Pulse Width Modulator Patents (Class 332/109)
  • Patent number: 7847639
    Abstract: A pulse width modulation device which a step form control signal generated by a control signal generating device and a triangular wavecarrier signal generated by a carrier generating device are compared by a digital comparator and the comparison signal is supplied to an edge detection device. Also, a top/bottom signal generated by a top/bottom signal generating device is supplied to the edge detection device. The edge detection device includes an edge detection function that generates an edge detection signal by detecting change of the comparison signal. The edge detection function is inhibited by the edge detection signal; and inhibition is cancelled by the top/bottom signal so that the edge detection signal is output. A PWM signal is output from the pulse generating device in accordance with the comparison signal, edge detection signal, and top/bottom signal.
    Type: Grant
    Filed: December 26, 2006
    Date of Patent: December 7, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Chongshan Yang, Hiroshi Ozaki, Hiroyuki Tanaka
  • Publication number: 20100301959
    Abstract: A pulse width modulator (PWM) includes a driver and a two-way integrator. The driver is coupled to output a first and a subsequent period of a PWM signal. Both the first and the subsequent periods include the PWM signal changing between first and second states. The two-way integrator is coupled to integrate an input current and coupled to generate a duty ratio signal in response to integrating the input current. The driver determines a duty factor of both the first and the subsequent periods by setting the PWM signal to the second state in response to the duty ratio signal. The two-way integrator includes a capacitor that integrates the input current during the first period by charging the capacitor and integrates the input current during the subsequent period by discharging the capacitor.
    Type: Application
    Filed: June 2, 2009
    Publication date: December 2, 2010
    Applicant: Power Integrations, Inc.
    Inventors: Jonathan Edward Liu, Giao Minh Pham
  • Patent number: 7830218
    Abstract: A communications device includes a supply terminal which is able to be connected to a two-position-controlled power supply; a pulse width recording device, which is coupled to the supply terminal and which records a pulse width of current pulses that flow through the supply terminal, and a signal processing device which assigns a first logical level to a first recorded pulse width and a second logical level to a second recorded pulse width.
    Type: Grant
    Filed: August 17, 2007
    Date of Patent: November 9, 2010
    Assignee: Robert Bosch GmbH
    Inventors: Karl-Heinz Schauer, Bernhard Mader, Ingo Pietsch, Timo Schmidt, Thomas Holst
  • Patent number: 7830219
    Abstract: Pulse-width modulation (PWM) finds wide use in many applications including motor control, communication systems, music synthesizers, power supplies, class-D and digital amplifiers, among others. The Fourier series expansion of each period of a pulse waveform includes an additive term that is a function of the pulse width in that period. As the pulse width is varied, this additive term varies, which can be problematic in many applications. In an embodiment, a single-pulse per period pulse width modulated waveform comprising a zero d.c. term in each period regardless of pulse width is generated. In various realizations these waveforms may be generated by electronic circuitry without the use of capacitive coupling or may be generated by algorithms. Further aspects include “through-zero” pulse width modulation and zero-centered asymmetric triangle waveforms and use in instrumentation for measurement of a phase angle of an exogenous system or phenomena.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: November 9, 2010
    Inventor: Lester F. Ludwig
  • Publication number: 20100278228
    Abstract: An apparatus comprising a signal generator for generating a polar representation of a signal. The apparatus comprises further a first filtering unit configured to filter a low frequency part of the amplitude component of said signal and a second filtering unit configured to filter a high frequency-part of the amplitude component of said signal. In addition, the apparatus includes a pulse width modulating unit configured to modulate the filtered high frequency part of the amplitude component of said signal together with the phase component of said signal. Finally the apparatus includes a DC-DC converter configured to convert the filtered low frequency part of the amplitude component of said signal. Said DC-DC converter supplies a switching mode power amplifier for amplifying the pulse width modulated signal.
    Type: Application
    Filed: August 18, 2008
    Publication date: November 4, 2010
    Inventors: Jan S. Vromans, Mark P. Van Der Heijden
  • Publication number: 20100254172
    Abstract: The PWM signal generator of the present invention generates a first pulse waveform in which a first on-time ?T1 calculated by a first on-time calculator (401) is used as an on-duration, and a second pulse waveform in which a second on-time ?T2, calculated by a second on-time calculator (402) when a preset delay time has elapsed from the start of the calculation of the first on-time ?T1, is used as an on-duration. Also, a PWM signal generator (413) generates a PWM signal on the basis of a composite pulse in which the generated first pulse waveform and second pulse waveform are combined, and the first on-time calculator (401) calculates the first on-time ?T1 at the end of the composite pulse waveform.
