Abstract: In order to supply controlled DC voltages to a plurality of loads at high efficiency by using smaller number of components, a multiple output DC-DC converter in accordance with the present invention comprises a first main switch 21, one terminal of which is connected to the negative electrode of an input DC power source 1, a first rectifying means 51 and a first smoothing means 61 connected to the other terminal of the first main switch 21, a second main switch 22, one terminal of which is connected to the positive terminal of the input DC power source 1, a second rectifying means 52 and a second smoothing means 62 connected to the other terminal of the second main switch 22, an inductor 31 connected between the other terminal of the first main switch 21 and the other terminal of the second main switch 22, and a control circuit 81 for driving the respective switches at predetermined ON/OFF period ratios.

Abstract: Systems that monitor and control energy distribution manage energy distribution or use for Energy Service Providers and end-users. A system includes a publicly or privately accessible distributed network, a network access device, and a management device. The network access device communicates with the management device through the distributed network to control loads at a remote location. The method of monitoring and controlling energy distribution receives data at an on-line Site, processes an application program that evaluates load and market supply data, and initiates power curtailment requests or power curtailment events.

Abstract: A step-down switching voltage regulator with a push-pull output stage is adapted to provide a voltage converter with an auxiliary voltage rail that supplies an auxiliary voltage that is higher than the input supply voltage. The push-pull output stage of the step-down voltage regulator is used to drive a charge pump voltage-doubler circuit. In this way, a single integrated topology provides a regulated low voltage output as well as an auxiliary high voltage output. The circuit topology enables a low component count resulting in lower component cost and smaller physical size.

Abstract: A multiple output voltage power supply includes a transformer having a primary winding and a plurality of secondary windings. The primary winding is adapted to have an input voltage coupled thereto. A primary side switch is coupled to the primary winding and is adapted to control power applied to the transformer in a power cycle responsive to a peak current mode control signal. A plurality of output circuits are coupled to respective ones of the plurality of secondary windings and provide respective output voltages. The plurality of output circuits each further includes a forward rectifier adapted to rectify power during a positive portion of the power cycle and a free-wheeling rectifier adapted to rectify power during a negative portion of the power cycle. One of the plurality of output circuits further includes a bypass switch adapted to interrupt operation of the respective forward rectifier. A secondary side post regulation circuit controls operation of the bypass switch.

Abstract: The converter uses the energy stored in the output filter of a step-down (or buck) converter and in the inductor of a step up/down (or buck-boost) converter to supply a second output of opposite sign. In particular, the converter has a first input receiving an input voltage; a first output supplying a first output voltage of a first sign; a second output supplying a second output voltage of opposite sign; a controlled switch connected between the first input and a first intermediate node; an inductor connected between the first intermediate node and the first output; a diode connected between the first intermediate node and a second intermediate node; and a dual voltage generating circuit connected between the second intermediate node and the second output.

Abstract: A charge pump power converter efficiently provides electrical power by dynamically controlling a switch matrix of the charge pump. Instead of open-loop oscillator-based control, a dynamic controller provides power upon demand by sensing the output voltage and changing the operating frequency of the charge pump in response. Moreover, this closed-loop dynamic control intrinsically voltage regulates the output voltage of the charge pump power converter without the inefficient addition of a step-down voltage regulator, downstream of the power converter. Additional efficiencies are achieved through maintaining the voltage ripple across the fly capacitor and/or the load capacitor. Also, a three-state control scheme is used to charge the fly capacitor, wait for the output voltage to drop to a predetermined level, and discharge the fly capacitor. Furthermore, a multiple-output charge pump power converter provides multiple voltage levels for devices such as portable communication electronic devices.

