Patents by Inventor Tsutomu Ishino

Tsutomu Ishino 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: 10389339
    Abstract: A slew rate control device for controlling a slew rate, includes: a setting part configured to set a voltage value used to determine the slew rate; and a control part configured to control the slew rate, based on the voltage value set by the setting part, so that the slew rate becomes slower as an output voltage of a power supply approaches from a transition starting voltage to a target voltage.
    Type: Grant
    Filed: April 13, 2017
    Date of Patent: August 20, 2019
    Assignee: ROHM CO., LTD.
    Inventors: Tetsuro Hashimoto, Tsutomu Ishino
  • Publication number: 20170346402
    Abstract: A pulse modulator generates a pulse signal, such that an output signal of a DC/DC converter approaches a target value. When a detection value of a coil current of the DC/DC converter crosses a threshold for zero crossing, a reverse flow detection circuit asserts a reverse flow detection signal and turns off a synchronous rectification transistor of the DC/DC converter. An optimizer controls an operation parameter of the reverse flow detection circuit, on the basis of a cycle of the pulse signal.
    Type: Application
    Filed: May 24, 2017
    Publication date: November 30, 2017
    Inventors: Tsutomu ISHINO, Tetsuro HASHIMOTO
  • Publication number: 20170317667
    Abstract: A slew rate control device for controlling a slew rate, includes: a setting part configured to set a voltage value used to determine the slew rate, and a control part configured to control the slew rate, based on the voltage value set by the setting part, so that the slew rate becomes slower as an output voltage of a power supply approaches from a transition starting voltage to a target voltage.
    Type: Application
    Filed: April 13, 2017
    Publication date: November 2, 2017
    Inventors: Tetsuro HASHIMOTO, Tsutomu ISHINO
  • Publication number: 20150015219
    Abstract: A DC/DC converter comprises: inductors L provided for respective channels; switching circuits provided for the respective channels; and a controller configured to change the number of channels to be activated, i.e., K, according to an amount of a load current IOUT that flows through a load, and to control the switching circuits that correspond to the activated channels such that a feedback voltage VFB that corresponds to an output voltage VOUT matches a predetermined target voltage VREF. The controller activates only a single channel in a lightest load state. The inductance L of the inductor L provided for the aforementioned single channel is set to a value that differs from the inductances of the inductors L of the other channels so as to provide high efficiency in the lightest load state.
    Type: Application
    Filed: April 15, 2014
    Publication date: January 15, 2015
    Applicant: ROHM CO., LTD
    Inventors: Tsutomu ISHINO, Tadayuki SAKAMOTO
  • Patent number: 8912777
    Abstract: The present invention improves the efficiency of a switching power supply in a light load. A control circuit is configured to repeat a driving duration enabling the switching element to be switched and a stop duration stopping the switching in a light load state. A pulse signal generating portion generates a driving pulse signal, in which the driving pulse signal at least includes a pulse in the driving duration, and the lighter a load is, the less the number of pulses in the driving duration is. A first driver drives a first switching transistor according to the at least one pulse in the driving pulse signal other than predetermined K pulses (K is a natural number). The K pulses are in the driving pulse signal when the number of the pulses is reduced to K.
    Type: Grant
    Filed: August 15, 2012
    Date of Patent: December 16, 2014
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Patent number: 8786247
    Abstract: A charging circuit receives electric power from a solar battery, and charges a secondary battery. A charging current detection unit generates a detection signal that corresponds to a charging current supplied from a DC/DC converter to the secondary battery. A control circuit generates a reference voltage that corresponds to the detection signal. A driving unit generates a pulse signal having a duty ratio that is adjusted such that the voltage output from the solar battery matches the reference voltage, and performs switching of a switching transistor according to the pulse signal. A control circuit adjusts the reference voltage such that the reference voltage becomes greater.
    Type: Grant
    Filed: September 14, 2011
    Date of Patent: July 22, 2014
    Assignee: Rohm Co., Ltd.
    Inventors: Tsutomu Ishino, Tadayuki Sakamoto
  • Patent number: 8716995
    Abstract: An error amplifier generates an error signal VERR that corresponds to the difference between a feedback signal VFB and a predetermined reference voltage VREF. A first oscillator generates a first cyclic signal VOSC1 having a sloping segment and a first frequency. A second oscillator generates a second cyclic signal VOSC2 having a sloping segment and a second frequency that is lower than the first frequency. A first pulse modulator generates a first pulse signal having a pulse width that corresponds to the error signal VERR, and clamps its pulse width such that it does not become smaller than a first minimum pulse width. A second pulse modulator generates a second pulse signal having a pulse width that corresponds to the error signal VERR. A synthesizing unit combines the first pulse signal and the second pulse signal so as to generate a driving pulse signal.
