Abstract: Systems and methods according to one or more embodiments are provided for sensing a current at an output of a switching amplifier. In one example, a system includes a first transistor switch coupled to a load configured to conduct a current in the load responsive to a first pulse width modulated control signal and a second transistor switch coupled to the load configured to conduct the current in the load responsive to a second pulse width modulated control signal. The system further includes a sample and hold circuit coupled between the load and a current sensing circuit configured to sample a voltage at the second transistor switch for a pre-determined sample time period in response to a midpoint of a second pulse width modulated control signal time period, and configured to provide the sampled voltage to the current sensing circuit.

Abstract: The present invention relates to a multiple output boost DC-DC power converter generating two, three or more separate DC output voltages, and to a multi-level power inverter and an alternating current generator both employing the multiple output boost DC-DC power converter.

Abstract: A self-oscillating class D amplifier includes an integration circuit configured to integrate an input signal and output a result of the integration as an integrated signal, a comparator configured to receive the integrated signal at an inverting input terminal and output a pulse width modulation signal by comparing voltages of a non-inverting input terminal being grounded and the inverting input terminal, a switching circuit configured to power-amplify the pulse width modulation signal output from the comparator, a low-pass filter configured to extract an amplified output signal from the power-amplified pulse width modulation signal, a first feedback circuit configured to feed back the output signal of the low-pass filter to the inverting input terminal of the comparator, and a second feedback circuit configured to feed back the output signal of the low-pass filter to the integration circuit.

Abstract: A circuit includes a final stage that includes an H-bridge comprising first and second half-bridges. A read circuit is configured to read a load current supplied by a class-D audio-amplifier to a load. The read circuit is configured for estimating the load current by reading a current at an output by the first or second half-bridge by measuring a drain-to-source voltage during an ON period of a power transistor of the H-bridge. A sensing circuit is configured to detect a first drain-to-source voltage from a transistor of the first half-bridge and a second drain-to-source voltage from a corresponding transistor of the second half-bridge. The sensing circuit is also configured to compute a difference between the first drain-to-source voltage and the second drain-to-source voltage and to perform an averaging operation on the difference to obtain a sense voltage value to be supplied to an analog-to-digital converter.

Abstract: In one general aspect, a method can include calculating, at a calibration temperature of a speaker, a calibration parameter through a coil of the speaker in response to a first test signal, and can include sending a second test signal through the coil of the speaker. The method can also include measuring a parameter through the coil of the speaker based on the second test signal, and calculating a temperature change of the coil of the speaker based on the parameter and based on the calibration parameter at the calibration temperature.

Abstract: A power-adjustable RF (radio frequency) output circuit is disclosed, which includes a RF frequency source transformer, wherein: one output end of the RF frequency source transformer is connected with a gate of a power amplifier module, another output end of the RF frequency source transformer is connected with a gate bias voltage control circuit; a source of the power amplifier module is connected with ground; the gate of the power amplifier module is connected with a resistor which is connected with ground, a drain of the power amplifier module is connected with a fixed voltage DC (direct current) power supply and also connected with a RF filtering network for outputting a RF power through the RF filtering network.

Abstract: According to one embodiment, a radio frequency coil unit includes cables, radio frequency coil elements and balun circuits. The cables correspond to channels. The radio frequency coil elements are directly or indirectly connected to the cables. The balun circuits suppress an influence of an unbalanced current flowing into partial radio frequency coil elements out of the radio frequency coil elements. A part of the cables pass through at least one of the balun circuits in contact with or in non-contact with at least one of the balun circuits.

Abstract: The present invention relates in one aspect to a class D audio amplifier with improved output driver topology supporting multi-level output signals such as 3-level, 4-level or 5-level pulse width or pulse density modulated output signals for application to a loudspeaker load. The present class D audio amplifiers are particularly well-suited for high-volume consumer audio applications and solutions.

Abstract: A temperature compensated current measurement device comprises a Rogowski coil having a terminating impedance arranged to adjust the attenuation of the coil to balance changes in coil sensitivity so that the output voltage indicative of measured current remains substantially unchanged, the terminating impedance having different values above and below a threshold frequency.