    Type: Application
    Filed: September 11, 2008
    Publication date: October 7, 2010
    Applicants: Daihen Corporation, Kyoto University, National University Corporation Nagaoka University of Technology
    Inventors: Nobuyuki Hattori, Yoshito Ohta, Kenji Hirata
  • Publication number: 20100253240
    Abstract: A PWM control method increases/decreases a duty ratio of a PWM signal with a predetermined resolution so to control the duty ratio of the PWM signal in the case of a PWM control. The resolution of the duty ratio of the PWM signal is increased to make a high period in the duty ratio of the PWM signal longer than a rise time of the PWM signal if the high period is shorter than the rise time. The resolution of the duty ratio of the PWM signal is increased to make a low period in the duty ratio of the PWM signal longer than a fall time of the PWM signal if the low period is shorter than the fall time.
    Type: Application
    Filed: October 24, 2008
    Publication date: October 7, 2010
    Applicant: SUMITOMO WIRING SYSTEMS, LTD.
    Inventor: Nobuya Inamori
  • Patent number: 7804378
    Abstract: There is described a method and an apparatus for pulse width modulation with a predefined switching period having an adjustable ratio of the switch-on duration to the switch-off duration, in which a quantized signal is converted into a pulse-width-modulated signal and is generated in the form of a discrete pulse sequence of switch-on operations and switch-off operations with the predefined switching period, the switching edge for the switch-on duration and/or the switch-off duration being determined on the basis of the ratio of the switch-on duration to the switch-off duration.
    Type: Grant
    Filed: January 8, 2008
    Date of Patent: September 28, 2010
    Assignee: Siemens Aktiengesellschaft
    Inventors: Uwe Krause, Uwe Nolte, Jan Spannberger
  • Patent number: 7804379
    Abstract: Dead time compensated complementary pulse width modulation (PWM) signals are derived from a PWM generator by first applying time period compensation to the PWM generator signal based upon the direction of current flow in an inductive load being controlled by the PWM generator. Dead time is then applied to the compensated PWM generator signal for producing complementary dead time compensated PWM signals for controlling power switching circuits driving the inductive load.
    Type: Grant
    Filed: May 7, 2008
    Date of Patent: September 28, 2010
    Assignee: Microchip Technology Incorporated
    Inventors: Bryan Kris, Stephen Bowling
  • Patent number: 7791521
    Abstract: In a particular embodiment, a circuit device includes a pulse edge control circuit to receive at least one pulse-width modulated (PWM) signal from a PWM source. The pulse edge control circuit is adapted to selectively apply a phase shift operation to the at least one PWM signal at integer submultiples of a frame repetition rate to produce at least one modulated PWM signal having a changed power spectrum. The pulse edge control circuit provides the at least one modulated PWM signal to at least one output of the pulse edge control circuit.
    Type: Grant
    Filed: August 26, 2008
    Date of Patent: September 7, 2010
    Assignee: Silicon Laboratories, Inc.
    Inventors: John Khoury, Richard Beale
  • Patent number: 7791427
    Abstract: Systems and methods for minimizing startup transients in digital audio controllers that may result in audible artifacts in the output of an audio amplification system. One embodiment comprises a digital PWM amplifier that includes a mechanism for controlling the amount of dead time in the audio output signal. When the amplifier starts up, the PWM signals provided to the output stage are simultaneously deasserted (i.e., there is dead time) for most of each switch period. The amount of dead time is gradually reduced over a series of switch periods until a nominal operating amount of dead time in each switch period is reached. Thus, the PWM signals are slowly ramped up from having a very large percentage of dead time (e.g., nearly 100%) to having a very small percentage of dead time (e.g., 1-2% to prevent shoot-through.
    Type: Grant
    Filed: August 30, 2007
    Date of Patent: September 7, 2010
    Assignee: D2Audio Corporation
    Inventor: Michael A. Kost
  • Publication number: 20100219899
    Abstract: The PWM control circuit is provided. The PWM control circuit includes: a PWM control signal generator that generates a PWM period signal defining a period of a PWM signal and a PWM resolution signal specifying a resolution in one period of the PWM period signal; and a PWM unit that generates the PWM signal based on the PWM period signal and the PWM resolution signal, wherein the PWM control signal generator changes a frequency of the PWM resolution signal while keeping a frequency of the PWM period signal unchanged.
    Type: Application
    Filed: May 11, 2010
    Publication date: September 2, 2010
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Kesatoshi TAKEUCHI
  • Patent number: 7782129
    Abstract: A system is provided for use in an audio signal processor to reduce the order of the loop to remove sound artifacts from an audio signal that includes an input for receiving an audio input signal a control loop of order greater than one configured to process the audio input signal and to output a Pulse Width Modulated audio output signal, a circuit for performing a gradual reduction of the order of the control loop such that prior to entering a shut down state the order is reduced to a single order and a circuit to disconnect a Driver Circuit from the Pulse Width modulated signal operated by a timing device designed to switch at the moment of zero average output value.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: August 24, 2010
    Assignee: ESS Technology, Inc.
