1. A relaxation oscillator circuit with reduced sensitivity of oscillation frequency to comparator delay variation, the relaxation oscillator circuit comprising:
a first current source that generates a charging current;
a second current source coupled to the first current source to generate a reference voltage;
a resistor coupled to the second current source to enable generation of the reference voltage;
a capacitor, coupled to the first current source, that is charged based on the charging current;
a comparator that is responsive to a voltage corresponding to the capacitor and the reference voltage to generate an output voltage;
a peak detector coupled to the capacitor to generate a peak voltage;
an error detector coupled to the peak detector and the second current source to generate an error based on the peak voltage and the reference voltage; and
a controller coupled to the error detector to control one of the charging current, an offset voltage input to the comparator, and a capacitance of the capacitor.
2. The relaxation oscillator circuit as claimed in claim 1 and further comprising:
a first switch, coupled between the first current source and the capacitor, that controls charging of the capacitor; and
a second switch, coupled across the capacitor, that controls discharge of the capacitor based on output of the comparator.
3. The relaxation oscillator circuit as claimed in claim 2 and further comprising
an offset voltage source, coupled to the input of the comparator, to generate the offset voltage; and
a logic gate, coupled between the first switch and the output of the comparator, that inverts the output voltage.
4. A relaxation oscillator circuit with reduced sensitivity of oscillation frequency to comparator delay variation, the relaxation oscillator circuit comprising:
a first current source that generates a charging current;
a second current source coupled to the first current source to generate a reference voltage;
a resistor coupled to the second current source to enable generation of the reference voltage;
a capacitor, coupled to the first current source, that is charged based on the charging current;
a comparator that is responsive to a voltage corresponding to the capacitor and the reference voltage to generate an output voltage;
a peak detector, coupled to the capacitor, to generate a peak voltage;
a divide by two circuit, coupled to the comparator, to divide an output of the comparator by two;
a switched capacitor amplifier that amplifies the reference voltage by a ratio of capacitance values to provide a voltage;
a switched capacitor integrator, coupled to the switched capacitor amplifier, to integrate an error between the peak voltage and the reference voltage; and
an inverting gain circuit, coupled between the capacitor and the switched capacitor integrator, that modifies capacitance of the capacitor.
5. The relaxation oscillator circuit as claimed in claim 4 and further comprising:
a first switch, coupled between the first current source and the capacitor, that controls charging of the capacitor; and
a second switch, coupled across the capacitor, that controls discharge of the capacitor based on the output of the comparator.
6. The relaxation oscillator circuit as claimed in claim 4, wherein the switched capacitor amplifier comprises an amplifier, one or more switches, and a plurality of capacitors.
7. The relaxation oscillator circuit as claimed in claim 4, wherein the switched capacitor integrator comprises an amplifier, one or more switches, and a plurality of capacitors.
8. The relaxation oscillator circuit as claimed in claim 4, wherein the divide by two circuit comprises a non-overlap clock generator that generates four non-overlapping phases to control one or more switches in the switched capacitor amplifier and the switched capacitor integrator.
9. The relaxation oscillator circuit as claimed in claim 4, wherein the inverting gain circuit comprises an amplifier and a plurality of resistors.
10. The relaxation oscillator circuit as claimed in claim 4, wherein the switched capacitor integrator and the inverting gain circuit is replaced with a comparator circuit and an accumulator for a digital control loop.
11. A relaxation oscillator circuit with reduced sensitivity of oscillation frequency to comparator delay variation, the relaxation oscillator circuit comprising:
a first current source that generates a charging current;
a second current source, coupled to the first current source, to generate a reference voltage;
a capacitor, coupled to the first current source, that is charged based on the charging current;
a comparator that is responsive to a voltage corresponding to the capacitor and the reference voltage to generate an output voltage;
a peak detector, coupled to the capacitor, to generate a peak voltage;
a resistor coupled to the peak detector to generate a current based on the peak voltage;
an integrator, coupled to the resistor, to integrate an error between a current based on the peak voltage and the charging current of the capacitor; and
an inverting gain circuit, coupled between the capacitor and the integrator, that modifies the charging current of the capacitor.
