Patents by Inventor Fredrik Wahledow

Fredrik Wahledow has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8816663
    Abstract: To calculate a control signal for the duty cycle of a switched mode power supply (SMPS), a voltage feed forward compensator is integrated into a feedback unit. A control unit has an adder with a first input to receive a signal dependent upon an output voltage. A second input receives a signal from a feedback circuit, and an output outputs a signal comprising the sum of the signals applied to the inputs; another output outputs a control signal for controlling the duty cycle, the control signal is dependent upon the output signal from the adder; a voltage feed forward compensation signal generator calculates a compensation signal to adjust the control signal depending upon an input voltage of the SMPS; and a feedback circuit between the output of the adder and the second input of the adder calculates a compensated feedback signal and to feed the compensated feedback signal to the second input of the adder.
    Type: Grant
    Filed: February 26, 2010
    Date of Patent: August 26, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventors: Magnus Karlsson, Fredrik Wahledow
  • Publication number: 20130343094
    Abstract: A control circuit for a switched mode power supply (SMPS) has an input voltage reference voltage generator arranged to receive a signal indicative of an input voltage of the SMPS and is arranged to generate a reference signal directly proportional to the input voltage. An error signal generator of the control circuit is arranged to receive a signal indicative of an output voltage of the SMPS and arranged to generate an error signal based on the reference signal generated by the input reference voltage generator and based on the output voltage of the SMPS. A duty cycle control signal generator of the control circuit is arranged to generate a control signal, to control the duty cycle of the SMPS, in dependence upon the error signal.
    Type: Application
    Filed: March 3, 2011
    Publication date: December 26, 2013
    Inventors: Magnus Karlsson, Anders Kullman, Fredrik Wahledow, Henrik Borgengren, Jonas Malmberg, Oscar Persson
  • Publication number: 20130141945
    Abstract: An isolated switched mode power supply, SMPS, comprises a switching controller operable to generate start-up switching control signals during start-up of the isolated SMPS, and operational switching control signals of period T during subsequent operation of the isolated SMPS. The SMPS further comprises a transformer having a primary winding and a full-bridge drive circuit arranged to drive the primary winding of the transformer in response to the switching control signals. The full-bridge drive circuit has: a first switching element and a boot-strap driving circuit arranged to switch the first switching element in response to the switching control signals, the boot-strap driving circuit having a boot-strap capacitor. The full-bridge drive circuit further comprises a second switching element connected to the first switching element and to the boot-strap driving circuit, and arranged to conduct a current to charge the boot-strap capacitor when switched ON in response to the switching control signals.
    Type: Application
    Filed: December 1, 2011
    Publication date: June 6, 2013
    Applicant: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Magnus Karlsson, Anders Kullman, Jonas Malmberg, Fredrik Wahledow
  • Patent number: 8456867
    Abstract: An isolated switched mode power supply (SMPS) is disclosed. The SMPS comprises a switching controller to generate start-up and operational switching control signals. The SMPS further includes a transformer, having a primary winding, and a full-bridge drive circuit to drive the primary winding. The full-bridge drive circuit comprises a first switching element, a boot-strap dnving circuit, and a second switching element. The switching controller is further used to start up isolated SMPS by determining a duty cycle for operational control signals and generating the start-up switching control signals.
    Type: Grant
    Filed: December 1, 2011
    Date of Patent: June 4, 2013
    Assignee: Telefonaktiebolaget LM Ericsson (Publ)
    Inventors: Magnus Karlsson, Anders Kullman, Jonas Malmberg, Fredrik Wahledow
  • Patent number: 8451038
    Abstract: A switched mode power supply (SMPS) comprising a feedback unit, voltage feed forward (VFF) compensation signal generator and a transient detector. A VFF compensation signal is only applied to the output of the feedback unit when a transient is detected by the transient detector on the input voltage of the SMPS, thereby saving power and computation time.
    Type: Grant
    Filed: February 2, 2011
    Date of Patent: May 28, 2013
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventors: Magnus Karlsson, Henrik Borgengren, Anders Kullman, Jonas Malmberg, Fredrik Wahledow
  • Publication number: 20120319504
    Abstract: To reduce power loss in an intermediate bus architecture power system, embodiments of the present invention provide an intermediate bus converter which converts an input voltage to an intermediate bus voltage using a converting unit; receives a signal indicative of an output of a converting unit; determines an intermediate bus voltage to reduce power loss in dependence upon the signal indicative of an output of the converting unit; generates a control signal to control the converting unit to convert the input voltage to the determined intermediate bus voltage; and generates an intermediate bus voltage in dependence upon the control signal.
    Type: Application
    Filed: April 20, 2011
    Publication date: December 20, 2012
    Inventors: Jonas Malmberg, Anders Kullman, Fredrik Wahledow, Henrik Borgengren, Magnus Karlsson, Oscar Persson
  • Publication number: 20120287681
    Abstract: A switching delay controller (150) for controlling a switching delay between the switching of a first and a second switching element (Q1 to Q4) in a switched mode power supply (300), the switched mode power supply comprising a feedback signal generator (140) operable to generate a feedback signal indicative of a difference between an output (Vout) of the switched mode power supply and a reference (Vref) for the output, and a drive circuit (120) for switching the first and second switching elements so as to convert an input voltage (Vin) to the switched mode power supply (300) into an output voltage (Vout) thereof based on the feedback signal.
    Type: Application
    Filed: May 10, 2011
    Publication date: November 15, 2012
    Applicant: Telefonaktiebolaget L M Ericsson (publ)
    Inventors: Fredrik Wahledow, Henrik Borgengren, Magnus Karlsson, Anders Kullman, Jonas Malmberg
  • Publication number: 20120200331
    Abstract: A switched mode power supply (SMPS) comprising a feedback unit, voltage feed forward (VFF) compensation signal generator and a transient detector. A VFF compensation signal is only applied to the output of the feedback unit when a transient is detected by the transient detector on the input voltage of the SMPS, thereby saving power and computation time.
    Type: Application
    Filed: February 2, 2011
    Publication date: August 9, 2012
    Applicant: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Magnus Karlsson, Fredrik Wahledow, Jonas Malmberg, Henrik Borgengren, Anders Kullman
  • Publication number: 20120049908
    Abstract: To calculate a control signal for the duty cycle of a switched mode power supply (SMPS), a voltage feed forward compensator is integrated into a feedback unit. A control unit has an adder with a first input to receive a signal dependent upon an output voltage.
    Type: Application
    Filed: February 26, 2010
    Publication date: March 1, 2012
    Inventors: Magnus Karlsson, Fredrik Wahledow