Abstract: A voltage converter for fast load transient response adapted for a boost type voltage converter determines whether a transient state occurs, that is, whether a load is converted from a heavy load to a light load, according to a transient detection circuit. When the transient state occurs, an inductive current quickly drops to a corresponding current value to accelerate the rate of an output voltage returning to a stable voltage value, and to shorten a time of load transient response, so as to avoid affecting the performance of a load, especially a sensitive load.

Abstract: A power supply system having a detection system for determining an unbalanced current condition and an over-current condition in a DC-DC voltage converter is provided. The detection system has a detection circuit that outputs a first diagnostic voltage indicating an unbalanced current condition between first and second switching banks in the DC-DC voltage converter based on a first voltage and an average voltage, or an over-current condition in the first switching bank based on the first voltage. The detection circuit outputs a second diagnostic voltage indicating the unbalanced current condition between the first and second switching banks in the DC-DC voltage converter based on a second voltage and the average voltage, or an over-current condition in the second switching bank based on the second voltage.

Abstract: In some examples, a device includes control circuitry configured to receive a first input signal, receive a second input signal, and cause gate driver circuitry to deliver a driver signal to a switch to cause the switch to deliver electrical power to an electrical load. In some examples, the control circuitry is further configured to determine whether the first input signal has an active value and determine whether the second input signal has an active value. In some examples, the control circuitry is also configured to cause the gate driver circuitry to change the driver signal across a switching cycle of the switch to increase or decrease the electrical power delivered by the switch to the electrical load in response to determining that the first input signal has the active value or in response to determining that the second input signal has the active value.

Abstract: The present application relates to the field of circuit design, and discloses a DC-DC conversion circuit system and a forming method thereof. The system may include a primary switch circuit, a charge/discharge circuit, and a secondary switch circuit. The primary switch circuit includes a voltage supply end configured to receive a first direct current voltage and an output end. The charge/discharge circuit includes an input end connected to the output end of the primary switch circuit, and a first output end configured to output a second direct current voltage. The secondary switch circuit includes a voltage supply end configured to receive the first direct current voltage, and an output end connected to the output end of the primary switch circuit. The primary switch circuit is configured to control the charge/discharge circuit to charge or discharge.

Abstract: Various embodiments of the present technology may comprise methods and apparatus for an integrated circuit (IC). The methods and apparatus may comprise an integrated circuit comprising a sensor circuit and a driver circuit coupled to the sensor circuit. The driver circuit may include an amplifier configured to generate a bias voltage, a signal converter circuit coupled to the amplifier, and a control circuit coupled to the amplifier. The control circuit may comprise a switch responsive to a control signal and a transistor coupled to the switch.

Abstract: Systems and methods are provided for signal processing. An example error amplifier for processing a reference signal and an input signal associated with a current of a power conversion system includes a first operational amplifier, a second operational amplifier, a first transistor, a second transistor, a current mirror component, a switch, a first resistor and a second resistor. The first operational amplifier includes a first input terminal, a second input terminal and a first output terminal, the first input terminal being configured to receive a reference signal. The first transistor includes a first transistor terminal, a second transistor terminal and a third transistor terminal, the first transistor terminal being configured to receive a first amplified signal from the first output terminal, the third transistor terminal being coupled to the second input terminal.

Abstract: Systems and methods are provided for voltage regulation of power conversion systems. An example system controller includes: a first sampling component configured to sample a sensing signal and determine a compensation signal based on at least in part on the sensing signal, the sensing signal being associated with a first current flowing through a primary winding of a power conversion system; a signal processing component configured to receive a feedback signal and the compensation signal and generate a first signal based at least in part on the feedback signal and the compensation signal, the feedback signal being associated with an auxiliary winding coupled with a secondary winding of the power conversion system; an error amplifier configured to receive the first signal and a reference signal and generate an amplified signal based at least in part on the first signal and the reference signal.

Abstract: Soft switching in Boundary Conduction Mode (BCM) flyback converters using a fixed dead time is presented. Embodiments disclosed herein relate to switching circuits and more particularly to soft switching in single stage isolated flyback converters with single switch. Embodiments herein disclose systems for soft switching in single stage isolated flyback converters by combining selection of transformers turn ratio and by incorporating the fixed dead time.

