Abstract: Presented is a voltage regulating circuit for a capacitive load, which is connected between first and second terminals of a supply voltage generator. The regulating circuit has an input terminal and an output terminal, and includes an operational amplifier having an inverting input terminal connected to the input terminal of the regulating circuit and a non-inverting input terminal connected to an intermediate node of a voltage divider. The voltage divider is connected between an output node, which is connected to the output terminal of the regulating circuit, and the second terminal of the supply voltage generator. The operational amplifier has an output terminal connected, for driving a first field-effect transistor, between the output node and the first terminal of the supply voltage generator. The output terminal of the operational amplifier is also connected to the output node through a compensation network.

Abstract: A method and apparatus are provided for transitioning a power converter between a switched mode of operation and a linear regulator mode of operation. The power converter operates according to one or more intermediate modes of operation in which the switched mode and linear regulator modes cooperate to produce a shared power converter output. The power converter transitions between the various modes of operation in response to changes in circuit parametric conditions as defined by a series of state transition diagrams. Power converter output voltage is maintained in regulation during all modes of operation and transitions therebetween. The method and apparatus includes an integrated device that may be operated as a switch or a variable resistance device.

Abstract: A charge compensator for a voltage regulator of a semiconductor device includes a process/voltage/temperature (PVT) detector for detecting characteristics of the semiconductor device varying dependent on a manufacturing process, a voltage in use and an operating temperature of the semiconductor device and for outputting state signals representing the detected characteristics; a plurality of pass transistors for providing charge to the load, connected between a power supply voltage and the output of the voltage regulator; and a decoder for selectively driving the plurality of pass transistors based on the state signals from the PVT detector. The charge compensator adjusts the amount of charge supplied to the voltage regulator in accordance with variations of the PVT characteristics, thereby suppressing voltage fluctuations in the output of the voltage regulator.

Abstract: A power supply device that feeds electric power to an output terminal that is to be connected to a load has first and second PNP-type transistors having their emitters connected to a supplied power line. The collector of the first transistor is connected to the output terminal, and is connected also through two serially connected resistors to ground. An operational amplifier controls the first and second transistors in such a way that the voltage at the node between the two serially connected resistors is kept equal to a setting voltage. To achieve this, a control current is fed to the bases of the first and second transistors. In accordance with the collector current of the second transistor, a limiter circuit limits the output current of the first transistor. The limiter circuit controls the first transistor through the operational amplifier. Between the collectors of the first and second transistors, a capacitor is connected.

Abstract: A circuit and method for controlling current drawn from two different voltage sources while maintaining regulation of a fixed output voltage during controlled switching of different sleep states required by the microprocessor and system board.

Abstract: Methods and apparatus for the soft start of linear regulators for controlling inrush current. In linear regulators having a pass transistor controlled by a regulator control circuit, the regulator control circuit is disabled until the regulator output reaches a predetermined threshold level. On startup, an additional transistor is coupled with a resistor and capacitor to the control terminal of the pass transistor in such a way as to provide for the slow turn-on of the pass transistor. During this time, the control circuit for the pass transistor is held inoperative. After the regulator output reaches a predetermined threshold, the pass transistor control circuit becomes operative and the slow start circuitry becomes inoperative.

Abstract: A low drop-out (LDO) voltage regulator (10) and system (100) including the same are disclosed. An error amplifier (38) controls the gate voltage of a source follower transistor (24) in response to the difference between a feedback voltage (VFB) from the output (VOUT) and a reference voltage (VREF). The source of the source follower transistor (24) is connected to the gates of an output transistor (12), which drives the output (VOUT) from the input voltage (VIN) in response to the source follower transistor (24). A current mirror transistor (14) has its gate also connected to the gate of the output transistor (12), and mirrors the output current at a much reduced ratio. The mirror current is conducted through network of transistors (18, 22), and controls the conduction of a first feedback transistor (28) and a second feedback transistor (35) which are each connected to the source of the source follower transistor (24) and in parallel with a weak current source (34).