Abstract: A multi-output DC/DC converter (1;10;30;40;50;60), comprising inductive electrical energy storage means (L), switching means (S0-S7) and control means (6;9;31;41;51;61). The control means (6;9;31;41;51;61) are arranged for selectively operating the switching means (S0-S7) for transferring an amount of electrical energy from the energy storage means (L) to an output (A;B;C;D) of the DC/DC converter (1;10;30;40;50;60) providing an output voltage in accordance with a switching sequence based on comparing, by the control means (6;9;31;41;51;61) of the output voltage of each output (A;B;C;D) with an associated reference voltage.

Abstract: A switching power supply unit includes a control output circuit, a non-control output circuit, and a regulator circuit. With this switching power supply unit, it is no longer necessary to set the voltage of the non-control output to be greater than a required value when the control output circuit is unloaded or lightly loaded. The regulator circuit is connected to the non-control output circuit and includes a first transistor defining a first impedance element connected in series to the non-control output circuit, a second transistor defining a second impedance element connected between the control output circuit and the base of the first transistor, and a voltage control circuit controlling the impedance of the second transistor such that the output voltage of the regulator circuit is maintained constant.

Abstract: The present invention provides a multi-output DC-DC converter which supplies an input direct voltage to a series circuit consisting of a primary winding (3a) of a transformer (3) and a switching circuit (2) to obtain first and second output direct voltages from a secondary winding (3b) of the transformer (3) via first and second rectifying circuits, wherein a switching signal of the switching circuit (2) is controlled corresponding to the first output direct voltage so that the first output direct voltage is caused to be constant, and a variable reactor (10) is inserted into the second rectifying circuit. Thus, loss of power can be reduced in a simplified configuration.

Abstract: A DC/DC converter (1; 20), comprising inductive electrical energy storage means (L), switching means (S1-S4) and means (6; 15) wherein said control means (6; 15) are arranged for selectively operating said switching means (S1-S4) for transferring an amount of electrical energy from said energy storage means (L) to an output of said DC/DC converter (1; 20), for providing a desired output voltage (Vout), characterized by digital control means (6; 15) which are configured for operatively controlling said switching means (S1-S4) for transferring electrical energy in accordance with a switching sequence comprising a ramp-up switching cycle and a ramp-down cycle for substantially charging and decharging of the energy storage means (L).

Abstract: A power control system and method of power control, the system consists of a power transformer having a primary portion and a secondary portion and a wiring run having a length and coupled at one end to the secondary portion. Also included is a constant voltage controller coupled to another end of the wiring run. The constant voltage controller receives an input power signal from the power transformer and outputs an output power signal at a specified voltage level to a plurality of low voltage electrical loads. The input power signal is at a higher voltage level than the specified voltage level and the output power signal is maintained at the specified voltage level regardless of a change in a voltage drop of the power control system. In preferred embodiments, the system uses low power logic rectifiers to rectify AC power signals to provide reset, current feedback and voltage feedback signals.

Abstract: The present invention provides a circuit and method having a fast response time for generating a regulated voltage from a first voltage source. The circuit includes a driver for generating a drive signal. The driver has a clock input coupled to a clock signal. A charge pump that has a first voltage input coupled to the first voltage source. In response to the drive signal, the charge pump provides a pump voltage that is boosted from the first voltage. An amplifier has a reference input coupled to a reference voltage, a sense input coupled to a sense signal representative of the pump voltage, and an output. The amplifier is operable in response to a difference between the reference voltage and the sense signal, to control the driver. A switch is coupled from the amplifier output to an output of the charge pump such that the pump voltage is controllably boosted by the amplifier output through the switch.

Abstract: A multiple output voltage power supply comprises a transformer having a primary winding and a plurality of secondary windings. The primary winding is adapted to have an input voltage coupled thereto. A primary side switch is coupled to the primary winding and is adapted to control power applied to the transformer in a power cycle responsive to a peak current mode control signal. A plurality of output circuits are coupled to respective ones of the plurality of secondary windings and provide respective output voltages. The plurality of output circuits each further comprises a forward rectifier adapted to rectify power during a positive portion of the power cycle and a free-wheeling rectifier adapted to rectify power during a negative portion of the power cycle. One of the plurality of output circuits further comprises a bypass switch adapted to interrupt operation of the respective forward rectifier. A secondary side post regulation circuit controls operation of the bypass switch.

