Abstract: Provided is a voltage control circuit which suppresses a calorific value that generates when short-circuit fault occurs even if a voltage value of an input voltage is large. At the time of short-circuit fault, an additional control voltage Va whose voltage value becomes larger when the voltage value of the input voltage Vin is larger is input to the voltage control p-channel MOS transistor (110) from a transistor control MOS transistor (160), to thereby increase resistance of the voltage control p-channel MOS transistor (110) to suppress a short-circuit current. As a result, when the input voltage Vin is larger, the current value of a holding current or a calorific value after the short-circuit protecting operation has been conducted can be suppressed.

Abstract: A constant-voltage power circuit incorporating an over-current protection circuit having a fold back current limiting capability operative through low input voltages, and being capable of arbitrarily setting current outputs. The constant-voltage power supply circuit is configured so that a voltage output with small amplitude from a differential amplifier circuit is subjected to amplitude expansion to be amplified to range fully from the ground potential approximately to the input voltage by means of an amplitude expansion circuit, which includes an inverter consisting of an NMOS transistor and a resistor, and that the voltage resulting from the amplitude expansion is subsequently input to the gate of a PMOS transistor configured to directly control an output transistor.

Abstract: In a direct-current stabilized power supply device provided with an output transistor that receives an input voltage from the outside and a control circuit that controls the output transistor so that an output voltage of the direct-current stabilized power supply device is stabilized, there is provided a voltage supply circuit that steps down the input voltage and outputs the voltage thus obtained as a voltage for driving the control circuit. The voltage supply circuit is built as a charge pump circuit that steps down the input voltage and then outputs the voltage thus obtained.

Abstract: A parallel circuit 27 of a frequency control circuit 11 is provided as an external circuit. Thereby, the charging time t1 depends on the characteristics of the circuit elements, which are provided in the package of a semiconductor device 70 and therefore subject to manufacturing variations of the semiconductor device 70. The discharging time t2 depends on the parallel circuit 27, which is provided external to the semiconductor device 70 and therefore can be selected to have appropriate characteristics after the semiconductor device 70 has been manufactured. The circuit constants of circuits are set so that the discharging time t2 that depends on the device characteristics of the external parallel circuit 27 is longer than the charging time t1 that depends on the device characteristics of the internal circuits of the semiconductor device 70.

Abstract: System and methodology for supplying power to a load using a pass device for connecting the load. A current limit circuit prevents current supplied to the load from exceeding a current threshold. A foldback circuit modifies the current threshold in accordance with a prescribed condition. The foldback circuit is configured to vary the current threshold in accordance with an approximate safe operating area of the pass device.

Abstract: A voltage-dividing circuit 60, which is formed of serially connected voltage-dividing resistors R1, R2, R3, is disposed between the source terminal S of a power MOSFET 15 and the ground. The divided voltage Va at a connecting point A is applied to one of the input terminals of a comparator 62, while the divided voltage Vb at a connecting point B is applied to one of the input terminals of a comparator 64. The other input terminals of the comparators 62, 64 are connected to the connecting line between an external terminal P4, to which an external resistor 12 is connected, and an FET 30.

Abstract: An improved capacitive feedback circuit (20) comprises a feedback capacitor (23) having its output terminal connected to a high-impedance node (N). More particularly, the improved capacitive feedback circuit comprises a first branch (24) having a bias current source (25), an amplifying element (26), and a current sensor (27) connected in series, the amplifying element having a high-impedance control terminal (26c). The feedback capacitor (23) has its output terminal connected to said control terminal (26c). A current-to-voltage converting feedback loop (28) has a high-impedance output terminal (28c) connected to said feedback capacitor output terminal.

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 method and device for measuring a switched current (IH) comprises: sensing the switched current (IH) with an AC current transformer to obtain an intermediate measuring signal (VHM); receiving a timing signal indicating on and off periods of the switched current (IH); during an off period, generating an auxiliary signal such that the sum of the intermediate measuring signal and the auxiliary signal is equal to zero; and during an on period, adding the intermediate measuring signal and said the auxiliary signal and providing the sum signal as the output measuring signal, the output measuring signal reflecting an actual value of the AC part and the DC part of the switched current (IH).