Abstract: A method for controlling a power converter switch includes operating the power converter switch in first, second, and third duty cycle control modes in response to a feedback signal representative of an output of the power converter. The first duty cycle control mode includes modulating a peak switch current of the power converter switch in response to the feedback signal, and switching the power converter switch at a substantially fixed first switching frequency value. The second duty cycle control mode includes modulating the switching frequency in response to the feedback signal, and maintaining the peak switch current substantially at a peak switch current threshold value. The third duty cycle control mode includes modulating the peak switch current of the power converter switch in response to the feedback signal, and switching the power converter switch at a substantially fixed second switching frequency value.

Abstract: A method and apparatus for secondary side current mode control of a converter are provided. In the method and apparatus, an output voltage of the converter is detected, where the converter has primary and secondary windings that are galvanically isolated in respective primary and secondary sides. A secondary control signal is generated in the secondary side based at least in part on the output voltage and a reference voltage. The secondary control signal is converted to a primary control signal provided in the primary side. The converter is driven in the primary side based at least in part on the primary control signal and a current sense signal indicative of a current flowing through the primary winding.

Abstract: A first winding, a second winding, a fourth winding, and a fifth winding functioning as a transformer are wound around respective side legs of a three-leg core. Third windings functioning as a DC reactor are wound around a center leg. Winding directions of the first winding, the second winding, and the third windings are set so that magnetic fluxes generated by DC currents flowing through the respective windings merge in the same direction at the center leg, and winding directions of the fourth winding and the fifth winding are set so that magnetic fluxes generated by AC currents flowing through the respective windings cancel each other at the center leg. Thus, the transformer and the DC reactor are integrated using the three-leg core, whereby size reduction and loss reduction of the integrated magnetic component are achieved.

Abstract: Disclosed is an integrated transformer used in a resonant converter. The integrated transformer includes a primary side circuit, a secondary side circuit and an integrated core. A first voltage received by the primary side circuit is converted to a second voltage due to the electromagnetic induction, and the second voltage is outputted by the secondary side circuit. The primary side circuit is configured on the integrated core. The integrated core includes many iron rings, and the iron rings have a common side. The common side of the iron rings is a center column of the integrated core, and the other sides of the iron rings are rim columns of the integrated core. The coils of the primary side circuit are configured respectively to the rim columns of the integrated core, and the coils of the primary side circuit are connected in serial.

Abstract: A direct current (DC) to DC power converter includes a first bus converter for converting a first DC bus voltage into a first high frequency AC voltage and a second bus converter for converting a second high frequency alternating current (AC) voltage into a second DC bus voltage. The DC to DC converter also includes a resonant circuit for coupling the first bus converter and the second bus converter and a controller for providing switching signals to the first bus converter and the second bus converter to operate the power converter in a soft switching mode. The controller includes a switching frequency controller for determining a switching frequency signal for the power converter based on a reference output current and a phase shift controller for determining a phase shift signal for the power converter.

Abstract: A control board of a power conversion device, the control board includes a board main body, a plurality of drive circuits, a power source control circuit, an insulation region, a plurality of insulation transformers, and a connecting line that electrically connects the plurality of insulation transformers and the power source control circuit to each other, and at least a part of which extends in a region in inner layers of the board main body that overlaps the insulation region when viewed in a perpendicular direction with respect to the surface of the board main body.

Abstract: A data processing device in a high voltage direct current (HVDC) transmission system is provided. The data processing device includes a measurement module measuring a voltage or current for one or more points in the HVDC system; a data processing unit generating measurement data units using measurement values measured at the measurement module; and a communication module using wavelength division multiplexing to transmit the measurement data units to the outside through one optical fiber, wherein the optical fiber includes a plurality of cores.

Abstract: According to one aspect, embodiments herein provide a DC-AC inverter comprising a DC-DC converter portion, an inverter portion, a clamp circuit, a controller configured to operate, in a first mode, the DC-DC converter portion to convert input DC power into DC power having a desired voltage level at a first polarity and the inverter portion to provide output power having the desired voltage level at the first polarity to the output, operate, in a second mode, the DC-DC converter portion to convert the input DC power into DC power having a desired voltage level at a second polarity and the inverter portion to provide output power having the desired voltage level at the second polarity to the output; and operate, in a third mode, the clamp circuit to drive voltage at the output to zero and to store energy discharged by a load capacitance in an energy storage device.

