Patents by Inventor Leif Lund
Leif Lund 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).
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Patent number: 8441309Abstract: A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.Type: GrantFiled: September 6, 2012Date of Patent: May 14, 2013Assignee: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Patent number: 8427848Abstract: An example integrated circuit for use in a power supply includes a feedback terminal and a controller having a variable time clamp (VTC). The feedback terminal is to be coupled to receive a feedback signal and the controller is to be coupled to enable or disable the conduction of a power switch during a switching cycle in response to the feedback signal. The controller includes a current limit comparator coupled to terminate the conduction of the power switch during an enabled switching cycle in response to a current through the power switch exceeding a variable current limit. The VTC is coupled to clamp the feedback terminal to a voltage for a clamp time that is responsive to the variable current limit.Type: GrantFiled: December 22, 2010Date of Patent: April 23, 2013Assignee: Power Integrations, Inc.Inventor: Leif Lund
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Patent number: 8374006Abstract: An example controller for a primary side control power converter includes a feedback circuit, a driver circuit, and an adjustable voltage reference circuit. The feedback circuit is coupled to compare a feedback signal representative of a bias winding voltage of the power converter with a voltage reference. The driver circuit is coupled to output a switching signal to control a switch of the power converter to regulate an output of the power converter in response the feedback circuit. The adjustable voltage reference circuit is coupled to adjust the voltage reference such that the bias winding voltage is adjusted nonlinearly in response to a load condition at the output of the power converter. The adjustable voltage reference circuit is further coupled to detect the load condition in response to the switching signal.Type: GrantFiled: March 2, 2012Date of Patent: February 12, 2013Assignee: Power Integrations, Inc.Inventors: Leif Lund, Alex B. Djenguerian, William M. Polivka
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Publication number: 20120326697Abstract: A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.Type: ApplicationFiled: September 6, 2012Publication date: December 27, 2012Applicant: POWER INTEGRATIONS, INC.Inventors: David Kung, Leif Lund
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Patent number: 8299772Abstract: An example circuit includes a regulator circuit coupled to first and second nodes. A capacitance circuit and a slew rate control circuit are coupled between the first and second nodes. The regulator circuit is coupled to charge a capacitance of the capacitance circuit with a charge current. The slew rate control circuit is coupled to control a change in voltage over change in time between the first and second nodes during a power up mode of the circuit. The slew rate control circuit further includes a switch and a resistor. The slew rate control circuit is coupled to switch the switch in response to a voltage between the first and second nodes. A voltage drop across the resistor is limited to a base-emitter voltage drop of a transistor coupled between the first and second nodes to set the change in voltage over change in time.Type: GrantFiled: October 13, 2011Date of Patent: October 30, 2012Assignee: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Publication number: 20120250368Abstract: A controller for regulating an output of a power supply includes a logic block and an oscillator. The logic block generates the drive signal to control switching of a power switch in response to a clock signal. The clock signal has a frequency that decreases responsive to a time period of the drive signal, where a decrease in the time period of the drive signal represents an increase in an input voltage of the power supply. The oscillator is coupled to generate the clock signal in response to a waveform having an amplitude swing. The oscillator alters the waveform in response to the time period of the drive signal.Type: ApplicationFiled: June 14, 2012Publication date: October 4, 2012Applicant: POWER INTEGRATIONS, INC.Inventors: Balu Balakrishnan, Alex B. Djenguerian, Leif Lund
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Patent number: 8278994Abstract: A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/(R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.Type: GrantFiled: February 16, 2012Date of Patent: October 2, 2012Assignee: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Publication number: 20120218786Abstract: An example power converter includes an energy transfer element, a switch, and a control circuit. The control circuit includes a drive signal generator and an unregulated dormant mode control circuit. The unregulated dormant mode control circuit renders dormant the drive signal generator thereby ceasing the regulation of the output by the drive signal generator when the energy requirement of the one or more loads falls below a threshold for more than a first period of time. The drive signal generator is unresponsive to changes in the energy requirements of the one or more loads when dormant. The unregulated dormant mode control circuit powers up the drive signal generator after a second period of time has elapsed, such that the drive signal generator is again responsive to changes in the energy requirement of the one or more loads after the second period of time has elapsed.Type: ApplicationFiled: May 7, 2012Publication date: August 30, 2012Applicant: Power Integrations, Inc.Inventors: Alex B. Djenguerian, Leif Lund
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Publication number: 20120206842Abstract: A switched mode power supply includes a transformer and an integrated circuit regulator. The integrated circuit regulator is coupled to the transformer and includes switching regulator logic, a counter, and a switching transistor. The regulator logic generates a switching signal in response to the feedback signal. The counter receives the feedback signal, where the feedback signal periodically cycles between a first state and a second state when the switched mode power supply operates normally. An output of the counter indicates an auto-restart mode of the regulator in response to the feedback signal remaining in the first state for a predetermined count due to a fault condition. The switching transistor is coupled to be turned on and off in response to the switching signal when the output of the counter does not indicate the auto-restart mode and is disabled when the output of the counter indicates the auto-restart mode.Type: ApplicationFiled: April 19, 2012Publication date: August 16, 2012Applicant: POWER INTEGRATIONS, INC.Inventors: Balu Balakrishnan, Alex Djenguerian, Leif Lund
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Patent number: 8222882Abstract: A controller for a power supply includes a logic block and a time-to-frequency converter. The logic block is to generate a drive signal in response to a clock signal. The drive signal is to be coupled to control switching of a power switch of the power supply to regulate an output of the power supply. The time-to-frequency converter is coupled to the logic block and generates the clock signal having a frequency responsive to a time period of the drive signal.Type: GrantFiled: January 30, 2009Date of Patent: July 17, 2012Assignee: Power Integrations, Inc.Inventors: Balu Balakrishnan, Alex B. Djenguerian, Leif Lund