Abstract: Provided is a voltage regulator in which a rush current of an output circuit can be limited and a rise time of an output voltage is short. The voltage regulator includes a first output current limiting circuit and a second output current limiting circuit which are used to control the output circuit, and a detecting circuit for detecting a rise speed of an input voltage. The operation of the first output current limiting circuit whose detection current value is low is controlled by the detecting circuit.

Abstract: One embodiment of the present invention includes a power supply system. The power supply system comprises a variable voltage source configured to provide and incrementally increase a control voltage associated with a pass-transistor. The power supply system also comprises an inrush current monitor configured to monitor a current-flow through the pass-transistor. The power supply system further comprises a voltage control circuit configured to halt the incremental increase of the control voltage in response to the current-flow exceeding a predetermined current limit.

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: In order to set with a high precision the value of rush current flowing in the power switch circuit at the time of turning “on” the power, the internal circuit Int_Cir of the LSI is supplied with the internal source voltage Vint from the output transistor MP1 of the regulator VReg of the power switch circuit PSWC. The power switch circuit PSWC includes a control circuit CNTRLR and a start-up circuit STC. During the initial period Tint following the turning “on” of the power supply, the start-up circuit STC controls the output transistor MP1 and reduces the primary rush current so that the output current Isup of the output transistor MP1 may represent an approximately constant increment as the time passes. The difference ?V between the internal current voltage due to the charge of load capacitance C with the output current Isup controlled by the start-up circuit STC and the current voltage Vint from the regulator VReg is set within the predetermined limit to reduce the secondary rush current.

Abstract: When a forward direction voltage of any of several LEDs 14 to 20 is lowered, a drain voltage of an NMOS transistor 70 employed in any of series regulators 24 to 30 becomes higher than a defined voltage. A zener diode ZD1, which is connected to the LED where the abnormal condition occurs, becomes conductive. A voltage, which is increased from the defined voltage, is applied to a negative input terminal of a comparing amplifier 72, and an output voltage of the comparing amplifier 72 is lowered by this increased voltage portion so that a gate voltage of the NMOS transistor 70 is lowered. A current flowing through the NMOS transistor 70 is decreased. Even if an abnormal condition caused by a voltage drop occurs in any of the LEDs 14 to 20, then the LEDs 14 to 20 can be protected.

Abstract: Effective power regulation may be achieved for a field instrument that derives power from a communication signal. In particular aspects, a system and process for power regulation include the ability to receive a communication signal and adjust the voltage supplied to a power converter based on the current of the communication signal. The system and method also include the ability to convert power of the communication signal with the power converter.

Abstract: Disclosed is an adjustable over current protection circuit which advances the timing of enabling an over current protection mechanism according to an input voltage, therefore the delay problem resulting from the non-instant response of the over current protection circuit is compensated with a low power loss. The over current protection circuit includes a voltage divider, a voltage-to-current converting circuit, an adjusting circuit and a comparing circuit. The voltage divider divides an input voltage to generate an adjusted input voltage, and the adjusted input voltage is converted into an adjusted input current by the voltage-to-current converting circuit. The adjusting circuit then adjusts a current sensing voltage according to the adjusted input current to generate an adjusted current sensing voltage.

Abstract: An over-current protection circuit for use with a constant voltage circuit that converts an input voltage to a predetermined output voltage and that outputs the predetermined output voltage.

Abstract: A constant voltage power supply circuit is provided with a constant voltage circuit part to convert an input voltage into a predetermined constant voltage, a first excessive current protection circuit part to control the constant voltage circuit part so as to reduce the output voltage while maintaining an output current that is output to a predetermined maximum value if the output current is greater than or equal to the predetermined maximum value when the output voltage is a rated voltage, and a second excessive current protection circuit part to control the constant voltage circuit part so as to reduce the output voltage and the output current and to output a short-circuit current if the output voltage decreases to a ground voltage when the output voltage is decreased to a predetermined value by the first excessive current protection circuit part. The second excessive current protection circuit part is disabled in response to a first test signal that is active.

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: Provided is a voltage regulator having an overcurrent protective circuit, which is excellent in detection precision and small in current consumption. The voltage regulator having the overcurrent protective circuit which detects that overcurrent flows in an output transistor, and limits the current of the output transistor, includes a regulated cascode circuit that makes a voltage at a source of the output transistor equal to a voltage at a source of the output current detection transistor, in which the operating current of the regulated cascode circuit is supplied by a transistor that is controlled by the output voltage of an error amplifier circuit.

