Link regulator with feed forward switching control
First Claim
1. A method for controlling a switching regulator to convert an unregulated DC voltage level to a regulated DC voltage level, comprising:
- generating a pulse waveform, each pulse therein turning a series switch on to conduct current from the unregulated DC voltage level;
sensing the level of the unregulated DC voltage level on the input of the switch;
generating an integrated voltage signal that is the integral of the sensed unregulated DC voltage level with respect to time;
generating a threshold voltage;
comparing the integrated voltage level with the threshold voltage and turning the switch off when the integrated voltage level exceeds the threshold voltage such that a constant volts/seconds signal is generated on the output of the switch;
resetting the integrated voltage level to zero when the generated pulse waveform turns on the switch;
filtering the output of the switch to provide the regulated DC voltage level, the regulated DC voltage level being proportional to the preset threshold voltage;
andvarying the threshold voltage in response to variations in the regulated DC voltage level to maintain the DC voltage level constant.
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Accused Products
Abstract
A link regulator is disclosed for providing a regulated voltage over a wide range of input frequencies and load currents. The frequency of an internal VCO and the input frequency are phase compared to provide a reference error signal. The unregulated DC voltage is integrated for a duration proportional to the error signal. This duration controls a series switching element to provide a constant volts/seconds. The output of the series switching element is filtered to a DC voltage that controls the frequency of the VCO. The DC voltage is proportional to the error signal, thus providing a feed forward system to regulate the DC voltage. During the period when the series switching element is not conducting, a shunt switch presents a low impedance to the input of the filter to clamp the input to ground. This allows for operation over a wide range of load currents without losing regulation.
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Citations
26 Claims
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1. A method for controlling a switching regulator to convert an unregulated DC voltage level to a regulated DC voltage level, comprising:
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generating a pulse waveform, each pulse therein turning a series switch on to conduct current from the unregulated DC voltage level; sensing the level of the unregulated DC voltage level on the input of the switch; generating an integrated voltage signal that is the integral of the sensed unregulated DC voltage level with respect to time; generating a threshold voltage; comparing the integrated voltage level with the threshold voltage and turning the switch off when the integrated voltage level exceeds the threshold voltage such that a constant volts/seconds signal is generated on the output of the switch; resetting the integrated voltage level to zero when the generated pulse waveform turns on the switch; filtering the output of the switch to provide the regulated DC voltage level, the regulated DC voltage level being proportional to the preset threshold voltage; and varying the threshold voltage in response to variations in the regulated DC voltage level to maintain the DC voltage level constant. - View Dependent Claims (2, 3)
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4. A method for controlling a link regulator to convert an unregulated DC level to a regulated DC level, comprising:
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generating a reference frequency signal; generating a driving frequency signal that has a frequency that is proporational to the regulated DC level; turning a series switch on to connect the unregulated DC voltage level on the input of the switch to the output thereof; sensing the level of the unregulated DC voltage on the input of the switch; integrating the unregulated DC voltage level over time to provide an integrated voltage level; comparing the phase of the driving signal to the phase of the reference signal and generating a threshold level; comparing the integrated voltage level with the threshold level and turning the switch off when the integrated voltage level exceeds the threshold level such that a constant volts/seconds relationship is obtained on the output of the switch; resetting the integrated voltage level to zero and turning the switch back on after a predetermined duration of time has elapsed from the preceding closure of the switch; filtering the output of the switch to provide the regulated DC voltage level that is proportional to the threshold level; sensing the regulated DC voltage level; and varying the threshold voltage level in response to changes in the sensed regulated DC voltage level such that the regulated DC voltage is maintained at a constant level. - View Dependent Claims (5, 6, 7)
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8. A method for regulating a link regulator to convert an unregulated DC voltage to a regulated DC voltage, comprising:
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generating a reference frequency signal; generating a variable frequency driving signal, the driving signal having a frequency that is variable as a function of the level of the regulated DC voltage; turning a series switching element on to conduct current from the unregulated DC voltage; comparing the phase of the reference signal and the phase of the driving signal to provide a phase error signal; sensing the unregulated DC voltage; integrating the sensed unregulated DC voltage with respect to time to generate an integrated voltage level; comparing the phase error signal and the integrated voltage level and turning the series switching element off when the integrated voltage level exceeds the level of the phase error signal such that the signal output from the switch has a volts/seconds relationship dependant upon the phase error signal; presenting a low impedance on the output of the switching element when the switching element is not conducting and removing the low impedance when the switch is turned back on; periodically resetting the integrated voltage level to zero and turning the series switching element on such that a series of signals are periodically output by the switching element having a volts/seconds relationship dependant on the level of the phase error signal; and filtering the output of the switching element to provide the regulated DC voltage level; variations in the regulated DC voltage level causing the frequency of the driving signal to change and thus changing the level of the phase error signal, a change in the phase error signal causing the volts/seconds relationship to change to compensate the regulated DC voltage. - View Dependent Claims (9, 10, 11)
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12. A circuit for controlling a switching regulator, comprising:
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a series switch having one end thereof connected to an unregulated DC voltage; means for turning said switch on; means for sensing the level of said unregulated DC voltage; means for integrating said unregulated DC voltage level over time to provide an integrated voltage level; means for generating a threshold voltage; means for comparing said integrated voltage level with said threshold voltage and turning said switch off when said integrated voltage level exceeds said threshold voltage such that the integral of said unregulated DC voltage over the time said switch is on is dependant on said threshold voltage to provide a volts/seconds relationship that is dependant on said threshold voltage; means for generating a pulse waveform, each pulse therein for turning on said switch and resetting said integrated voltage level to zero such that a series of integrated signals are generated having a volts/seconds relationship dependant upon said threshold voltage; means for filtering the output of said switch to remove the time portion of the volts/seconds relationship on the signal output from said switch to provide a regulated DC voltage; and means for varying said threshold voltage to maintain the volts/seconds relationship constant such that said regulated DC voltage also remains constant. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A circuit for controlling a link regulator, comprising:
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a series switch having one end and thereof connected to an unregulated DC voltage; means for generating a reference frequency signal; means for generating a driving frequency signal; means for turning said switch on to conduct current from said unregulated DC voltage; means for sensing the level of said unregulated DC voltage; means for integrating said sensed unregulated DC voltage level over time to provide an integrated voltage level; first means for comparing the phase of said driving frequency to the phase of said reference frequency and generating a threshold level that is dependant on the phase difference between said driving and reference frequencys; second means for comparing said integrated voltage level with said threshold level and turning the switch off when said integrated voltage level exceeds said threshold level such that the integral of said unregulated DC voltage over the time said switch is closed provides a volts/seconds relationship that is dependant upon said threshold; means for generating a pulse waveform, each pulse therein for turning on said switch and resetting said integrated voltage level to zero to provide a sequence of signals having a volts/seconds relationship determined by said threshold; means for filtering the output of said switch to provide a regulated DC voltage that is proportional to said threshold level; and means for varying said driving frequency as a function of said regulated DC voltage to provide feedback to control the level of said threshold to maintain a constant level for said regulated DC voltage. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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Specification