Patent application number | Description | Published |
20100202175 | METHOD AND APPARATUS TO REDUCE AUDIO FREQUENCIES IN A SWITCHING POWER SUPPLY - A controller for use in a power supply regulator is disclosed. One controller includes a feedback circuit coupled to generate a feedback current signal that corresponds to a peak switching current in response to a sense signal from a power supply regulator output. A comparator is coupled to compare the feedback current signal with a reference voltage. A modulation circuit is coupled to the feedback circuit to generate a pulse width modulated switching signal with fixed switching frequency in response to the feedback current signal and the reference voltage. A multi-cycle modulator circuit is coupled to the output of the comparator. The multi-cycle modulator circuit is coupled to enable or disable a switch signal from the controller to be coupled to a switch of the power supply regulator. A group of two or more consecutive switching cycles is separated from a next group having two or more switching cycles by a time of no switching. The time of no switching is adjusted in closed loop to regulate a transfer of energy from a power supply regulator input to the power supply regulator output. | 08-12-2010 |
20100246222 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - Various techniques directed to the digital control of a switching regulator are disclosed. In one aspect, a power supply regulator includes a compare circuit to be coupled to receive a feedback signal representative of an output level of a power supply. This causes a feedback state signal to be generated having a first feedback state that represents an output level of the power supply that is above a threshold level and a second feedback state that represents an output level of the power supply that is below the threshold level. An adjustment circuit is coupled to the compare circuit to adjust the feedback state signal in response to at least one of adjusting the threshold level or adjusting the feedback signal. The adjustment to the feedback state signal tends to cause the feedback state signal to revert from a state at the time of adjustment to a state immediately preceding the adjustment. A control circuit is to be coupled to a power switch and is to be coupled to receive an oscillating signal and the feedback state signal. The control circuit is to control switching of the power switch in response to the oscillating signal and the feedback state signal to regulate the output level of the power supply. | 09-30-2010 |
20110019441 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - In one aspect, a power supply regulator includes a feedback terminal, a node, a control circuit, a first current source, and a second current source. The node is coupled to the feedback terminal to provide a feedback state signal in response to a feedback current through the feedback terminal. The feedback state signal has feedback states that represent an output of the power supply. The control circuit is to be coupled to a power switch and to receive the feedback state signal to regulate the output of the power supply. The first current source is coupled to the node to provide a first current to the node. The second current source is coupled to the node to selectively remove a second current from the node to modulate the feedback current and to alter the feedback state of the feedback state signal. | 01-27-2011 |
20110089761 | METHOD AND APPARATUS FOR POWER CONVERSION AND REGULATION - Techniques are disclosed to control a power converter with multiple output voltages. One example regulated power converter includes a an energy transfer element coupled between a power converter input and first and second power converter outputs. A switch is coupled between the power converter input and the energy transfer element such that switching of the switch causes a first output voltage to be generated at the first power converter output and a second output voltage to be generated at the second power converter output. A current in the energy transfer element is coupled to increase when a voltage across the energy transfer element is a difference between an input voltage at the power converter input and the first output voltage. The current in the energy transfer element is coupled to decrease when the voltage across the energy transfer element is a sum of the first and second output voltages. | 04-21-2011 |
20110157943 | METHOD AND APPARATUS TO REDUCE LINE CURRENT HARMONICS FROM A POWER SUPPLY - A method and apparatus for controlling a power converter. In one aspect, a controller for use in a power converter includes a first calculator coupled to determine an end of an on time of a power switch of the power converter by integrating an input current to output an on time signal representative of the end of the on time of the power switch. The controller also includes a second calculator coupled to determine an end of an off time of the power switch by integrating a difference between an input voltage and an output voltage to output an off time signal representative of the end of the off time of the power switch. | 06-30-2011 |
20110211373 | METHOD AND APPARATUS TO REDUCE AUDIO FREQUENCIES IN A SWITCHING POWER SUPPLY - An example controller for use in a power supply regulator includes a switch signal generator, a modulation circuit, and a multi-cycle modulator circuit. The modulation circuit modulates the duty cycle of a pulse width modulated switching signal to provide a fixed peak switching current in the switch during light load conditions and a variable peak switching current during load conditions other than the light load condition. The multi-cycle modulator circuit enables the switch signal generator to provide a switch signal uninterrupted if the load condition is other than the light load condition and disables the switch signal generator for a first time period and then enables the switch signal generator for a second time period when the load condition is the light load condition. The multi-cycle modulator circuit adjusts the first time period in response to the feedback signal to regulate the output. | 09-01-2011 |
