Abstract: A power control system and method senses input and/or output voltages of a power supply using sense currents in order for an integrated circuit (IC) switch state controller to generate a control signal to control a switch of the power control system. By sensing sense currents, the power control system can eliminate at least one sense resistor used in a voltage sense system. The sense current(s) can be used to provide power and sensing to the switch state controller. In at least one embodiment, the sense current(s) provide power to the switch state controller when auxiliary IC power is unavailable or diminished, such as during start-up of the IC. In at least one embodiment, the IC draws more sense current from an input of the power control system than the output of the power control system to, for example, minimize impact on the output voltage of the power supply.

Abstract: An apparatus is provided. The apparatus comprises a reference circuit and a startup circuit. The reference circuit is adapted to provide a startup current, while the startup circuit receives the startup current and outputs an output voltage. The startup circuit includes a current mirror, a first NMOS transistor, a second NMOS transistor, diodes, and a third NMOS transistor, and a control circuit. The first and second NMOS transistors are coupled to the current mirror at their sources and are coupled to one another and to the reference circuit at their gates. The diodes are coupled between the gate of the second NMOS transistor and the source of the second NMOS transistor, and the third NMOS transistor is coupled to the source of the second NMOS transistor at its gate (which also provides the output voltage at its source). The control circuit is then coupled to the drains of the first and second NMOS transistors.

Abstract: A circuit for minimizing voltage inrush upon startup in a switching power converter having a switching stage including high and low switches connected at a common node, a feedback loop for maintaining a target output voltage, an output capacitor connected between an output node and the ground, an inductor connected between the common node and the output node, and a control circuit having a first error amplifier for providing a first signal based on a comparison of a reference voltage and voltage provided by the feedback loop, the control circuit including a level switch connected between the ground and the common node, the level switch being controlled in accordance with the first signal, wherein a large inrush current flowing into the output capacitor when the circuit is starting up is minimized.

Abstract: There is provided a regulator with soft-start using a current source. The regulator with soft-start may include: a power switch unit including first and second power switches connected between a power supply terminal and an output terminal; a load capacitor connected between the output terminal and a ground; a voltage detection unit detecting a voltage of the output terminal; a comparison unit comparing a detection voltage and a predetermined reference voltage, and outputting first and second switching signals; a current generating a predetermined constant current; a current control unit switching a connection between a control terminal of the first power switch and the current source unit according to the first switching, and switching a connection between the control terminal of the first power switch and the ground according to the second switching signal; and an error amplification unit amplifying an error voltage between the detection.

Abstract: A boosted auxiliary winding power supply for a switched-power converter circuit provides operating voltage for control and other circuits early in the start-up phase of converter operation. A boost circuit has an input coupled to the auxiliary winding to boost the voltage available from the auxiliary winding at least during start-up of the switched-power converter. The boost thereby provides a voltage that is greater than the voltage across the auxiliary winding during start-up of the switched-power converter. The boost circuit may be actively switched at a rate higher than a switching rate of the switched-power converter, to increase a rate of rise of the operating voltage. Polarity information, which may be provided from the switched-power converter control circuit, can be used to actively rectify the output of the auxiliary winding.

Abstract: A power supply circuit includes a first voltage regulator, a second voltage regulator, and a voltage comparator. The first voltage regulator is connected to a direct current power supply, and regulates a direct current supply voltage down to a first voltage level to output a first voltage at a first output terminal. The second voltage regulator is connected to the first voltage regulator, and regulates the first output voltage down to a constant, second voltage level to output a second voltage at a second output terminal. The voltage comparator is connected to the first and second voltage regulators, compares the first output voltage against a given threshold level greater than the second voltage level, and deactivates the second voltage regulator until the first output voltage exceeds the given threshold level upon startup of the power supply circuit.

Abstract: A power supply input circuit includes an input node configured to removeably couple to an electrical source. A solid state switch is coupled between the input node and a capacitive load. An RC soft start circuit is coupled to the input node and the switch. The soft start circuit has a capacitor that causes the switch to increasingly pass electrical power from the source to the load as the capacitor charges from the source. An active reset circuit is coupled to the soft start circuit. The reset circuit is configured to detect when the source is removed from the input node and in response to the source being removed from the input node, the reset circuit discharges the capacitor to reset the soft start circuit.