    Inventors: Andrew Martin Mallinson, Dustin Forman
  • Patent number: 7782154
    Abstract: A power amplifier including a loop filter, a frequency generator, a quantizer, and an output stage module is provided. The frequency generator outputs a signal with a reference frequency to the loop filter, and includes a logic circuit, a current array, and a dummy load. The dummy load representing a load circuit in the loop filter is coupled to the current array. An equivalent impedance of the dummy load is proportioned to an equivalent impedance of the load circuit. The current array outputs the signal and a dummy signal to the loop filter and the dummy load, respectively, according to a logic signal. By using the frequency generator to modulate the frequency automatically, an impact on the power amplifier caused by passive devices therein due to process variationscan be reduced.
    Type: Grant
    Filed: December 22, 2008
    Date of Patent: August 24, 2010
    Assignee: Industrial Technology Research Institute
    Inventors: Hsin-Hong Hou, Chung-Wei Lin
  • Patent number: 7778324
    Abstract: A system for controlling the delay applied to one branch of a pulse width modulation amplifier. The delay typically incorporated whether input signal level is low and diminished when the input signal level increases. The system may be implemented using a switch, a level detector and a timer, which in conjunction determine whether the delay unit is included in the branch or bypassed. The system may also use a programmable delay that can adjust the period of delay applied or be programmed to operate as a pass-through where delay is no longer beneficial for providing high signal quality.
    Type: Grant
    Filed: November 18, 2005
    Date of Patent: August 17, 2010
    Assignee: Harman International Industries, Incorporated
    Inventor: Gerald R. Stanley
  • Patent number: 7777587
    Abstract: The rising edge of a pulse width modulated output signal occurs after an input ramp signal starts to rise. The ramp signal starts to rise after the rising edge of a periodic set signal and before the falling edge of a periodic set signal. A feedback control signal intersects a substantially linear region of the ramp signal to generate a reset signal using a PWM comparator. The periodic set signal and reset signal are input to a latching circuit to generate the pulse width modulated output signal. The minimum pulse width can approach zero while having adequate overdrive to the PWM comparator. Having the rising edge of the reset signal rise before the falling edge of the set signal can allow a zero percent duty cycle without the need for a ramp offset voltage.
    Type: Grant
    Filed: August 6, 2008
    Date of Patent: August 17, 2010
    Assignee: International Rectifier Corporation
    Inventors: Brian Stevenson, Parviz Parto, Yang Chen
  • Publication number: 20100201455
    Abstract: Embodiments of the present method and system permit an effective method for determining the optimum selection of pulse width modulation polarity and type including determining machine parameters, inputting the machine parameters into a predicted duty cycle module, determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm, and determining the optimum type of the pulse width modulation for a predicted duty cycle based on the pulse width modulation generation algorithm.
    Type: Application
    Filed: September 23, 2009
    Publication date: August 12, 2010
    Applicant: AeroVironment, Inc.
    Inventor: Zaher Abdallah Daboussi
  • Patent number: 7764734
    Abstract: Digital pulse width modulation with variable period and error distribution that improves the tradeoff between resolution and clock speed in pulse width modulation circuits so that a higher resolution can be achieved with a lower clock speed. A preferred method includes, for a signal sample S and each value of P in a range Pmin to Pmax of pulse periods P, determining a pulse width V=round(P*S), where round(P*S) is the closest integer value of P*S, and the magnitude of the error |E|=|S?V/P|, for the value of V (Vopt) and P (Popt) associated with the lowest value of the magnitude of the error |E|, providing an output pulse of a pulse width Vopt during the pulse period Popt, and successively repeating a) and b). Other aspects of the invention may include error distribution, error squelching to prevent idle-tone, idle-noise artifacts, 2-samples-per-pulse and non-uniform sampling and pulsing. Other features are disclosed.
    Type: Grant
    Filed: October 31, 2006
    Date of Patent: July 27, 2010
    Assignee: Winbond Electronics Corporation
    Inventor: Samuel Chi Hong Yau
  • Patent number: 7760041
    Abstract: Otherwise conventional pulse-width modulators (PWMs) generate signals that can be converted into other forms by reshapers, and thereby overcome many of the problems of conventional PWMs in applications that demand high performance, such as switched-mode amplifiers and radio-frequency transmitters in modern communication systems. With a suitable reshaper, a conventional PWM differential signal can be converted into a signal more typical of linear amplification with nonlinear components (LINC) and still retain low-frequency information, such as the information needed for linearization of a switched-mode amplifier. Apparatus and methods of transforming signals are disclosed.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: July 20, 2010
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventor: Carl Bryant
  • Publication number: 20100176881
    Abstract: A pulse width modulation (PWM) circuit comprises a first integrator (g m1) with a first feedback capacitor (C1), a second integrator (gml) with a second feedback capacitor (C2) and a comparator (A0) having a first input (V1) connected to the output of the first integrator (gm1) and a second input (V2) connected to the output of the second integrator (gm2). A connection path comprising a resistor (R2) is established from the output of the first integrator (gm1) to an input of the second integrator (gm2). The first and second feedback capacitors (C1, C2) have capacities with a non-linear factor X(V) and a circuit with an inversely non-linear factor X?1(V) is arranged in the connection path between the output of the first integrator (gm1) and said input of the second integrator (gm2). The PWM circuit may form path of a Class-D amplifier.