Abstract: A non-polar rectifying circuit includes two input terminals, two output terminals, two P-channel MOS transistors, and two N-channel MOS transistors. The two input terminals are respectively connected with a drain of one of the two P-channel MOS transistors and a drain of one of the two N-channel MOS transistors. One of the output terminals is electrically connected with the source of two P-channel MOS transistors, and the other output terminal is electrically connected with the source of two N-channel MOS transistors. In application, regardless of the two input terminals which is the positive polarity or negative polarity, one of the output terminals will output high level, and another will also output low level. As a result, it make the power plug no need to divide the positive and negative, which can reduce the installation time of LED lamps, especially for installing a large number of LED lightings.

Abstract: A direct-current power supply device includes a first capacitor and a second capacitor connected in series between output terminals to a load, a charging unit including a first switching element that switches charging and non-charging of the first capacitor, a second switching element that switches charging and non-charging of the second capacitor, a first backflow preventing element that prevents charged electric charges of the first capacitor from backflowing to the first switching element, and a second backflow preventing element that prevents charged electric charges of the second capacitor from backflowing to the second switching element, and a control unit that controls the first backflow preventing element to an ON state at timing when the charging of the first capacitor is started and controls the second backflow preventing element to the ON state at timing when the charging of the second capacitor is started.

Abstract: Provided is a power conversion device including: a step-up converter unit, including a reactor to which a DC voltage is to be input, a switching element connected to the reactor in parallel, and a backflow prevention element connected to the reactor in series; a smoothing capacitor configured to smooth an output voltage from the step-up converter unit; an inverter unit configured to convert the output voltage smoothed in the smoothing capacitor into an AC voltage; a dew condensation state detection unit configured to detect a state of dew condensation, which occurs due to a cooler configured to cool the step-up converter unit and the inverter unit; and a control unit configured to control an operation of the step-up converter unit, wherein the control unit includes: a determination unit configured to determine the state of dew condensation detected by the dew condensation state detection unit; and a step-up control unit configured to control a step-up operation of the step-up converter unit based on a result

Abstract: A device and method for generating single/split or three phase AC voltages from a DC source with 1 to 2 times gain in output voltage without using any DC/DC boost or an output transformer. An isolation/multiplexer/mixer circuit successively charges multiple power modules, allowing each power module to generate output voltage(s) with desired magnitudes and phases, and allows independent outputs of each power converter modules to be reconnected to obtain up to two times the conventional possible output voltage. An isolation block eliminates the common mode noise problem. The gain in output voltage and isolation between the output converters eliminates the need of the front end DC/DC converter or an output transformer for most of the DC voltage sources, which improves cost, power density, efficiency and reliability of the inverter.

Abstract: The various implementations described herein include inverter devices and systems. In one aspect, an inverter includes: a case; a capacitor within the case having a first terminal and a second terminal; a first bus bar including a first portion within the case and a second portion extending from the case to contact a first transistor; a second bus bar including a first portion situated in the case and a second portion extending from the case to contact a second transistor; and a phase-out bus bar including a first portion situated in the case, a second portion extending from the case to contact the first transistor, and a third portion extending from the case to contact the second transistor.

Abstract: An inverter circuit provided in a power conversion device includes a full-bridge inverter, and a short circuit part. The short circuit part includes switching elements and clamp elements connected to the switching elements. The clamp elements suppress application of an excessive voltage such as a surge voltage to the switching elements.

Abstract: An apparatus is provided. The apparatus includes a bidirectional comb drive actuator. The apparatus may also include a cantilever. The cantilever includes a first end connected to the bidirectional comb drive actuator and a second end connected to an inner frame. In addition, the cantilever may include first and second conductive layers for routing electrical signals. Embodiments of the disclosed apparatuses, which may include multi-dimensional actuators, allow for an increased number of electrical signals to be routed to the actuators. Moreover, the disclosed apparatuses allow for actuation multiple directions, which may provide for increased control, precision, and flexibility of movement. Accordingly, the disclosed embodiments provide significant benefits with regard to optical image stabilization and auto-focus capabilities, for example in size- and power-constrained environments.

