Abstract: A charging device that may perform charging with larger current is provided. The charging device comprises a switching element for increasing or decreasing charging power, a PWM controlling circuit for intermittently turning the switching element on or off, a current detecting circuit for detecting current flowing through the switching element, and a rectifying circuit for rectifying output voltage of the current detecting circuit in response to power supply voltage. The PWM controlling circuit has a limiter terminal for turning off the switching element when voltage equal to or above a determined value is input, and rectified voltage from the rectifying circuit is input to the limiter terminal. In this charging device, an amount of temperature increase of the switching element is suppressed so as to remain within a fixed range, and the charging power is not restricted unnecessarily.

Abstract: A voltage down converter includes a voltage comparator for comparing a first reference voltage and an internal voltage to provide a first driving signal; a driving signal controller coupled with the voltage comparator, the driving signal controller configured to generate a second driving signal in response to an external voltage and selectively providing any one of the first and second driving signals; and a voltage supply coupled with the driving signal controller, the voltage supply configured to receive the selectively provided first and second driving signals, wherein the voltage supply is activated in accordance with the first or second driving signal, thereby providing the internal voltage.

Abstract: A low-power programmable low-drop-out voltage regulator system and methods are presented. The regulator includes a local reference generator circuit that receives a voltage input signal and outputs a reference voltage signal, a buffer circuit that receives the reference voltage signal and outputs an output voltage signal, and a comparison device. The comparison device receives and compares the output voltage signal and an accurate reference voltage signal and outputs an adjustment signal to adjust the output voltage signal in the direction of a value of the accurate reference voltage signal. The regulator can include an attenuator circuit to attenuate the reference voltage signal. The output voltage signal can be regulated or programmed by adjusting the gain of the buffer circuit and/or the attenuator circuit. Current consumption can also be programmed by turning on or off one or more amplifier tiers located in the buffer circuit.

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

Abstract: A high-speed voltage regulating apparatus and a method for high-speed voltage regulation. The apparatus includes: (A) a regulator, adapted to provide a regulated voltage; (B) switching circuitry, connected to the regulator, adapted to either (i) connect the regulator to an output node or (ii) disconnect the regulator from the output node; whereas the output node is connected to a dynamic power consuming device and to a load capacitor; (C) control logic, connected to the regulator, adapted to receive at least an indication reflecting a voltage of the output node and to control the switching circuitry such that the regulator is disconnected from the output node to facilitate a decrease in the voltage of the output node.

Abstract: A fan controller may be integrated in silicon and may use an embedded microcontroller to implement a digital fan control algorithm. The microcontroller may continually monitor temperature and sample the speed of the controlled fan. The speed of the fan may be compared to RPM values fitted on a desired curve that is representative of the Temperature-versus-RPM function for the controlled fan. The fan control algorithm may be based on a ramp-rate closed-loop controller (RRCC), which may be operated to drive the fan to the desired speed at different rates, depending on the difference between the desired RPM and the actual RPM of the fan. The fan may also provide a Fan ID feedback signal to the microcontroller, which may use the Fan ID feedback signal upon system start-up to initialize the RRCC range settings and select the appropriate Temperature-versus-RPM function curve based on pre-determined values for the given fan.

Abstract: A hysteretic DC/DC converter is proposed that operates at a high switching frequency without producing undesired pulse bursts at the output. The converter has a converter power stage with a supply voltage input, a controlled voltage output and an enable input. A comparator has a reference voltage input, a feedback input and an output, and a gating circuit connected between the output of the comparator and the enabling input of the converter power stage. The gating circuit inhibits as a function of load requirements the propagation of enabling pulses from the output of the comparator to the enabling input of the converter power stage. By gating the output of the comparator in a way to separate the output from the enabling input of the converter power stage immediately after the start of each conversion pulse, the generation of further pulses immediately after each conversion pulse is prevented, thereby keeping the output voltage ripple low.

Abstract: A series regulator circuit that enables detection of a voltage drop and reduces consumed current in a static state. A constant current source, which is connected to a power supply voltage line, is connected to a bipolar transistor. The bipolar transistor includes an emitter terminal and base terminal connected to a ground line via first and second resistors, respectively. The constant current source is connected to the source terminal of a PMOS transistor and the gate terminal of an NMOS transistor. The source terminal of the NMOS transistor is connected via third and fourth resistors to the base terminal of the bipolar transistor.