Abstract: A switching power supply unit is provided which provides improved response for frequency switching with a smooth rise in voltage. The switching power supply unit includes: a rectifier circuit for rectifying an alternating current from an AC power source into a direct current; a switching circuit for switching the current rectified by this rectifier circuit using a switching device; a pulse oscillator circuit for outputting a switching signal to the switching device; and a transformer circuit for stepping a voltage up or down depending on the current switched by this switching circuit. A frequency switching unit is also used to detect a pulse output from the switching circuit. Based on the state of this pulse output, the frequency switching unit changes a resistance using resistors, thereby switching the frequency of the switching signal in the pulse oscillator circuit.

Abstract: A method and circuit for controlling the start-up of a shunt regulator that uses an error amplifier for normal operation in a linear range of a target value output voltage set by a reference voltage upon circuit start-up clamps the output voltage to a first level value below the target value, next applies regenerative positive feedback independent of the error amplifier to force the output voltage through a range where adverse conditions can occur to a second level value below the target value, and then releases the positive feedback near the target value where the error amplifier assumes control of the regulation.

Abstract: A regulation circuit comprises an error detector, an integrator, and a voltage regulator. The error detector comprises an input for an input voltage, a further input for a reference voltage and an output for an error signal, wherein the error signal depends on the input voltage and the reference voltage. The integrator comprises an input for the error signal and an output for an integrated error signal. The voltage regulator comprises an input for the input voltage and a terminal for the integrated error signal, wherein the voltage regulator is configured to adjust a shunt current responsive to the integrated error signal such that the input voltage is adjusted towards the target voltage.

Abstract: A DC-DC conversion circuit is configured by including a plurality of control signal generation circuits, a plurality of soft-start control circuits, and a start control circuit. The plurality of control signal generation circuits correspond to the plurality of control signals, and generate a corresponding control signal of the plurality of control signals based on a corresponding output value of a plurality of output values. The plurality of soft-start control circuits correspond to the plurality of control signals, and control a variation of the corresponding control signal at a start time of the DC-DC conversion circuit. The start control circuit instructs the corresponding soft-start control circuit to start operation in accordance with a change of the control signal taking part in an output control at the start time of the DC-DC conversion circuit.

Abstract: A method and structure for preventing operation of a circuit in a high current operating region by disabling a start-up circuit until a power supply headroom is detected at a predetermined voltage level.

Abstract: Provided is a switching regulator which is capable of reducing soft start time when being activated, and prolonging battery life. The switching regulator has a configuration in which a clamp circuit for clamping a reference voltage is provided in a soft start circuit, and a predetermined period of time since the switching regulator has been activated is divided into a plurality of segments to increase the reference voltage with different slopes for each of the plurality of segments. At an early stage of the activation, the reference voltage is set to be low for preventing an inrush current from a power source, and thereafter, a rate of increase in reference voltage is gradually increased, to thereby reduce the soft start time.

Abstract: A high voltage start-up circuit with constant current control applied to a switching mode power converter is provided. The high voltage start-up circuit includes a high voltage junction transistor, a control transistor, a current detecting resistor and a bias resistor. The drain of the junction transistor is connected to a high power supply, the gate of the junction transistor is connected to the drain of the control transistor, and the source of the junction transistor is connected to the current detecting resistor. The voltage drop crossing the current detecting resistor is kept constant to have the junction transistor output a constant current. The bias resistor which is connected between the gate of the junction transistor and the output end of the high voltage start-up circuit has the gate to source bias voltage of the junction transistor kept constant to output constant current.

Abstract: A soft-start voltage circuit includes an operational amplifier, a first and a second capacitors, a first and a second switches, and a voltage level shifter. The operational amplifier includes a positive end, a negative end, and an output end coupled to the negative end of the operational amplifier for outputting the soft-start voltage. The voltage level shifter is coupled between the first capacitor and the positive end of the operational amplifier for shifting a level of the voltage on the first capacitor. The first switch is coupled between the first and the second capacitors for coupling the first and the second capacitors according to the clock. The second switch is coupled between the second capacitor and the negative end of the operational amplifier for coupling the second capacitor and the negative end of the operational amplifier according to the inverted clock.

Abstract: An apparatus, such as a Buck converter system, for generating an output voltage while at the same time monitoring whether an overload or over current condition occurs at the output, and protecting the system if the overload or over current condition occurs. The apparatus includes a first circuit adapted to monotonically change a control voltage from a first voltage (e.g., approximately ground potential) towards a second voltage (e.g., a reference voltage VREF); a second circuit adapted to generate the output voltage based on the control voltage; a third circuit adapted to detect whether a magnitude of an output current exceeds a current threshold; and a fourth circuit adapted to change the control voltage from the second voltage towards the first voltage in response to the third circuit detecting that the magnitude of the output current exceeds the current threshold.