Abstract: A friction electric generator and a manufacturing method thereof are provided. The friction electric generator includes a first substrate and a second substrate disposed oppositely, a first electrode and a polymer insulating layer sequentially formed on a side of the first substrate facing the second substrate; a second electrode formed on a side of the second substrate facing the first substrate; wherein, the first electrode and the second electrode are each made of a flexible conductive substance, the first substrate and the second substrate are each made of a flexible insulating substance, and the polymer insulating layer and the second electrode is capable of generating electricity by friction.

Abstract: A piezoelectric ultrasonic motor includes: a drive piezoelectric material wherein a plurality of piezoelectric elements, which are polarized by opposite polarities along a circumferential direction around a rotation shaft, are alternately arranged, and a vibration-control piezoelectric material wherein a plurality of piezoelectric elements, which are arranged along a circumferential direction around the rotation shaft and polarized by opposite polarities, are arranged to correspond to the plurality of piezoelectric elements of the drive piezoelectric material, wherein AC power and another AC power having a phase difference with respect to the AC power are respectively applied to the piezoelectric material and the vibration-control piezoelectric material, in a vibration damping area of the drive piezoelectric material.

Abstract: Aspects of the present disclosure relate to systems and methods for harvesting energy from the pressure ripple of a fluid system. In an example embodiment, a system comprises a housing; a piezoelectric stack in fluid communication with a pressure ripple of a fluid system and configured to generate a piezoelectric voltage and an associated piezoelectric current in response to pressure ripple characteristics, wherein the piezoelectric stack is disposed within the housing; and regulatory circuitry in electrical communication with the piezoelectric stack and configured to convert the piezoelectric current into DC voltage.

Abstract: A drive circuit for an electric motor having a wound stator and a permanent magnet rotor, includes a controllable bidirectional AC switch connected in series with a stator winding between two terminals for connecting to an AC power supply. First and second position sensors detect the position of magnetic poles of the rotor. A voltage regulating circuit is connected between the two terminals and the controllable bidirectional AC switch and configured to supply power to the first sensor during the positive cycle and to the second position sensor during the negative cycle of the AC power supply such that the controllable bidirectional AC switch is switched between a conductive state and a non-conductive state in a preset manner, thus enabling the stator to rotate the rotor in only one predetermined direction during start-up.

Abstract: As speed operation range identification system for motion systems driven by permanent magnet synchronous motors (PMSMs) or induction motors leverages both characteristics of the motor as well as dynamic characteristics of the motion system—including the friction and load—to identify suitable maximum speeds for operation of the motion system in the normal speed and field weakening regions. The identification system can model both motor characteristics as well as real-time dynamics of the controlled mechanical system that may vary during operation. The system can apply an optimization algorithm to this model to determine suitable maximum speeds for operation in the normal speed and/or field weakening regions. The determined maximum speeds can be used to perform substantially real-time adjustments to motion profile limits or current reference values generated by the motor controller in order to ensure that the speed of the system remains below the determined maximum.

Abstract: A short-circuit detection circuit is adapted to a full-bridge driver which includes the first and second high-side transistors respectively coupled from a supply voltage to the first and second output nodes and the first and second low-side transistors respectively coupled from the first and second output nodes to a ground. The short-circuit detection circuit includes the first and second voltage dividers respectively receiving voltages of the first and second output nodes to respectively generate the first and second voltages, the high-side and low-side selectors respectively selecting the first voltage and the second voltage to respectively generate a high-side voltage and a low-side voltage, a high-side comparator generating a high-side short-circuit signal when the high-side voltage is lower than a high-side reference voltage, and a low-side comparator generating a low-side short-circuit signal when the low-side voltage exceeds the low-side reference voltage.

Abstract: A motor control device includes a position sensor that detects a position of a motor, an AD converter that converts an analog signal, which is a detection value of a motor current, into a digital signal, and a control circuit that drives an inverter using an output signal of the AD converter. The control circuit starts the AD converter during a permission period, and performs processing for the analog-digital converter during an electrical half cycle including a permission period. The length of a prohibition period obtained by excluding a permission period from an electrical half cycle decreases as the rotating speed of the motor increases.

Abstract: The present disclosure relates to a multi-turn angle controlling method based on an absolute position encoder, including: obtaining a target angle according to a starting position and a target position, and obtaining number of times N that the target angle passes a predetermined position, determining whether an absolute value of the target angle being greater than 360 degrees, conducting a first operation mode upon determining that the absolute value of the target angle being greater than 360 degrees, incrementing M by one when the operation angle passes the predetermined position until M equals to N, M is a positive integer and an initial value of M is zero, and conducting a second operation mode when M equals to N, N is a positive integer greater than 1.

Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: A control method of direct current (DC) machine includes the following steps: obtaining a target speed n, detecting a current speed nk, calculating a current rotating speed difference ek, calculating a speed base voltage W according to the current speed nk, calculating a PID adjustment voltage V according to the current rotating speed difference ek, calculating an output voltage U according to the PID adjustment voltage V and the speed base voltage W, and driving the DC machine according to the output voltage U.

Abstract: There is provided a motor drive control device comprising: a temperature detection unit to detect a temperature of a motor; a rotational frequency detection unit to detect a rotational frequency of the motor based on an output of a rotational position sensor provided in the motor; a supply voltage detection unit to detect a supply voltage; a load calculation unit to calculate a magnitude of a load of the motor based on a detection result of the supply voltage detection unit; an advance angle instruction unit to set an advance angle instruction value based on a detection result of the temperature detection unit, a detection result of the rotational frequency detection unit and a calculation result of the load calculation unit; and a motor drive unit to supply a driving electric power to the motor based on a speed instruction value relevant to a rotational speed of the motor and the advance angle instruction value set by the advance angle instruction unit.

Abstract: A drive apparatus is provided with a motor, a plurality of substrates and a plurality of connectors. The substrates are provided in one side of the motor in the axial direction thereof, the substrates including switching elements and control components mounted thereon. The connectors are provided in an opposite side against the motor across the substrates, the connectors including connector terminals connected to one of the substrates. The substrates include two or more non-overlapped regions where no substrates are overlapped when projecting the substrates in the axial direction. The non-overlapped regions include a connector connecting region connected to the connector terminals, and a motor line connecting region connected to winding groups of the motor corresponding to every phase of each winding group.

Abstract: A method for operating an electric machine with a power source, an electric motor, and an intermediary power converter, in which an input current of the power source is converted to a multi-phase output current for the electric motor by a pulse width modulated control of a number of semiconductor switches of the converter, wherein the or each pulse is generated at a first point in time and terminated after a pulse duration at a second point in time, in which for each alternating current component, which is generated in the course of the pulse-width-modulated driving of the semiconductor switches in an intermediate circuit of the power source, a frequency spectrum is determined, and in which the pulse durations of the pulses of the pulse width modulated control can be set such that the sum of the frequency spectra of the alternating current components is minimal.

Abstract: A solar panel mounting device that allows for position adjustment along a base mountable to a roof surface and height-adjustment relative to the roof surface. The solar panel mounting device includes a height-adjuster and a dual-locking mechanism separate from the height-adjuster. The dual-locking mechanism acts as a guide surface during level adjustment and can separately lock the position adjustment and height-adjustment upper limit.

Abstract: The present invention provides a mounting assembly for attaching solar panels to a rooftop. The assembly allows for convenient installment and adjustment of the panels.

Abstract: A roof mounting system for the attachment of an article to a roof, the system comprising a plurality of PV modules each having at least one corner and a frame member, a flashing member having a top surface; an upstanding sleeve attached to the top surface of the flashing member; an elevated water seal having a borehole formed therethrough, the elevated water seal further comprising at least one screw for providing a waterproof seal between the article and the roof structure; and whereby the plurality of PV modules are interlocked in a way to provide a corner-to-corner coupling arrangement supported above the roof through the frame members of the plurality of PV modules.

Abstract: Disclosed are novel forms of operable windows capable of producing an electrical current utilizing a transparent or semi-transparent solar collecting substrate. A scaffold assembly is utilized to enclose the perimeter of the substrate and one or more solar cells. The scaffold may comprise a scaffold port providing passage for an exit conductor from a sash lead in electrical communication with a solar cell. The assembly may include a bridge portion of an exit conductor that carries electrical current from a sash portion to a frame portion of the window assembly. A frame port extending through the frame of the window may provide passage of the exit conductor to electronic accessories or to circuits that can store or reuse the electrical energy produced. Various forms of electronic accessories are disclosed for fixed or releasable mounting to portions of the window.

Abstract: The output of a photovoltaic power generator is estimated by estimating a solar radiation amount at a point different from solar radiation measurement points and determining an estimation error amount from solar radiation values measured at limited points. A photovoltaic power generator output estimation method estimates an output of a photovoltaic power generator based on a measured solar radiation value.