Abstract: There is disclosed a current control circuit, disposed between a primary terminal and a secondary terminal, for controlling a current flowing from the primary terminal to the secondary terminal. An overcurrent flowing through a resistance R1 is detected by a PNP transistor. A maximum value of a current flowing through a MOSFET is determined by a voltage dropped by a voltage drop correspondence by a diode from a voltage of the collector of the PNP transistor.

Abstract: A regulator circuit (10, 50) is connected to a high voltage generator (16, 52). The regulator circuit may be coupled to the generator in either a series or a shunt configuration. In the shunt configuration, the regulator circuit (10) varies the amount of current through a shunt resistor (R1) to change the output voltage provided to a load. The amount of current that is shunted by the regulator circuit is controlled by a feedback circuit consisting of a voltage divider (20) and an error amplifier (22). In the series configuration, the voltage across the regulator circuit (50) is added to the output from the high voltage generator. The current conducted through the regulator circuit therefore varies the summed output provided to the load.

Abstract: A device which rectifies and regulates high voltage alternating current without the use of transformers, large capacitive coupling circuits or high voltage linear regulators. The device includes a rectifier, a control circuit for sensing the output voltage of the rectifier and switching on and off the input power, a storage capacitor and a low voltage linear regulator. The control circuit, which incorporates a voltage sensing circuit and a switch, limits the output voltage of the rectifier as seen by the linear regulator.

Abstract: A current-limited switch contains a pilot circuit in parallel with a power MOSFET and a reference circuit containing a series of parallel circuits, each of which contains a current mirror MOSFET in parallel with a resistor. A current mirror compensation circuit contains circuitry which shorts out the parallel circuits in sequence as the current through the power MOSFET increases, thereby limiting the size of the current through the power MOSFET. In a preferred embodiment a second MOSFET is used in each parallel circuit in place of the resistor.

Abstract: A circuit comprising a first voltage shifter, a second voltage shifter and a comparator configured to control a switchable current source. The first voltage shifter may be configured to provide a first reference voltage signal in response to a reference input signal. The second voltage shifter may be configured to provide a second reference voltage signal in response to the reference input signal. The comparator may be configured to control a switchable current source in response to said first and second reference voltage signals.

Abstract: A power-supply circuit which makes available a voltage that is obtained from at least two input-voltage sources. Connected to each input-voltage source is a current mirror which makes a current available at a control input of an output transistor joint output transistor is connected, via decoupling diodes to the input-voltage sources. Decoupling of input-voltage sources is assured by output transistors which are interconnected at output. The power-supply circuit induces a small voltage difference between the output of the power-supply circuits and the voltage of the determining input-voltage source.

Abstract: The present invention relates to a voltage regulator of a voltage meant to supply a load from a battery, including a first switched-mode power supply type voltage regulation component, a second linear regulator type voltage regulation component, and a control circuit that selects one of the two regulation components according to the voltage difference between the battery voltage and the output voltage.

Abstract: A direct-current to direct-current conversion (DC/DC) apparatus includes a control circuit having an error amplifier for voltage control and controlling a direct-current to direct-current conversion based on a pulse width modulation control using an output of the error amplifier. The error amplifier inputs a voltage signal corresponding to an output voltage of a DC/DC result and a plurality of reference voltage signals. The DC/DC apparatus also includes a soft start capacitor to provide one of the plurality of reference voltage signals. The error amplifier amplifies a difference between the voltage signal corresponding to the output voltage of a DC/DC result and a voltage signal of a lower potential among the plurality of reference voltage signals and, based on the amplified output, carries out the pulse width modulation control.