Abstract: A switching power supply circuit for generating an output voltage at an output node based on an input voltage at an input node includes a reference voltage generating circuit configured to generate a reference voltage such that during an initial start-up period of the reference voltage a voltage rise rate of the reference voltage within a first predetermined period from a start point of the initial start-up period and a voltage rise rate thereof within a second predetermined period immediately preceding an end point of the initial start-up period are smaller than a voltage rise rate thereof in a period between the first predetermined period and the second predetermined period, a coil disposed between the input output nodes, and a switch circuit configured to switch on and off to control current through the coil in response to comparison between the reference voltage and a voltage proportional to the output voltage.

Abstract: A power converter for and method of producing a monotonic rise in output voltage at start-up. In one embodiment, the power converter includes a switch and an error amplifier coupled to an output terminal of the power converter. The power converter also includes a comparator with an output terminal coupled to a control terminal of the switch and an input terminal coupled to an output terminal of the error amplifier configured to enable the switch to conduct for a duty cycle. Additionally, the switch is configured to be turned off at a start-up of the power converter until a voltage of the output terminal of the error amplifier provides a duty cycle for the switch corresponding to an output characteristic pre-charge condition.

Abstract: A power supply device includes a clamp circuit that increases the upper limit value of an error voltage stepwise after the device is started up. This makes it possible to shorten the rise time of an output voltage and to reduce the maximum current at start-up.

Abstract: A low-voltage current reference providing a current being substantially constant with temperature includes a low voltage bandgap, a start circuit coupled to the low voltage bandgap, and a current summer coupled to the low voltage bandgap and to the start circuit. The low voltage bandgap is for providing a constant voltage reference, and the start circuit is for starting the low voltage bandgap from a non-start mode and for providing a proportional to absolute temperature (PTAT) current reference. The current summer is for providing a constant current reference according to the constant voltage reference and the PTAT current reference.

Abstract: A full digital soft-start circuit adapted for a power supply system is provided. The full digital soft-start circuit includes a ring oscillator, a pulse generator, a counter, and a multiplexer. The ring oscillator generates a plurality of clock signals which are different in phase, while equivalent in duty cycle and frequency. The pulse generator generates a plurality of pulse signals with different duty cycles. The counter generates a multi-bit counting signal. The multiplexer determines whether to transmit the pulse signals generated by the pulse generator so as to generate an output pulse which becomes stable as time going on.

Abstract: Control circuitry controls a boost regulator during a start-up period. The control circuitry may comprise an oscillator for generating a clock signal. The oscillator may be configured for ramping up a frequency of the clock signal in accordance with an voltage to be applied to the oscillator and varied during the start-up period. The control circuit may further include a switching circuit configured for controlling a power switch of the boost regulator in response to the clock signal from the oscillator. The switching circuit can control the power switch to have an on-time which is largely independent of the operating frequency of the oscillator. The voltage to be applied to the oscillator may have the same initial voltage level upon startup of the control circuit, independent of an output voltage of the boost regulator.

Abstract: A switching regulator includes a first switch, an inductor, a second switch, a control circuit to control a switching operation by switching the first switch and switching the second switch complementally to the first switch, a reverse current protection circuit to shut off a current through the second switch to prevent a reverse current from an output terminal toward the second switch, and a soft-start circuit to cause the control circuit to perform a soft-start operation in which the output voltage is being increased gradually during a time period from a start-up to a predetermined elapsed time. The soft-start circuit causes the reverse current protection circuit to stop a shutoff operation of the current through the second switch when a generation or an indication of the reverse current is detected during the soft-start operation instructed by the control circuit.

Abstract: A circuit and a method for reducing output noise when a pulse width modulation mode is started. A pulse width modulation circuit generates a first pulse signal having a duty cycle that is in accordance with an output voltage of a regulator circuit. A drive circuit generates the output voltage from an input voltage in response to the first pulse signal provided from the pulse width modulation circuit. A feed forward circuit controls the pulse width modulation circuit in a manner to generate the first pulse signal having a duty cycle that maintains the output voltage at a desired level before the pulse width modulation circuit provides the first pulse signal to the drive circuit.

