Abstract: Devices and methods are provided for generating a regulated output voltage with improved line rejection based on an input voltage and a reference voltage. The device may include a pass transistor and a replica transistor, wherein source ports of the pass transistor and the replica transistor are coupled to the input voltage, a drain port of the pass transistor is coupled to the output voltage, and a gate port of the pass transistor is coupled to a gate port of the replica transistor. The device may further include a coupling circuit configured to couple current from the drain port of the replica transistor to the gate port of the replica transistor, the coupling circuit further configured to control voltage on the drain port of the replica transistor based on the reference voltage.

Abstract: Methods and circuits for linearly controlling a limited, constant current during startup of LDOs, amplifiers, or DC-to-DC converters independent of load capacitor size and controlling a clean transition without glitches from a constant current (CC) mode during startup to a constant voltage (CV) mode during normal operation (CC-CV method) are disclosed. The constant current control loop and the constant voltage control loop are implemented in such a way that at the end of startup the voltage loop has taken over control and the current loop is moved far away from its active transistor region, allowing a switch of modes to occur without any nasty transitions on the output.

Abstract: Advantageous analog and/or digital logic cells and methods of powering circuit blocks using the same are provided. A digital logic cell can include a charge storage device, a logic block, and connections to a power supply. The charge storage device may be a capacitor. The capacitor or other charge storage device can be disconnected from the logic block and a power supply to discharge the capacitor, and then connected to the power supply, via the power supply connections, to charge the capacitor. The capacitor can be disconnected from a ground connection of the power supply while the capacitor is discharged. After being charged via the power supply, the capacitor can also be disconnected from the power supply (including ground) and connected to the logic block to power the logic block.

Abstract: Provided is a voltage regulator capable of suppressing excessive overshoot at the output terminal when the power supply fluctuates in a non-regulate state. The voltage regulator includes: an error amplification circuit that amplifies a difference between reference voltage and divided voltage, thus controlling a gate of an output transistor; an amplifier that compares the reference voltage and the divided voltage to detect overshoot at the output voltage; a first transistor that lets current that is proportional to current flowing through the output transistor pass therethrough; a current mirror circuit that mirrors current that is proportional to the current flowing through the output transistor; and a first bias circuit connected to the amplifier via the current mirror circuit, the first bias circuit increasing bias current of the amplifier to increase a response speed.

Abstract: A regulator includes a first transistor, a first bias circuit, a second bias circuit, a differential circuit having second to fifth transistors, and a current mirror circuit. The first transistor outputs an output voltage lower than the input voltage. The first bias circuit generates a first bias voltage lower than a reference voltage. The second bias circuit generates a second bias voltage lower than a feedback voltage relating to the output voltage. The second transistor into which the reference voltage is inputted and the third transistor into which the feedback voltage is inputted are a pair of differential transistors. The fourth transistor is complementarily connected to the second transistor. The fifth transistor is complementarily connected to the third transistor. The differential circuit outputs a comparison signal to the first transistor. The current mirror circuit is connected to the second and third transistors.

Abstract: A hybrid power supply architecture including a microcontroller, a linear regulator, a first current sensing unit, a second current sensing unit, a switching regulator, a PWM controller and a hybrid output stage is disclosed. The linear and switching regulators respectively perform linear and switching regulation according to a first enable signal and a second enable signal generated by the microcontroller to generate a linear output power and a switching output power. The first and second current sensing units respectively generate a first current sensing signal and a second current sensing signal by sensing the linear and switching output powers. The microcontroller receives the first and second current sensing signals to determine a loading state. The switching regulator is enabled to actuate in case of heavy loading, and particularly the linear regulator is shut off only when the switching output power is stable, thereby implementing the best conversion efficiency.