Abstract: The present invention is to provide an apparatus for driving a flat panel display which allows the amount of electrons emitted from a cell to be easily controlled and which performs a stable display gradation processing. To this end, the present invention comprises a shift register for sequentially shifting a video signal input from the exterior in synchronism with a clock signal; a latch for temporarily storing and outputting said video signal which has been sequentially inputted from said shift register; an AND gate for adjusting the time of outputting said video signal output from said latch; and an output driving circuit for inputting said video signal from said AND gate and performing a display gradation control. The present invention allows the amount of electrons emitted from a cell to be easily adjusted so that a 16 step of gradation processing of a display is made possible.

Abstract: A converter is provided for stepping-down a DC power input to produce a DC power output of lower voltage. The converter includes a regulating unit (3), and, in series with it, an input resistor (4). In use, the resistor (4) is separated from the regulating unit (3) and is mounted on a body of a piece of machinery, so that heat produced within the resistor is transmitted to that machinery, and does not interfere with the operation of the regulating unit (3). The regulating unit (3) employs a linear conversion circuit which produces a stable (DC) output but, unlike conventional DC-DC converters, generates substantially no stray electromagnetic fields.

Abstract: In a switching power supply generating at least a first output voltage and a second output voltage, the second output voltage, being of lower potential is applied to a linear regulator, the power supply further including a storage capacitor on the first output, a holdover circuit includes a comparator circuit for monitoring the first output voltage and for generating an output signal when the first output voltage decreases below predetermined value. A switch is connected to the storage capacitor, the comparator circuit, and the linear regulator. The switch is activated by the comparator output signal and applies the voltage stored in the storage capacitor to the linear regulator. A clamp circuit is connected to the switch for limiting the magnitude of the voltage from the storage capacitor to the linear regulator when the switch is activated.

Abstract: The invention concerns a back-up power supply of the type serving to compensate temporarily for an absence of a DC input voltage (Ve) from a main power supply (15) by delivering a voltage that is higher than a threshold value (Vmin) to a load (10). The main power supply (15) delivers the DC input voltage (Ve) to the load (10) under normal operating conditions, the DC input voltage (Ve) being higher than the threshold value (Vmin), and lying in the range defined by a minimum input voltage (Ve1) and by a maximum input voltage (Ve2). The back-up power supply includes a capacitor (13) charged by the DC input voltage (Ve). According to the invention, the back-up power supply includes means (20, 21) for limiting the charge on the capacitor (13) to a reference voltage (Vr) that is lower than the maximum input voltage (Ve2). The invention makes it possible to reduce the size and the cost of the capacitor (13) of the back-up power supply.

Abstract: A voltage regulator circuit for regulating an input voltage supply. The voltage regulator includes an n-channel transistor that has a gate and a source/drain region. The source/drain region of the transistor provides an output signal for the regulator circuit. The regulator circuit also includes a pull-up device that is coupled between a pumped voltage supply and a gate of the n-channel transistor. A pull-down device is also coupled between the gate of the n-channel transistor and ground potential. The voltage regulator also includes a level sensing circuit that is responsive to the gate of the n-channel transistor. The level sensing circuit generates a control signal for a control input of the pull-down device to provide feedback control of the n-channel transistor to regulate the output of the source/drain of the n-channel transistor.

Abstract: Power supply voltage step-down circuitry comprises a control unit for enabling either a first voltage step-down unit or a second voltage step-down unit according to a control signal applied thereto, a voltage checking unit for checking whether or not the value of a voltage generated by a power supply is equal to or greater than a predetermined value, and for furnishing a checking result signal at a predetermined level when the value of the voltage generated by the power supply is equal to or greater than a predetermined value, and a switching unit for connecting either the power supply or an output of the first step-down unit with a receiver, such as a ROM, according to whether or not the checking result signal from the voltage checking unit is at the predetermined level.