Abstract: An apparatus and method are disclosed for providing output signal swings that are greater than the supply voltage in a class-D amplifier. The amplifier circuit boosts the voltage across the amplifier load, such as a loudspeaker, by using capacitors to “charge pump” the voltage across the load and thus increase the voltage temporarily. This is done by using two or more output bridges rather than one, and connecting the bridges through the capacitors. For signals of less than the supply voltage, only an inner bridge, similar to a full bridge of the prior art, operates. For signals above the supply voltage, an outer bridge charges capacitors, which are then used to ‘boost’ the voltage on the bridge output for the short period of the Class-D switching period. Thus, only relatively small value boosting capacitors are needed, as they do not need to supply charge for very long.

Abstract: The present disclosure relates to a class-D audio amplifier. When the class-D audio amplifier is powered on, an auxiliary power amplifier and an auxiliary feedback circuit constitute an auxiliary close loop so that a control loop is established in advance. The auxiliary close loop is disconnected after various circuit modules reach their steady operation points, and the class-D audio amplifier operates at a normal state. A soft start circuit is provided for suppressing noise which occurs when the class-D audio amplifier is powered on. Thus, the class-D audio amplifier suppresses POP noise at an output terminal when the class-D audio amplifier is powered on.

Abstract: Circuitry includes a first RF power amplifier, a second RF power amplifier, a third RF power amplifier, a first bias signal generator, and a second bias signal generator. The first RF power amplifier and the second RF power amplifier are each configured to amplify RF signals for transmission in a first carrier network. The third RF power amplifier is configured to amplify RF signals for transmission in a second carrier network. In a first mode, the first bias signal generator provides a bias signal to the first RF power amplifier and the second bias signal generator provides a bias signal to the second RF power amplifier. In a second mode, the first bias signal generator and the second bias signal generator each provide a portion of a bias signal to the third RF power amplifier.

Abstract: An amplifier includes an amplifier circuit comprising a switch, the switch configured to provide an output signal responsive to an input signal, the output signal comprising a first output signal at a fundamental frequency and a second signal at a second harmonic of the fundamental frequency, the input signal configured to control the switch according to a nominal 25% off, 75% on cycle, a filter circuit configured to control an impedance presented to the amplifier circuit and a load circuit, at least a part of which is configured to combine with the filter circuit to form an impedance transformation circuit configured to be resonant at the second harmonic of the fundamental frequency.

Abstract: A circuit for measuring a bandwidth of an amplifier includes a switch-capacitor circuit and a controller. The switch-capacitor circuit is coupled to an output and an input of the amplifier. The switch-capacitor circuit is switchable between a sampling mode and an amplification mode. The controller is coupled to the switch-capacitor circuit and the output of the amplifier. The controller is configured to switch the switch-capacitor circuit between the sampling mode and the amplification mode, control the amplification mode to have various durations, and determine the bandwidth of the amplifier based on the various durations of the amplification mode and corresponding voltages at the output of the amplifier.

Abstract: A switching power stage for producing a load voltage may include a first processing path having a first output, a second processing path having a second output, a first plurality of switches comprising at least a first switch coupled between the first output and a first load terminal and a second switch coupled between the first output and the second load terminal, a second plurality of switches comprising at least a third switch coupled between the second output and the first load terminal and a fourth switch coupled between the second output and the second load terminal, and a controller configured to control switches in order to generate the load voltage as a function of an input signal such that one of the first switch and the second switch operates in a linear region of operation and one of the third switch and the fourth switch operates in a saturated region of operation for a predominance of a dynamic rage of the load voltage.

Abstract: A power supply circuit (10) includes: a linear amplifier (11) for generating a linear amplification signal based on an input signal; a first switching amplifier (12) for generating a first switching amplification signal of a first frequency band based on the linear amplification signal; a second switching amplifier (13) for generating a second switching amplification signal of a second frequency band based on the first switching amplification signal; and a power supply unit (14) for supplying a combined signal in which the linear amplification signal and the first and second switching amplification signals are combined to an external circuit as a power supply. It is therefore possible to improve the power efficiency.

Abstract: The present invention provides an apparatus and a method for amplifying a radio-frequency signal and an MRI system comprising the apparatus.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for providing a user with feedback regarding power consumption in a battery-operated electronic device. In one aspect, a method performed by data processing apparatus includes identifying, using the data processing apparatus, usage of a hardware component of a battery-operated electronic device that includes the data processing apparatus, attributing the usage of the hardware component to the hardware component or to a software application that uses the hardware component, recording, using the data processing apparatus, a power consumption resulting from the usage, and presenting power consumption feedback to a user using the data processing apparatus. The power consumption feedback identifies the hardware component or the software application of the electronic device and the power consumption resulting from the usage.