Abstract: A voltage regulator includes an output stage including a control terminal and a load path, with the load path coupled between the input terminal and the output terminal. The voltage regulator also includes a control circuit with an input stage, a first current mirror, and a second current mirror. The input stage includes a first control input configured to receive a first reference voltage, a second control input configured to receive a second reference voltage, a feedback input coupled to the output terminal, a first output terminal, and a second output terminal. The first current mirror includes a reference current path coupled between a first supply terminal and the first output terminal of the input stage, and an output current path coupled between the first supply terminal and the control terminal of the pass device.

Abstract: An intelligent power control system and method adapted for use with a digital rack interface pod (DRIP). A switching regulator generates a set output voltage. If power is available from a USB port of an external device, such as an external server, then the system uses this power to power the DRIP. If DC power is detected as being received on a different input from an external power transformer, then the system may still continue to use the power being received from the USB port to power the DRIP. If power from the USB port of the external device is lost but power from the external transformer is present, then the system may use the power available from the external transformer to power the DRIP.

Abstract: A circuit is provided with inrush current protection through control of the output current at start-up by a current source that does not rely on the output capacitor and which provides a smooth transition from a controlled current mode during a start-up phase to a voltage regulation mode.

Abstract: A ballast circuit for a Light Emitting Diode (LED) has a regulator element coupled to the LED and to an input voltage source. A control circuit is coupled to the LED and to an input voltage source. A first switching device is coupled in series with the regulator element. A second switching device is coupled to the input voltage and the control circuit.

Abstract: A voltage regulator includes an amplifier having a first input coupled to a first reference voltage and a second input coupled to a voltage feedback signal; a multiplexer having a first input coupled to an output of the amplifier, a second input coupled to a voltage clamp signal, and a control input; and a control circuit having a first input coupled to an over current indicator, a second input coupled to a no over voltage indicator, a third input coupled to a timer signal, and an output coupled to the control input of the multiplexer.

Abstract: A matrix converter according to an embodiment includes a plurality of bidirectional switches disposed between an AC power source and an AC load, and a controller that controls the bidirectional switches. The controller corrects an output voltage reference based on an oscillation component of an input current and/or an input voltage from the AC power source.

Abstract: A self-adjustable current source control circuit utilizes a replica output stage, a sink current source that generates a reference current, and a negative feedback circuit to generate a sink current between a linear regulator output terminal and ground only when a load circuit connected to the linear regulator is in a low power consuming state. The replica output stage includes an 1:N scaled replica of the linear regulator's NMOS (or NPN) output stage transistor, and the negative feedback circuit utilizes two PMOS (or PNP) negative feedback transistors having the same N:1 size ratio and connected as a common gate amplifier, whereby one of the two negative feedback transistors turns on to draw the desired sink current from the regulator output terminal only when the load current falls below N times the reference current (i.e., only the load current is drawn through the output stage transistor during high load current conditions).

Abstract: Circuits and methods to compensate leakage current of a LDO are disclosed. The compensation is achieved by a temperature dependent sink current generation, which has a nearly zero current consumption increase of about 50 nA at room temperature and starts sink current at temperatures about above 85 to 100 degrees Celsius, which is corresponding to a range of temperature wherein leakage currents come into account.

Abstract: A voltage regulator includes a regulating transistor and a control circuit. The regulating transistor has a first current electrode for providing a regulated voltage, a second current electrode, and a control electrode. The control circuit has an output coupled to the control electrode of the regulating transistor, and an input coupled to the first current electrode of the regulating transistor. The control circuit includes a first inverting gain stage having a first load element, and a second inverting gain stage having a second load element. One of the first or second load elements is characterized as being a diode and the other of the first or second load elements is biased by a bias circuit.

Abstract: A semiconductor integrated circuit includes a plurality of output transistors each controlling the magnitude of an output voltage relative to the magnitude of a load current according to a control value indicated by an impedance control signal applied to a control terminal, a voltage monitor circuit outputting an output voltage monitor value indicating a voltage value of the output voltage, and a control circuit controlling the magnitude of the control value according to the magnitude of an error value between a reference voltage indicating a target value of the output voltage and the output voltage monitor value, and controls based on the control value whether any of such transistors be brought to a conducting state. The control circuit increases a change step of the control value relative to the error value during a predetermined period according to prenotification signals for notifying a change of the load current in advance.