Abstract: A voltage regulator circuit (100), coupled between a high power supply voltage (VCC) and a lower power supply voltage (VSS), provides a regulated voltage (XDD) that is greater than the high power supply voltage (VCC). The voltage regulator circuit (100) includes a temperature compensating detect circuit (102) which activates a trigger signal when the XDD voltage exceeds a predetermined level. In response to an active trigger signal, a shunt circuit (104) couples the regulated voltage (XDD) to the high power supply voltage (VCC). The regulated voltage (XDD) is translated to the detect circuit (102) by the regulated voltage (XDD) being applied to the gate of a transistor (N112) disposed between the high power supply voltage (VCC) and a detect node (108). This arrangement allows monitoring of the regulated voltage (XDD) level without loading the regulated voltage (XDD).

Abstract: The circuits and methods of the present invention provide multiple-input, single-output, low-dropout voltage regulators that use at least two output stages to drive an output terminal that may be connected to an output load. An error amplifier may also be used to regulate the voltage provided by these output stages to the output terminal. In one embodiment, this error amplifier also is used in conjunction with detection and control circuitry to select the output stage or stages providing power to the output terminal. In other embodiments, only the detection and control circuitry is used to select the output stage or stages providing power to the output terminal. The regulators allow power to be provided by a primary power source regardless of the primary power source's voltage relative to other power sources by measuring the voltage provided at the output terminal or by detecting dropout in an output stage, rather than by comparing the voltages provided by the power sources.

Abstract: A voltage regulator that has a first mode circuit having a gating device and an amplifier, the gating device with a first input for receiving a first voltage, a second input, and an output. The amplifier is configured to receive a reference voltage and the gating device output as the second input. The gating device is configured to receive an amplifier output at said second input and responsive thereto to couple the first voltage with the gating device output when the gating device output is within a voltage range. The voltage regulator also has a second mode circuit having a voltage divider with an output. The voltage divider is configured to received the first voltage and supply a second voltage to the voltage divider output. The invention also relates to an integrated circuit having a power bus line and at least two voltage regulator cells coupled to the power bus line.

Abstract: A voltage generation circuit includes a voltage comparing circuit to compare a reference voltage signal Vi and an internal power supply voltage Vcc and a current supply transistor to supply current based on the output voltage of the voltage comparing circuit and maintain Vcc. The voltage generation circuit also includes a reference voltage signal generation circuit which responds to a control signal ACT activated for a prescribed time period prior to the operation timing of a load and sets Vi=Vref when control signal ACT is inactive and Vi=Vref+.DELTA.V when control signal ACT is active.

Abstract: A voltage regulator that has a first mode circuit having a gating device and an amplifier, the gating device with a first input for receiving a first voltage, a second input, and an output. The amplifier is configured to receive a reference voltage and the gating device output as the second input. The gating device is configured to receive an amplifier output at said second input and responsive thereto to couple the first voltage with the gating device output when the gating device output is within a voltage range. The voltage regulator also has a second mode circuit having a voltage divider with an output. The voltage divider is configured to received the first voltage and supply a second voltage to the voltage divider output. The invention also relates to an integrated circuit having a power bus line and at least two voltage regulator cells coupled to the power bus line.

Abstract: A voltage upconverter circuit wherein a switching voltage regulator circuit is used to charge a capacitor from a battery during an idle interval of portable phone transmission and wherein the charged capacitor is thereafter switched in series with the battery voltage for supply to a load during signal transmission, resulting in a smaller, less expensive and more efficient voltage upconverter circuit.

Abstract: An amplifier (32) is provided which allows for reduced system power dissipation. The amplifier (32) can dynamically draw power from different supply voltages in response to an input voltage signal. The amplifier (32) includes a plurality of complementary transistor pairs (40-46), where each transistor pair is coupled to a respective power supply. Each transistor pair provides output current when the input voltage signal is within a respective predetermined voltage range. This arrangement permits the amplifier (30) to interpolate between the supply voltages to generate a continuous amp output. System power is conserved by selecting the power supply which can most efficiently supply the required current within the voltage range.