Abstract: A method for producing an output voltage to a load may include, in a power stage comprising power converter having a power inductor, a plurality of switches arranged to sequentially operate in a plurality of switch configurations, and an output for producing the output voltage comprising a first output terminal and a second output terminal, controlling the linear amplifier to transfer electrical energy from the input source of the power stage to the load in accordance with one or more least significant bits of a digital input signal, and controlling the power converter in accordance with bits of the digital input signal other than the one or more least significant bits to sequentially apply switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from the input source of the power stage to the load.

Abstract: A wave shaping circuit reduces slope magnitudes during increasing and decreasing voltage transitions. The wave shaping circuit includes a first switch that receives an input voltage having at least two voltage values where an input voltage transition between the at least two voltage values has a first slope magnitude; an inductor connected in series with the first switch; a second switch connected in a parallel arrangement with the first switch and the inductor; and a capacitor having a first end connected between the inductor and an output port and a second end connected to ground. When the input voltage begins the input voltage transition to a higher voltage value, the first switch turns on and the second switch turns off, such that the inductor limits current flow from the input voltage, decreasing a second slope magnitude of an output voltage transition to less than the first slope magnitude.

Abstract: A signal conditioner that includes a transition-detection module and a current-injection module. The transition-detection module is configured to receive a pair of differential signals from a data line and generate one or more comparator output signals and a transition-indication signal to indicate whether a transition has been detected on the differential signals. The current-injection module is configured to receive the comparator output signals and transition-indication signal from the transition-detection module, and generate appropriate currents for injection into the data line to boost edge rates of the differential signals when the transition-detection module detects a transition of the differential signals or remain high impedance when no transition occurs on the differential signals.

Abstract: A device and a method for power conversion to DC using zero-current and/or zero-voltage switching. Provides output voltage of any level and polarity. Operates with any input voltage, including DC and AC. Power loss is substantially eliminated. The conversion efficiency is independent of load consumption, from the idle to the maximum power. The EMI level is very low. Provides for input to output isolation without use of transformers.

Abstract: Presented herein are low-power active bone conduction devices that comprise an actuator that is subcutaneously implanted within a recipient so as to deliver mechanical output forces to hard tissue of the recipient. The low-power active bone conduction devices include an energy recovery circuit configured to extract non-used energy from the actuator and to store the non-used energy for subsequent use by the actuator. The low-power active bone conduction devices may also include a multi-bit sigma-delta converter that operates in accordance with a scaled sigma-delta quantization threshold value to convert received signals representative of sound into actuator drive signals.

Abstract: An output impedance-matching network for an RF power amplifier die includes a harmonic-prevention circuit that functions like a short circuit at a fundamental frequency of the amplifier and an open circuit at a second harmonic frequency of the amplifier. In certain implementations, the harmonic-prevention circuit has one or more parallel, reactive (LC) legs that resonate at the fundamental frequency and a parallel, reactive (capacitive) leg that causes the harmonic-prevention circuit to resonate at the second harmonic frequency. The harmonic-prevention circuit improves power transfer and efficiency of the RF power amplifier.

Abstract: Embodiments of the disclosure may include a method and apparatus for improving the efficiency and extending the operation time between recharges or replacement batteries of a portable audio delivery system. The audio delivery system may include a processor, an audio processing device, a speaker, and a rechargeable power source. The audio delivery system is generally configured to generate and/or receive an audio input signal and efficiently deliver an amplified, high quality audio output signal to a user. In some embodiments of the disclosure, the audio processing device of the audio delivery system may include a switch mode power supply (SMPS), a signal delay element, an envelope detector, and a switching signal amplifier.

Abstract: Circuits and devices related to multi-harmonic control of amplified signals. In some embodiments, an amplifier circuit assembly can include an amplifier configured to provide a signal at an output. The amplifier circuit assembly can further include a matching network configured to provide impedance matching for the signal having a fundamental frequency, a broadband harmonic trap configured to substantially trap a plurality of harmonics associated with the fundamental frequency, and a dipole network configured to tune reactances associated with the broadband harmonic trap. The matching network, the broadband harmonic trap and the dipole network can be implemented in series from the output of the amplifier.

