Anticipatory feedback technique for pulse width modulated power supply

Claim 2

A power supply, powered by a power source, for generating an output signal to a load, which output signal includes a desired signal waveform on which is superimposed a ripple waveform, comprising: a switch for alternately connecting and disconnecting said load to and from said power source; a filtering element for smoothing the application of said output signal to said load, to provide said desired signal waveform on which is superimposed a ripple waveform; and a control circuit responsive to a current in said filtering element for operating said switch at times to generate a varying instantaneous ripple waveform as a function of said desired signal waveform to provide a substantially constant selected frequency for said ripple waveform.

Claim 3

A power supply, powered by a power source, for generating an output voltage proportional to a reference voltage, comprising: an output circuit which generates said output voltage; a semiconductor switch having an active state to alternately connect and disconnect said output circuit to and from said power source; and a control circuit for periodically activating said semiconductor switch at a selected frequency, said control circuit comprising: a first means for calculating a peak ripple voltage as a function of said selected frequency and said output voltage, and for generating a signal proportional to said peak ripple voltage; a second means for generating a signal proportional to a function of the current through a filtering element in said output circuit; and a third means responsive to said signals generated by said first and second means, to a signal proportional to said reference voltage, and to a signal proportional to said output voltage, said third means generating an output signal connected to said semiconductor switch to selectively activate said semiconductor switch.

Claim 4

A power supply, powered by a power source, for generating an output voltage proportional to a reference voltage, comprising: an output circuit which generates said output voltage; a semiconductor switch having an active state to alternately connect and disconnect said output circuit to and from said power source; and a control circuit for periodically activating said semiconductor switch at a selected frequency, said control circuit comprising: a first means for calculating a peak ripple voltage as a function of said selected frequency and said output voltage, and for generating a signal proportional to said peak ripple voltage; a second means for generating a signal proportional to a function of the current through a filtering element in said output circuit; and a third means responsive to said signals generated by said first and second means, to a signal proportional to said reference voltage, and to a signal proportional to said output voltage, said third means generating an output signal connected to said semiconductor switch to selectively activate said semiconductor switch.

Claim 9

A power supply powered by a power source, for generating an output voltage having a desired voltage component responsive to a reference signal and having a ripple voltage component superimposed on said desired voltage component, comprising: a semiconductor switch which is periodically activated to connect said power source to an output circuit; a first computational circuit responsive to said output voltage which computes an instantaneous peak value for said ripple voltage component such that the frequency of said ripple voltage can be maintained at a substantially constant selected frequency; and a second computational circuit responsive to a function of said first computational circuit, the instantaneous current through a filter element in said output circuit, and to the instantaneous amplitude of said output voltage, which calculates the time to activate and deactivate said semiconductor switch at said selected frequency while maintaining the amplitude of said ripple voltage component within said calculated peak value.

Claim 10

A power supply powered by a power source, for generating an output voltage having a desired voltage component responsive to a reference signal and having a ripple voltage component superimposed on said desired voltage component, comprising: a semiconductor switch which is periodically activated to connect said power source to an output circuit; a first computational circuit responsive to said output voltage which computes an instantaneous peak value for said ripple voltage component such that the frequency of said ripple voltage can be maintained at a substantially constant selected frequency; and a second computational circuit responsive to a function of said first computational circuit, the instantaneous current through a filter element in said output circuit, and to the instantaneous amplitude of said output voltage, which calculates the time to activate and deactivate said semiconductor switch at said selected frequency while maintaining the amplitude of said ripple voltage component within said calculated peak value.

Claim 11

A power supply, powered by a power source, having an output circuit for generating an output voltage having a desired voltage component and a ripple voltage component superimposed on said desired voltage component, comprising: a semiconductor switch which is periodically activated to connect said power source to said output circuit; a filtering element for smoothing said output voltage; and a feedback circuit responsive to the current in said filtering element which calculates the time at which the switch must be activated in order that the ripple voltage component will reach a predetermined peak voltage that varies with the magnitude of said desired voltage component.

Claim 12

A power supply, powered by a power source, having an output circuit for generating an output voltage having a desired voltage component and a ripple voltage component superimposed on said desired voltage component, comprising: a semiconductor switch which is periodically activated to connect said power source to said output circuit; a filtering element for smoothing said output voltage; and a feedback circuit responsive to the current in said filtering element which calculates the time at which the switch must be activated in order that the ripple voltage component will reach a predetermined peak voltage that varies with the magnitude of said desired voltage component.

Claim 13

A power supply as defined in claim 6 wherein said feedback circuit compares a function of said current against a function of said ripple voltage and activates said switch when said functions are balanced.