    Type: Grant
    Filed: November 17, 2011
    Date of Patent: May 6, 2014
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Publication number: 20130043851
    Abstract: The present invention improves the efficiency of a switching power supply in a light load. A control circuit is configured to repeat a driving duration enabling the switching element to be switched and a stop duration stopping the switching in a light load state. A pulse signal generating portion generates a driving pulse signal, in which the driving pulse signal at least includes a pulse in the driving duration, and the lighter a load is, the less the number of pulses in the driving duration is. A first driver drives a first switching transistor according to the at least one pulse in the driving pulse signal other than predetermined K pulses (K is a natural number). The K pulses are in the driving pulse signal when the number of the pulses is reduced to K.
    Type: Application
    Filed: August 15, 2012
    Publication date: February 21, 2013
    Applicant: ROHM CO., LTD.
    Inventor: Tsutomu ISHINO
  • Publication number: 20120235623
    Abstract: A charging circuit receives electric power from a solar battery, and charges a secondary battery. A charging current detection unit generates a detection signal that corresponds to a charging current supplied from a DC/DC converter to the secondary battery. A control circuit generates a reference voltage that corresponds to the detection signal. A driving unit generates a pulse signal having a duty ratio that is adjusted such that the voltage output from the solar battery matches the reference voltage, and performs switching of a switching transistor according to the pulse signal. A control circuit adjusts the reference voltage such that the reference voltage becomes greater.
    Type: Application
    Filed: September 14, 2011
    Publication date: September 20, 2012
    Applicant: ROHM CO., LTD.
    Inventors: Tsutomu ISHINO, Tadayuki Sakamoto
  • Publication number: 20120126768
    Abstract: An error amplifier generates an error signal VERR that corresponds to the difference between a feedback signal VFB and a predetermined reference voltage VREF. A first oscillator generates a first cyclic signal VOSC1 having a sloping segment and a first frequency. A second oscillator generates a second cyclic signal VOSC2 having a sloping segment and a second frequency that is lower than the first frequency. A first pulse modulator generates a first pulse signal having a pulse width that corresponds to the error signal VERR, and clamps its pulse width such that it does not become smaller than a first minimum pulse width. A second pulse modulator generates a second pulse signal having a pulse width that corresponds to the error signal VERR. A synthesizing unit combines the first pulse signal and the second pulse signal so as to generate a driving pulse signal.
    Type: Application
    Filed: November 17, 2011
    Publication date: May 24, 2012
    Applicant: ROHM CO., LTD.
    Inventor: Tsutomu ISHINO
  • Patent number: 7888926
    Abstract: A pulse signal generating circuit generates a pulse signal having a duty ratio controlled such that the output voltage approaches a reference voltage. A driver circuit generates first and second gate voltages, which are to be respectively applied to the gates of a switching transistor and a synchronous rectifier transistor, based upon the pulse signal. A threshold voltage generating unit generates a threshold voltage which is synchronous with the second gate voltage, and which is in the high-level state during a period when the synchronous rectifier transistor is to be turned off and in the low-level state during a period when the synchronous rectifier transistor is to be turned on. A light-load detection comparator compares a switching voltage with the threshold voltage, and outputs a light-load detection signal.
    Type: Grant
    Filed: July 14, 2009
    Date of Patent: February 15, 2011
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Patent number: 7868598
    Abstract: A switching regulator according to the invention includes a resistor (R3) and a capacitor (C3) for generating a ramp signal from the AC component in the output of a hysteresis comparator (1). The switching regulator is characterized in that the hysteresis comparator (1) compares with a reference voltage outputted from a reference voltage source (2) a voltage obtained by superimposing the ramp signal on the divided voltage of the output voltage (VO) as obtained between resistors (R1 and R2).
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: January 11, 2011
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Patent number: 7759917
    Abstract: A power supply unit comprises a series regulator and a switching DC-DC converter controlled by a PWM signal and connected in parallel with the series regulator, which are switchably enabled by a mode instruction signal depending on the magnitude of a load current. In switching the series regulator and the DC-DC converter, they are simultaneously enabled for a predetermined overlapping time. Further, in changing the operating condition of the DC-DC converter, the width of the PWM signal is shortened to extend the dead time of the DC-DC converter by a predetermined period, thereby suppressing free oscillations and accompanying overshoots that could take place in the power supply unit during switching.
    Type: Grant
    Filed: June 4, 2008
    Date of Patent: July 20, 2010
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Publication number: 20090273329
    Abstract: A pulse signal generating circuit generates a pulse signal having a duty ratio controlled such that the output voltage approaches a reference voltage. A driver circuit generates first and second gate voltages, which are to be respectively applied to the gates of a switching transistor and a synchronous rectifier transistor, based upon the pulse signal. A threshold voltage generating unit generates a threshold voltage which is synchronous with the second gate voltage, and which is in the high-level state during a period when the synchronous rectifier transistor is to be turned off and in the low-level state during a period when the synchronous rectifier transistor is to be turned on. A light-load detection comparator compares a switching voltage with the threshold voltage, and outputs a light-load detection signal.