12. The relaxation oscillator circuit as claimed in claim 11 and further comprising:
a first switch, coupled between the first current source and the capacitor, that controls charging of the capacitor; and
a second switch, coupled across the capacitor, that controls discharge of the capacitor based on output of the comparator.
13. The relaxation oscillator circuit as claimed in claim 11, wherein the integrator comprises an amplifier and a capacitor.
14. The relaxation oscillator circuit as claimed in claim 11, wherein the inverting gain circuit comprises an amplifier and a plurality of resistors.
15. The relaxation oscillator circuit as claimed in claim 11, wherein the integrator and the inverting gain circuit is replaced with a comparator circuit and an accumulator for a digital control loop.
16. The relaxation oscillator circuit as claimed in claim 15, wherein the comparator circuit compares the peak voltage and a voltage corresponding to the charging current of the capacitor.
17. A relaxation oscillator circuit with reduced sensitivity of oscillation frequency to comparator delay variation, the relaxation oscillator circuit comprising:
a first current source that generates a charging current;
a second current source, coupled to the first current source, to generate a reference voltage;
a resistor coupled to the second current source to enable generation of the reference voltage;
a capacitor, coupled to the first current source, that is charged based on the charging current;
a comparator that is responsive to a voltage corresponding to the capacitor and the reference voltage to generate an output voltage;
a peak detector, coupled to the capacitor, to generate a peak voltage; and
an integrator, coupled between the peak detector and the second current source, to control the second current source by integrating an error between the peak voltage and the reference voltage.
18. The relaxation oscillator circuit as claimed in claim 17 and further comprising:
a first switch, coupled between the first current source and the capacitor, that controls charging of the capacitor; and
a second switch, coupled across the capacitor, that controls discharge of the capacitor based on output of the comparator.
19. The relaxation oscillator circuit as claimed in claim 17, wherein the integrator comprises an amplifier, a resistor, and a capacitor.
20. The relaxation oscillator circuit as claimed in claim 17, wherein the integrator is replaced with a comparator circuit and an accumulator for a digital control loop.
21. A method for reducing effect of comparator delay on oscillation frequency in a relaxation oscillator circuit, the method comprising:
generating a reference voltage;
comparing the reference voltage with a voltage corresponding to a capacitor to control charging and discharging of the capacitor;
generating a peak voltage of the capacitor;
generating a control signal based on an error between the peak voltage and the reference voltage; and
adjusting one of current, capacitance, and voltage based on the control signal.
22. The method as claimed in claim 21, wherein the relaxation oscillator circuit comprises one of an analog control loop and a digital control loop.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A power conduit having a length greater than fifteen feet for coupling a stationary fitting to a pool cleaner for propelling the cleaner through a water pool for capturing debris from the surface of the pool andor the surface of a wall containing the pool, said conduit including:
at least one axially stiff elongate section having first and second ends spaced by greater than one foot, said stiff elongate section configured to transfer energy therealong from said first to said second end; and
coupling means respectively coupling said first and second ends of said stiff elongate section to said stationary fitting and said pool cleaner for avoiding the formation of persistent coils andor knots in said conduit, said coupling means including a swivel coupling for enabling said stiff elongate section to swivel axially relative to said fitting andor pool cleaner and an axially flexible section for enabling said stiff elongate section to variably angulate relative to said fitting andor pool cleaner.
2. The conduit of claim 1 wherein said stiff elongate section comprises a rigid tube defining an interior flow path.
3. The conduit of claim 1 wherein said axially flexible section has a length shorter than the length of said stiff elongate section.
4. The conduit of claim 1 wherein said stiff elongate section comprises a rigid tube defining an interior flow path and said axially flexible section comprises a flexible hose defining an interior flow path coupled in series with said rigid tube flow path.
5. The conduit of claim 1 wherein said stiff elongate section includes an electrically conductive path.
6. The conduit of claim 1 wherein said stiff elongate section carries a source of illumination.
7. The conduit of claim 1 further including at least one propulsion device carried by said conduit.
8. A power conduit for transferring energy from a power source via a stationary fitting to a pool cleaner body for propelling said body through a water pool to capture debris from the surface of said water pool andor the surface of a wall containing said water pool, said conduit comprising:
a first conduit end adapted for coupling to said stationary fitting;
a second conduit end spaced by at least fifteen feet from said first end adapted for coupling to said pool cleaner body;
said conduit including:
at least one axially stiff elongate section; and
at least one axially flexible elongate member coupled between said stiff elongate section and at least one of said conduit ends for enabling said stiff section to variably angulate relative to said fitting andor said pool cleaner body; and
swivel means in said conduit for enabling said stiff section to swivel axially relative to said fitting andor said pool cleaner body for avoiding the formation of persistent coils andor knots in said conduit.
