Patents by Inventor Takakazu Imai
Takakazu Imai 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: 7078884Abstract: A selector sets respective phases of pulse driving signals in reverse when a proportion signal or integration signal does not exceed a threshold. Shifting the respective phases of the pulse driving signals from each other lowers the ripple voltage. When the load current increases drastically, the output voltage Vo tends to decrease remarkably because of the shortage of capacity in the power supply. In this case, when the proportion signal or integration signal exceeds its corresponding threshold, a phase control unit causes the pulse driving signals to synchronize their phases, i.e., the selector supplies the same ramp wave to the comparators, so that respective output voltages supplied from the DC voltage converter circuits attain the same phase, thereby restraining the output voltage supplied to the load from decreasing remarkably.Type: GrantFiled: March 30, 2004Date of Patent: July 18, 2006Assignee: TDK CorporationInventors: Koichiro Miura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Ken Matsuura
-
Patent number: 7075278Abstract: A controller 7A for generating a drive signal (PWM signal) PS for controlling a switching power supply, comprises control signal setting means 10, 11 for setting a control signal CS on the basis of an output voltage Vo and a target voltage Vr; current estimating means 12 for estimating an inductor current on the basis of the drive signal PS and for generating an estimated current signal PC; DC component removing means 14, 15 for extracting a DC component DC included in the estimated current signal PC and for removing the DC component DC from the estimated current signal PC; DC component resetting means 13, 14 for resetting the extracted DC component DC every predetermined time; and comparing means 16 for comparing the control signal CS with the estimated current signal PC? after the removal of the DC component DC.Type: GrantFiled: March 11, 2004Date of Patent: July 11, 2006Assignee: TDK CorporationInventors: Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura, Ken Matsuura
-
Patent number: 7071666Abstract: An output voltage of a switching power supply is regulated to a target value. When the target value of the output voltage is altered, the reference value is changed monotonously and linearly a plurality of times at a plurality of gradients to the altered target value. An input voltage of the power supply is switched in response to a switching pulse with the duty ratio calculated according to a difference between the reference value and the output voltage.Type: GrantFiled: March 16, 2004Date of Patent: July 4, 2006Assignee: TDK CorporationInventors: Takakazu Imai, Takeshi Uematsu, Hiroshi Kawasaki, Koichiro Miura, Ken Matsuura
-
Patent number: 7002324Abstract: This invention provides a switching power supply control circuit based on the parallel operation scheme that suppresses ripples in the output voltage. The control circuit comprises switching circuit blocks 10 and 20 connected in parallel, output reactors 31 and 32 connected in parallel corresponding to the switching circuit blocks 10 and 20, and a control circuit 40 that controls the operation of the switching circuit blocks 10 and 20.Type: GrantFiled: March 7, 2003Date of Patent: February 21, 2006Assignee: TDK CorporationInventors: Takeshi Uematsu, Takakazu Imai, Hiroshi Kawasaki
-
Patent number: 6960904Abstract: An adder 11 outputs a signal VS indicating a value of (Vr?Vo), and a multiplier 12 outputs a control signal GS indicating a value of G(Vr?Vo) on the basis of the signal VS. An adder 13 outputs a signal HS on the basis of the control signal GS and a signal FS outputted from an operation circuit 30, and a PWM signal generating circuit 20 generates a PWM signal KS on the basis of the signal HS and a ramp signal RS outputted from a ramp signal circuit 15, and outputs this signal KS to a switching power supply. A counter 14 counts an on time of the PWM signal KS and retains a count value at a time of receiving a sample signal SMP. The operation circuit 30 has a high-pass filter 31 and an integrator 32, performs an operation based on a signal DS indicating the count value outputted from the counter 14, and outputs the signal FS after the operation.Type: GrantFiled: March 17, 2004Date of Patent: November 1, 2005Assignee: TDK CorporationInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
-
Patent number: 6956360Abstract: A controller 7A for generating a drive signal PS for switching control of a switching element in a switching power supply, includes a duty ratio generator 10, 11 for detecting a duty ratio D of the drive signal PS for controlling the switching element of the switching power supply, and generating a signal corresponding to the duty ratio; a control signal generator 13, 14 for generating a control signal CS on the basis of a difference between a target voltage VREF in the switching power supply and an output voltage Vo detected in the switching power supply; an operation unit 15 for generating a signal corresponding to a product of the signal corresponding to the duty ratio, and the control signal CS; and a drive signal generator 16, 17 for generating the drive signal PS on the basis of the signal generated by the operation unit 15.Type: GrantFiled: March 17, 2004Date of Patent: October 18, 2005Assignee: TDK CorporationInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
-
Publication number: 20040189273Abstract: An output voltage of a switching power supply is regulated to a target value. When the target value of the output voltage is altered, the reference value is changed monotonously and linearly a plurality of times at a plurality of gradients to the altered target value. An input voltage of the power supply is switched in response to a switching pulse with the duty ratio calculated according to a difference between the reference value and the output voltage.Type: ApplicationFiled: March 16, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Takakazu Imai, Takeshi Uematsu, Hiroshi Kawasaki, Koichiro Miura, Ken Matsuura
-
Publication number: 20040189266Abstract: A selector sets respective phases of pulse driving signals in reverse when a proportion signal or integration signal does not exceed a threshold. Shifting the respective phases of the pulse driving signals from each other lowers the ripple voltage. When the load current increases drastically, the output voltage Vo tends to decrease remarkably because of the shortage of capacity in the power supply. In this case, when the proportion signal or integration signal exceeds its corresponding threshold, a phase control unit causes the pulse driving signals to synchronize their phases, i.e., the selector supplies the same ramp wave to the comparators, so that respective output voltages supplied from the DC voltage converter circuits attain the same phase, thereby restraining the output voltage supplied to the load from decreasing remarkably.Type: ApplicationFiled: March 30, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Koichiro Miura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Ken Matsuura