Abstract: In one embodiment, an apparatus is provided for a system including an integrated circuit coupled to a node to receive a supply voltage and having bypass capacitors coupled in parallel with the integrated circuit to the node. The apparatus comprises a first capacitor, a switch coupled to the first capacitor, and a voltage source configured to charge the first capacitor. The switch is coupled to receive a control signal that is asserted, during use, if the supply voltage to an integrated circuit is to be increased. The switch is configured to electrically couple the first capacitor to the node in response to an assertion of the control signal. When electrically coupled to the node, the first capacitor supplies charge to the bypass capacitors. A system comprising the apparatus, the node, the integrated circuit, and the bypass capacitors is also contemplated in some embodiments.

Abstract: A switching control circuit comprises: an error amplifying circuit configured to output an error voltage obtained by amplifying an error between a feedback voltage corresponding to an output voltage and a lower voltage selected out of a first reference voltage increasing with time passage and a second reference voltage used as a reference for a target level; a comparison circuit configured to output a comparison signal obtained by comparing the feedback voltage with the error voltage output from the error amplifying circuit; and a drive circuit configured to output first and second control signals for controlling first and second transistors, respectively, in order to turn the output voltage to the target level by complementarily turning on and off the first and second transistors, after the error voltage exceeds the feedback voltage, based on the comparison signal output from the comparison circuit.

Abstract: An electronic power device for controlling a load includes: a high-voltage integrated switch having an output terminal to be connected to the load; an integrated, and low-voltage driving circuit for driving the switch, and a start-up integrated circuit comprising a high-voltage resistor and such that it can be enabled, during a step of turning on the power device, in order to activate the driving circuit. The switch and the start-up circuit are integrated in a first semiconductor chip and the driving circuit is integrated in a different, second semiconductor chip.

Abstract: In one embodiment, a soft start circuit includes a slew rate controller to limit inrush current to a voltage regulator during start up. The output voltage of the regulator may be compared to a previous sampled value to determine the slew rate of the output voltage. The slew rate of the output voltage may be controlled by adjusting the current limit of the regulator. The current limit of the regulator may be adjusted using digital circuits, such as a counter and a digital to analog converter, or analog circuits using a pulsed current source, for example. The slew rate may be controlled to exceed a target slew rate or to stay within a range of slew rate limits.

Abstract: A power control device for an electronic device for enhancing power stability when the electronic device is powered on including a high-pass filtering unit for performing a filtering process on an input signal for generating an output signal, and a control unit coupled to the high-pass filtering unit and a first voltage generator of the electronic device for outputting the output signal to the first voltage generator according to the voltage level of the output signal.

Abstract: To provide a power supply unit capable of realizing a multiphase power supply at low cost. For example, each of a plurality of semiconductor devices DEV[1]-DEV[n] comprises a trigger input terminal TRG_IN, a trigger output terminal TRG_OUT, and a timer circuit TM that delays a pulse signal input from TRG_IN and outputs it to TRG_OUT. DEV[1]-DEV[n] are mutually coupled in a ring shape by its own TRG_IN being coupled to TRG_OUT of one semiconductor device other than itself. Each of DEV[1]-DEV[n] performs switching operation by using the pulse signal from TRG_IN as a starting point, and feeds a current into an inductor L corresponding to itself. Moreover, DEV[1] generates the above-described pulse signal only once during startup by a start trigger terminal ST being set to a ground voltage GND, for example.

Abstract: An under voltage lock out circuit which monitors an input voltage and executes a predetermined sequence when the input voltage satisfies a predetermined condition may include a voltage comparison unit which compares the input voltage and a predetermined threshold voltage, and outputs a comparison signal; a logic circuit which receives the comparison signal output from the voltage comparison unit and a start-up signal instructing start-up of an equipment mounted with the under voltage lock out circuit, and asserts a sequence control signal when start-up is instructed by the start-up signal in a state the input voltage is higher than the threshold voltage; and a sequence circuit which executes a predetermined sequence when the sequence control signal is asserted, wherein the predetermined threshold voltage is switched according to the sequence control signal.

Abstract: A system and method for determining an initial duty cycle for startup of a voltage regulator involves generating a first current source responsive to an input voltage to the voltage regulator and generating a second current source responsive to an output voltage of the voltage regulator. A first capacitor is charged using the first current source responsive to a duty cycle of a PWM signal of the voltage regulator to a first voltage. A second capacitor is charged to a second voltage responsive to a period of the PWM signal of the voltage regulator. The initial duty cycle for startup of the voltage regulator is established as the duty cycle of the PWM signal when the first voltage is substantially equal to the second voltage.