Abstract: A hysteretic regulator may be set to an active mode when voltage at an output falls to a first threshold level. In the active mode, charge is applied to an output node by a current having a set limit value. The regulator is set to an inactive mode when the voltage at the output node rises to a second threshold level. The current limit value is automatically adjusted as a function of average regulator current. An indication of average regulator current may be obtained by charging a sense capacitor during the active mode and discharging the sense capacitor during the inactive mode. The voltage of the sense capacitor, which is representative of the average regulator current, is used to generate an offset adjustment applied to a regulator controller.

Abstract: A voltage regulator as a stable power supply to internal circuits in a semiconductor memory device is provided. This regulator includes a comparing unit, a first driver transistor, a feedback unit, an auxiliary control unit, a first switch, a second switch, and a second driver transistor. The comparing unit compares a reference voltage with a feedback signal to control the first driver transistor and maintain the internal power supply at a stable level. The second driver transistor, controlled by the first and second switches responsive to a trigger signal corresponding abrupt current consumptions and the auxiliary control unit responsive to the comparing result, supplies sufficient and appropriate current to the internal circuits and prevents the internal power supply from excessive overshoot and drop-out.

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 voltage regulator has a sense transistor through which a sense current flows in accordance with a magnitude of a load current, and a sense resistor through which the sense current flows. A control transistor controls the load current in accordance with a voltage across the sense resistor. A current measurement transistor measures the sense current flowing through the sense transistor and is disposed adjacent to the sense transistor. A measuring characteristics transistor measures characteristics of the control transistor and is disposed adjacent to the control transistor.

Abstract: The present invention discloses a power supply comprising: a switching regulator circuit converting an input voltage to an intermediate voltage; a low dropout linear regulator circuit converting the intermediate voltage to an output voltage so as to supply a load current to a load; and a feedback control circuit which increases the noise filtering effect of the low dropout linear regulator circuit when the load current increases.

Abstract: A stabilized DC power supply circuit of the present invention includes an output current limiting circuit for limiting an output current of an output transistor, and a correction circuit for correcting variation of restriction in the output current caused by variation in a current amplification factor of the output transistor. The correction circuit includes a correcting transistor that is manufactured in the same manufacturing process as the output transistor and formed so as to have the same tendency of manufacturing process variation in current amplification factor etc. as that of the output transistor.

Abstract: A bi-directional switch comprising first and second semiconductor switching devices, a current sensor connected in series with the switching devices, thereby forming a series circuit, a driver circuit controlling the on/off operation of the first and second switching devices such that the first and second switching devices are substantially simultaneously turned on and off, the driver circuit turning the first and second switching devices on in response to a control input and turning the first and second switching devices off when current in the current sensor substantially drops to near a zero current. A discharge sustain driver circuit employing the bi-directional switches for a plasma display panel (PDP) is also described.

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 current sensing circuit and power supply using the same are provided. The current sensing circuit includes a transistor, a control circuit and a sensing circuit, wherein the voltage endurance capability between a drain terminal of the transistor and a gate of the transistor is larger than the voltage endurance capability between a source terminal of the transistor and the gate of the transistor. The drain terminal is coupled to an under testing current source with an external high voltage. The control circuit is coupled to the gate of the transistor to control the conduction between the drain and the source terminals. The sensing circuit receives a sensing current signal from the source terminal of the transistor and transfers thereof to be a current sensing voltage.

Abstract: In a switching power supply apparatus for performing a switching control of a power MOS transistor that flows current to a coil and converting input voltage into output voltage, even if there occurs offset voltage in a current sensing operational amplifier, source potential of a current sensing MOS transistor is precisely kept at source potential of a low side power MOS transistor. For example, an offset cancel capacitor is arranged at an inverting input terminal of the current sensing operational amplifier, and voltage in the direction to offset the offset voltage occurring in the operational amplifier is charged to this capacitor.

Abstract: A charging circuit has a battery 12, switching element 14, and resistor 16 for current detection arranged on the primary side of transformer 10. Diode 18 and capacitor 20 for storing electric power are arranged on the secondary side of transformer 10. In a normal state, the ON/OFF states of switching element 14 are repeated corresponding to output signals U1, U2 of two comparators 28, 30. However, if switching element 14 stays on or off longer than a prescribed period of time for some reason, the status of switching 14 will be switched forcibly by an auxiliary sequence of the logic parts in control logic 42.

