dimming. In a first process, the phase angle of the input voltage is used to control the duty cycle of a line frequency pulse width modulation (PWM). In a second process, a proportional-current limit adjustment is used to control the average current to the LED during the ON time of the line frequency by PWM. As a result, at relatively low phase angles, peak currents can be lowered, reducing flicker and improving the audible noise levels generated by the circuit.

Abstract: A current detector circuit detects a current supplied to a load and generates as a detection result a voltage corresponding to the detected current. A first p-channel transistor has a source connected to a power supply and a gate connected to a ground, and is configured to allow the passage therethrough of a current that is 1/N of a current flowing through a transistor which drives the load. A second p-channel transistor has a source connected to a drain of the first p-channel transistor, and a third p-channel transistor is connected to the load. A voltage mirror circuit has first and second terminals connected to respective drains of the second and third p-channel transistors. A n-channel transistor has a drain connected to the drain of the first p-channel transistor and outputs a source voltage as the detection result of the current detector circuit.

Abstract: Provided is a voltage regulator for limiting a rush current from an output stage transistor. The voltage regulator includes an output current limiting circuit having a low detection current value and an output current limiting circuit having a high detection current value, and is structured so as to enable operation of the output current limiting circuit having a low detection current value during a time period from a state in which an overheat protection circuit detects overheat and an output current is stopped to a state in which an overheat protection is canceled and a predetermined time passes. Accordingly, after the overheat protection is cancelled, an excessive rush current can be limited.

Abstract: A current sensing circuit for sensing an output current generated by a voltage regulator includes a first double-diffused metal-oxide semiconductor transistor and a current-voltage converter. The first double-diffused metal-oxide semiconductor transistor has a first gate terminal to receive an output control signal from a control circuit of the voltage regulator. The first double-diffused metal-oxide semiconductor transistor is configured to output a current proportional to the output current according to the output control signal. The current-voltage converter is connected to the first double-diffused metal-oxide semiconductor transistor. The current-voltage converter is configured to convert the proportional current to a corresponding voltage.

Abstract: A series regulator with fold-back over current protection has a high ratio current mirror circuit located between a sense transistor and its voltage output terminal. The series regulator receives an input voltage at an input terminal and generates a stable output voltage at an output terminal. A first amplifier receives a reference voltage. An output transistor is connected between the input terminal and the output terminal and has a gate connected to an output of the first amplifier. A current limiting transistor and the current sense transistor are connected to the input terminal, the output terminal of the first amplifier, and the gate of the output transistor. A voltage divider, connected between the output terminal and ground, generates first and second voltage signals. The first voltage signal is provided to a non-inverting input of the first amplifier. A first current source is connected to the voltage divider and receives the second voltage signal.

Abstract: The present invention discloses an LDO (Low DropOut) linear voltage regulator, which is based on an NMC (Nested Miller Compensation) architecture and can be capacitor-free, wherein an active resistor is added to the feedback path of the Miller compensation capacitor to increase the controllability of the damping factor, solve the problem of extensively using the output capacitor with a parasitic resistance, and solve the problem that a compromise must be made between the damping factor control and the system loop gain. Further, the present invention utilizes a capacitor-sharing technique to reduce the Miller capacitance required by the entire system and accelerate the stabilization of output voltage without influencing stability.

Abstract: A direct current (DC) remote power controller for remotely controlling DC power between a DC power source and a DC load, comprises: a current sensor for sensing the level of current that the power source supplies to the load and generating a current feedback signal representative of the sensed current level; a current limit controller that compares the current feedback signal to a reference current level and generates a current regulation signal representative of the value of sensed current level above the reference current level; a current limiting device that is responsive to the current regulation signal to limit load current to the reference current level up to a first predetermined level of potential difference across the current limiting device; a load resistance; and a switched-mode DC-to-DC converter in parallel with the current limiting device that senses potential difference across the current limiting device and diverts a portion of the load current from the current limiting device through the load