20110267846 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A controller for use in a power converter providing sensing of an isolated output is disclosed. An example controller includes a current controller to be coupled to an energy transfer element and an input of the power converter. A control circuit is included that generates a mode select signal coupled to be received by the current controller. A first, second or third current is enabled in the current controller in response to a selection of a first, second or third mode of operation, respectively, of the current controller by the control circuit. The first current is substantially zero, the second current is greater than the third current and the third current is greater than the first current. A first feedback circuit is coupled to the control circuit and is coupled to generate a first feedback signal representative of an output of the power converter during the first mode of operation after a period of operation of the second mode of operation of the current controller. A second feedback circuit is coupled to the control circuit and is coupled to generate a second feedback signal representative of the output of the power converter during the first mode of operation after a period of operation of the third mode of operation of the current controller. The control circuit is coupled to control selections of the first, second or third modes of operation in response to the first and second feedback signals to control a transfer of energy from the input of the power converter to the output of the power converter. | 11-03-2011 |
20110267847 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A controller for use in a power converter to detect changes in output voltage. An example controller includes a drive circuit to generate a switching signal. The switching signal is coupled to be received by a power switch to be coupled to an energy transfer element and an input of the power converter to control a transfer of energy from the input of the power converter to an output of the power converter. An output voltage sensor is coupled to the drive circuit and coupled to receive a feedback signal representative of the output of the power converter. The output voltage sensor includes first and second pulse sampler circuits. The first pulse sampler circuit is coupled to capture a first peak voltage representative of a second peak of a ringing voltage of the feedback signal at a first time in the feedback signal. The second pulse sampler circuit is coupled to capture a second peak voltage representative of the second peak of the ringing voltage of the feedback signal at a second time in the feedback signal. The output voltage sensor is coupled to output a change signal to the drive circuit in response to the first and second peak voltages. | 11-03-2011 |
20120014141 | RESET VOLTAGE CIRCUIT FOR A FORWARD POWER CONVERTER - A reset voltage circuit for a forward power converter includes a reset capacitor and a memory capacitor. The reset capacitor is to be coupled to recycle energy from a primary winding of a transformer to an input bulk capacitor during a resetting of the transformer. The memory capacitor is to be coupled to store a first voltage equal to an input voltage of the power converter when the input voltage is at a steady-state value. The memory capacitor is further to set a voltage across the primary winding during the resetting of the transformer to a magnitude greater than or equal to the first voltage when the input voltage of the forward power converter drops below the steady-state value. | 01-19-2012 |
20120147632 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A controller for use in a power converter includes a control circuit to be coupled to a current controller coupled to an energy transfer element. A first, second or third current is enabled in the current controller in response to the control circuit. The first current is substantially zero, the second current is greater than the third current, and the third current is greater than the first current. The third current only partially discharges a capacitance coupled to a terminal coupled between the energy transfer element and the current controller. A first feedback circuit coupled to the control circuit generates a first feedback signal after a full discharge pulse of current through the current controller. A second feedback circuit coupled to the control circuit generates a second feedback signal after a partial discharge pulse of current through the current controller. | 06-14-2012 |
20120170327 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - An output voltage sensor for use in a power converter controller includes a first pulse sampler circuit coupled to receive a feedback signal representative of an output of a power converter. The first pulse sampler circuit is coupled to capture a first peak voltage representative of a second peak of a ringing voltage of the feedback signal at a first time in the feedback signal. A second pulse sampler circuit is coupled to receive the feedback signal representative of the output of the power converter. The second pulse sampler circuit is coupled to capture a second peak voltage representative of the second peak of the ringing voltage of the feedback signal at a second time in the feedback signal. The output voltage sensor is coupled to output a change signal to a drive circuit of the power converter controller in response to the first and second peak voltages. | 07-05-2012 |