Abstract: A power supply is provided. The power supply is comprised of a first power module, a second power module, and a controller. The first power module is capable of delivering a first preselected amount of power. The second power module is capable of delivering a second preselected amount of power. The first and second power modules are coupled together to be capable of delivering an aggregate amount of power related to the first and second preselected amounts of power. The controller is adapted to selectively enable the first and second power modules to make power available in one of the first preselected amount, the second preselected amount, and the aggregate amount.

Abstract: A voltage regulator is provided for taking an input voltage and providing a multiple of output voltages of differing voltage values. The voltage regulator includes a power switch and an inductor for providing inductor current to various output nodes. Control switches and a decision logic block are used to regulate the flow of inductor current to the output nodes, in accordance with predetermined values stored in the decision logic block. In one exemplary arrangement, the voltage regulator may provide a multiple of positive and negative voltage outputs. In another arrangement, the voltage regulator may provide a multiple of positive or negative voltage outputs or both.

Abstract: To provide a switching power supply unit that is configured in that a stand-by power supply does not stop before a main power supply does at the time of cutting an AC input without having excesses of capacity and a power-factor improvement circuit that is not fundamentally necessary, provided is a back-up circuit 140 that supplies the direct current output obtained by a main rectifying and smoothing circuit 111 of a main power supply circuit 110 to a sub converting circuit 122 of a stand-by power supply circuit 120.

Abstract: A regulator for supplying the power of internal circuits, which makes the power of internal circuits independent of the voltage of the outlet power supply by using multi-stage method to control the power supplied from the outlet power source, and avoids the dropping of voltage to affect the system operation. The voltage is able to return to the normal voltage level quickly by increasing the voltage level of the internal circuits in advance, and make the voltage of the internal power supply reduce the variation when output and return to normal voltage level quickly when charge by dynamic adjusting the loading in the regulator.

Abstract: A power control system for a display apparatus comprises: a reactor, including a pair of inductors, for calibrating a power factor of an AC voltage supplied from an external source; a rectifier for rectifying the AC voltage having the power factor calibrated by the reactor; a power supply for outputting the rectified voltage with a plurality of voltage levels so as to allow them to be supplied to a power-consuming component; a switch unit for selectively connecting the pair of inductors in series or in parallel based on a driving power according to the levels of the AC voltage supplied to the reactor; and a microcomputer for determining whether a DPMS is in an off mode so as to cut off the power supply to the component, and for cutting off the power supply to the switch unit when it is in the off mode. With this configuration, since the power supply to the switch unit is cut off in the off mode, power consumption in the off mode can be minimized.

Abstract: An arrangement and method for protecting a multiple voltage supply system against voltage arc-over between the different voltage planes. For this, the voltage in the low-voltage plane of the supply system is clamped to the low-voltage value with a voltage limiter until a battery disconnect switch in the high-voltage plane of the supply system is opened and the generator output voltage in the high-voltage plane is adjusted back to the voltage value of the low-voltage plane. As a result, the high-voltage plane of the supply system is disconnected from the high-voltage sources. Consequently, the voltage in the low-voltage plane is prevented from increasing even in case of a short-circuit between both voltage planes of the supply system and the consumers in the low-voltage plane can continue to be operated safely.

Abstract: A main-output circuit section includes a synchronous rectifying circuit composed of a NMOS, therefore, even if a load RL1 become light, a rise of direct current output voltage is prevented without a dummy resistor and electric dummy circuit, accordingly, when a NMOS is in an ON state, an abrupt narrowing of a time width does not occur. Therefore the product of voltage and time is ensured, direct current output voltage is easily produced stably.