Abstract: The present invention related to a voltage-stabilizing circuit in the power supply apparatus of automobiles, and comprising a battery, a voltage-stabilizing capacitor, and a switching circuit. The battery provides a voltage; the voltage-stabilizing capacitor couples to the battery, and stabilizes the output voltage of the power supply apparatus of the automobiles; and the switching circuit opens the circuit between the voltage-stabilizing capacitor and the battery when the voltage of the battery is detected to be smaller than a threshold value. Thereby, power consumption of the battery is reduced, and the voltage-stabilizing capacitor is protected and thus the lifetime thereof is lengthened.

Abstract: A full bridge circuit includes a first switch, a second switch, a third switch, a fourth switch, a first controller, a second controller, a first operational amplifier, a first multiplexer, a second operational amplifier, and a second multiplexer. The first controller includes a first output coupled to the first switch. The second controller includes a first output coupled to the third switch. The first operational amplifier includes a first input coupled to the first switch and the second switch, and a second input for receiving a first reference voltage. The second operational amplifier includes a first input coupled to the third switch and the fourth switch, and a second input for receiving a second reference voltage. The first multiplexer is coupled to the first operational amplifier, the first controller, and the second switch. The second multiplexer is coupled to the second operational amplifier, the second controller, and the fourth switch.

Abstract: An oscillation sensor for a regulator that provides dynamic control of a connection/disconnection of a compensation capacitance. The compensation capacitor is disconnected under normal operation and is automatically connected if oscillation is detected in the output and regulator's error amplifier. In this way, oscillations are stopped in the regulator almost immediately after it occurs. Also, once the circuit is stable again, the compensation capacitor is quickly disconnected again. Consequently, the compensation capacitor does not adversely affect the overall performance of the regulator.

Abstract: A voltage regulator comprising two feedback loops for regulating a load voltage, where the first feedback loop comprises a pass transistor to source current to the load, and the second feedback loop comprises a shunt transistor to shunt current from the pass transistor to ground. The use of two feedback loops allows the design of a voltage regulator in which it small-signal impedance, as seen by a power rail, has a phase not less than ?90 degrees. This mitigates interactions between the power rail and the voltage regulator that may lead to oscillations, without the need for a relatively large de-coupling capacitor. Other embodiments are described and claimed.

Abstract: The present invention includes a control part for controlling switching elements on diagonal lines in the upper and lower stage of an H bridge circuit respectively by different duty ratios based on a steering torque exerted on a steering system, and an electric power supply source for supplying an electric power. When the voltage of the electric power supply source is lower than a prescribed voltage, the control part causes the switching element EET 1 or FET2 on the upper-stage side to be driven by a pulse width modulation signal PWM1 or PWM2, the switching element FET 4 or FET3 on the lower-stage side to be turned on, and the frequency of the pulse width modulation signal to be lowered to an audible frequency range.

Abstract: A system and method to provide a slow start up voltage, such as that can slowly ramp up or down by cyclically coupling a pair of associated energy storage devices, such as capacitors, during a start-up phase. The cyclic coupling of the capacitors, in conjunction with causing a change in charge associated with a first of the storage devices, results in incremental changes in the energy of the second energy storage device over a plurality of cycles. The energy associated with the second storage device can be used to control output circuitry that provides a desired ramp output signal.

Abstract: A power conversion system, preferably a buck converter, having (i) an oscillator, (ii) a pulse width modulator, (iii) and a nonoverlap clock generator and level shifter, wherein the improvement comprises the elimination of an external resistor divider is described. The buck converter can convert input voltage ranging from approximately 3V to 5V down to approximately 0.7-1.0V, 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V without the use of resistor dividers. The voltage input identifiers select one of the possible output settings for flexibility and accuracy. The integrated field emitting transistors can provide a continuous current of at least 6 A. Additionally, peak current mode and an oscillator enable multiphase operation, up to ten buck converters, for up to 60 A output current. The multiphase operation reduces the output inductor size, and number of bulk capacitors. Moreover, the multiphase operation yields higher efficiency and provides high transient response for demanding applications.