Claim 14

The power supply as defined in claim 7 wherein said feedback circuit solves the equation: (E.sub.nb +e.sub.o).sup.2 +(iZ).sup.2 =(E.sub.nb +E.sub.r +e.sub.p).sup.2 where E nb is the magnitude of a negative source voltage, e o is the instantaneous output voltage, iZ is proportional to the current through the filtering element, E r is a reference voltage proportional to the desired voltage component, and e p is the peak ripple voltage.

Claim 15

The power supply as defined in claim 8 wherein said feedback circuit calculates said peak ripple voltage according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E pb is a positive bus voltage.

Claim 16

The power supply as defined in claim 7 wherein said feedback circuit solves the equation: (E.sub.pb -e.sub.o).sup.2 +(iZ).sup.2 =(E.sub.pb -E.sub.r +e.sub.p).sup.2 ; where E pb is the magnitude of a positive source voltage, e o is the instantaneous output voltage, iZ is proportional to the current through the filter element, E r is a reference voltage proportional to the desired voltage component, and e p is the peak ripple voltage.

Claim 17

The method as defined in claim 10 wherein feedback circuit calculates said peak ripple voltage according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f ix a preselected frequency, L and C are magnitudes of filter elements, and E nb is a negative bus voltage.

Claim 18

The power supply as defined in claim 7 wherein said feedback circuit solves the equation: e.sub.o -E.sub.r ±K.sub.1 e.sub.p =K.sub.2 iZ where e o is the instantaneous output voltage, E r is a reference voltage, K 1 e p is proportional to the peak ripple voltage, and K 2 iZ is proportional to the current through the filtering element.

Claim 19

The power supply as defined in claim 12 wherein said feedback circuit calculates said peak ripple voltage e p according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E nb and E pb are negative and positive bus voltages.

Claim 22

The method as defined in claim 14 wherein said calculating step solves the equation: (E.sub.nb +e.sub.o).sup.2 +(iZ).sup.2 =(E.sub.nb +E.sub.r +e.sub.p).sup.2 ; where E nb is the magnitude of a negative source voltage, e o is the instantaneous output voltage, iZ is proportional to the current through the filter element, E r is a reference voltage proportional to the desired voltage element, and e p is the peak ripple voltage.

Claim 23

The method as defined in claim 15 wherein said peak ripple voltage is calculated according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E pb is the magnitude of a positive bus voltage.

Claim 24

The method as defined in claim 14 wherein said calculating step solves the equation: (E.sub.pb -e.sub.o).sup.2 +(iZ).sup.2 =(E.sub.pb -E.sub.r +e.sub.p).sup.2 ; where E pb is the magnitude of a positive source voltage, e o is the instantaneous output voltage, iZ is proportional to the current through the filter element, E r is a reference voltage proportional to the desired voltage component, and e p is the peak ripple voltage.

Claim 25

The method as defined in claim 17 wherein said peak ripple voltage is calculated according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E nb is the magnitude of a negative bus voltage.

Claim 26

The method as defined in claim 14 wherein said calculating step solves the equation: e.sub.o -E.sub.r ±K.sub.1 e.sub.p =K.sub.2 iZ; where e o is the instantaneous output voltage, E r is a reference voltage, K 1 e p is proportional to the peak ripple voltage, and K 2 iZ is proportional to the current through the filter element.

Claim 27

The method as defined in claim 19 wherein said peak ripple voltage is calculated according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E nb and E pb are the magnitudes of negative and positive bus voltages.

Claim 28

The method defined in claim 14 wherein said calculating step solves the equation: ##EQU13## where e o is the instantaneous output voltage, E r is a reference voltage, e p is the peak ripple voltage, E nb is the magnitude of a negative bus voltage, and iZ is proportional to the current through the filter element.

Claim 29

The method as defined in claim 21 wherein said peak ripple voltage is calculated according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E nb and E pb are the magnitudes of negative and positive bus voltages.

Claim 30

The method as defined in claim 14 wherein said calculating step solves the equation: ##EQU14## where e o is the instantaneous output voltage, E r is a reference voltage, e p is the peak ripple voltage, E pb is the magnitude of a positive bus voltage, and iZ is proportional to the current through the filter element.

Claim 31

The method as defined in claim 23 wherein said peak ripple voltage is calculated according to the equation: e.sub.p =(E.sub.nb +e.sub.o)(E.sub.pb -e.sub.o)/16f.sup.2 LC(E.sub.pb +E.sub.nb); where f is a preselected frequency, L and C are magnitudes of filter elements, and E nb and E pb are the magnitudes of negative and positive bus voltages.