Abstract: A photovoltaic power generation system includes at least one photovoltaic power generation microgrid and a central server configured to communicate with the photovoltaic power generation microgrid via Internet.

Abstract: A voltage controlled oscillator comprises a negative resistance, a first inductor, a fixed capacitor, and a frequency control component. The frequency control component comprises at least one varactor and at least a second inductor connected in series with the at least one varactor. A magnitude of an inductance of the second inductor is selected such that the frequency control component has an effective capacitance range larger than a capacitance range of the at least one varactor.

Abstract: An apparatus includes a first circuit and a second circuit. The first circuit may have a first diode and a second diode connected as anti-parallel diodes and physically adjacent to each other in a substrate. The second circuit may have a third diode and a fourth diode connected as anti-parallel diodes and physically adjacent to each other in the substrate. The first circuit and the second circuit may be configured to mix two input signals to generate an output signal. A polarity of every other physically neighboring diode may be reversed.

Abstract: The present invention relates to a novel and inventive compound device structure, enabling a charge-based approach that takes advantage of sub-threshold operation, for designing analog CMOS circuits. In particular, the present invention relates to a solid state device based on a complementary pair of n-type and p-type current field-effect transistors, each of which has two control ports, namely a low impedance port and gate control port, while a conventional solid state device has one control port, namely gate control port. This novel solid state device provides various improvement over the conventional devices.

Abstract: A rail-to-rail sense amplifier includes a PMOS differential pair and an NMOS differential pair that are arranged in parallel with regard to a biasing network for driving a class AB output stage. The sense amplifier includes a first current differential amplifier and a second current differential amplifier for increasing the output swing while reducing power consumption.

Abstract: A power amplification module includes a first transistor which amplifies and outputs a radio frequency signal input to its base; a current source which outputs a control current; a second transistor connected to an output of the current source, a first current from the control current input to its collector, a control voltage generation circuit connected to the output and which generates a control voltage according to a second current from the control current; a first FET, the drain being supplied with a supply voltage, the source being connected to the base of the first transistor, and the gate being supplied with the control voltage; and a second FET, the drain being supplied with the supply voltage, the source being connected to the base of the second transistor, and the gate being supplied with the control voltage.

Abstract: An amplifier includes first, second, and third inputs to receive an RF signal, first and second amplifiers, and an input phase adjustment circuit coupling the first, second, and third inputs to the first and second amplifiers, the input phase adjustment circuit having first and second outputs coupled to the first and second amplifiers, respectively. The input phase adjustment circuit includes a pair of inputs, where the pair of inputs includes the first and second inputs, for the first output and a pair of phase adjustment paths coupling the pair of inputs to the first output, respectively. The pair of phase adjustment paths are configured to adjust a phase of the RF signal differently for the first output.

Abstract: An embodiment of a Doherty amplifier includes first and second amplifier paths with first and second amplifiers, respectively, a power divider, a series delay element, and a short-circuited stub. The power divider is configured to receive a radio frequency (RF) signal and to divide the RF signal into first and second input signals that are produced at first and second power divider outputs. The series delay element is coupled between the first power divider output and the first amplifier. The short-circuited stub is coupled between the first power divider output and the first amplifier or between the second power divider output and the second amplifier. The first amplifier path is characterized by a first frequency-dependent insertion phase, the second amplifier path is characterized by a second frequency-dependent insertion phase, and a slope of the first or second frequency-dependent insertion phase is altered by the short-circuited stub.

Abstract: The disclosed technology includes device, systems, techniques, and methods for amplifying a complex modulated signal with a mixed-signal power amplifier. A mixed-signal power amplifier may include an input network for splitting an input signal to multiple signals with corresponding phase and amplitude offsets, a main power amplification path including at least an analog power amplifier for amplifying a first signal, one or more auxiliary power amplification paths including at least one digitally controlled analog power amplifier in each path for amplifying a second signal, and an output network for combining the two amplified signals. The main power amplification path and the auxiliary power amplification paths can operate together to achieve load modulation to enhance the overall power amplifier efficiency at power back-off mode and the overall power amplifier linearity. The disclosed technology further includes transmission systems incorporating the mixed-signal power amplifier.