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 direct current stabilization power supply apparatus, comprising: an output control device which generates a voltage corresponding to a drive current given and outputs it as an output voltage; a direct current stabilization portion which gives the drive current to the output control device to equalize a comparison voltage corresponding to the output voltage with a predetermined reference voltage and makes the output control device generate a desired output voltage; and a drive current limitation portion which monitors the comparison voltage and lowers the drive current according to a drop in the comparison voltage, wherein, when the comparison voltage is equal to or lower than a predetermined threshold voltage, the drive current limitation portion carries out an operation to hold the drive current at a predetermined lower-limit current value, or an operation to clamp a lower-limit value of the comparison voltage at a predetermined voltage value.

Abstract: The present invention mainly relates to a current limiting circuit, also known as over-current protection circuit, and a power regulator using the same. The purpose for the circuit is to protect the power device and the loading circuit for the power regulator. The conventional current limiting circuit takes advantage of a resistor and a MOS to convert the detected over current into a voltage and then turn on a P-typed MOS to clamp the gate voltage of a power transistor so as to achieve the goal of current limiting. However, the process variation for the resistor and said MOS and their temperature variation lead to a significant error to the limiting current. The present invention, therefore, takes advantage of the current comparison to enhance the accuracy for the current limiting circuit.

Abstract: The present invention mainly relates to a voltage regulator, comprising: a P typed power MOS; a feedback circuit; a differential amplifier; a protecting circuit having a N-typed transistor current mirror; and an active foldback current limiting circuit rather than using a resistor. When the P typed power MOS is under short circuit current situation, the current at the output side of the current mirror is increased in order to limit the current flown through the power MOS. Meanwhile, the same purpose can also be served by increasing the current at the input side of the DC current mirror.

Abstract: A constant-voltage power supply circuit which limits the consumption current inside at startup or when overloaded and suppresses the occurrence of an overshoot at startup, comprises an error amplifying part; an output part having an outputting PMOS; a load current monitoring part that monitors a load current flowing through the PMOS and increases the bias current of the error amplifying part according to the load current; and a gain adjusting part having a current limiting resistor and that monitors the load current and decreases a gain of the error amplifying part according to this load current. Hence, at startup or when overloaded, the gain adjusting part operates as a limiter circuit. Hence, at startup or when overloaded, the consumption current inside can be limited. Further, at startup, the response is made slower by this limiter operation, thus suppressing the occurrence of an overshoot.

Abstract: In one embodiment, an LED current control circuit is configured with a sample and hold circuit that samples an error signal of an error amplifier during one time and holds the sampled value during a second time.

Abstract: In one embodiment, a power converter system includes a power device coupled between a first node and second node. The power device is operable to be turned on and off by a control signal. Current flows through the power device when the power device is turned on for delivering power to a load. A sensing circuit is coupled in parallel to the power device between the first node and the second node. The sensing circuit is operable to develop a signal indicative of the current flowing through the power device and is further operable to be turned on and off by the same control signal as for the power device. The sensing circuit turns on when the power device turns on and turns off when the power device turns off.

Abstract: A current sensing circuit includes a first resistor, a second resistor and a sense amplifier. The first resistor converts a current flowing through the first resistor to a voltage drop between positive and negative sides of the first resistor. The second resistor is coupled to the negative side of the first resistor. The sense amplifier is coupled to the positive side of the first resistor via a first pin of the sense amplifier, and coupled to the negative side of the first resistor through the second resistor via a second pin of the sense amplifier. The sense amplifier employs a negative feedback to generate a sensing current proportional to the current flowing through the first resistor.

Abstract: Even when one of IGBTs fails in a semiconductor power converter apparatus in which a plurality of semiconductor elements are connected in parallel, the remaining IGBT(s) is prevented from failing with a simple circuit configuration. The semiconductor power converter apparatus includes: a semiconductor power conversion circuit in which a first IGBT having a temperature sensing unit and a second IGBT having a current sensing unit are connected in parallel, for causing the first and second semiconductor elements to perform switching operations; an overheat protection circuit for performing overheat protection for the first and second IGBTs based on temperature information obtained from the temperature sensing unit of the first IGBT; and an overcurrent protection circuit for performing overcurrent protection for the first and second IGBTs based on current information obtained from the current sensing unit of the second IGBT.