Abstract: An integrated power stage device includes a switch node that is coupled to an output inductor. The integrated power stage device generates a monitor current that is a scaled version of the current through the output inductor. The integrated power stage device outputs a single-ended offset monitor current that is equal to the monitor current plus a DC offset current. A PWM controller senses the current through the output inductor by receiving a monitor voltage that is developed from the offset monitor current. The PWM controller generates a PWM signal in accordance with the sensed output inductor current to control a switching operation of a power switch of the integrated power stage device.

Abstract: Cascode power amplifier with voltage limiter. A power amplification system can include an input transistor having an input transistor gate configured to receive a radio-frequency (RF) signal, an input transistor source coupled to a ground voltage, and an input transistor drain. The power amplification can further include an output transistor having an output transistor drain configured to output an amplified version of the RF signal, an output transistor gate coupled to a bias voltage, and an output transistor source. The power amplification system can further include a high voltage limiter coupled between the output transistor drain and output transistor gate. The high voltage limiter can be configured to prevent a gate-drain voltage of the output transistor from exceeding a high voltage threshold.

Abstract: A mobile communication device may use sensor data to identify the current device state based on sensor data, device parameter values and/or device usage data. The mobile communication device may then measure the impedance value of a characteristic circuit, such as the antenna or the power amplifier. Responsive to determining that the measured impedance value differs from a pre-defined base impedance value by more than a certain threshold value, the mobile communication device may retrieve, from a memory, a set of envelope tracking (ET) parameter values corresponding to the current state of the communication device and the measured impedance value. The mobile communication device may calculate, using the retrieved ET parameter values, a target supply voltage to be applied to the power amplifier.

Abstract: This application relates to Class D amplifier circuits (200). A modulator (201) controls a Class D output stage (202) based on a modulator input signal (Dm) to generate an output signal (Vout) which is representative of an input signal (Din). An error block (205), which may comprise an ADC (207), generates an error signal (?) from the output signal and the input signal. In various embodiments the extent to which the error signal (?) contributes to the modulator input signal (Dm) is variable based on an indication of the amplitude of the input signal (Din). The error signal may be received at a first input (204) of a signal selector block (203). The input signal may be received at a second input (206) of the signal selector block (203).

Abstract: A method for producing an output voltage to a load may include, in a power stage comprising power converter having a power inductor, a plurality of switches arranged to sequentially operate in a plurality of switch configurations, and an output for producing the output voltage comprising a first output terminal and a second output terminal, controlling the linear amplifier to transfer electrical energy from the input source of the power stage to the load in accordance with one or more least significant bits of a digital input signal, and controlling the power converter in accordance with bits of the digital input signal other than the one or more least significant bits to sequentially apply switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from the input source of the power stage to the load.

Abstract: The power amplifying device includes a first potential line to which a first potential is supplied, a second potential line to which a second potential that is lower than the first potential is supplied and a third potential line to which a third potential that is between the first potential and the second potential is supplied. The power amplifying device includes a first BTL amplifier unit. The power amplifying device includes a second BTL amplifier unit. The power amplifying device includes a third BTL amplifier unit. The power amplifying device includes a fourth BTL amplifier unit that has a seventh output amplifier and an eighth output amplifier.

Abstract: A single-stage buffer apparatus includes a first transistor, a second transistor, and a high pass filter network. The first transistor is configured to receive an input signal from a microphone. The second transistor is configured to operate as a cascode transistor. The high pass filter network is coupled to the first transistor and the second transistor. The second transistor electrically decouples the first transistor from an output of the single-stage buffer apparatus. A gate terminal of the second transistor is driven by the high-pass filter network, and the high-pass filter network is driven by the first transistor.

Abstract: A transmitter in a wireless communication system is provided. The transmitter includes a baseband signal processor for detecting an envelope signal, a supply modulator (SM) for producing power to be supplied to a power amplifier using the detected envelope signal, and the power amplifier for receiving voltage from the SM and for amplifying power of a transmit signal. The SM generates a compensation signal corresponding to switching noise generated via switching amplification, and adds the compensation signal and the switching noise. The amplifier of the wireless communication system can produce low switching noise, and the envelope tracking power amplifier can prevent reception degradation due to the noise of the supply modulator.