Abstract: A device for providing power to suppress transient load demands and a system including the device are disclosed. The device includes a sense circuit to detect when a transient event occurs and one or more transistors configured to supply or sink current to the load. The system may include a second power regulator configured to respond to fast transient power demands. In this case, a first power regulator supplies power to the load and responds to slow transient events, while the second regulator responds only to fast transient events.

Abstract: A system and method for operating a motor drive unit. The motor drive unit is coupled to a motor driving a load and is configured to selectively control the motor according to a torque control mode and a speed control mode. The motor drive unit includes a circuit configured to generate an operational condition signal indicating an operational condition of the motor and a regulator configured to receive the operational condition signal and generate a motor control signal. The motor drive unit also includes a first controller configured to receive the motor control signal and a reference control signal and select either the motor control signal or the reference control signal to use as a control signal to drive the motor according to either torque control or speed control.

Abstract: A constant voltage power supply circuit includes oscillation means; a step-up or step-down circuit including coil means and capacitive means; detecting means that detects an outputted voltage value of the step-up or step-down circuit, and compares the detected value with a predetermined reference value to output a detected information, at which either the detected value exceeds the reference value or becomes lower than the reference value; and control means that controls, based on the detected information of the detecting means, supply of the pulse signals outputted from the oscillation means to the step-up or step-down circuit.

Abstract: An apparatus comprises a linear power supply and an auxiliary power supply powered from the linear power supply. The auxiliary power supply comprises a switching regulator connected to receive, at an input thereof, the output voltage of the linear power supply and to generate therefrom an output voltage of the auxiliary power supply. The auxiliary power supply further comprises a detection circuit, connected to the linear power supply and to the switching regulator, that detects one of (i) a level of current drawn from the linear power supply and (ii) a level of voltage at an output of the linear power supply and that causes the switching regulator to reduce its load on the linear power supply when the detected level reaches a predetermined threshold.

Abstract: A power supply system includes an adapter to receive power from a power source, and output a regulated output voltage (Vout). A tip receives Vout from the adapter, and output Vout to an electronic device. The tip includes active circuitry to adjust a programming voltage (Vprog). Vprog is fed back to the adapter to control a magnitude of Vout.

Abstract: A voltage regulator with output accelerated recovery circuit is disclosed, which is substantially a low dropout voltage regulator (LDO) having a comparator and a pull-down transistor, both being connected between the positive feedback input node of its operational amplifier (OP) and the ground end thereof. In a preferred aspect, the comparator is used for detecting the voltage variation of a reference node, whereas the reference node is defined to be a node located between a first feedback resistor and a second feedback resistor. Operationally, as the voltage detected at the reference node is larger than a predetermined voltage, the pull-down transistor is forced to turn on so as to sink the output voltage rapidly for returning the same back into regulation.

Abstract: A multiple output stage converter (MOSC) and an operating method thereof are provided. The MOSC includes a first transistor, a second transistor, a third transistor, and a logic control module. A terminal of the first transistor, a terminal of the second transistor, and a terminal of the third transistor are coupled to a power source via an inductor. Another terminal of the first transistor is coupled to a first output terminal. Another terminal of the second transistor is coupled to a second output terminal. Another terminal of the third transistor is coupled to a ground voltage. The logic control module is used to control the on/off state of the second transistor. The well of the second transistor is floating when the first transistor or the third transistor is on. The well of the second transistor is floated or coupled to the second output terminal when the second transistor is on.

Abstract: A voltage regulator has a device for regulating an output voltage, having an input to receive an input voltage and an output to deliver an output voltage of a constant level, and a device for correcting a drop-out voltage violation, coupled to the device for regulating, to determine an occurrence of a drop-out voltage violation and to cause the device for regulating to change the level of the output voltage upon detection of the drop-out voltage violation. A method for regulating an output voltage has the steps of receiving an input voltage, generating and outputting a regulated output voltage of a constant level, monitoring occurrence of a drop-out voltage violation, and causing a change of the level of the output voltage upon detection of the drop-out voltage violation.