    Type: Application
    Filed: June 19, 2008
    Publication date: July 15, 2010
    Applicant: NXP B.V.
    Inventors: Marco Berkhout, Benno Krabbenborg
  • Patent number: 7751471
    Abstract: A pulse width modulation (PWM) Regulator System with automatically switching pulse skipping mode (PSM) is disclosed. The PWM regulator system comprises a PWM regulator, a PSM switching module and a pulse generator. The PWM regulator converts the input voltage by PWM. The PSM switching module determines to enter or exit the PSM. The pulse generator adaptively produces pulse signal for the switching regulator to operate in PSM.
    Type: Grant
    Filed: January 6, 2009
    Date of Patent: July 6, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Kwan-Jen Chu, Chung-Lung Pai, Po-Shun Chung, Jing-Meng Liu
  • Patent number: 7746926
    Abstract: A pulse width modulation (PWM) Regulator System with automatically switching pulse skipping mode (PSM) is disclosed. The PWM regulator system comprises a PWM regulator, a PSM switching module and a pulse generator. The PWM regulator converts the input voltage by PWM. The PSM switching module determines to enter or exit the PSM. The pulse generator adaptively produces pulse signal for the switching regulator to operate in PSM.
    Type: Grant
    Filed: November 15, 2005
    Date of Patent: June 29, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Kwan-Jen Chu, Chung-Lung Pai, Po-Shun Chung, Jing-Meng Liu
  • Patent number: 7741927
    Abstract: The PWM control circuit is provided. The PWM control circuit includes: a PWM control signal generator that generates a PWM period signal defining a period of a PWM signal and a PWM resolution signal specifying a resolution in one period of the PWM period signal; and a PWM unit that generates the PWM signal based on the PWM period signal and the PWM resolution signal, wherein the PWM control signal generator changes a frequency of the PWM resolution signal while keeping a frequency of the PWM period signal unchanged.
    Type: Grant
    Filed: October 29, 2008
    Date of Patent: June 22, 2010
    Assignee: Seiko Epson Corporation
    Inventor: Kesatoshi Takeuchi
  • Patent number: 7728689
    Abstract: The invention relates to pulse width modulator system (PWMS) comprising a modulator system input (MI),a modulator output (MO), an amplitude distribution filter (ADF) ,and a pulse width modulator (PMOD), wherein said amplitude distribution filter (ADF) establishes an intermediate output signal (OS) by modifying the level of the amplitude distribution of an input signal (IS) within at least one predetermined amplitude range of said input signal (IS), said input signal (IS) being received from said modulator system input (MI), and wherein said pulse width modulator (PMOD) provides a modulator output signal (MOS) on said modulator output(MO) on the basis of said intermediate output signal (OS).
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: June 1, 2010
    Assignee: The TC Group A/S
    Inventors: Kim Rishøj Pedersen, Lars Arknæs-Pedersen
  • Publication number: 20100127789
    Abstract: In one embodiment, the digital pulse width modulator of these teachings includes comparators and a number of phases and capable of increasing resolution without increasing clock frequency. In another embodiment, the digital pulse width modulator (DPWM) of these teachings includes equality comparators and a number of phases and increases resolution without increasing clock frequency. A further embodiment of the system of these teachings includes a priority encoded comparator component (in one instance including a number of comparators) comparing duty cycle commands against preset minimums, that embodiment being referred to as a frequency Foldback component. Other embodiments and embodiments of the method of these teachings are also disclosed.
    Type: Application
    Filed: November 20, 2009
    Publication date: May 27, 2010
    Inventors: Stewart Kenly, Paul W. Latham, II
  • Patent number: 7724105
    Abstract: In a particular embodiment, a circuit device is disclosed that includes a data generator adapted to output a random pulse sequence having a particular spectral shape. The circuit device further includes a pulse edge control circuit to selectively apply a carrier suppression operation to at least one pulse-width modulated (PWM) signal in response to the random pulse sequence to produce at least one modulated PWM output signal. The spectral energy associated with a PWM carrier of the modulated PWM output signal at a carrier frequency and associated harmonics is changed such that the modulated PWM output signal has a spectral shape defined by the particular spectral shape.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: May 25, 2010
    Assignee: Silicon Laboratories, Inc.