Abstract: Systems and methods are provided to regulate a supply voltage of a load circuit. For example, a system includes a voltage regulator circuit that includes a passgate device. The system includes a passgate strength calibration control module which is configured to (i) obtain information which specifies operating conditions of the voltage regulator circuit, (ii) access entries of one or more look-up tables using the obtained information, (iii) use information within the accessed entries to determine a maximum load current that could be demanded by the load circuit under the operating conditions specified by the obtained information, and to predict a passgate device width which is sufficient to supply the determined maximum load current, and (iv) set an active width of the passgate device according to the predicted passgate device width.

Abstract: Aspects are directed to low dropout regulation. In accordance with one or more embodiments, an apparatus includes a charge pump that generates an output using a reference voltage, a low dropout (LDO) regulator circuit, current-limit and a voltage-limit circuit. The LDO circuit includes an amplifier powered by the charge pump and that provides an LDO voltage output. The voltage-limit circuit includes a transistor coupled between a voltage supply line and the LDO regulator circuit and a gate driven by the charge pump. The voltage-limit circuit limits voltage coupled between the voltage supply line and the LDO regulator circuit based upon the output of the charge pump, such as by coupling the voltage at the voltage supply line via source/drain connection of the transistor under low-voltage conditions, and providing a limited voltage to the LDO regulator circuit under high voltage conditions on the voltage supply line.

Abstract: A power supplying circuit for generating an output voltage, which comprises: a noise detecting circuit, for receiving a first reference voltage and for generating a second reference voltage according to the output voltage and the first reference voltage, wherein a noise component of the second reference voltage is the same as which of the output voltage; a control voltage generating unit, for receiving a feedback voltage and the second reference voltage, and for generating a control voltage according to the feedback voltage and the second reference voltage; a voltage providing device, for generating the output voltage according to the control voltage and an input voltage; and a feedback module, for generating the feedback voltage according to the output voltage.

Abstract: A low-drop regulator (LDO) apparatus includes an operational amplifier, a buffer stage circuit, and a power transistor. The operational amplifier is used for receiving a reference voltage and a feedback voltage to generate a first voltage. The buffer stage circuit is coupled to the power transistor and the operational amplifier and used for buffering the first voltage to generate a second voltage. The power transistor is coupled to the buffer stage circuit and used for generating an output voltage according to the second voltage wherein the output voltage is proportional to the feedback voltage. In addition, the buffer stage circuit is arranged to determine whether to mirror and generate a mirrored current according to the first voltage and to generate the second voltage for providing the second voltage to the power transistor to control on/off state of the power transistor when the mirrored current is generated.

Abstract: A signal generating circuit includes: a first signal amplifying circuit arranged to generate a first amplified signal according to a first supply current, a reference signal, and an output signal of the signal generating circuit; a soft-start circuit arranged to generate a control signal according to a soft-start signal; a current controlled circuit arranged to generate the first supply current according to the soft-start signal; and a pass transistor arranged to generate an output signal according to an error amplified signal and the control signal. The error amplified signal is derived from the first amplified signal.

Abstract: An internal voltage generation circuit includes a comparison unit suitable for comparing a voltage level of a feedback voltage with that of a reference voltage, and generating a comparison signal and an acceleration voltage, a pull-up driving unit suitable for driving an internal voltage terminal to be pulled up in response to the comparison signal, a discharging unit suitable for discharging the internal voltage terminal in response to the acceleration voltage, and a voltage division unit suitable for dividing a voltage level of the internal voltage terminal, and generating the feedback voltage.