Abstract: A load driving circuit includes a first transistor and a second transistor that are bipolar transistors connected in series between a first fixed voltage (Vdd) and a second fixed voltage (GND), and supplies a drive current, according to ON-OFF states of the two transistors, to a load connected to an output terminal that is a connection point of the two transistors. A current source controls a base current supplying the first transistor. A protection circuit compares output voltage of the output terminal with a predetermined threshold voltage, and additionally monitors ON and OFF states of the first transistor. In a state in which Vout<Vth, and the first transistor is ON, the protection circuit reduces the base current of the first transistor.

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: Methods and apparatus are disclosed for providing stable voltage references from within a low dropout voltage regulator. Some embodiments utilize dependable semiconductor inherent attributes to generate a voltage reference, such as a band-gap voltage reference.

Abstract: A regulator circuit is offered to resolve a problem that an unnecessary operating current flows in a semiconductor integrated circuit in a low power consumption state. Channel width to channel length ratios of an output transistor in a first operational amplifier and a first control MOS transistor are designed large in order to obtain an operating current in a normal operation state, while channel width to channel length ratios of an output transistor in a second operational amplifier and a second control MOS transistor are designed small to obtain an operating current in the low power consumption state. There is provided a switching circuit that selectively put in operation one of the operational amplifiers according to the state of the integrated circuit. The first operational amplifier and the first control MOS transistor having higher current driving capabilities operate in the normal operation state.

Abstract: A regulating apparatus having an output node and being operative for regulating the voltage level at the output node in response to a reference signal provided as an input to the regulating apparatus. The regulating apparatus includes a linear amplifier stage operative for receiving the reference signal and being capable of sourcing current to the output node when the reference signal indicates that a present voltage level at the output node is less than a desired voltage level at the output node. The regulating apparatus also includes a switching regulator, which is controlled by the linear amplifier stage, and which is operative for sourcing current to the output node when the amount of current being sourced to the output node by the linear amplifier stage exceeds a predetermined threshold.

Abstract: A low-dropout regulator with a single-transistor-control providing improved transient response and stability is disclosed. The single-transistor-control provides a dynamic resistance at the output of the regulator for minimizing undershoot and overshoot, and hence improves transient response. Since the single-control transistor reduces the output resistance of the regulator, the output pole is pushed to a sufficiently high frequency without affecting stability. Therefore, the limited choice of combinations of the output capacitance and its equivalent-series-resistance is substantially relaxed.

Abstract: A power supply device includes a first transistor connected in series between an input terminal to which an input voltage is applied and an output terminal from which an output voltage is led out; a second transistor connected between the input terminal and the output terminal in parallel with the first transistor, and which is arranged to supply a portion of the output current to a load as a detection current; a control voltage production unit arranged to produce a control voltage of the first and second transistors so that the output voltage is maintained at a specified target value; a first constant current source arranged to produce a first constant current; a variable current source arranged to produce a variable current in accordance with the output voltage; a first resistor arranged to produce a reference voltage in accordance with a combined current of the first constant current and the variable current; a second constant current source arranged to produce a second constant current; a second resistor

Abstract: A voltage regulator includes first and second transistors arranged in parallel and configured to regulate current flow to an output node, and a sensing circuit configured to sense a voltage level at the output node and provide a signal proportional thereto. the regulator also includes a control circuit configured to receive the signal from the sensing circuit and provide control signals at control terminals of the first and second transistors such that voltage at the output node is maintained substantially at a selected level. The control circuit further configured to hold the second transistor in an off state while a demand for current at the output node remains below an output threshold. The second transistor is configured to control a large portion of load current above the output threshold. The regulator may also include a current bypass circuit configured to shunt leakage current of the second transistor to ground, away from the sensing circuit.

Abstract: A constant voltage outputting apparatus includes an input terminal, an output terminal, a control unit, a plurality of output control transistors, and a switching unit. The input terminal receives an input voltage, and the output terminal outputs an output voltage. The control unit detects the output voltage and outputs a control signal equalizing the detected output voltage with a predetermined constant voltage. Each of the plurality of output control transistors receives the control signal and controls, according to the control signal, currents flowing from the input terminal to the output terminal. The switching unit switches the plurality of output control transistors to input the control signal thereto according to a predetermined setting. A constant voltage outputting method is also described.