Abstract: A start up circuit of power converters is presented. It includes a first transistor, a resistive device, a second transistor, a third transistor and a diode. The first transistor is coupled to a voltage source. The third transistor is connected in serial with the first transistor to output a supply voltage to a control circuit of the power converter in response to the voltage source. The diode is connected from a transformer winding of the power converter to supply a further supply voltage to the control circuit of the power converter. The second transistor is coupled to control the first transistor and the third transistor in response to a control signal. The resistive device provides a bias voltage to turn on the first transistor and the third transistor when the second transistor is turned off. Once the second transistor is turned on, the third transistor is turned off and the first transistor is negative biased.

Abstract: The present invention discloses a method and a circuit for controlling a start-up cycle of an integrated circuit in a circuit system. The method and circuit determine whether or not an input power of the circuit system and a bias voltage power of the integrated circuit have reached a normal operating voltage range to control the bias voltage power to produce a start-up cycle of the integrated circuit. The method and circuit also provides a protection mechanism for an overload of the circuit system overload, so that the integrated circuit can moderate surges and prevent damages.

Abstract: A switching power converter with a controlled startup mechanism includes a switching stage which provides a voltage Vout at an output node in response to a switching control signal, with the output node adapted for connection to a non-linear load. A feedback network compares a signal which varies with the current conducted by the load (Iload) with a reference signal, and provides the switching control signal so as to maintain Iload at a desired value. A capacitor connected to the output node provides a current Ic to the feedback network which varies with dVout/dt. The feedback network is arranged to limit dVout/dt in response to current Ic when Iload is substantially zero. In this way, large inrush currents or damage that might otherwise occur during startup are avoided.

Abstract: In a method and apparatus for controlling power factor correction in mixed operation modes, a frequency of the input voltage is obtained by detecting the zero crossing points of the input voltage. A peak of the input voltage is obtained by detecting input voltage with 90 degree phase. Thus, the present invention predicts the input voltage by its frequency and peak and the characteristic of the sine wave. A digital signal processor computes the duty and frequency of a boost switch, switching the operation mode of the boost converter among continuous mode, critical mode and discontinuous mode according to input voltage or the load. According to another aspect, the operation is switched to critical mode from the average current mode when a zero current is detected before the charging and recharging cycle of the boost switch is finished. Overcurrent protection may be achieved by controlling current in response to detected voltage to provide a substantially constant power level.

Abstract: A reference generator circuit generates a reference signal for use by a regulator in generating operational power for circuits and devices. A start-up circuit includes a self-biased voltage reference and a differential amplifier configured to generate a start-up signal to induce current flow in response to the voltage independent reference during the start-up phase of the circuit and cease inducing the current flow following the start-up phase of the circuit. The reference signal is generated by receiving a supply voltage and inducing current flow into a node of a bandgap reference circuit during a start-up phase of the bandgap reference circuit and ceasing inducing the current flow following the start-up phase of the bandgap reference circuit.

Abstract: An active start judgment circuit is electrically connected to an AC/DC transforming power supply which has at least one standby power unit to transform AC to DC in regular conditions and a main power unit to transform the AC to the DC in an ON condition for operation of an electronic equipment. The start judgment circuit bridges the standby power unit and the main power unit, and generates a reference potential based on a voltage output from the standby power unit, and gets a power signal from the standby power unit to be compared with the reference potential to output a start signal to the main power unit to transform the AC to the DC. Thus the standby power unit can actively drive the main power unit to supply DC power to activate the electronic equipment.

Abstract: In one embodiment, a soft-start circuit is configured to form drive pulses that increase in width independently of the current through the power switch during a first portion of the soft-start operation period.

Abstract: According to an embodiment, a DC-DC converter comprises: an error amplifier that receives a soft start signal and amplifies a difference between an output voltage signal and a reference voltage signal; a PWM control circuit that controls ON and OFF states of a first switching transistor and a second switching transistor based on the output of the error amplifier; a frequency divider that divides a frequency signal and outputting a divided frequency signal; an accumulator that performs an adding operation based on the divided frequency signal and a control signal; and a DA converter that generates the soft start signal based on an output of the accumulator.