Abstract: A regulator applied to regulate a first reference voltage on an output terminal, the regulator includes: a sensing circuit, arranged to sense a variation of the first reference voltage on the output terminal to generate a sensing signal; and a gain stage, arranged to provide an adjusting current to the output terminal in response to the sensing signal for reducing the variation of the first reference voltage, and the gain stage is coupled in parallel to a loading circuit powered by the first reference voltage.

Abstract: A circuit may include a differential amplifier and a feedback network. The feedback network may have a chain of resistance sets coupled in series, with a first end terminal coupled to an output terminal of the differential amplifier and a second end terminal coupled to a power reference terminal of the differential amplifier. Respective nodes may be coupled between successive ones of the resistance sets. A feedback terminal may be coupled to an inverting input terminal of the differential amplifier. A controller may control a set of switches to electrically couple a given node to the feedback terminal. A first resistance set of the chain adjacent the first end terminal may be two resistance subsets coupled in series, with an intermediate node coupled therebetween. A programmable current generator may have a current output coupled to the intermediate node and may produce a controlled current flowing at the current output terminal.

Abstract: The present invention discloses a load driving circuit, comprising a voltage differential generation circuit and a common mode voltage generation circuit; wherein the voltage differential generation circuit is configured to generate a driving voltage for driving a load; and the common mode voltage generation circuit is configured to: when the voltage differential generation circuit generates the driving voltage for driving the load, regulate the voltages output by a first output terminal and a second output terminal of the voltage differential generation circuit to the same voltage value. The present invention also provides a load driving method and application devices thereof. With the technical solutions according to the present invention, a central value of a voltage output by the first output terminal and a voltage output by the second output terminal of the voltage differential generation circuit is effectively regulated.

Abstract: An embodiment of a voltage regulation circuit includes a DC-DC converter configured to control a first current provided from a source to a load via a first output, and a linear regulator configured to control a second current provided from the source to the load via a second output. The voltage regulation circuit further includes a single control loop configured to receive an output voltage across the load and a first reference voltage. The single control loop is further configured to generate a single error signal between the output voltage across the load and the first reference voltage and to control the DC-DC converter and the linear regulator using the single error signal such that when the single error signal is outside of a predetermined range the DC-DC converter provides the first current to the load and the linear regulator provides the second current to the load simultaneously.

Abstract: A circuit for regulating and monitoring a signal current, comprising a regulating circuit; and a monitoring circuit. The regulating circuit comprises: a first controlled voltage source for outputting a target value dependent controlled voltage; a current adjust circuit for adjusting the signal current in dependence on the controlled voltage and a first feedback voltage by means of a potentiometer; and a first feedback path, with at least one first resistance element across which the signal current flows. The voltage drop across the resistance element or one of the voltages of the current adjust circuit dependent thereon is supplied as a first feedback voltage.

Abstract: Circuits and methods to reduce the size of output capacitors of LDOs or amplifiers are disclosed. Nonlinear mirroring of the load current allows scaling of gain or adapting small signal impedance of a pass transistor depending on other inputs, in case of a preferred embodiment, allows to reduce small signal impedance at the gate of the pass transistor as the load current increases, hence allowing to reduce the size of an output capacitor without compromising stability of the system.

Abstract: In a linear voltage regulator, a first stage outputs an output signal. The first stage is configured with a first switchable bias current, and is configured to receive a feedback signal. A second stage provides a regulated voltage output. A decoupling capacitor is coupled to the regulated voltage output. A feedback circuit is coupled with the second stage and configured to generate the feedback signal. A frequency compensation circuit includes a second switchable bias current. The frequency compensation circuit: pushes away an existing pole to a higher frequency when the first and second switchable bias currents are operated in a sleep mode; and creates a left-hand-side zero when the first and second switchable bias currents are operated in an active mode. The active mode comprises the first and second switchable bias currents supplying greater currents than are provided in the sleep mode.