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: A power regulator includes a pass transistor, a feedback circuit, an error amplifier and a protection circuit. The pass transistor receives an unregulated first power supply voltage, and an output terminal of the power regulator outputs an output voltage varying depending upon a control signal. The feedback circuit senses a current flowing through the pass transistor and generates a feedback signal. The error amplifier compares a reference signal to the feedback signal and generates a control signal varying depending upon a voltage difference between the reference signal and the feedback signal. The protection circuit scales down a current flowing through the pass transistor by a prescribed ratio and changes a voltage of the control signal when the scaled-down current has a value higher than a prescribed value.

Abstract: A resister network having a negative temperature coefficient (NTC) may be utilized to create a temperature compensated equivalent resistance “R” for a current sensing RC network used in measuring inductor current of a DC-to-DC converter or a general switching regulator that needs to use inductor current as a control signal. The NTC resistor of the RC network effectively compensates for the positive temperature coefficient of the switching regulator inductor's inherent DC resistance (DCR). Keeping the time constants of the RC network and the switching regulator inductor substantially matched improves operation of cycle by cycle based control modes such as peak current sensing by the switching regulator controller in performing peak current control for the DC-to-DC converter.

Abstract: A constant voltage source is disclosed having an output current control element, which adjusts an output voltage of the constant voltage source by varying its output current, a control circuit, which acquires a measure for an actual value of the output voltage and processes it to a control signal for the control of the output current control element, and a limiting circuit, which limits the output current to a predefined maximum value by action on the control signal, whereby the limitation is independent of an actual value of the output current.

Abstract: A power control system includes a voltage control circuit and a plurality of balance circuits. The voltage control circuit controls a voltage level at an output of the power control system according to a reference voltage. Each of the plurality of balancing circuits outputs a current, whose magnitude is a specific ratio to an output current outputted from the voltage control circuit. The power control system is capable of balancing output currents of the voltage control circuit and the plurality of balance circuits in order to share output load of the power control system.

Abstract: System and methodology for supplying power to a load using a pass device for connecting the load. A current limit circuit prevents current supplied to the load from exceeding a current threshold. A foldback circuit modifies the current threshold in accordance with a prescribed condition. The foldback circuit is configured to vary the current threshold in accordance with an approximate safe operating area of the pass device.

Abstract: A power supply circuit includes two pass transistors that conduct current from a voltage supply terminal to an output terminal. One of the pass transistors is smaller whereas the other is larger. Current through the smaller transistor is controlled by the voltage control loop such that the voltage on the output terminal is regulated to a predetermined voltage. Current through the larger transistor is controlled by a high gain current control loop such that the current flowing through the larger transistor is a multiple of the current flowing through the smaller pass transistor. By reducing current flow in the smaller transistor, the power supply rejection ratio (PSRR) of the power supply circuit is improved for frequencies up to 100 kHz. Die space occupied by the two pass transistors is reduced in comparison to the amount of pass transistor die space in a conventional power supply circuit of similar performance.

Abstract: Control loops in a voltage regulator can be stabilized using minimal silicon area. A current limit signal, generated by a current limit control loop in the voltage regulator, can be divided to minimize a zero provided in a compensation set associated with a voltage control loop, thereby stabilizing both loops. The compensation set can include a resistor (the zero) and a capacitor (a pole) connected in series between output and input terminals of an amplifier. Dividing the current limit signal can include injecting a first portion of the current limit signal on a first side of the resistor and injecting a second portion of the current limit signal on a second side of the resistor. The ratio of the first and second portions can be based on a gain of the amplifier, thereby minimizing an effect of the resistor.

Abstract: A low drop out (LDO) regulator that includes a novel error amplifier, which is arranged with a first stage that employs both NMOS and PMOS devices that are similarly doped in differential pairs and a second stage that operates with NMOS and PMOS devices in a push-pull arrangement. In addition to the error amplifier, the LDO regulator can also include a startup circuit coupled to an enable voltage, a reference filter circuit coupled to a reference voltage, an output circuit, a quiescent current control circuit, and a pulse generator circuit. Also, an internal RC network is provided to compensate for phase shift. The integrated operation of the components of the regulator enables stable and fast operation of an LDO regulator with no external capacitors connected to the input or output terminals.