Abstract: A power supply apparatus includes: a plurality of input ports configured to receive input of electric power from a plurality of power sources, respectively; a charge and discharge circuit configured to receive the input electric power to be charged and discharged so as to generate electric power to be supplied to a load circuit; a switching circuit configured to individually switch connections between the plurality of input ports and the charge and discharge circuit; and a control circuit configured to perform control so as to give different timing of the switch among the input ports.

Abstract: The power stage at the output of a high-frequency generates operates in class D and comprises a voltage supply and a common earth, a first and a second switch linked to the common earth and periodically switched on at a high frequency F; these switches are linked to two common-mode inductors connected in a Guanella balun. Each common-mode inductor comprises two inductive lines with strong mutual coupling.

Abstract: Techniques for providing multiple power supplies in electronic devices are disclosed. According to one aspect of the present invention, an appropriate power supply is provided only to accommodate a volume setting. In other words, there are at least two power supplies, one with a low voltage and the other with a high voltage. The high voltage power supply is only applied when there is a need to accommodate a volume setting. Thus the power consumption of the amplifiers is well controlled. As a result, the designs of the device and heat dissipation therein can be simplified and lowered in cost.

Abstract: A current limiter for Class-D amplifiers measures and stores a position of an over-current event. By comparing the stored position, output signals can be selectively inverted. As a result, the Class-D amplifier remains in a defined modulation scheme even during period of current limiting.

Abstract: The present invention relates in one aspect to a class D audio amplifier with improved output driver topology supporting multi-level output signals such as 3-level, 4-level or 5-level pulse width or pulse density modulated output signals for application to a loudspeaker load. The present class D audio amplifiers are particularly well-suited for high-volume consumer audio applications and solutions.

Abstract: Aspects of this disclosure relate to efficient power amplifiers, such as class-F power amplifiers. A power amplifier transistor can provide an amplified RF signal. A termination can be coupled to an output of the power amplifier transistor and configured to provide a short circuit at a second harmonic. In some instances, the termination circuit can provide an open circuit at a third harmonic. A resonant circuit can be coupled to the output terminal of the power amplifier transistor and configured to provide an open circuit at the third harmonic. In certain embodiments, an input termination circuit coupled to an input terminal of the power amplifier transistor can provide a short circuit at the second harmonic. The power amplifiers of this disclosure can be implemented, for example, in envelope tracking applications.

Abstract: A hearing aid (21) is devised, comprising a first output converter (26), a second output converter (27), a first acoustic output transducer (34) and at least a second output transducer (35). The first output converter (26) and the first output transducer (34) are configured to reproduce the high frequencies of the processed signals, and the second output converter (27) and the second output transducer (35) are configured to reproduce the low frequencies of the processed signals. The output converters (26, 27) may preferably be embodied as direct digital drive output converters.

Abstract: An ink jet printer is provided with a piezoelectric element which is provided corresponding to a pressure chamber in order to discharge liquid droplets, a driving signal generating section which generates a driving signal, a residual vibration detecting section which detects changes in an electromotive force of the piezoelectric element in accordance with the residual vibration inside the pressure chamber which occur after the driving signal is applied, a first switch which switches whether or not a driving signal is applied to the piezoelectric element, and a second switch which switches whether or not a change in the electromotive force is supplied to a first high-pass filter, where the second switch and the residual vibration detecting section are connected via a first capacitor of the first high-pass filter.

Abstract: Adaptive loop filtering in accordance with video coding. An adaptive loop filter (ALF) and/or other in-loop filters (e.g., sample adaptive offset (SAO) filter, etc.) may be implemented within various video coding architectures (e.g., encoding and/or decoding architectures) to perform both offset and scaling processing, only scaling processing, and/or only offset processing. Operation of such an ALF may be selective in accordance with any of multiple respective operational modes at any given time and may be adaptive based upon various consideration(s) (e.g., desired complexity level, processing type, local and/or remote operational conditions, etc.). For example, an ALF may be applied to a decoded picture before it is stored in a picture buffer (or digital teacher buffer (DPB)). An ALF can provide for coding noise reduction of a decoded picture, and the filtering operations performed thereby may be selective (e.g., on a slice by slice basis, block by block basis, etc.).