Abstract: A control circuit for suppressing generation of inrush current during activation of a DC-DC converter, which controls output with control signals. The control circuit includes first and second error amplification circuits, each of which generates a control signal based on the difference between a reference voltage and voltage derived from an output voltage or an output current. During activation of the DC-DC converter, a soft start circuit generates a soft start signal having voltage lower than voltage of each control signal to control the output of the DC-DC converter. During activation of the DC-DC converter, a clamp circuit, which is connected to the first and second error amplification circuits, clamps the voltage of the first and second control signals to substantially the same voltage as the soft start signal.

Abstract: A regulator system for supplying power to a microelectronic device is disclosed. The system includes an array of a plurality of regulators, where each regulator provides a portion of power required to operate the device. The system may further include an intermediate power regulator that supplies power to the array of regulators.

Abstract: A low drop-out voltage regulator having a pass device (Mp), an error amplifier (M1-M51) and a double regulation loop including DC feedback loop (R1, R2) and an AC feedback loop (Rf, Cf) including a high pass filter (Cf). Combining these two loops creates an ultra low frequency internal pole which makes the regulator stable substantially independent of the output bypass capacitor's value. This provides the following advantages: allows the use of very low bypass capacitors; allows to extend the PSRR frequency behavior; allows an increase in the regulator's efficiency (reduced power consumption on heavy loads).

Abstract: A voltage regulator includes a voltage divider connected between a soft-start pin and the voltage regulator's error amplifier. The voltage divider has the same divider ratio as that of the voltage regulator's feedback voltage divider, which is used to divide the regulated output voltage fed back to the error amplifier. To facilitate soft-start operations, an external, user-supplied capacitor is connected to the soft-start pin. To facilitate voltage tracking operations, a predetermined master supply voltage is applied to the soft-start pin.

Abstract: A linear voltage regulator provides a selectable output voltage to a load. The linear voltage regulator includes: a regulating circuit including an input terminal for receiving an input voltage, an output terminal for providing an output voltage to a load, and an adjusting terminal; a first resistor and a second resistor connected between the output terminal and ground for receiving the output voltage; and a voltage sampling control circuit electrically connected to a node between the first resistor and the second resistor for receiving logic signals from a controlling chip, and generating a reference current to the adjusting terminal of the regulating circuit to provide the selectable output voltage.

Abstract: Switchmode DC-DC power converters using one or more non-Silicon-based switching transistors and a Silicon-based (e.g. CMOS) controller are disclosed. The non-Silicon-based switching transistors may comprise, but are not necessarily limited to, III–V compound semiconductor devices such as gallium arsenide (GaAs) metal-semiconductor field effect transistors (MESFETs) or heterostructure FETs such as high electron mobility transistors (HEMTs). According to an embodiment of the invention, the low figure of merit (FoM), ?FET, of the non-Silicon-based switching transistors allows the converters of the present invention to be employed in envelope tracking amplifier circuits of wireless devices designed for high-bandwidth technologies such as, for example, EDGE and UMTS, thereby improving the efficiency and battery saving capabilities of the wireless devices.

Abstract: A voltage regulator includes a first stage capable having a first current flowing through it. A second stage has a second current. A third stage is capable of outputting an output voltage and has a third current flowing through it. The first, second and third currents are proportional to each other throughout a range of operation of the voltage regulator between substantially zero output current and maximum output current. The first stage drives the second stage as a low input impedance load.

Abstract: A method regulates the time constant matching of a DC/DC converter phase, further to a variation of a load applied to an output of said phase. Such phase being associated with a coil network, with a series RL circuit and a reading network 10, with a series RC circuit connected in parallel to the coil network. The method includes an acquisition step, suitable to acquire the trend of a voltage detected across the capacitance CD of the reading network 10, transforming it into a current trend, a detection step suitable to identify a variation above a certain threshold value of said current trend, an identification step, enabled by said detection step, suitable to determine a slope of said current trend and a regulation step suitable to adapt the value of said resistance RD based on said slope determined by said identification step.