Abstract: A linear voltage regulator is provided which has a pair of complementary power transistors connected “back to back” in series between a voltage input and a voltage output. A current sense circuit is connected in parallel across one of the power transistors, such as the one connected to the voltage input. The current sense circuit includes a current sense resistor. A reference current path has a reference resistor connected in series with a current sink between the voltage input and a reference terminal, usually ground. A comparator has a first input connected to a terminal of the current sense resistor and a second input connected to a node between the reference resistor and the current sink. The comparator compares the voltage drop across the current sense resistor with the constant voltage drop across the reference resistor and provides an output signal indicative of an open load condition when the voltage drop across the current sensor falls below that of across the reference resistor.

Abstract: A power supply unit is adapted to automatically switch its operational mode between a light load mode and a heavy load mode depending on the level of its output current. The unit has a first error amplification circuit for controlling a first output circuit in the heavy load mode, and a second error amplification circuit for controlling the second output circuit in the light load mode. The first and the second output circuits are controllably enabled and disabled in the opposite manner based on the level of the output current. Thus, the unit can operate on a reduced consumption current with an improved transient response when operating in the light load mode.

Abstract: A direct current (DC) remote power controller for remotely controlling DC power between a DC power source and a DC load, comprises: a current sensor for sensing the level of current that the power source supplies to the load and generating a current feedback signal representative of the sensed current level; a current limit controller that compares the current feedback signal to a reference current level and generates a current regulation signal representative of the value of sensed current level above the reference current level; a current limiting device that is responsive to the current regulation signal to limit load current to the reference current level up to a first predetermined level of potential difference across the current limiting device; a load resistance; and a switched-mode DC-to-DC converter in parallel with the current limiting device that senses potential difference across the current limiting device and diverts a portion of the load current from the current limiting device through the load

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: An LDO with over-current protection includes a first and a second P-type transistor, a sensing resistor, a comparator, and an error amplifier. The channel aspect ratio of the first P-type transistor is much higher than that of the second P-type transistor. The first P-type transistor generates output voltage source according to input voltage source and current control signal. The sensing resistor is coupled among the input voltage source, the second P-type transistor, and the comparator, providing a sensing voltage. The comparator generates a current limiting signal according to first reference voltage and the sensing voltage. When the current limiting signal enables the error amplifier, the error amplifier adjusts voltage of the current control signal according to second reference voltage and voltage divided from the output voltage source; when the current limiting signal disables the error amplifier, voltage of the current control signal is not adjusted.

Abstract: A voltage regulator architecture for an integrated circuit is described. An apparatus may comprise a power switch array having multiple pass transistors, a voltage regulator array having multiple voltage regulators each coupled to a subset of the pass transistors, a subsystem circuit array having multiple subsystem circuits each coupled to a subset of the pass transistors, and a power management control unit coupled to the pass transistors and the voltage regulators. The power management control unit may be arranged to control the pass transistors and voltage regulators to provide different amounts of power to the subsystem circuits. Other embodiments are described and claimed.

Abstract: A linear regulator with an N-type pass transistor includes an over-current protection circuit. A current sink is used as an indicator for an over-current condition and is coupled to the output of the linear regulator. The indicator is coupled to a feedback logic circuit that controls the current through the output load. The over-current protection circuit extensively uses N-type devices for various components including the output driver stage in the circuit. This results in reduced area for the over-current protection circuit.

Abstract: A system and method is provided for providing integrated over-current protection in a switching power supply. In one embodiment, a switching power supply could comprise a gate drive circuit operative to receive a pulse-width modulated (PWM) signal and to drive at least one power field effect transistor (FET) between alternating activated and deactivated states based on a pulse-width of the PWM signal. The switching power supply could also comprise a current sense circuit operative to measure a current associated with the at least one power FET during the activated state. The switching power supply could also comprise a first over-current protection circuit providing a first adjustment to the PWM signal in response to the current being substantially between a first threshold and a second threshold. The second threshold could be greater than the first threshold.