    Inventors: Jeffrey D. Alderson, John M. Khoury, Richard Gale Beale
  • Patent number: 7719377
    Abstract: A pulse step modulator employs a plurality of series connected unit step power amplifier modules. Each module is turned on by a turn-on signal to provide a unit step voltage of a given value. An output circuit is connected to the modules for providing an output voltage to a load and wherein the output voltage is a multiple of the unit step voltages in dependence upon the number of modules that are turned on. The modules are sequentially turned on in a given order and are turned off in the reverse order. An encoder provides turn-on signals with each turn-on signal being applied to a selected one of the modules. The number of turn-on signals provided varies as a function of the magnitude of a time varying input signal. A controller alternately turns enables or disables (in a swapping manner) one of a pair of associated modules as the magnitude of the input signal increases and decreases.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: May 18, 2010
    Assignee: Harris Corporation
    Inventors: Ky Thoai Luu, David Geier
  • Publication number: 20100117752
    Abstract: A multiple channel Digital Pulse Width Modulator (DPWM) can include a single delay locked loop with a delay line, the delay line producing a number of outputs. Circuitry can use a delay line mask to mask a portion of the delay line outputs to produce a modified outputs so as to prevent premature pulse width reset. Jitter tolerance look ahead circuits can prevent jitter from causing premature reset of pulse width modulated signals. The pulse width modulators can include multiple alternately used multiplexers so that the operation of the pulse width modulators is not affected by the load time of the multiplexers.
    Type: Application
    Filed: October 29, 2009
    Publication date: May 13, 2010
    Applicant: EXAR CORPORATION
    Inventors: ERIC IOZSEF, IRV LUSTIGMAN, ABDELKARIM GADIRI
  • Publication number: 20100117751
    Abstract: The present invention relates to the application of a free-tunning clock signal in a pulse-width modulator (PWM) Specifically there is disclosed an integrated circuit comprising a pulse-width modulator (2) for converting an input signal (6) into a pulse-width-modulated signal (8), the pulse-width modulator (2) being clocked by a clock signal (4) generated by a clock generator (3) which generates a free-running clock signal In a preferred embodiment of the invention, the clock generator (3) is provided in the same integrated circuit (1), such as a chip, as the digital pulse-width modulator (2).
    Type: Application
    Filed: December 11, 2007
    Publication date: May 13, 2010
    Inventors: Morten Kragh, Ole Neis Nielsen
  • Patent number: 7714675
    Abstract: Methods and systems for modulating an input electrical signal are disclosed and may comprise modulating input signals utilizing a digital Class-D modulator and generating a digital output signal that is proportional to the input signals. The digital Class-D modulator may be comprised of four stages. To avoid integrator saturation, the output of at least one integrator stage may be limited by utilizing limiters in integrator feedback loops. The digital Class-D modulator utilizes a pulse width modulation technique. For increased signal to noise ratio (SNR) at a desired output power, the magnitude of a triangular waveform oscillator voltage may be greater than the magnitude of an integrated input signal. The digital output signal may be fed back to an input of at least one of the four stages in the digital Class-D modulator. The triangular waveform oscillator frequency may be adjusted to match desired output frequency.
    Type: Grant
    Filed: December 5, 2006
    Date of Patent: May 11, 2010
    Assignee: Broadcom Corporation
    Inventor: Minsheng Wang
  • Publication number: 20100110743
    Abstract: To suppress an unbalance of a dwell period in a changeover of phases in which switching is dwelled in an inverter controller. A PWM operation unit 5 includes a modulation-wave generating unit 11 that generates a modulation wave as a voltage command value to an inverter main circuit 2, a carrier-wave generating unit 12 that generates a carrier wave used as a reference for a switching command, and a comparing unit 13 that compares the modulation wave generated by the modulation-wave generating unit 11 and the carrier wave generated by the carrier-wave generating unit 12. During an operation in a two-phase modulation mode in which switching of any one of three phases configuring the inverter main circuit 2 is dwelled, the PWM operation unit 5 controls the carrier-wave generating unit 12 to set a carrier wave frequency to an integral multiple of a modulation wave frequency.
