1. A method of controlling a freewheel switch during start-up of a switch mode power supply to inhibit negative output current, the switch mode power supply having alternating first and second intervals, the freewheel switch having an ON-time and an OFF-time, the method comprising gradually increasing the ON-time of the freewheel switch over a plurality of said second intervals during start-up of the switch mode power supply until the ON-time of the freewheel switch is substantially equal to a duration of the second interval.
2. The method of claim 1 wherein gradually increasing includes gradually increasing the ON-time of the freewheel switch over a plurality of successive second intervals until the ON-time of the freewheel switch is substantially equal to the duration of the second interval.
3. The method of claim 2 wherein the switch mode power supply includes a first switch that is closed during each first interval and a second switch that is closed during each second interval.
4. The method of claim 3 wherein the first switch is a power switch and the second switch is clamp switch.
5. The method of claim 1 further comprising adjusting durations of the first and second intervals in response to a load condition.
6. A switch mode power supply having alternating first and second intervals, the switch mode power supply comprising a main switch, a freewheel switch, and a control circuit for defining an ON-time of the freewheel switch, the power supply configured to close the main switch during each first interval, the control circuit configured to gradually increase the ON-time of the freewheel switch over a plurality of the second intervals during start-up of the switch mode power supply until the ON-time of the freewheel switch is substantially equal to a duration of the second interval to thereby inhibit negative output current in the switch mode power supply.
7. The switch mode power supply of claim 6 wherein the control circuit is configured to gradually increase the ON-time of the freewheel switch over a plurality of successive second intervals during start-up of the switch mode power supply.
8. The switch mode power supply of claim 6 further comprising a drive switch coupled to the freewheel switch, wherein the control circuit is configured to gradually increase the ON-time of the freewheel switch via the drive switch.
9. The switch mode power supply of claim 8 wherein the control circuit includes a first capacitor coupled to the drive switch, the first capacitor configured to charge during each second interval, and wherein the ON-time of the freewheel switch during the second interval is defined by charge stored in the first capacitor.
10. The switch mode power supply of claim 9 wherein the control circuit includes a second capacitor coupled to the first capacitor, the second capacitor configured to charge from the first capacitor during the first interval.
11. The switch mode power supply of claim 10 further comprising a transformer coupled to the control circuit and configured to charge the first capacitor during the second interval.
12. A control circuit for controlling a switch mode power supply having a drive switch, a freewheel switch, a main switch, and alternating first and second intervals, the main switch configured to close during each first interval, the control circuit comprising a first capacitor for providing a drive signal to the freewheel switch via the drive switch, the drive signal defining the ON-time of the freewheel switch, and a resistor coupled to the first capacitor, the first capacitor configured to charge during the second interval, the resistor and the first capacitor configured to gradually increase the drive signal over a plurality of said second intervals during start-up of the switch mode power supply until the ON-time of the freewheel switch is substantially equal to a duration of the second interval.
13. The control circuit of claim 12 wherein the freewheel switch has a threshold voltage and wherein the drive signal turns ON the freewheel switch when the drive signal is equal to or greater than said threshold voltage.
14. The control circuit of claim 12 wherein the control circuit includes a second capacitor coupled to the first capacitor and a charging switch coupled to at least one of the first and second capacitors, the charging switch configured to transfer at least a portion of charge stored in the first capacitor to the second capacitor during the first interval.
15. The control circuit of claim 14 further comprising a voltage limiting device in parallel with at least one of the first capacitor and the second capacitor, the voltage limiting device defining a maximum voltage across at least one of the first capacitor and the second capacitor.
16. The control circuit of claim 14 wherein the second capacitor has a capacitance at least ten times greater than the first capacitor.
17. The control circuit of claim 12 further comprising a transformer winding and a diode coupled in series with the resistor and the first capacitor for forward biasing the diode during the second interval and reverse biasing the diode during the first interval.
18. The control circuit of claim 12 further comprising a reset switch coupled in parallel with the first capacitor to at least partially discharge at least one of the first capacitor and the second capacitor when a reset signal is received.
19. A switch mode power supply comprising the control circuit of claim 12.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method of matching an pet with an appropriate product comprising the steps of
a. assigning a breed code to a plurality of breeds of a pet based on predetermined criteria;
b. categorizing a product to determine whether said product is appropriate for said plurality of breeds of said pet assigned to said breed code;
c. publishing said assignment of said breed code and said categorization of said product to allow a consumer to appropriately match said product to said breeds of said pet.
2. The method of claim 1, said pet being a dog, said predetermined criteria for assigning said breed code to said plurality of breeds of said pet comprising:
a. assigning an exercise factor to each of said breeds of said pet based on predetermined criteria;
b. assigning a weight factor to each of said breeds of said pet based on predetermined criteria;
c. combining said exercise factor and said weight factor in a predetermined manner to determine said breed code.
3. The method of claim 2, said weight factor being a numerical weight factor and said exercise factor being a numerical exercise factor, said predetermined manner for combining said exercise factor and said weight factor comprising addition of said exercise factor and said weight factor.
4. The method of claim 1, said pet being a cat, said predetermined criteria for assigning said breed code to said plurality of breeds of said pet comprising:
a. assigning a temperament factor to each of said plurality of breeds of said pet based on predetermined criteria;
b. assigning a need for attention factor to each of said plurality of breeds of said pet based on predetermined criteria;
c. combining said temperament factor and said need for attention factor to determine said breed code.
5. The method of claim 6, said temperament factor being a numerical temperament factor and said need for attention factor being a numerical need for attention factor, said predetermined manner for combining said temperament factor and said need for attention factor comprising addition of said temperament factor and said need for attention factor.
6. A method for matching a pet with an appropriate product comprising placing indicia on a product for a pet or on a container therefor, or on any means in the proximity thereof, that indicates its compatibility with the pet having the same indicia or a corresponding indicia.
7. The method of claim 6, said indicia comprising a breed code.
8. A product for a pet or a container therefor having thereon indicia indicating that the product is compatible with a pet having the same or corresponding indicia to the indicia assigned thereto.
9. The product of claim 8, said indicia comprising a breed code.
10. An apparatus for matching a pet with an appropriate product comprising a client computer programmed to receive from a server computer over a computer network and to display to a user an identification of a product and further programmed to display indicia indicating that the product is compatible with a pet having the same indicia or corresponding indicia.
11. The apparatus of claim 10, said indicia comprising a breed code.
12. An apparatus for matching a pet with an appropriate product comprising a server computer programmed to transmit over a computer network to a server computer for display to a user an identification of a product and indicia indicating that the product is compatible with a pet having the same or corresponding indicia.
13. The apparatus of claim 12, said indicia comprising a breed code.