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Publication number: 20120163043Abstract: An example controller for a primary side control power converter includes a feedback circuit, a driver circuit, and an adjustable voltage reference circuit. The feedback circuit is coupled to compare a feedback signal representative of a bias winding voltage of the power converter with a voltage reference. The driver circuit is coupled to output a switching signal to control a switch of the power converter to regulate an output of the power converter in response the feedback circuit. The adjustable voltage reference circuit is coupled to adjust the voltage reference such that the bias winding voltage is adjusted nonlinearly in response to a load condition at the output of the power converter. The adjustable voltage reference circuit is further coupled to detect the load condition in response to the switching signal.Type: ApplicationFiled: March 2, 2012Publication date: June 28, 2012Applicant: POWER INTEGRATIONS, INC.Inventors: Leif Lund, Alex B. Djenguerian, William M. Polivka
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Publication number: 20120161739Abstract: An example integrated circuit for use in a power supply includes a feedback terminal and a controller having a variable time clamp (VTC). The feedback terminal is to be coupled to receive a feedback signal and the controller is to be coupled to enable or disable the conduction of a power switch during a switching cycle in response to the feedback signal. The controller includes a current limit comparator coupled to terminate the conduction of the power switch during an enabled switching cycle in response to a current through the power switch exceeding a variable current limit. The VTC is coupled to clamp the feedback terminal to a voltage for a clamp time that is responsive to the variable current limit.Type: ApplicationFiled: December 22, 2010Publication date: June 28, 2012Applicant: POWER INTEGRATIONS, INC.Inventor: Leif Lund
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Publication number: 20120146715Abstract: A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/(R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.Type: ApplicationFiled: February 16, 2012Publication date: June 14, 2012Applicant: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Patent number: 8194421Abstract: A method for controlling an output of a power converter includes generating a drive signal with a control circuit, entering a dormant mode of operation that includes powering down the control circuit if a flow of energy to an output of the power converter is less than a threshold value for more than a first period of time, and powering up the control circuit after it is in the dormant mode of operation for a second period of time.Type: GrantFiled: June 27, 2011Date of Patent: June 5, 2012Assignee: Power Integrations, Inc.Inventors: Alex B. Djenguerian, Leif Lund
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Patent number: 8159843Abstract: An example apparatus to regulate an output voltage of a power converter at light/no load conditions includes a driver circuit, a feedback circuit, and an adjustable voltage reference circuit. The driver circuit is coupled to output a drive signal to switch a power switch between an ON state and an OFF state to regulate an output of the power converter. The feedback circuit is coupled to the driver circuit and is further coupled to output an enable signal to switch the power switch to an ON state in response to an output voltage signal. The adjustable voltage reference circuit is coupled to adjust a voltage reference such that a bias winding voltage of the power converter is adjusted nonlinearly in response to a load that is to be coupled to the output of the power converter.Type: GrantFiled: January 30, 2009Date of Patent: April 17, 2012Assignee: Power Integrations, Inc.Inventors: Leif Lund, Alex B. Djenguerian, William M. Polivka
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Publication number: 20120068680Abstract: An example circuit includes a regulator circuit coupled to first and second nodes. A capacitance circuit and a slew rate control circuit are coupled between the first and second nodes. The regulator circuit is coupled to charge a capacitance of the capacitance circuit with a charge current. The slew rate control circuit is coupled to control a change in voltage over change in time between the first and second nodes during a power up mode of the circuit. The slew rate control circuit further includes a switch and a resistor. The slew rate control circuit is coupled to switch the switch in response to a voltage between the first and second nodes. A voltage drop across the resistor is limited to a base-emitter voltage drop of a transistor coupled between the first and second nodes to set the change in voltage over change in time.Type: ApplicationFiled: October 13, 2011Publication date: March 22, 2012Applicant: POWER INTEGRATIONS, INC.Inventors: David Kung, Leif Lund
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Patent number: 8125265Abstract: A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/(R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.Type: GrantFiled: August 15, 2011Date of Patent: February 28, 2012Assignee: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Publication number: 20110298529Abstract: A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/(R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.Type: ApplicationFiled: August 15, 2011Publication date: December 8, 2011Applicant: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Patent number: 8063622Abstract: A circuit to control the slew rate of charging a capacitance using the capacitance is disclosed. An example circuit includes a regulator circuit to regulate a supply voltage during a normal operation mode of the circuit. A capacitance circuit is coupled to the regulator circuit. The regulator circuit is coupled to charge a capacitance between a first node and a second node of the capacitance circuit with a charge current. A slew rate control circuit is coupled to the regulator circuit and the capacitance circuit. The slew rate control circuit sets a slew rate of a voltage between the first and second nodes during a power up mode of the circuit.Type: GrantFiled: October 2, 2009Date of Patent: November 22, 2011Assignee: Power Integrations, Inc.Inventors: David Kung, Leif Lund
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Publication number: 20110255310Abstract: A method for controlling an output of a power converter includes generating a drive signal with a control circuit, entering a dormant mode of operation that includes powering down the control circuit if a flow of energy to an output of the power converter is less than a threshold value for more than a first period of time, and powering up the control circuit after it is in the dormant mode of operation for a second period of time.Type: ApplicationFiled: June 27, 2011Publication date: October 20, 2011Applicant: POWER INTEGRATIONS, INC.Inventors: Alex B. Djenguerian, Leif Lund