    Type: Application
    Filed: April 20, 2007
    Publication date: May 6, 2010
    Applicant: Mitsubishi Electric Corproation
    Inventor: Hisanori Yamasaki
  • Patent number: 7710214
    Abstract: A pulse width modulation (PWM) structure enabling regulated duty cycle includes a DC power supply unit, a signal generating unit, a voltage-dividing resistor unit, a reference voltage unit, and a comparing unit. When the DC power supply unit supplies a voltage signal to the voltage-dividing resistor unit, the latter receives the voltage signal and sets voltage levels before sending the voltage signal to the signal generating unit, so that a waveform signal generated by the signal generating unit regulates its voltage levels according to the received voltage signal before sending the waveform signal to the comparing unit. The comparing unit receives and compares the signals from the signal generating unit and the reference voltage unit, and outputs a comparison signal for driving a fan motor to operate, so that the finally output signal is substantially linear and smooth.
    Type: Grant
    Filed: March 13, 2008
    Date of Patent: May 4, 2010
    Assignee: Anpec Electronics Corporation
    Inventor: Ching-Sheng Li
  • Patent number: 7710174
    Abstract: A low-power digital pulse-width modulator (DPWM) architecture for high frequency dc-dc switch-mode power supplies (SMPS) is disclosed that is well-suited for integration in power management systems of small handheld devices. The DPWM can operate in a stand-alone mode, without external clock, and can be implemented on a portion of silicon area needed for other DPWM solutions. In addition it has low power consumption and provides a good linearity of the input-to-output characteristic, also not characteristic for other architectures.
    Type: Grant
    Filed: February 20, 2008
    Date of Patent: May 4, 2010
    Assignee: Exar Corporation
    Inventors: Aleksandar Prodić, Kun Wang, Amir Parayandeh
  • Patent number: 7705689
    Abstract: Synchronously stackable double-edge modulated pulse width modulation generators are disclosed. An example pulse width modulation generator includes a ramp generator to generate first and second ramp signals that interact to form a virtual ramp signal; and a comparator module coupled to the ramp generator configured to produce a pulse width modulated signal based on a comparison between the virtual ramp signal and an input signal.
    Type: Grant
    Filed: May 19, 2008
    Date of Patent: April 27, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: William Todd Harrison, Xuening Li, Stefan Wlodzimierz Wiktor
  • Publication number: 20100097153
    Abstract: Switch-modulation of a radio-frequency power amplifier by-representing the input signal by the I-signal (1) and Q-signal (9) of the complex components (I+j?Q), and pulse width modulating the I-signal and the Q-signal separately to create a modulated I-signal pulse sequence (3a) and a modulated Q-signal pulse sequence (3b). Further, the pulses corresponding to negative sample values are time-shifted relative the pulses corresponding to positive sample values, and each pulse of the I-signal pulse sequence is delayed by introducing a delaying time shift.
    Type: Application
    Filed: October 27, 2006
    Publication date: April 22, 2010
    Inventors: Leonard Rexberg, Håkan Malmqvist, Thomas Lejon
  • Patent number: 7701307
    Abstract: In a particular embodiment, a circuit device includes a pulse edge control circuit to receive at least one pulse-width modulated (PWM) signal from a PWM source. The pulse edge control circuit is adapted to selectively invert and swap the at least one PWM signal with a logic-inverted duty-cycle complement of the at least one PWM signal at discrete time intervals to produce at least one modulated PWM signal having a changed power spectrum. The pulse edge control circuit provides the at least one modulated PWM signal to at least one output of the pulse edge control circuit.
    Type: Grant
    Filed: August 7, 2008
    Date of Patent: April 20, 2010
    Assignee: Silicon Laboratories, Inc.
    Inventors: Richard Beale, John Khoury
  • Publication number: 20100073102
    Abstract: An apparatus and methods for a baseband modulator configured to code amplitude signals into pulse width modulated time signals comprising at least two amplitude levels is disclosed. A pulse width modulator can receive a component signal of a baseband complex signal and generate a discrete-time pulse width modulated signal. This signal can be converted to a continuous time signal, such as a pulse-width modulated time signal and can be shifted to a carrier signal corresponding respectively to the component signal by a switch. Bursts sequences are generated to an input of a switched amplifier for driving operation of the amplifier therein.
    Type: Application
    Filed: September 25, 2008
    Publication date: March 25, 2010
    Applicant: Infineon Technologies AG
    Inventors: Peter Singerl, Thomas Blocher, Andreas Wiesbauer
  • Patent number: 7679464
    Abstract: A method and apparatus for frequency modulating a PWM involves 1) generating a high frequency carrier signal much greater in frequency than the PWM signal; 2) modulating the high frequency signal to generate a spread spectrum carrier signal; and, 3) retiming a PWM signal with this high frequency SS carrier signal so that the binary transitions of the PWM signal are aligned with the frequency varying carrier signal. In another embodiment, a PWM oscillator is driven by a second, FM oscillator having spread spectrum characteristics. In another embodiment a PWM oscillator is driven and modulated by a counter/frequency divider comprised of modules.