Abstract: A voltage-current converter includes a signal voltage source (2), a series resistor (4) and an electronic circuit with a first transconductance amplifier (12) and a second transconductance amplifier (22). The corresponding inputs (16, 20; 24, 26) of the transconductance amplifiers (12, 22) are connected to receive a voltage difference (V.sub.A) between a node (18) and a reference terminal (8). The output (14) of the first transconductance amplifier (12) is connected to an input terminal (6) to which the series resistor (4) is connected as well. The output (25) of the second transconductance amplifier (22) is connected to an output terminal (10). Due to feedback around the first transconductance amplifier (12) an input current (i.sub.1) can flow into the input terminal (6). The input current (i.sub.1) is amplified or copied by the second transconductance amplifier (22) and is available at an output terminal (10). The input current (i.sub.

Abstract: A stable voltage regulator circuit of simple circuit configuration 174,222 includes a differential amplifier (M2, M3) which is powered from a supply line (1) at a nominal voltage level (Vin), by being coupled between the supply line and a return line (2). A reference device (M1) is coupled to a first input (4) of the differential amplifier (M2, M3) for defining a desired output voltage (Vca) on an output line (3) coupled to an output (6) of the differential amplifier (M2, M3). The differential amplifier (M2, M3) is coupled to the return line (2) by a varying current source (M4) which feeds a varying bias current to the differential amplifier (M2, M3) and which is controlled from the supply line (1) in accordance with variations in the nominal voltage level (Vin) on the supply line (1). The varying bias current to the differential amplifier (M2, M3) provides a first-order compensation of the output voltage (Vca) for these voltage variations on the supply line (1).

Abstract: A voltage regulator which has two regulation circuits and a comparator for controlling the two regulation circuits is disclosed. The input of the comparator is connected to a power supply voltage such that the output of the comparator changes states when the power supply voltage reaches a predetermined voltage of around 8 volts. The first regulation circuit is enabled to provide the Vcc from the battery voltage until the power supply voltage reaches around 8 volts which is when the comparator changes states. At that point, the first regulation is disabled and the second regulation circuit is enabled to provide the Vcc voltage from the power supply voltage. Since the power supply voltage never reaches the load dump high voltages, the second pass transistors never gets exposed to a high voltage condition. Also, the first transistor can withstand higher voltages since its base is grounded.

Abstract: A method and apparatus for using feedback to control the output voltage of a Switch Mode Power Supply (SMPS) that is used as the input voltage to subsequent Low Drop Out (LDO) linear voltage regulators. A multiplexer and Analog to Digital Converter (ADC) are used to successively sample the output voltages of multiple parallel LDO regulators. The digitized voltage values are input to a digital processor that compares the LDO regulator output voltages with acceptable limits previously stored in memory. The digitized voltage values are used by the digital processor to control the output voltage of a SMPS that is used as the input voltage to the LDO regulators. The output voltage of the SMPS, and thus the input of the LDO regulators, is reduced to the minimum value that retains full performance of the LDO regulators. Operating each LDO regulator at full regulation ensures full performance of the LDO regulators. Minimizing the input voltage to the LDO regulators maximizes the efficiency of the total power supply.

Abstract: A signal processing unit for a controller of a trolley pole switch is disclosed. The trolley pole switch switches the path of travel that an energy collector takes through the switch at a junction of catenaries at which a turn catenary and a straight catenary diverge from the straight catenary. The signal processing unit includes an input stage, a detection stage, turn and straight signal demodulation stages and an output stage. The input stage conditions modulated signals, each of which indicating a request to switch the path of travel through the trolley pole switch to the desired catenary diverging therefrom. The detection stage generates a validation signal if the conditioned modulated signal falls within a predetermined band. If the turn demodulation stage receives a conditioned modulated turn signal from the input stage and the validation signal from the detection stage simultaneously, it generates a low logic signal.

Abstract: A control circuit for controlling a DC current and an AC current through an acoustic transducer such as a ringer or a buzzer in a telephone. The control circuit comprises a current controlled output stage with an output terminal for the acoustic transducer, and a driver transistor of which a main current path drives the output stage. The driver transistor has a single control input for controlling both the DC current and the AC current through the acoustic transducer.