Abstract: A voltage generator is disclosed. The voltage generator includes an operational amplifier, an offset voltage tuner, and an output stage circuit. The operational amplifier receives an input voltage and adjusts an offset voltage of the operating amplifier according to a control signal. The offset voltage tuner provides the control signal. The output stage circuit generates an output voltage according to a voltage on an output terminal of the operational amplifier, and provides the output voltage to the operational amplifier.

Abstract: An uninterruptible power supply (UPS) includes a rectifier, a buck converter, a solar energy module, a boost converter, a controller, and a power distribution unit (PDU). The solar energy module receives solar energy and converts the solar energy to a first DC voltage. The controller compares the first DC voltage with a preset voltage, and outputs a control signal to turn the boost converter on or off. When the boost converter is turned off, the rectifier receives an AC voltage from the AC power source and converts this to a rectified DC voltage which is output to the buck converter. When the boost converter is turned on, the boost converter converts the first DC voltage to a second DC voltage. The buck converter converts the rectified DC voltage or the first DC voltage to a working DC voltage and outputs to a power supply unit through the PDU.

Abstract: Techniques for generating a control voltage for a pass transistor of a linear regulator to avoid in-rush current during a start-up phase. In an aspect, a digital comparator is provided to generate a digital output voltage comparing a function of the regulated output voltage with a reference voltage, e.g., a ramp voltage. The digital output voltage is provided to control a plurality of switches selectively coupling the gate of the pass transistor to one of a plurality of discrete voltage levels, e.g., a bias voltage or a ground voltage to turn the pass transistor on or off. In another aspect, the digital techniques may be selectively enabled during a start-up phase of the regulator, and disabled during a normal operation phase of the regulator.

Abstract: The voltage regulator comprises a regulation loop (2), which comprises at least a pass transistor (18), a source transistor (28), a sensing transistor (22) and a retention transistor (24), and a stability compensation circuit (10), which comprises a first MOS resistor (12) and a second MOS resistor (14) coupled with the first MOS resistor (12). The gate of the second MOS resistor (14) is coupled to the gate of the pass transistor (18).

Abstract: An embodiment of the invention relates to a power converter formed with an error amplifier and a related method. In an embodiment, a first switch is coupled in series with an error amplifier compensation capacitor. Upon detection of a current level greater than a threshold level, the compensation capacitor is decoupled from the error amplifier by opening the first switch. In an embodiment, a second switch is coupled in parallel with the compensation capacitor, and the current-sensing circuit enables conductivity of the second switch to discharge the compensation capacitor upon detection of the current level greater than the threshold level. The second switch is opened upon detection of the current level less than the threshold level. In an embodiment, the current-sensing circuit controls an output current of the power converter at a current-limit level upon detection of the internal current level greater than the threshold level.

Abstract: Voltage regulators are disclosed herein. An embodiment of a voltage regulator includes a MOS-type pass transistor, wherein a first node of the pass transistor is connectable to a voltage source and wherein a second node of the pass transistor is connected to the output of the voltage regulator. The voltage regulator also includes an error amplifier having a reference input and an output, the output being connected to the gate of the pass transistor, and the reference input being connected to a reference voltage source.

Abstract: A system including a first transistor, a first capacitor and a circuit. The first transistor has a first control input and is configured to regulate an output voltage. The first capacitor is coupled at one end to the first control input and at another end to a circuit reference. The circuit is configured to provide a first voltage to the first control input, where the first voltage includes an offset voltage that is referenced to the output voltage and adjusted to compensate for variations in the first transistor.

Abstract: An output stage circuit is provided, which includes a power supply, a quiescent current control circuit, an output circuit, and a quiescent current equalization circuit. The quiescent current equalization circuit is configured to decrease or increase a quiescent current flowing through a quiescent current biasing circuit in the quiescent current control circuit when a change of a voltage of the power supply is detected, such that a quiescent current flowing through the output circuit remains constant. A quiescent current equalization method, a Class AB amplifier and an electronic device are also provided. When the voltage of the power supply is increased, the quiescent current of the output circuit of the output stage circuit can maintain constant. As such, the power supply rejection ratio (PSRR) of the output circuit can be efficiently increased and the power consumption of the device can be reduced.