    Type: Application
    Filed: July 14, 2009
    Publication date: November 5, 2009
    Applicant: ROHM CO., LTD.
    Inventor: Tsutomu ISHINO
  • Patent number: 7576529
    Abstract: A pulse signal generating circuit generates a pulse signal having a duty ratio controlled such that the output voltage approaches a reference voltage. A driver circuit generates first and second gate voltages, which are to be respectively applied to the gates of a switching transistor and a synchronous rectifier transistor, based upon the pulse signal. A threshold voltage generating unit generates a threshold voltage which is synchronous with the second gate voltage, and which is in the high-level state during a period when the synchronous rectifier transistor is to be turned off and in the low-level state during a period when the synchronous rectifier transistor is to be turned on. A light-load detection comparator compares a switching voltage with the threshold voltage, and outputs a light-load detection signal.
    Type: Grant
    Filed: June 26, 2006
    Date of Patent: August 18, 2009
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Publication number: 20090033299
    Abstract: A pulse signal generating circuit generates a pulse signal having a duty ratio controlled such that the output voltage approaches a reference voltage. A driver circuit generates first and second gate voltages, which are to be respectively applied to the gates of a switching transistor and a synchronous rectifier transistor, based upon the pulse signal. A threshold voltage generating unit generates a threshold voltage which is synchronous with the second gate voltage, and which is in the high-level state during a period when the synchronous rectifier transistor is to be turned off and in the low-level state during a period when the synchronous rectifier transistor is to be turned on. A light-load detection comparator compares a switching voltage with the threshold voltage, and outputs a light-load detection signal.
    Type: Application
    Filed: June 26, 2006
    Publication date: February 5, 2009
    Applicant: ROHM CO., LTD.
    Inventor: Tsutomu Ishino
  • Publication number: 20090021232
    Abstract: A switching regulator according to the invention includes a resistor (R3) and a capacitor (C3) for generating a ramp signal from the AC component in the output of a hysteresis comparator (1). The switching regulator is characterized in that the hysteresis comparator (1) compares with a reference voltage outputted from a reference voltage source (2) a voltage obtained by superimposing the ramp signal on the divided voltage of the output voltage (VO) as obtained between resistors (R1 and R2).
    Type: Application
    Filed: March 9, 2006
    Publication date: January 22, 2009
    Applicant: ROHM CO., LTD.
    Inventor: Tsutomu Ishino
  • Publication number: 20080284402
    Abstract: A power supply unit comprises a series regulator and a switching DC-DC converter controlled by a PWM signal and connected in parallel with the series regulator, which are switchably enabled by a mode instruction signal depending on the magnitude of a load current. In switching the series regulator and the DC-DC converter, they are simultaneously enabled for a predetermined overlapping time. Further, in changing the operating condition of the DC-DC converter, the width of the PWM signal is shortened to extend the dead time of the DC-DC converter by a predetermined period, thereby suppressing free oscillations and accompanying overshoots that could take place in the power supply unit during switching.
    Type: Application
    Filed: June 4, 2008
    Publication date: November 20, 2008
    Applicant: ROHM CO., LTD.
    Inventor: Tsutomu ISHINO
  • Patent number: 7397151
    Abstract: A power supply unit comprises a series regulator and a switching DC-DC converter controlled by a PWM signal and connected in parallel with the series regulator, which are switchably enabled by a mode instruction signal depending on the magnitude of a load current. In switching the series regulator and the DC-DC converter, they are simultaneously enabled for a predetermined overlapping time. Further, in changing the operating condition of the DC-DC converter, the width of the PWM signal is shortened to extend the dead time of the DC-DC converter by a predetermined period, thereby suppressing free oscillations and accompanying overshoots that could take place in the power supply unit during switching.
    Type: Grant
    Filed: December 7, 2004
    Date of Patent: July 8, 2008
    Assignee: Rohm Co., Ltd.
    Inventor: Tsutomu Ishino
  • Publication number: 20070262448
    Abstract: A semiconductor device capable of suppressing diffusion of noise signals is provided. The semiconductor device has a BGA (Ball Grid Array) structure in which a plurality of electrode terminals to do input and/or output of signals from and to the outside is arranged in a matrix form. The semiconductor device includes a noise source electrode terminal to do input and/or output of signals, and low-impedance electrode terminals. The noise source electrode terminal does input and/or output of signals acting as a source of noises. The low-impedance electrode terminal are arranged so as to be adjacent to the noise source electrode terminal in a vertical or horizontal direction. The low-impedance electrode terminal is arranged so as to be adjacent to the noise source electrode terminal in a slanting direction.
    Type: Application
    Filed: July 7, 2005
    Publication date: November 15, 2007
    Inventor: Tsutomu Ishino