Abstract: Provided is a buffer amplifier. The buffer amplifier includes: a replica bias unit dividing an internal power voltage received from an internal power node to generate a bias voltage; an input unit including a first differential amplifier comparing a first differential input signal with the bias voltage to output a first internal signal and a second differential amplifier comparing a second differential input signal with the bias voltage to output a second internal signal; and an output unit including a third differential amplifier comparing the first internal signal with the second internal signal to output a first differential output signal and a second differential output signal.

Abstract: The present invention relates to a method and a circuit for testing a tweeter. The tweeter is part of a loudspeaker system. The method includes the steps of: applying a high-frequency voltage signal to one terminal of the tweeter, whereby the high-frequency voltage signal is generated by first electronic means. The method also includes applying a constant voltage signal to the other terminal of the tweeter, whereby the constant voltage signal is generated by second electronic means. The method includes measuring a current (Iload) that flows through the tweeter into the second electronic means and determining a connect/disconnect state of the tweeter from the value of the current.

Abstract: An embodiment of an amplifier includes N (N>1) switch-mode power amplifier (SMPA) branches. Each SMPA branch includes two drive signal inputs and one SMPA branch output. A module coupled to the amplifier samples an input RF signal, and produces combinations of drive signals based on the samples. When an SMPA branch receives a first combination of drive signals, it produces an output signal at one voltage level. Conversely, when the SMPA branch receives a different second combination of drive signals, it produces the output signal at another voltage level. At least two of the SMPA branches produce output signals having different absolute magnitudes. A combiner combines the output signals from all of the SMPA branches to produce a combined output signal that may have, at any given time, one of 2*N+1 quantization states.

Abstract: A system for driving a plurality of loads each connected to respective signal terminals and to a shared common load terminal. Multiple conventional signal amplifiers each provide a content signal at one of the signal terminals. The signal amplifiers each have a primary-power upper terminal, to receive a first voltage (V1) from a first power supply, and a primary-power lower terminal, to receive a second voltage (V2) from the first power supply. A bias amplifier biases the common load terminal, and has a secondary-power upper terminal to receive a third voltage (V3) from a second power supply and a secondary-power lower terminal to receive a fourth voltage (V4) from the second power supply, wherein V2?V4<V3?V1.

Abstract: A method and device for driving a digital speaker based on code conversion are provided in the invention. The method comprises the steps of: (1) converting input format; (2) performing multi-bit ?-? modulation; (3) thermometer code conversion; (4) dynamic mismatch-shaping processing; (5) pulse width modulation code conversion; and (6) controlling on/off status switching of the MOSFET of a full-bridge power amplification network to drive a digital speaker load sound. The device comprises a sound source, an input format converter, a multi-bit ?-? modulator, a thermometer coder, a dynamic mismatch shaper, a code converter, a multi-channel digital amplifier and a digital speaker load which are connected to each other in sequence.

Abstract: A hybrid amplifier includes a linear amplifier coupled in series with a switching amplifier. The linear amplifier may generate an intermediate amplified signal according to an input signal. The switching amplifier may generate an output signal according to the intermediate amplified signal, the output signal having an amplitude with respect to a reference voltage provided at a reference node. The linear amplifier may drive the reference node to adjust the reference voltage responsive to transient changes in the output signal. A high-pass filter coupled to the linear amplifier and the switching amplifier may enable the switching amplifier to provide most of the steady-state current, which may drive a load, from actual ground. The linear amplifier and switching amplifier may be independently powered, for example from a power supply having a primary winding and two electrically isolated secondary windings that respectively provide power to the linear amplifier and the switching amplifier.

Abstract: This disclosure relates generally to radio frequency (RF) switching converters and RF amplification devices that use RF switching converters. For example, an RF switching converter may include a switching circuit that receives a power source voltage and a switching controller that receives a target average frequency value identifying a target average frequency. The switching circuit is switchable so as to generate a pulsed output voltage from the power source voltage. The switching controller switches the switching circuit such that the pulsed output voltage has an average pulse frequency. The switching controller also detects that the average pulse frequency of the pulsed output voltage during a time period differs from the target average frequency, and reduces a difference between the average pulse frequency and the target average frequency. In this manner, the effects of manufacturing variations and operational variations on the average pulse frequency can be eliminated, or at least diminished.