9. The conduit of claim 8 wherein said axially flexible member has a length shorter than the length of said stiff section.
10. The conduit of claim 9 wherein said stiff section comprises a rigid member defining an interior flow path and said axially flexible member comprises a flexible hose defining an interior flow path coupled in series with said rigid member flow path.
11. The conduit of claim 9 wherein said stiff section includes an electrically conductive path.
12. The conduit of claim 8 wherein said stiff elongate section carries a source of illumination.
13. The conduit of claim 8 further including at least one propulsion device carried by said conduit.
14. A power conduit for transferring energy from a power source via a stationary fitting to a pool cleaner body for propelling said body through a water pool to capture debris from the surface of said water pool andor the surface of a wall containing said water pool, said conduit comprising:
at least one first elongate member configured to transfer energy therealong from a first to a second end thereof;
at least one second elongate member configured to transfer energy therealong from a first to a second end thereof;
at least one third elongate member configured to transfer energy therealong from a first to a second end thereof;
means coupling said first, second, and third elongate members in tandem to form a conduit having a length greater than fifteen feet for extending between said fitting and said pool cleaner body;
said second elongate member having a length greater than one foot and configured to exhibit a significantly greater axial stiffness than said first and third elongate members; and
means for enabling at least one of said elongate members to swivel axially relative to said fitting andor pool cleaner body for avoiding the formation of persistent coils andor knots in said conduit.
15. The conduit of claim 14 wherein said means coupling said members in tandem includes swivel means for enabling at least one of said elongate members to swivel axially relative to another of said elongate members.
16. The conduit of claim 14 wherein said second elongate member exhibits high axial stiffness and said first andor third elongate members exhibits high axial flexibility.
17. The conduit of claim 14 wherein each of said elongate members includes an elongate lumen defining a fluid path.
18. The conduit of claim 14 wherein each of said elongate members includes an electrically conductive path.
19. The conduit of claim 14 wherein said first andor third elongate members comprises a tube exhibiting high axial flexibility and defining an interior fluid flow path.
20. The conduit of claim 19 wherein said second elongate member comprises a tube exhibiting high axial stiffness and defining an interior fluid flow path.
21. The conduit of claim 20 wherein said means coupling said members in tandem includes swivel means for enabling at least one of said elongate members to swivel axially relative to another of said elongate members.
22. The conduit of claim 14 wherein said second elongate member carries a source of illumination.
23. In combination:
a pool cleaner configured to move along a travel path through a water pool for capturing debris from the surface of a wall containing the pool andor the water surface of the pool; and
a conduit assembly for supplying energy to said pool cleaner from a power source via a stationary fitting for propelling said pool cleaner along said travel path;
said conduit assembly comprising:
at least one axially stiff elongate section having first and second ends spaced by greater than one foot, said stiff elongate section configured to transfer energy therealong from said first to said second end; and
coupling means respectively coupling said first and second ends of said stiff elongate section to said stationary fitting and said pool cleaner for avoiding the formation of persistent coils andor knots in said conduit, said coupling means including (1) a swivel coupling for enabling said stiff elongate section to swivel axially relative to said fitting andor said pool cleaner and (2) an axially flexible section for enabling said stiff elongate section to variably angulate relative to said fitting andor said pool cleaner.
24. The conduit of claim 23 wherein said stiff elongate section comprises a rigid tube defining an interior flow path.
25. The conduit of claim 23 wherein said axially flexible section comprises a flexible elongate member having a length shorter than the length of said stiff elongate section.
26. The conduit of claim 23 wherein said axially stiff elongate section comprises a rigid tube defining an interior flow path and said axially flexible section comprises a flexible hose defining an interior flow path coupled in series with said rigid tube flow path.
27. The conduit of claim 23 wherein said stiff elongate section includes an electrically conductive path.
28. The conduit of claim 23 wherein said stiff elongate section carries a source of illumination.