Abstract: A low dropout voltage (LDO) regulator comprises an output stage (EtS) of the amplifier (AMP), which has a main output and n auxiliary outputs which can respectively deliver a main control voltage (VGPRINC) and n auxiliary control voltages (VG1, . . . , VGn); and a power stage (EtP) which has a main power transistor (PmosPrinc), controlled at its gate by the main control voltage (VGPRINC), and p power modules (module 1, . . . , module n) of identical layout with p less than or equal to n, respectively having p auxiliary power transistors (PMos1, . . . , PMosn) each controlled at their gate by p auxiliary control voltages (VG1, . . . , VGn). The number p is selected as a function of an intended maximum output current.

Abstract: Provided is a digitally-controlled linear regulator having noise-shaped component selection. The digitally-controlled linear regulator has a regulated-voltage sensor, a comparator module, a quantization module, and an impedance switching network. The regulated-voltage sensor is operably coupled to sense an output voltage of the digitally-controlled linear regulator to produce a sensed output voltage. The comparator module is operably coupled to compare the sensed output voltage with a reference voltage at a predetermined clock rate to produce a digital regulation signal. The quantization module is operably coupled to quantize the digital regulation signal to produce a quantized regulation signal. The impedance switching network is operably coupled to convert a source voltage into the output voltage of the digitally-controlled linear regulator based on the quantized regulation signal.

Abstract: A power supply circuit relating to the present invention comprises a differential amplifier for feeding out a voltage as a control voltage in accordance with a difference between a feedback voltage commensurate with an output voltage and a reference voltage, an output current control element for feeding out an output current in accordance with the control voltage fed thereto from the differential amplifier, an output line by way of which the output current is supplied to a load, a feedback line by way of which a voltage on the output line is fed back as the feedback voltage to the differential amplifier, the feedback line connected to the output line, and a clamping circuit for maintaining the control voltage so as not drop below a predetermined value.

Abstract: A low-dropout (LDO) voltage regulator for generating an output voltage is disclosed. The voltage regulator includes a startup circuit, a curvature corrected bandgap circuit, an error amplifier, a metal oxide semiconductor (MOS) pass device and a voltage slew rate efficient transient response boost circuit. The MOS pass device has a gate node which is coupled to the output of the error amplifier, and a drain node for generating the output voltage. The voltage slew rate efficient transient response boost circuit applies a voltage to the gate node of the MOS pass device to accelerate the response time of the error amplifier in enabling the LDO voltage regulator to reach its final regulated output voltage when an output voltage drop occurs in the LDO voltage regulator.

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.

Abstract: A linear regulator having an input node receiving an unregulated voltage, an output node providing a regulated voltage, a voltage regulator, a bias circuit, and a current control device. The voltage regulator has an input terminal, a reference terminal, and an output terminal which forms the output node of the linear regulator circuit. The bias circuit has a first terminal coupled to the output terminal of the voltage regulator and a second terminal. The current control device has a first current electrode which forms the input node of the linear regulator circuit, a second current electrode coupled to the input of the voltage regulator, and a control electrode coupled to the second terminal of the bias circuit. The bias circuit develops a voltage sufficient to drive the control terminal of the current control device and to operate the voltage regulator.

Abstract: A power supply system includes an adapter to receive power from a power source, and output a regulated output voltage (Vout). A tip receives Vout from the adapter, and output Vout to an electronic device. The tip includes active circuitry to adjust a programming voltage (Vprog). Vprog is fed back to the adapter to control a magnitude of Vout.

Abstract: A DC-to-DC converter as described herein is suitable for use as a variable voltage supply for an RF power amplifier. The DC-to-DC converter includes a buck converter for providing relatively low voltage and current output, and a linear voltage regulator for providing relatively high voltage and current output. When operating in a buck converter mode, the DC-to-DC converter disables the linear voltage regulator, thus providing efficient low-level operation. When operating in a linear regulator mode, the DC-to-DC converter enables the linear voltage regulator while maintaining at least some current flow through the buck converter; this is accomplished by keeping an output transistor of the buck converter continuously on during the linear regulator mode. The DC-to-DC converter can transition between operating modes in a smooth manner that does not result in discontinuous voltage drops.

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.