    Type: Grant
    Filed: March 3, 2008
    Date of Patent: March 16, 2010
    Inventors: Dan Ion Hariton, Narendar Venugopal
  • Publication number: 20100052805
    Abstract: The invention relates to a high-mode self-oscillating pulse modulator. According to the invention, a complete rethinking of preconditions for oscillation and modulation in an oscillating modulator as all conventional thinking of how to apply oscillation in a modulator has been set aside. Thus, according to the invention, high-mode oscillation refers to an oscillation at a higher mode than the first mode, which is conventionally regarded as the one and only applicable mode in an oscillating modulator.
    Type: Application
    Filed: July 11, 2006
    Publication date: March 4, 2010
    Applicant: TC GROUP A/S
    Inventors: Kim Rishoj Pedersen, Lars Arknaes-Pedersen
  • Publication number: 20100052804
    Abstract: A pulse width modulation device in which a step form control signal generated by a control signal generating device and a triangular wave carrier signal generated by a carrier generating device are compared by a digital comparator and the comparison signal is supplied to an edge detection device. Also, a top/bottom signal generated by a top/bottom signal generating device is supplied to the edge detection device The edge detection device includes an edge detection function that generates an edge detection signal by detecting change of the comparison signal. The edge detection function is inhibited by the edge detection signal; and inhibition is cancelled by the top/bottom signal so that the edge detection signal is output. A PWM signal is output from the pulse generating device in accordance with the comparison signal, edge detection signal, and top/bottom signal.
    Type: Application
    Filed: December 26, 2006
    Publication date: March 4, 2010
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Chongshan Yang, Hiroshi Ozaki, Hiroyuki Tanaka
  • Patent number: 7667552
    Abstract: A system is described for generating a discrete noise-shaped variable switching frequency signal that may be used to define a digital pulse width modulation (“PWM”) period. The system may define a switching frequency waveform that may be used to generate a current switching frequency signal as a function of a system clock. The system may quantize the current switching frequency signal to generate a discrete switching frequency signal that is realizable with the system clock. The system may detect quantization noise and input the noise into the current switching frequency signal to eliminate or reduce discrete tones at the switching frequencies of a PWM signal spectrum.
    Type: Grant
    Filed: April 10, 2007
    Date of Patent: February 23, 2010
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Pallab Midya, Xin Geng
  • Publication number: 20100033261
    Abstract: The rising edge of a pulse width modulated output signal occurs after an input ramp signal starts to rise. The ramp signal starts to rise after the rising edge of a periodic set signal and before the falling edge of a periodic set signal. A feedback control signal intersects a substantially linear region of the ramp signal to generate a reset signal using a PWM comparator. The periodic set signal and reset signal are input to a latching circuit to generate the pulse width modulated output signal. The minimum pulse width can approach zero while having adequate overdrive to the PWM comparator. Having the rising edge of the reset signal rise before the falling edge of the set signal can allow a zero percent duty cycle without the need for a ramp offset voltage.
    Type: Application
    Filed: August 6, 2008
    Publication date: February 11, 2010
    Applicant: INTERNATIONAL RECTIFIER CORPORATION
    Inventors: Brian Stevenson, Parviz Parto, Yang Chen
  • Patent number: 7659789
    Abstract: A class-D amplifier (10) includes a logic circuit (40) for controlling the operation of a switching bridge (11). The logic circuit (40) transmits the differential mode of a differential pulse width modulation input signal and deletes a central portion of the common mode of input signal, while preserving pulses of a minimum pulse width following a rising edge and preceding a falling edge in common mode of the input signal. Deleting the central portion of the common mode signal improves the efficiency and reduces the electromagnetic interference radiation of the class-D amplifier (10). Preserving the pulses of the minimum pulse width ensures the proper operation of the switching elements (12, 14, 16, 18) in the switching bridge (11), thereby reducing the distortion in the signal amplification.
    Type: Grant
    Filed: February 9, 2006
    Date of Patent: February 9, 2010
    Assignee: Apexone Microelectronics Ltd.
    Inventors: Hao Zhu, Haibin Huang, Yongqing Ren
  • Patent number: 7656946
    Abstract: The invention provides a pulse width modulation amplifier that includes a correction circuit, an envelope detector, a level detector, a PWM carrier generator, an interpolation arithmetic circuit, and a PWM circuit. The envelope detector detects an envelope of digital data to be input. The correction circuit performs distortion correction, frequency characteristic correction, and ?? correction, for the input digital data. The level detector detects levels of the digital data supplied by the envelope detector. The PWM carrier generator gates a carrier signal having a frequency corresponding to the output of the level detector. The interpolation arithmetic circuit generates interpolation data synchronous with the carrier signal from the digital data. The PWM circuit converts the interpolation data into a pulse width modulation signal based on the carrier signal.