Abstract: The converter uses the energy stored in the output filter of a step-down (or buck) converter and in the inductor of a step up/down (or buck-boost) converter to supply a second output of opposite sign. In particular, the converter has a first input receiving an input voltage; a first output supplying a first output voltage of a first sign; a second output supplying a second output voltage of opposite sign; a controlled switch connected between the first input and a first intermediate node; an inductor connected between the first intermediate node and the first output; a diode connected between the first intermediate node and a second intermediate node; and a dual voltage generating circuit connected between the second intermediate node and the second output.

Abstract: A power supply according to the principles of the inventions comprises two stages. The first stage is a power factor corrector stage. This stage provides the required line regulation, including greater than 95% power factor correction, and provides a range of outputs from approximately 5 volts to 200 volts with good load regulation at low voltages. The second stage is a soft switching power supply having good load regulation from approximately 40 to approximately 175 volts. An intermediate high voltage of the first stage supplies the input to the second stage, thereby achieving extremely good line regulation and low regulation.

Abstract: A method and system for measuring the capacitance of a backup power source in a backup power supply system is disclosed by the present invention. The regulated output voltage is set to a nominal regulated output voltage during normal operation and then adjusted to a predetermined regulated output voltage during a capacitance measurement. A pair of predetermined loads is connected to the backup power source in consecutive order for discharging energy from the backup power source. A counter is used to count the time that elapses before the regulated output voltage reaches the lower regulated output voltage or the backup power supply system begins regulating. The resulting counts are used by a main control unit, together with several other known values, to determine the capacitance of the backup power source.

Abstract: The switching transistors in multiple switching regulators sharing the same input power source are coordinated to lower the peak current drain on the input power source. The turn on times of the transistors in each regulator are set so that each switching transistor turns on at a predetermined time in a cycle. The predetermined time for each regulator is chosen so that the maximum peak current drain on the input power source is minimized. The predetermined times may be changed on-the-fly by inputs to the system when information about current or projected output loads are known. The transistors in each regulator may also be turned on when the transistor in the previous regulator in a sequence turns off. Another embodiment lets the regulator with the largest change in input current over a cycle run independently. The other regulators then switch in a designated order, or at designated times after the first regulator turns its switch off.

Abstract: A DC/DC converter (10; 30; 40; 50; 60), comprising inductive energy storage means (2), switching means (S0-S7) and control means (9; 31; 41; 51; 61), wherein said control means (9; 31; 41; 51; 61) are arranged for selectively operating said switching means (S0-S7) for providing electrical energy from said energy storage means (2) to an output (A; B; C; D) of said DC/DC converter (10; 30; 40; 50; 60) in both a Pulse Width Modulation (PWM) mode and a Pulse Frequency Modulation (PFM) mode switching cycle.

Abstract: The present invention provides a regulator used in an active terminator of a bus. The regulator comprises a voltage-regulated terminal, a first operational amplifier and a non-inverting input terminal thereof coupled to a reference voltage. An inverting input terminal of a second operational amplifier is coupled to the reference voltage. A control gate of a first transistor is coupled to an output terminal of the first operational amplifier. A source of the first transistor is coupled to an inverting input terminal of the first operational amplifier to form a feedback network and to provide a stable circuit of sourcing current. A control gate of a second transistor is coupled to an output terminal of the second operational amplifier and a drain of the second transistor to a non-inverting input terminal of the second operational amplifier to form the feedback network and to provide a stable circuit of sinking current.

Abstract: A power control system and method of power control, the system consists of a power transformer having a primary portion and a secondary portion and a wiring run having a length and coupled at one end to the secondary portion. Also included is a constant voltage controller coupled to another end of the wiring run. The constant voltage controller receives an input power signal from the power transformer and outputs an output power signal at a specified voltage level to a plurality of low voltage electrical loads. The input power signal is at a higher voltage level than the specified voltage level and the output power signal is maintained at the specified voltage level regardless of a change in a voltage drop of the power control system. In preferred embodiments, the system uses low power logic rectifiers to rectify AC power signals to provide reset, current feedback and voltage feedback signals.