Abstract: A converter is provided for stepping-down a DC power input to produce a DC power output of lower voltage. The converter includes a regulating unit (3), and in series with it an input resistor (4). In use, the resistor (4) is separated from the regulating unit (3) and is mounted on a body of a piece of machinery, so that heat produced within the resistor is transmitted to that machinery, and does not interfere with the operation of the regulating unit (3). The regulating unit (3) employs a linear conversion circuit which produces a stable (DC) output but, unlike conventional DC-DC converters, generates substantially no stray electromagnetic fields.

Abstract: A voltage balancing device is to be used in a dc power supplying system which includes first and second power supplying units that are connected in series to supply power concurrently operate an electrical load. The first power supplying unit has a negative terminal and a positive terminal to be connected to the electrical load. The second power supplying unit has a positive terminal connected to the negative terminal of the first power supplying unit, and a negative terminal to be connected to a ground.

Abstract: A device for controlling a current to a load by means of mirroring is described. Two transistor units are connected to a common reference point. By driving a current through one of the transistor units, a corresponding current is generated in the second transistor unit. A control unit, connected between the transistors can regulate a voltage difference between transistors. Accordingly, the size of the load attached is determined through mirroring with accuracy and minimal power loss.

Abstract: The present invention provides a power amplifier operating with a single power supply. The amplifier includes at least one depletion-mode FET for amplifying an ac signal and a negative voltage generator for providing a bias to the FET. Preferably the amplifier further includes a negative voltage regulator to provide a regulated bias to bias the FET for a class A, AB or B operation. The negative generator includes a multivibrator for producing two clock signals and a charge pump which receives the clock signals and produces a negative voltage. Advantageously the negative voltage is provided as a low reference potential to the multivibrator so that the clock signals it produced include a negative voltage period, which enables the charge pump to operate in a power efficient manner.

Abstract: A programmable low dropout regulator includes an operational amplifier which is used both to provide a bandgap voltage and to drive an output load. In one embodiment implemented in an integrated circuit, external resistors are provided by the user to achieve a user-selected regulated voltage. In that embodiment, an input pin allows the user to select also internal resistors which provide a predetermined regulated voltage.

Abstract: A low dropout (LDO) voltage regulator for generating a well-regulated voltage which is stable with variations in load resistance and in supply voltage includes a non-complex reference voltage generator. In the preferred embodiment, the reference voltage generator is configured to function as an amplifier as well as a reference voltage generator. In one embodiment, a single gain stage LDO voltage regulator utilizes the single function reference voltage generator which is compared to a feedback voltage that is proportional to an output voltage. The feedback voltage and the reference voltage control two currents which are used to generate a control signal to a pass transistor. Depending on the supply voltage, the pass transistor either increases or decreases the current to an output terminal to raise or lower the output voltage until the output voltage equals the regulated voltage. In another embodiment, a two gain stage LDO voltage regulator utilizes the dual function reference voltage generator.

Abstract: A portable data device employs an integrated circuit having a signal processor that receives a power signal from an external source via a power node. A decoupling device is placed between the power node and the signal processor. An energy reservoir is placed in parallel with the signal processor, which acts in concert with the decoupling device to isolate the effects of the signal processor from the rest of the integrated circuit.

Abstract: A voltage regulator with a very low drop-out voltage. The regulator utilizes an inversely biased metal-oxid semiconductor field effect transistor as a regulating element. The field effect transistor is linearly controlled by an error amplifier which compares the regulated output with a reference voltage. The field effect transistor creates a voltage drop between the input and the regulated output by a diode function within the field effect transistor. The field effect transistor bypasses this diode function with a linearly controlled resistance function to thereby create a regulated output.