20130027990 | VARYING SWITCHING FREQUENCY AND PERIOD OF A POWER SUPPLY CONTROLLER - An example integrated circuit controller for use in a switching power supply includes a pulse width modulation (PWM) circuit and a timing circuit. The PWM circuit controls a switch to regulate an output of the power supply in response to a switch current flowing through the switch and in response to a clock signal having a switching period. The timing circuit provides the clock signal and increases the switching period in response to an on time of the switch exceeding a threshold time. | 01-31-2013 |
20130027996 | VARIABLE FREQUENCY TIMING CIRCUIT FOR A POWER SUPPLY CONTROL CIRCUIT - An example integrated circuit controller includes a pulse width modulation (PWM) circuit and a timing circuit. The PWM circuit controls a switch to regulate an output of a power supply in response to a switch current flowing through the switch and in response to a clock signal having a switching period. The timing circuit provides the clock signal and includes a timing capacitor where the switching period of the clock signal is equal to a charging time that the timing capacitor charges to an upper reference voltage plus a discharging time that the timing capacitor discharges to a lower reference voltage. The timing circuit increases the charging time of the timing capacitor by decreasing a rate at which the timing capacitor is charged to increase the switching period of the clock signal if an on time of the switch is greater than or equal to a threshold time. | 01-31-2013 |
20130077355 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A power converter controller includes a drive circuit coupled to control switching of a power switch coupled to an energy transfer element and an input of the power converter. An output voltage sensor including first and second pulse sampler circuits is coupled to capture first and second peak voltages, respectively, that are representative of a second peak of a ringing voltage of a feedback signal representative of an output of the power converter. The first pulse sampler circuit is coupled to capture the first peak voltage at a first time in the feedback signal. The second pulse sampler circuit is coupled to capture the second peak voltage at a second time in the feedback signal. The drive circuit is coupled to receive a change signal from the output voltage sensor in response to the first and second peak voltages. | 03-28-2013 |
20130083579 | PRE-BIASED SAMPLING FILTER - Methods and apparatuses are disclosed for sampling a feedback signal representative of an output of a power converter using a pre-biased filter capacitor. The pre-biased filter capacitor provides accurate sampling of the feedback signal during various load conditions. The pre-biased filter may be pre-charged to a pre-bias voltage that is below the regulated voltage of the feedback signal to reduce the amount of time required to charge the pre-biased filter capacitor to the regulated voltage of the feedback signal. | 04-04-2013 |
20130128625 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A power converter includes a current controller coupled to an energy transfer element to selectively enable a first, second or third current in the current controller. The first current is substantially zero, the second current is greater than the third current, and the third current is greater than the first current. The third current only partially discharges a capacitance coupled to the energy transfer element and the current controller. A control circuit is to be coupled to the current controller to selectively enable the first, second or third current in the current controller. A first feedback circuit is coupled to generate a first feedback signal while the first current is enabled by the current controller after a full discharge pulse. A second feedback circuit is coupled to generate a second feedback signal while the first current is enabled in the controller after a partial discharge pulse. | 05-23-2013 |
20130242619 | RESET VOLTAGE CIRCUIT FOR A FORWARD POWER CONVERTER - An example method includes controlling a duty ratio of a switch to regulate an output of a forward power converter and storing a first voltage. The first voltage is equal to an input voltage of the forward power converter when the input voltage is at a steady-state value. The method also includes resetting a transformer of the forward power converter when the switch is in an OFF state by setting a voltage across a primary winding of the transformer to the stored first voltage in response to a drop in the input voltage to below the steady-state value. Further included in the method is increasing the duty cycle of the switch to greater than fifty (50) percent in response to the drop in the input voltage to maintain regulation at the output of the forward power converter. | 09-19-2013 |
20130336020 | METHOD AND APPARATUS TO REDUCE AUDIO FREQUENCIES IN A SWITCHING POWER SUPPLY - An example power supply regulator includes an energy transfer element, a switch, and a controller. The controller includes a switch signal generator, a modulation circuit, and a multi-cycle modulator circuit. The modulation circuit modulates the period of a modulation switching signal when an equivalent switching frequency is greater than a reference frequency and fixes the switching period when the equivalent switching frequency is less than the reference frequency. The multi-cycle modulator circuit enables the switch signal generator to provide a switch signal uninterrupted if the equivalent switching frequency is greater than the reference frequency and disables the switch signal generator for a first time period and then enables the switch signal generator for a second time period when the equivalent frequency is less than the reference frequency. The multi-cycle modulator circuit varies the first time period to regulate the output. | 12-19-2013 |