    Type: Grant
    Filed: December 23, 2005
    Date of Patent: February 2, 2010
    Assignee: Yamaha Corporation
    Inventor: Morito Morishima
  • Publication number: 20100019745
    Abstract: A method of and system for modulating buck and boost modulation ramps of a multiple switch node power converter without overlap. As the pulse width or duty cycle of the signal to a modulated complementary switching pair approaches a pre-established reference pulse width or duty cycle, plural fixed-width or fixed duty cycle pulses are generated and introduced to a nonmodulated complementary switching pair. A controller detects proximity to the pulse width or duty cycle limit and, correspondingly, initiates prematurely a pseudo-buck-boost mode in the power converter by generating fixed-width or fixed duty cycle pulses to the nonmodulated complementary switching pair while the duty cycles or pulse widths to the modulated complementary switching pair are still controlled by the appropriate modulation ramp. The net effect is that the power converter reaches its optimal operating point without overlap and eliminates any sub-harmonic switching.
    Type: Application
    Filed: July 22, 2008
    Publication date: January 28, 2010
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Neeraj Arun Keskar, Peter James Miller
  • Publication number: 20100013569
    Abstract: Systems and methods are disclosed that can be used to control an output signal, such as for controlling a heater for a hard disk drive. A system can include a pre-driver configured to provide a pulse-width modulated (PWM) signal to an output system in response to a control signal and a feedback signal, the output system being configured to provide an output signal for driving a load, the pre-driver comprising a modulator that provides the PWM signal in response to the control signal and a filtered feedback signal. A low pass filter is configured to receive a feedback signal with a voltage corresponding to a voltage of the output signal, wherein the low pass filter provides the filtered feedback signal that controls a frequency of the PWM signal to the modulator, the low pass filter having a bulk driven operational transconductance amplifier.
    Type: Application
    Filed: July 15, 2008
    Publication date: January 21, 2010
    Inventors: William Martin Torres Escajadillo, Pankaj Pandey, Reza Sharifi
  • Patent number: 7642876
    Abstract: A PWM generator system provides improved duty cycle resolution using a sub-cycle generator for generating a sub-cycle with a period that is a small fraction of the maximum PWM period to be generated. An integral sub-cycle estimator is coupled to said sub-cycle generator for determining the integral number of said sub-cycles for on and off time of the PWM waveform. An additional sub-cycle estimator determines the additional fractional sub-cycle required to provide the on and off time. A timer coupled to the integral sub cycle estimator and the additional sub cycle estimator controls PWM output switching for the on and off time of the integral and additional fractional sub cycles.
    Type: Grant
    Filed: October 28, 2005
    Date of Patent: January 5, 2010
    Assignee: STMicroelectronics PVT. Ltd.
    Inventor: Nitin Agarwal
  • Patent number: 7642877
    Abstract: A self-oscillating pulse-width modulator comprises an input, an output and a control loop. The control loop comprises a forward branch and a feedback loop. The forward branch is connected between the input and the output and comprises a comparator and a delay element. The feedback loop loops back to the input a feedback signal which depends on an output signal present at the output. The phase shift of the open control loop is 180° at the frequency of an oscillation to be generated by the modulator. At least a part of the phase shift is realized in the forward branch by means of the at least one delay element.
    Type: Grant
    Filed: September 8, 2006
    Date of Patent: January 5, 2010
    Assignee: Infineon Technologies AG
    Inventors: Martin Clara, Thomas Poetscher, Sergio Walter, Andreas Wiesbauer
  • Publication number: 20090296805
    Abstract: A pulse width modulation (PWM) controller includes: a first counter for counting a reference clock signal, and thus outputting a first count value, a leading edge control signal generator for outputting a leading edge control signal on a basis of the first count value, an adjustment clock generator for generating an adjustment clock signal, a second counter controller for instructing the adjustment clock generator to start to output the adjustment clock signal, a second counter for outputting a second count value, a trailing edge control signal generator for outputting a trailing edge control signal on a basis of the second count value, and a PWM pulse generator for synthesizing the leading edge control signal and the trailing edge control signal, and thus generating a pulse width modulation signal.
    Type: Application
    Filed: May 15, 2009
    Publication date: December 3, 2009
    Applicant: NEC Electronics Corporation
    Inventor: Hideyuki Takahashi
  • Publication number: 20090284322
    Abstract: Synchronously stackable double-edge modulated pulse width modulation generators are disclosed. An example pulse width modulation generator includes a ramp generator to generate first and second ramp signals that interact to form a virtual ramp signal; and a comparator module coupled to the ramp generator configured to produce a pulse width modulated signal based on a comparison between the virtual ramp signal and an input signal.
    Type: Application
    Filed: May 19, 2008
    Publication date: November 19, 2009
    Inventors: William Todd Harrison, Xuening Li, Stefan Wlodzimierz Wiktor