Abstract: A method and apparatus for a Regulator that automatically configures to work in either SMPS mode or linear mode are disclosed. In one embodiment, the method includes inputting a constant current source to a CBoot_pin for a first predetermined amount of time upon enabling an autodetect circuit by a Regulator control circuit. The CBoot voltage at the CBoot_pin is then determined to see if the CBBoot voltage at the CBoot_pin is above a predetermined CBoot voltage for a second predetermined amount of time. The Regulator is then switched to operate in SMPS mode if the CBoot voltage is substantially continuously above the predetermined CBoot voltage for a second predetermined amount of time. The SMPS is operated in linear mode if the CBoot voltage is substantially continuously below or equal to the predetermined CBoot voltage for a second predetermined amount of time.

Abstract: Provided is a switching regulator for preventing generation of an inrush current flowing through a switching element of an output stage, which is provided in the switching regulator. A soft start control circuit (116) detects a current flowing through a PMOS transistor (104) serving as a switching element of an output stage. When the detected current is equal to or larger than a current limiting value for limiting the current flowing through the PMOS transistor (104), the soft start control circuit (116) controls the PMOS transistor (104) to be turned off. Accordingly, it is possible to prevent generation of the inrush current flowing through the PMOS transistor (104).

Abstract: The power circuit includes a switching regulator part, a series regulator part and a control circuit part for controlling operation of the switching regulator and controlling the second predetermined voltage of the series regulator part.

Abstract: The present invention discloses a soft-start circuit having a reference signal generator, a first current generator, a second current generator, and a soft-start capacitor. The reference signal generator generates a first signal and a second signal. The first current generator generates a first current according to the first signal, and the second current generator generates a second current according to the second signal. The soft-start capacitor is coupled to the first current generator and the second current generator, and charged by a current difference of the first current and the second current to generate a soft-start signal.

Abstract: A switching regulator which does not require a capacitor having large time constant as a soft start circuit, reduces variation of the soft start time and the time until a start of a power source voltage stabilizing control The output voltage signal of the soft start circuit is set to a step voltage signal which increases or decreases stepwise at a predetermined rate. A changing period of the step voltage signal is set to a predetermined period after a power source is turned ON. The changing period of the step voltage of the output signal of the soft start circuit is made larger than the predetermined period according to a timing of changing of the PWM pulse output from “H” to “L” or “L” to “H” after an initial period, and after the power source is turned ON by monitoring the PWM pulse output by a detection circuit.

Abstract: A bandgap voltage reference circuit includes a bandgap voltage generation circuit that can produce a bandgap reference voltage in response to an activation voltage signal, a start-up circuit that can produce the activation voltage signal in response to one-shot voltage pulse and an one-shot pulse generator circuit configured to produce the one-shot voltage pulse. The start-up circuit can be automatically shut off after the one-shot voltage pulse.

Abstract: A method for operating a device in which typically a very high current is generated when the device is turned on compared to the rated current, e.g. an analogue operated PTC heating device for a mobile device, such as a vehicle, is disclosed. In this method, the power on the device is increased in a defined limited manner or in a ramp-like manner in the connection phase to avoid a high current when the device is switched on.

Abstract: A soft start circuit is connected to a pulse width modulation controller including an oscillator, and a functionality of modulating amplitude to a pulse width and a power supply includes the soft start circuit. The soft start circuit includes a frequency controlling unit, a duty ratio establishing unit, and a variable switching unit. The frequency controlling unit generates first and second parameter signals for determining a frequency signal frequency by a power source from the PWM controller and provides them to the PWM controller. The duty ratio establishing unit generates a third parameter for determining amplitude of the frequency signal generated by the PWM controller according to a reference voltage, and provides it to the PWM controller. The variable switching unit determines whether it is a first predetermined time from a start-up state, and controls the first parameter of the frequency controller during the first predetermined time.

Abstract: Methods and apparatus for softstarting a voltage regulation circuit. A circuit for generating an output voltage at an output thereof includes a capacitor having a first terminal configured to be coupled to a reference potential and having a second terminal coupled to the output, and a switchable current source coupled to the capacitor for intermittently charging the capacitor until the output voltage is reached.

Abstract: A step-like operation command signal is inputted into a time-constant circuit to generate a gradually rising operation command input voltage, which is supplied to a power supply unit. Enablement and disablement of the power supply unit is controlled on the basis of the operational command input voltage. When the operation command input voltage exceeds a first predetermined voltage level, a detection signal and a reference voltage are generated, and at the same time an error amplification circuit is enabled. On the other hand, when the operation command input voltage exceeds a second predetermined voltage level, a level shift voltage for initiating a soft start is generated, which enables execution of a soft start of the power supply unit without increasing its consumption current and reduction of the number of its terminals.