20130336021 | VARIABLE FREQUENCY TIMING CIRCUIT FOR A POWER SUPPLY CONTROL CIRCUIT - A timing circuit of a controller generates a clock signal having a switching period for use by a pulse width modulation (PWM) circuit to control a switch of a power supply. The switching period of the clock signal is based on a charging time plus a discharging time of a capacitor included in the timing circuit. A first current source charges the capacitor while the timing circuit is in a normal charging mode. A second current source charges the capacitor while the timing circuit is in an alternative charging mode that is when the on time of the switch exceeds a threshold time. The current provided by the second current source is less than the current provided by the first current source such that the switching period of the clock signal is increased in response to the timing circuit entering the alternative charging mode. | 12-19-2013 |
20140063862 | VARYING SWITCHING FREQUENCY AND PERIOD OF A POWER SUPPLY CONTROLLER - A controller includes a PWM circuit and a timing circuit. The PWM circuit controls a switch in response to a clock signal. A switching period of the clock signal is based on a charging and discharging time of a capacitor included in the timing circuit. Both first and second current sinks discharge the capacitor while the timing circuit is in a normal discharging mode that is when an on time of the switch is less than a threshold time. The second current sink is prevented from discharging the capacitor such that the capacitor is discharged with the first current sink and not the second current sink while the timing circuit is in an alternative discharging mode that is when the on time of the switch exceeds the threshold time. The discharging of the capacitor in the alternative discharging mode increases the switching period of the clock signal. | 03-06-2014 |
20140063867 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A switched-mode power supply includes an energy transfer element coupled between a primary side and a secondary side. A first main terminal of a switch is coupled to the energy transfer element and a second main terminal of the switch is coupled to an input of the primary side. A driver circuit is coupled to drive the switch to be open at a first one of a plurality of levels and closed at a second one of the plurality of levels. The driver circuit is coupled to drive the switch to be substantially independent of a voltage between the first and second main terminals at a third one of the plurality of levels. A current conducted between the first and second main terminals at the third one of the plurality of levels is sufficient to only partially discharge a capacitance that is coupled to the first main terminal. | 03-06-2014 |
20140126246 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - An on/off controller device includes a control circuit to generate a control signal to switch a power switch between an on state and an off state to transfer energy from a primary side to a secondary side of a switched mode power supply. A comparator is coupled to generate an enable signal that enables and disables the switching of the power switch by the control circuit. The comparator compares a feedback signal with a variable threshold and switches the enable signal between enabling and disabling the switching of the power switch. The variable threshold is modulated to increase a fundamental frequency of the switching of the power switch by the control circuit. The variable threshold is modulated with a fixed amplitude pulse that is combined with a second threshold to modulate the variable threshold between a first higher value and a second lower value. | 05-08-2014 |
20140133194 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A power converter controller includes a drive circuit coupled to control switching of a power switch to control a transfer of energy from an input of the power converter to an output of the power converter. A voltage sensor is coupled to the drive circuit to receive a feedback signal. The voltage sensor includes pulse sampler circuitry coupled to sample a first voltage representative of one of the peaks other than a first peak of ringing of the feedback signal in a first enabled switching cycle, sample a second voltage representative of the same peak of ringing of the feedback signal in a subsequent enabled switching cycle, and compare the sample of the first voltage with the sample of the second voltage and output a change signal based on the comparison. The drive circuit is further coupled to control switching of the power switch in response to the change signal. | 05-15-2014 |
Patent application number | Description | Published |
20090073733 | METHOD AND APPARATUS TO REDUCE AUDIO FREQUENCIES IN A SWITCHING POWER SUPPLY - A controller for use in a power supply regulator is disclosed. One controller includes a feedback circuit coupled to generate an equivalent switching frequency signal in response to a sense signal from a power supply regulator output. A comparator is coupled to compare the equivalent switching frequency signal with a reference signal. A period modulation circuit is coupled to the feedback circuit to generate a period modulation switching signal in response to the equivalent switching frequency signal. A multi-cycle modulator circuit is coupled to the output of the comparator. The multi-cycle modulator circuit is coupled to enable or disable a switch signal from the controller, which is to be coupled to a switch of the power supply regulator. A group of two or more consecutive switching cycles is separated from a next group having two or more switching cycles by a time of no switching. The time of no switching is adjusted in closed loop to regulate a transfer of energy from a power supply regulator input to the power supply regulator output. | 03-19-2009 |