Abstract: Systems and methods for reducing power consumption of a voltage regulator are disclosed. In accordance with one embodiment of the present disclosure a voltage regulator comprises an input node configured to receive a reference voltage and an output node configured to output an output voltage. The output voltage is a function of the reference voltage and a regulating current. The regulator further comprises a proportional to absolute temperature (PTAT) circuit coupled to at least one of the output node and the input node. The PTAT circuit is configured to vary at least one of the reference voltage and the regulating current as a function of temperature.

Abstract: A method to maintain stability of a low drop-out (LDO)/load switch linear voltage regulator (LVR). The method includes determining, during a power-up phase and by a capacitance sensing circuit, an estimated output capacitance value at an output node of the LDO/load switch LVR, and adjusting, based on the estimated output capacitance value, an adaptive RC network in the LDO/load switch LVR, wherein the adaptive RC network produces an adaptive zero in a feedback network transfer function of the LDO/load switch LVR, wherein the adaptive zero reduces an effect of a non-dominant pole in the open loop transfer function of the LDO/load switch LVR, and wherein a frequency of the adaptive zero is inversely proportional to the estimated output capacitance value.

Abstract: A low drop-out (LDO) voltage regulator which parallels a second pass device to a first pass device, where the second pass device has in series a small resistor. The small value resistor is a substitute for bond wires or capacitors with very low equivalent series resistances (ESR). A fast feedback loop is coupled to the junction of the second pass device and the small resistor and provides, via a Miller capacitor, a feedback signal to the amplifier of the voltage regulator. The added second pass device returns circuit stability by moving the fast-loop high frequency zero node back within the bandwidth of the circuit.

Abstract: An electronic circuit includes a switchable circuit domain that operates in a RUN mode and a STANDBY mode and receives a supply current from a core power supply. A power regulator is connected between the core power supply and the switchable circuit domain to regulate the supply current provided to the switchable circuit domain when the electronic circuit is in the RUN mode. A capacitor is connected between the power regulator and ground and is charged by a refresh circuit when the electronic circuit is in the STANDBY mode. The refresh circuit maintains a voltage across the capacitor when the electronic circuit is in the standby mode, which reduces the time for the electronic circuit to transition from the STANDBY mode to the RUN mode.

Abstract: A power supply system includes a PID control circuit, a signal shaping circuit, and a PWM control circuit. The PID control circuit generates a signal based on an error voltage of the power supply system. The signal shaping circuit receives and converts the signal outputted from the PID control circuit into a linear control signal. To reduce cost, the shaping circuit can include a piecewise linear implementation. During non-transient load conditions, the PWM control circuit utilizes the linear control signal outputted from the signal shaping circuit to adjust a switching period of a power supply control signal. The switching period of the power supply control signal is maintained within a desired range. During transients, settings of the PID control circuit are modified to provide a faster response. The switching period of the power supply control signal may be adjusted outside of the desired frequency range.

Abstract: Provided is a voltage regulator capable of accurately adjusting a tail current of a differential amplifier circuit without adding a test terminal. The voltage regulator includes: a constant current circuit for causing the tail current of the differential amplifier circuit to flow; a protection circuit; a current output circuit for outputting a current of the constant current circuit to a test terminal for measuring characteristics of the protection circuit; a switch circuit for stopping a function of the protection circuit; and a fuse provided between the test terminal and the current output circuit.

Abstract: A system and method for dimming an LED lighting installation using an AC power source are disclosed. The disclosed LED lighting system includes an LED light having one or more LEDs, a dimming control module for controlling and adjusting brightness level of the LED light toward a desired target brightness, and a user-operated lighting control device including a power on/off switch and a dimmer. The power on/off switch passes or interrupts the AC power fed into the dimming control module. A series of turned-off operations of the power on/off switch of transitory duration causes LED light target brightness levels to be progressively increasing or decreasing leading to a desired target brightness. Operations of the dimmer result in a target brightness setting signal being generated for the dimming control module, representative of a desired target brightness as well.