Abstract: A multi-output DC/DC converter (1; 10; 30; 40; 50; 60), comprising inductive electrical energy storage means (L), switching means (S0-S7) and control means (6; 9; 31; 41; 51; 61). The control means (6; 9; 31; 41; 51; 61) are arranged for selectively operating the switching means (S0-S7) for transferring an amount of electrical energy from the energy storage means (L) to an output (A; B; C; D) of the DC/DC converter (1; 10; 30; 40; 50; 60) providing an output voltage in accordance with a switching sequence based on comparing, by the control means (6; 9; 31; 41; 51; 61) of the output voltage of each output (A; B; C; D) with an associated reference voltage.

Abstract: The invention provides a new hybrid 4-in-1 power controller chip for a PC mainboard which integrates a synchronous buck switching regulator to supply the CPU core voltage, a standard buck switching regulator for I/O circuits, a linear controller for the GTL bus, and a linear regulator with built-in pass transistor for a clock generator. On this basis, a hybrid power system for a PC mainboard is constructed.

Abstract: A power supply for a computer is disclosed. The power supply is capable of providing power in both a DC domain and a high frequency AC domain. A first power consuming component can be coupled to the power supply to receive power in the DC domain, and a second power consuming component can be coupled to the power supply to receive power in the high frequency AC domain.

Abstract: A power control system for a display apparatus comprises: a reactor, including a pair of inductors, for calibrating a power factor of an AC voltage supplied from an external source; a rectifier for rectifying the AC voltage having the power factor calibrated by the reactor; a power supply for outputting the rectified voltage with a plurality of voltage levels so as to allow them to be supplied to a power-consuming component; a switch unit for selectively connecting the pair of inductors in series or in parallel based on a driving power according to the levels of the AC voltage supplied to the reactor; and a microcomputer for determining whether a DPMS is in an off mode so as to cut off the power supply to the component, and for cutting off the power supply to the switch unit when it is in the off mode. With this configuration, since the power supply to the switch unit is cut off in the off mode, power consumption in the off mode can be minimized.

Abstract: An electric power distributor is mountable on a motor vehicle for distributing power from a power source installed in the motor vehicle to a plurality of electric load units equipped in the vehicle, and is provided with an input conductive strip having an input terminal at one end thereof, a plurality of output conductive strips each having an output terminal at one end thereof, an insulating holder for holding the input conductive strip and the output conductive strips on the same plane, and a plurality of semiconductor switching elements. The input terminal and the output terminals are projected in the same direction substantially orthogonal to the plane of the insulating holder.

Abstract: The invention provides a circuit for supplying electric power to a load using a high voltage battery, the circuit supplying a dark current when the load is not being operated. A high voltage load and a low voltage load are attached to a battery and electric power is supplied to the low voltage load through a main DC-DC converter and a sub DC-DC converter. When an ignition switch is OFF, only the sub converter supplies the dark current to the low voltage load and the main DC-DC converter is turned OFF. When the ignition switch is ON, the main DC-DC converter supplies required electric power. Since a low-capacity sub DC-DC converter supplies the dark current, the battery discharge can be prevented.

Abstract: To accomplish low power consumption of a semiconductor memory device, an internal voltage generating apparatus of the present invention applies an internal power voltage having the lower potential level as an operation voltage of a chip. By differentiating the internal power voltage for each of a peripheral circuit and a core circuit within a DRAM to use them as an operational voltage of the cell, i.e., by supplying the lowered internal power voltage to the core circuit unit, the reliability of the cell and noise characteristic is improved.

Abstract: A high efficiency light emitting diode (LED) driving circuit includes a first LED coupled in a forward current path between first and second nodes and a second LED being coupled in a reverse current path between the second and first nodes. A power supply is drives the first node with voltage pulses. A capacitor is coupled to the second node and stores charge while the power supply is driving the first LED in the forward current path during voltage pulses. A discharge circuit drains charge from the capacitor to drive the second LED in the reverse current path between voltage pulses.