20090201701 | COMPENSATION FOR PARAMETER VARIATIONS IN A FEEDBACK CIRCUIT - Techniques to compensate for parameter variations in a feedback circuit are disclosed. In one embodiment, a regulator circuit includes an energy source coupled to output a generated current in response to a control current. A feedback resistor is coupled to an output of the regulator circuit. The feedback resistor is coupled to conduct a feedback current responsive to the output of the regulator circuit. A current amplifier is coupled to the feedback resistor to generate the control current in response to the feedback current. A compensation network is coupled to the current amplifier to adjust the control current in response to an extrinsic parameter of the regulator circuit. The compensation network includes a transistor and first, second and third resistors. The first resistor is coupled between the feedback resistor and a collector of the transistor. The second resistor coupled between the collector and the base of the transistor. The third resistor coupled between the base and an emitter of the transistor. | 08-13-2009 |
20090251116 | METHOD AND APPARATUS FOR POWER CONVERSION AND REGULATION - Techniques are disclosed to control a power converter with multiple output voltages. One example regulated power converter includes a an energy transfer element coupled between a power converter input and first and second power converter outputs. A switch is coupled between the power converter input and the energy transfer element such that switching of the switch causes a first output voltage to be generated at the first power converter output and a second output voltage to be generated at the second power converter output. A current in the energy transfer element is coupled to increase when a voltage across the energy transfer element is a difference between an input voltage at the power converter input and the first output voltage. The current in the energy transfer element is coupled to decrease when the voltage across the energy transfer element is a sum of the first and second output voltages. | 10-08-2009 |
20100067270 | METHOD AND APPARATUS TO REDUCE LINE CURRENT HARMONICS FROM A POWER SUPPLY - A method and apparatus for controlling a power converter. In one aspect, a controller for use in a power converter includes a first calculator coupled to determine an end of an on time of a power switch of the power converter by integrating an input current to output an on time signal representative of the end of the on time of the power switch. The controller also includes a second calculator coupled to determine an end of an off time of the power switch by integrating a difference between an input voltage and an output voltage to output an off time signal representative of the end of the off time of the power switch. | 03-18-2010 |
20110018343 | METHOD AND APPARATUS FOR REGULATING AN ADDITIONAL OUTPUT OF A POWER CONVERTER - An example post regulator controller for use in a power converter having a regulated output and an additional output is disclosed. The post regulator controller includes an inductor to be coupled between the regulated output of the power converter and a post regulator switch of the power converter. The inductor is to be coupled to drive the post regulator switch with an induced voltage across the inductor to redirect energy from the regulated output to the additional output of the power converter. | 01-27-2011 |
20120218788 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - In one aspect, a power supply includes an energy transfer element, a switch, a feedback circuit, a comparator, a state machine, and a control circuit. The feedback circuit generates a feedback signal representative of an output level of the power supply. The comparator provides a feedback state signal having a first feedback state that represents the output level of the power supply being above a threshold level and a second feedback state that represents the output level being below the threshold level. The state machine selectively modulates a first signal in response to the feedback state signal, where the first signal is the feedback signal or the threshold value signal. The control circuit is coupled to control switching of the switch to regulate the output level of the power supply in response to the feedback state signal. | 08-30-2012 |
20120224399 | METHOD AND APPARATUS TO REDUCE AUDIO FREQUENCIES IN A SWITCHING POWER SUPPLY - An example controller for use in a power supply regulator includes a switch signal generator, a modulation circuit, and a multi-cycle modulator circuit. The modulation circuit modulates the period of a modulation switching signal when an equivalent switching frequency is greater than a reference frequency and fixes the switching period when the equivalent switching frequency is less than the reference frequency. The multi-cycle modulator circuit enables the switch signal generator to provide a switch signal uninterrupted if the equivalent switching frequency is greater than the reference frequency and disables the switch signal generator for a first time period and then enables the switch signal generator for a second time period when the equivalent frequency is less than the reference frequency. The multi-cycle modulator circuit varies the first time period to regulate the output. | 09-06-2012 |
20120243277 | METHOD AND APPARATUS TO REDUCE LINE CURRENT HARMONICS FROM A POWER SUPPLY - In one aspect, a power converter includes a power switch, an energy storage element, a driver, a first calculator, and a second calculator. The first calculator coupled to determine an end of an on time of a power switch of the power converter by integrating an input current to output an on time signal representative of the end of the on time of the power switch. The second calculator coupled to determine an end of an off time of the power switch by integrating a difference between an input voltage and an output voltage to output an off time signal representative of the end of the off time of the power switch. The driver controls the power switch such that an input current of the power converter is substantially proportional to an input voltage of the power converter in response to the on time signal and the off time signal. | 09-27-2012 |