-
Publication number: 20040189264Abstract: An adder 11 outputs a signal VS indicating a value of (Vr−Vo), and a multiplier 12 outputs a control signal GS indicating a value of G(Vr−Vo) on the basis of the signal VS. An adder 13 outputs a signal HS on the basis of the control signal GS and a signal FS outputted from an operation circuit 30, and a PWM signal generating circuit 20 generates a PWM signal KS on the basis of the signal HS and a ramp signal RS outputted from a ramp signal circuit 15, and outputs this signal KS to a switching power supply. A counter 14 counts an on time of the PWM signal KS and retains a count value at a time of receiving a sample signal SMP. The operation circuit 30 has a high-pass filter 31 and an integrator 32, performs an operation based on a signal DS indicating the count value outputted from the counter 14, and outputs the signal FS after the operation.Type: ApplicationFiled: March 17, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
-
Publication number: 20040189272Abstract: A controller 7A for generating a drive signal PS for switching control of a switching element in a switching power supply, includes a duty ratio generator 10, 11 for detecting a duty ratio D of the drive signal PS for controlling the switching element of the switching power supply, and generating a signal corresponding to the duty ratio; a control signal generator 13, 14 for generating a control signal CS on the basis of a difference between a target voltage VREF in the switching power supply and an output voltage Vo detected in the switching power supply; an operation unit 15 for generating a signal corresponding to a product of the signal corresponding to the duty ratio, and the control signal CS; and a drive signal generator 16, 17 for generating the drive signal PS on the basis of the signal generated by the operation unit 15.Type: ApplicationFiled: March 17, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
-
Publication number: 20040178783Abstract: A controller 7A for generating a drive signal (PWM signal) PS for controlling a switching power supply, comprises control signal setting means 10, 11 for setting a control signal CS on the basis of an output voltage Vo and a target voltage Vr; current estimating means 12 for estimating an inductor current on the basis of the drive signal PS and for generating an estimated current signal PC; DC component removing means 14, 15 for extracting a DC component DC included in the estimated current signal PC and for removing the DC component DC from the estimated current signal PC; DC component resetting means 13, 14 for resetting the extracted DC component DC every predetermined time; and comparing means 16 for comparing the control signal CS with the estimated current signal PC′ after the removal of the DC component DC.Type: ApplicationFiled: March 11, 2004Publication date: September 16, 2004Applicant: TDK CORPORATIONInventors: Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura, Ken Matsuura
-
Patent number: 6791305Abstract: This invention provides a switching power supply control circuit that can switch the output voltage with high precision and at high speed. The control circuit comprises an A/D converter 31 that generates a output voltage digital value D1 indicating the actual output Vo in response to clock signal CLK1, a reference voltage generating circuit 32 that generates a reference voltage digital value D2 that indicated the target value of the output voltage in response to clock signal CLK2, a subtracter 33 that compares the output voltage digital value D1 and reference voltage digital value D2 and generates an error voltage digital value D3 based thereupon, a latch circuit 34 that reads the error voltage digital value D3 in response to clock signal CLK3 and controls the operation of the switching circuit block 10 based thereupon and an arithmetic circuit 35.Type: GrantFiled: February 24, 2003Date of Patent: September 14, 2004Assignee: TDK CorporationInventors: Takakazu Imai, Takeshi Uematsu
-
Publication number: 20030173937Abstract: This invention provides a switching power supply control circuit based on the parallel operation scheme that suppresses ripples in the output voltage. The control circuit comprises switching circuit blocks 10 and 20 connected in parallel, output reactors 31 and 32 connected in parallel corresponding to the switching circuit blocks 10 and 20, and a control circuit 40 that controls the operation of the switching circuit blocks 10 and 20.Type: ApplicationFiled: March 7, 2003Publication date: September 18, 2003Applicant: TDK CorporationInventors: Takeshi Uematsu, Takakazu Imai, Hiroshi Kawasaki
-
Publication number: 20030160598Abstract: This invention provides a switching power supply control circuit that can switch the output voltage with high precision and at high speed. The control circuit comprises an A/D converter 31 that generates a output voltage digital value D1 indicating the actual output Vo in response to clock signal CLK1, a reference voltage generating circuit 32 that generates a reference voltage digital value D2 that indicated the target value of the output voltage in response to clock signal CLK2, a subtracter 33 that compares the output voltage digital value D1 and reference voltage digital value D2 and generates an error voltage digital value D3 based thereupon, a latch circuit 34 that reads the error voltage digital value D3 in response to clock signal CLK3 and controls the operation of the switching circuit block 10 based thereupon and an arithmetic circuit 35.Type: ApplicationFiled: February 24, 2003Publication date: August 28, 2003Applicant: TDK CorporationInventors: Takakazu Imai, Takeshi Uematsu
-
Publication number: 20030117118Abstract: A switching power supply which can obtain high accuracy of the output voltage without increasing the clock frequency is disclosed. A switching power supply according to the present invention employs an output detector for detecting an output voltage Vo of the switching power supply and a signal generator for generating a switching control signal SW based on the output voltage Vo of the switching power supply. The switching control signal SW includes during each control period Tc a plurality of pulses each having either a first pulse width or a second pulse width different from the first pulse width. According to the present invention, the accuracy of the output voltage Vo can in effect be enhanced by controlling the number of the pulses having the second pulse width in each control period.Type: ApplicationFiled: December 19, 2002Publication date: June 26, 2003Applicant: TDK CorporationInventors: Takakazu Imai, Takeshi Uematsu