Abstract: A multiple output regulating charge pump includes a load current regulator to balance currents in multiple branches of at least one load, such as light emitting diodes in a parallel configuration. The load current regulator includes current mirror circuits to provide substantially identical currents to the respective light emitting diodes, thereby producing uniform light from each of the light emitting diodes. The multiple output charge pump includes a charge storage component that is alternately charged during a charge cycle and discharged during a discharge cycle. The charge pump provides current to a second load during the charge cycle and to a first load during a discharge cycle.

Abstract: A main-output circuit section includes a synchronous rectifying circuit composed of a NMOS, therefore, even if a load RL1 become light, a rise of direct current output voltage is prevented without a dummy resistor and electric dummy circuit, accordingly, when a NMOS is in an ON state, an abrupt narrowing of a time width does not occur. Therefore the product of voltage and time is ensured, direct current output voltage is easily produced stably.

Abstract: A structure and related method for generating phase enable signals for a multi-phase switching power supply with the characteristic that each signal has the same frequency, but each differs in phase relationship. The structure includes a clock circuit coupled to a shift register and clocking the shift register. The shift register has one of its outputs coupled to its shift input signal line. Clocking of the shift register with the clock circuit produces a series of phase enable signals, at the shift register's shift output signal lines, to be coupled to switching phases of a multi-phase switching power supply. The circuit easily adapts to varying number of phases of the multi-phase switching power supply by changing which of the several shift output signals couples back to the shift input signal.

Abstract: A rail tracking system and method for providing precise tracking of voltage levels to a dual supply voltage Integrated Circuit. A switch mode DC-DC voltage regulator is used to derive the lower of the two voltage levels from the higher level. The switch mode regulator employs a pulse width modulator (PWM) to derive the lower voltage level. A separate supply source is utilized to power the PWM and the timing of the supply voltage is such that the PWM has reached steady state before the higher voltage level is provided to the regulator.

Abstract: The switching transistors in multiple switching regulators sharing the same input power source are coordinated to lower the peak current drain on the input power source. The turn on times of the transistors in each regulator are set so that each switching transistor turns on at a predetermined time in a cycle. The predetermined time for each regulator is chosen so that the maximum peak current drain on the input power source is minimized. The predetermined times may be changed on-the-fly by inputs to the system when information about current or projected output loads are known. The transistors in each regulator may also be turned on when the transistor in the previous regulator in a sequence turns off. Another embodiment lets the regulator with the largest change in input current over a cycle run independently. The other regulators then switch in a designated order, or at designated times after the first regulator turns its switch off.

Abstract: A voltage regulator is provided for limiting overcurrents when used with a plurality of loads, particularly in flash memories, which are connected between an output node of the regulator and a voltage reference by way of a plurality of switches. The voltage regulator includes at least one differential stage that has a non-inverting input terminal for a control voltage, and an inverting input terminal connected to the voltage reference and the output node of the regulator through a feedback network. There is an output terminal connected to the output node of the voltage regulator to produce an output reference voltage from a comparison of input voltages. In the voltage regulator is a main control transistor connected between a high-voltage reference and the output terminal of the regulator.

Abstract: A low cost, multiple output buck converter is provided using a single inductor, a single pulse width modulator integrated circuit, and two MOSFETs plus one additional MOSFET and capacitor for each voltage output.

Abstract: A dual supply device having a reference terminal, an input terminal for the application of a substantially constant input voltage relative to the reference terminal, a first output terminal for supplying a first supply voltage different from the input voltage, a second output terminal for supplying a second supply voltage substantially opposite to the first supply voltage a direct-current/direct-current converter connected between the input terminal and the first output terminal for converting the input voltage into the first supply voltage, and a capacitive translator connected between the first and second output terminals for translating the first supply voltage into the second supply voltage.