Abstract: A bleeding resistor is required to discharge EMI filter of the power converter for the safety purpose. In order to save power and reduce device count, the present invention further uses this bleeding resistor for both start-up and feedforward compensation. It includes an input terminal for connecting the bleeding resistor. A voltage divider is connected to the input terminal. A sample-and-hold circuit samples and holds a voltage signal from the voltage divider. After that, a low-pass filter is connected to the sample-and-hold circuit to generate an offset signal in accordance with the voltage signal. The offset signal is connected to a limit circuit to generate a limit signal that limits the switching current of the power converter.

Abstract: A voltage regulator includes an undervoltage detector having a charge transistor smaller than an output transistor of the voltage regulator, providing a detection path for fast response, compensating undervoltage without large control current when loading changes from light to heavy.

Abstract: A circuit arrangement and associated method for reducing crosstalk are disclosed. A load impedance is connected via a controlled current source to an input connection for supplying a supply voltage (Vin) in the circuit arrangement. The current source is actuated using a control means such that the current source outputs a current which corresponds to the average current drawn by the load impedance. In this manner, merely a small voltage drop occurs on the supply voltage while radio-frequency interference is concurrently mitigated.

Abstract: Provided is a voltage regulator including an overcurrent protection circuit, which is capable of enhancing accuracy of a limit current value and a short-circuit current value, and suppressing electric power loss when an overcurrent flows through an output transistor. The overcurrent protection circuit includes: an output current detection transistor controlled by an output voltage of an error amplifier circuit, for feeding a detection current; a detection resistor for generating a detection voltage based on the detection current; a second error amplifier circuit for amplifying a difference between a voltage set by a second reference voltage and a divided voltage, and the voltage of the detection resistor, and outputting the amplified difference; and an output current limiting circuit in which a gate thereof is controlled by an output of the second error amplifier circuit, for controlling a gate voltage of the output transistor.

Abstract: A circuit for detecting overcurrent flowing to an output transistor. A replica transistor generates a reference voltage that is in accordance with a reference current flowing from a constant current circuit. A voltage-current conversion circuit generates a determination reference current proportional to the reference current based on the reference voltage. A current-voltage conversion circuit converts the determination reference current to a determination reference voltage. A detector detects overcurrent flowing to the output transistor based on the determination reference voltage.

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 power supply is provided, which includes a DC-DC converter being supplied with an external DC input voltage and a first switching control signal and outputting a duty sensing signal of which a magnitude is varied in accordance with the first switching control signal, the duty sensing signal being indicative of a duty ratio of the first switching control signal, and the DC-DC converter converting the input voltage into a DC output voltage of a predetermined magnitude based on the first switching control signal; and a feedback controlling unit comparing the duty sensing signal with a first reference signal to adjust the duty ratio of the first switching control signal.

Abstract: A stable high-precision current detection circuit capable of continuously detecting load current through a load with extremely reduced power loss. The current detection circuit has a power transistor and a current detection transistor that are fed with a common power supply voltage and a common switching signal. A buffer circuit is provided for supplying an idling current to the output node of the current detection transistor while realizing the same virtual potential at the output terminals of these transistors. Thus, the buffer circuit always functions as a class-A amplifier.

Abstract: A DC-to-DC converter includes one or more power switches, a pulse width modulation circuit for generating control pulses for the power switches, and an output inductor connected to the power switches. A thermally compensated current sensor is connected to an intrinsic current sensing element exhibiting a temperature-based parameter non-linearity. The thermally compensated current sensor has a temperature coefficient that substantially matches a temperature coefficient of an intrinsic power converter element used to measure current flow, thus linearizing the current measurement. Also, a current feedback loop circuit cooperates with the pulse width modulation circuit to control the power switches responsive to the thermally compensated current sensor.