Abstract: An inrush current limiting circuit (12) includes a transistor (Q), a switch element (M), and a short-circuit protection circuit (121). An emitter of the transistor is as an input of the inrush current limiting circuit. An input of the switch element is connected to a collector of the transistor. A second output of the switch element is as an output of the inrush current limiting circuit. A first terminal of the short-circuit protection circuit is connected to a first output of the switch element. A second terminal of the short-circuit protection circuit is connected to a base of the transistor. A third terminal of the short-circuit protection circuit is connected to the second output of the switch element.

Abstract: An overcurrent protection circuit has an output voltage detection resistor for detecting an output voltage. A foldback overcurrent protection circuit detects an output current flowing through an output transistor and controls the output current flowing through the output transistor in accordance with the detected output current. A first logic generating circuit receives an overcurrent detection signal from the foldback overcurrent protection circuit corresponding to the detected output current. A second logic generating circuit receives a detection signal from the output voltage detection resistor corresponding to a decrease in the detected output voltage. An AND circuit receives and processes an overcurrent delay signal generated by the first logic generating circuit and a voltage detection signal generated by the second logic generating circuit.

Abstract: A selected bandgap reference (11) of a voltage generator (10) is operated at a duty cycle that is less than one hundred percent. The seclectable bandgap reference (11) has at a high current consumption when enabled and a low current consumption when disabled. The output voltage of the selectable bandgap reference (11) is stored on a storage element (13) when the selectable bandgap reference (11) is enabled. A high impedance amplifier (16) receives the stored voltage and generates the reference voltage.

Abstract: A switching power converter comprises a switch, a pulse width modulation (PWM) circuit, a rectifying filter circuit and a current limited protection circuit. The input terminal of the rectifying filter circuit is coupled to an input voltage via the switch. The current limited protection circuit comprises an amplifier and a pulse-width modulator. The amplifier detects an induced voltage while a working current flows through the switching power converter, and amplifies the induced voltage so as to generate a comparison voltage. The pulse-width modulator receives an output from the amplifier, determines an output of the pulse-width modulator according the comparison voltage and a reference voltage, and limits the working current according to the output of the pulse-width modulator.

Abstract: An overshoot suppression circuit comprises a switch for coupling to an output of a voltage regulation module and a voltage detector for detecting an output voltage at the output. When the load to the voltage regulation module changes from heavy to light to result in the output voltage higher than a threshold, the voltage detector turns on the switch to release energy from the output, and thereby the output voltage is suppressed to produce overshoot to damage the load coupled to the output.

Abstract: In a method for regulating the power supply of a plurality of field devices S1, S2, S3, A1, A2, connected to a data bus DBL and supplied with electrical current over the data bus DBL, the electrical current requirements of the individual field devices S1, S2, S3, A1, A2 are determined, and the electrical current consumptions of the field devices S1, S2, S3, A1, A2 are adjusted by means of corresponding control signals. In this way, the electrical current consumption of individual field devices S1, S2, S3, A1, A2 can be centrally adjusted and therewith the process conditions matched.

Abstract: A method and circuit for automatically lowering a quiescent current at a predetermined threshold. A compact and low power current comparator is employed to detect the power consumption conditions, and issues a control signal to lower current consumption within a power management circuit. By dynamically resizing bias device geometries, a minimum quiescent current of an electronic device may be further reduced. Moreover, the control signal may also be used to engage modification of circuit dynamics to improve circuit performance and mitigate a response profile during recovery from a low power operation.

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 voltage regulator has an output transistor connected between a power supply and an output terminal, and a voltage amplifying circuit that compares a feedback voltage with a reference voltage to control the output transistor. A transient response improving circuit has a detecting portion that detects fluctuations in the power supply voltage and controls the operating current of the voltage amplifying circuit based on the detected fluctuation level of the power supply voltage thereby improving the responsiveness and reducing power consumption of the voltage regulator.

Abstract: A switching regulator has a soft start circuit having a current source, a capacitor, and a MOS transistor connected between the current source and the capacitor for undergoing controlled operations between ON/OFF states to control a time period required for soft start of the switching regulator.