Abstract: A voltage-switching regulator with built-in voltage-switching module is provided, which is capable of supplying a terminal voltage to a memory unit operating under DDR (DRAM of Double Rate) mode. The voltage-switching regulator is implemented as a single IC chip with a built-in voltage-switching module, and is capable of generating a terminal voltage in response to an input reference voltage and transferring the terminal voltage via a transmission logic line to the memory unit operating under DDR mode. The terminal voltage is pulled up when the voltage-switching module supplies a drive current and is pulled down when the voltage-switching module supplies a sink current. This allows the memory unit to be operated under DDR mode.

Abstract: A computer storage system includes director boards which control transfer of data to and between a host computer, a system cache memory and a disk array. The directors are provided with features which enhance system performance and reliability. A hardware emulation controller permits a high performance processor to be used with existing system circuitry. A control store memory is organized with primary and secondary data areas and primary and secondary parity areas. Data is written to both the primary and secondary areas. A read request accesses data in the primary area and performs a retry in the secondary area in the event of a parity error. A power supply system includes on-board marginable power supplies to facilitate testing and power-up by-pass circuits for protection of sensitive circuitry. A system clock configuration employs primary and secondary clocks to ensure redundancy of synchronized timekeeping.

Abstract: A electric power conversion unit generates a DC output according to a pulse signal from a PWM unit. An A/D conversion unit converts the output voltage from the electric power conversion unit into digital data. A digital filter amplifies the difference between the digital data output from the A/D conversion unit and a reference value. A pulse width computation unit computes the on-time of a pulse signal provided to the electric power conversion unit based on the output from the digital filter. The on-time is written to an on-time register. The PWM unit generates a pulse signal according to the cycle set in a cycle register and the on-time written to the on-time register, and provides the signal to the electric power conversion unit.

Abstract: A power switching and voltage regulation system utilizing a conventional switching element to provide distributed power switching and voltage regulation. The system utilizes a switching element to impose an impedance in a controlled manner to provide power to a load such as a plug-in module in an electronic apparatus. The power source supplying an input DC voltage is intentionally set to a higher voltage than the level required by the plug-in module. The voltage supplied is required to be sufficiently high such that the voltage delivered to the plug-in module, exceeds the maximum permitted voltage level of the voltage required by the particular plug-in module. Once the switching device is turned on, the switching element exerts an impedance which functions to drop the voltage supplied to the load to the required value. The impedance is generated in accordance with a feedback control signal.

Abstract: A power source circuit which is suitable as a power source for use in driving a liquid crystal display, wherein on the basis of the power source electric potentials (VDD, VEE), the voltage is divided by voltage dividing resistors (R1 to R5), and passes through operational amplifiers (OP1 to OP4) that comprise voltage followers, so that output electric potentials (V1 to V5) are output. The power source electric potential (VDD) and the intermediate electric potential (Va) which is output from a voltage dividing circuit (S) are supplied to the operational amplifiers (OP1, OP2), and the intermediate electric potential (Va) and the power source electric potential (VEE) are supplied to the operational amplifiers (OP3, OP4).

Abstract: A rail tracking system and method for providing precise tracking of voltage levels to a dual supply voltage Integrated Circuit. A switch mode DC—DC voltage regulator is used to derive the lower of the two voltage levels from the higher level. The switch mode regulator employs a pulse width modulator (PWM) to derive the lower voltage level. A separate supply source is utilized to power the PWM and the timing of the supply voltage is such that the PWM has reached steady state before the higher voltage level is provided to the regulator.

Abstract: A power supply for supplying a main electrical circuit during normal operation and an auxiliary electrical circuit during standby operation, includes a switched power converter, which is connected between an input voltage and the main electrical circuit and has an inductor, a controllable switch, a first rectifying unit and a control unit for the switch. A second rectifying unit couples the voltage dropping across the inductor into the auxiliary electrical circuit. During standby operation, the control unit controls the switch in such a way that the switched power converter is operated in resonance mode.