Abstract: A low drop-out regulator 16 includes an error amplifier 18 having a first input for receiving a reference voltage Vref, a second input, and an output, a pass element 22 having a control terminal coupled to the output of the error amplifier and a current path coupled between an input voltage Vin and an output terminal Vout, and a pair of resistors 24, 26 coupled in series between the output terminal Vout and ground. The second input of the error amplifier 18 coupled to a node B between the pair of resistors. The error amplifier provides an added pole/zero pair in the frequency response of the regulator.

Abstract: A voltage regulator circuit having a series device external to an integrated circuit voltage regulator. The external series device provides a voltage drop prior to the voltage being input to the voltage regulator during high power applications. Depending on the power level, low or high, one of two transistors will be activated. For low power applications, a transistor attached directly to the input voltage is active and the external series device is bypassed. For high power applications, the external series device provides a voltage drop prior to the input voltage reaching the second transistor thereby lowering the power to be dissipated by the integrated circuit.

Abstract: The invention is directed to a method for balancing a current controller for controlling a current. The current controller is configured to adjust the current to a desired value of current while considering an actual value of the current determined by a measurement. The current controller is balanced while considering the deviation between the real magnitude of the current and the actual value applied to adjust the current.

Abstract: A voltage regulator that has a first mode circuit having a gating device and an amplifier, the gating device with a first input for receiving a first voltage, a second input, and an output. The amplifier is configured to receive a reference voltage and the gating device output as the second input. The gating device is configured to receive an amplifier output at said second input and responsive thereto to couple the first voltage with the gating device output when the gating device output is within a voltage range. The voltage regulator also has a second mode circuit having a voltage divider with an output. The voltage divider is configured to received the first voltage and supply a second voltage to the voltage divider output. The invention also relates to an integrated circuit having a power bus line and at least two voltage regulator cells coupled to the power bus line.

Abstract: A voltage regulator with load pole stabilization is disclosed. An error amplifier has a non-inverting input receiving a reference voltage and an inverting input receiving a feedback voltage from the output of the voltage regulator. A gain stage has an input connected to the output of the error amplifier and an output connected to a pass transistor that provides current to a load. A variable impedance device such as a FET transistor configured as a variable resistor is connected between the input and output of the gain stage to provide variable zero to cancel the varying pole when the output current drawn by the load fluctuates. Consequently, the disclosed voltage regulator has high stability without a significant increase in power dissipation.

Abstract: A power status indicator and method of using the same. An apparatus utilizing a power status signal includes a circuit and a variable voltage supply. The circuit is capable of generating a power status signal indicating a power consumption mode in which the circuit operates. The variable voltage supply is coupled to receive the power status signal and to provide the circuit with a supply voltage which is a function of the power status signal.

Abstract: A self-biased power isolator system is disclosed that provides a fault tolerant power system without the need for auxiliary power. Enhancement-mode MOSFET 120 includes a drain coupled to a first node, a source coupled to a second node, and a gate. Amplifier 50 includes inputs for comparing the voltages from the first and second nodes and an output coupled to the gate of MOSFET 120 by which amplifier 50 controls the state of enhancement-mode MOSFET 120. Amplifier 50 further includes a positive power input coupled to the second node and a negative power input coupled to ground. In one embodiment, the first node is operable to be coupled to a power supply 10 and the second node is operable to be coupled to a load 18. A further embodiment allows the architecture to be replicated, each coupled at the second node to provide an N+1 fault tolerant power system.

Abstract: A voltage regulator circuit for regulating an input voltage supply. The voltage regulator includes an n-channel transistor that has a gate and a source/drain region. The source/drain region of the transistor provides an output signal for the regulator circuit. The regulator circuit also includes a pull-up device that is coupled between a pumped voltage supply and a gate of the n-channel transistor. A pull-down device is also coupled between the gate of the n-channel transistor and ground potential. The voltage regulator also includes a level sensing circuit that is responsive to the gate of the n-channel transistor. The level sensing circuit generates a control signal for a control input of the pull-down device to provide feedback control of the n-channel transistor to regulate the output of the source/drain of the n-channel transistor.