Abstract: Provided is a voltage regulator which includes an inrush current prevention circuit so that no current is consumed after the start-up of the voltage regulator. A start-up circuit of the voltage regulator includes: a constant current circuit; a first transistor connected between the constant current circuit and a constant voltage generation circuit; a second transistor including a drain connected to a gate of the first transistor, and a gate to which a voltage based on an output voltage is input; a first depletion transistor including a gate connected to the drain of the second transistor, and a source connected to a source of the second transistor; and a third transistor including a gate connected to the gate of the second transistor, and a drain connected to the drain of the second transistor.

Abstract: A regulator includes a current path unit coupled between an input terminal and a ground terminal and including a first current determination unit coupled between the input terminal and a control node and configured to supply the high voltage to the control node so that a first or second current path is selected depending on a voltage of the control node, and a second current determination unit coupled between the control node and the ground terminal and configured to control the voltage of the control node depending on an input voltage, a voltage supply unit configured to supply the high voltage to an output terminal depending on the voltage of the control node, a voltage division unit configured to create a division voltage, and an amplification unit configured to amplify a difference between the division voltage and a first reference voltage.

Abstract: A voltage regulator and a memory device including same are provided. The voltage provider includes a resistive circuit configured to output at least one divided voltage; at least one driver circuit configured to be connected to the resistive circuit and to set the at least one divided voltage; and a compensation circuit configured to be connected to the at least one driver circuit, to receive a predetermined voltage, and to apply a power supply voltage to the at least one driver circuit. The at least one driver circuit may set the at least one divided voltage based on the power supply voltage received from the compensation circuit.

Abstract: In one embodiment, a regulator circuit for generating a regulated output voltage Vout has an error amplifier using a pair of bipolar transistors at its front end. The error amplifier compares the regulated output voltage to a reference voltage Vref. A precision current source draws a first current through a user-selected set resistance to generate the desired Vref. The regulator circuit controls a power stage to cause Vout to be equal to Vref. The base current into one of the bipolar transistors normally distorts the current through the set resistance. A base current compensation circuit is coupled to the current source to adjust the first current by a value equal to the base current to offset the base current. Therefore, Vref is not affected by the base current. The error amplifier may be in a linear regulator or a switching regulator. The compensation circuit may be used in other applications.

Abstract: A linear regulator contains an additional AC-coupled feedback loop between the output of the error amplifier and the base of the pass transistor that increases the frequency of the pole at the output of the error amplifier at light load currents to at least partially offset the decreased frequency of the output pole at the lighter load currents. Thus, a desired phase margin is preserved. The AC-coupled feedback loop includes a bipolar feedback transistor connected in parallel with the pass transistor. A resistor is connected to the emitter of the feedback transistor to reduce the relative gain of the feedback transistor above light load currents. A feedback capacitor Cfb is connected between the collector of the feedback transistor and the output of the error amplifier. The negative AC feedback increases the pole frequency at the output of the error amplifier and the base of the pass transistor.

Abstract: A multi-stage power supply for a load control device is able to operate in a low-power mode in which the power supply has a decreased power consumption when an electrical load controlled by the load control device is off. The load control device comprises a load control circuit and a controller, which operate to control the amount of power delivered to the load. The power supply comprises a first efficient power supply (e.g., a switching power supply) operable to generate a first DC supply voltage. The power supply further comprises a second inefficient power supply (e.g., a linear power supply) operable to receive the first DC supply voltage and to generate a second DC supply voltage for powering the controller. The controller controls the multi-stage power supply to the low-power mode when the electrical load is off, such that the magnitude of the first DC supply voltage decreases to a decreased magnitude and the inefficient power supply continues to generate the second DC supply voltage.