1. A method comprising:
based on one or more burst-related sub-commands of a transmit command corresponding to a current packet to be transmitted during a burst period, applying a protection scheme to one or more subsequent packets of said burst period.
2. The method of claim 1 comprising:
receiving said transmit command from an upper media-access-controller portion, and
transmitting said current packet using a lower media-access-controller portion.
3. The method of claim 1, wherein applying said protection scheme comprises applying to said subsequent packets either one of an entire-burst protection scheme and a next-frame protection scheme.
4. The method of claim 1, wherein applying said protection scheme comprises applying said protection scheme based on a protection-type field in said transmit command.
5. The method of claim 1 comprising generating said transmit command including said one or more sub-commands.
6. The method of claim 5, wherein generating said transmit command comprises generating a transmit command including a next-frame duration value corresponding to an expected transmission duration of a packet successive to said current packet.
7. The method of claim 5, wherein generating said transmit command comprises generating a transmit command including a burst duration value corresponding to an expected transmission duration of said one or more subsequent packets.
8. The method of claim 1, comprising determining a protection-duration value to be transmitted in a duration field of said current packet based on said one or more burst-related sub-commands.
9. The method of claim 8, wherein determining said protection duration value comprises determining said protection-duration value based on a next-frame duration value corresponding to an expected transmission duration of a packet successive to said current frame.
10. The method of claim 8, wherein determining said protection duration value comprises determining said protection-duration value based on a burst duration value corresponding to an expected transmission duration of said one or more subsequent frames.
11. The method of claim 10 comprising:
determining a duration remainder value corresponding to an expected duration of said burst period after transmitting said current packet; and
determining a protection-duration value of a packet successive to said current packet based on said duration-remainder value.
12. An apparatus comprising:
a controller to apply a protection scheme to one or more subsequent packets of a current packet to be transmitted during a burst period, based on one or more burst-related sub-commands of a transmit command corresponding to said current packet.
13. The apparatus of claim 12, wherein said controller is able to apply to said subsequent packets either one of an entire-burst protection scheme and a next-frame protection scheme.
14. The apparatus of claim 12, wherein said controller is able to apply said protection scheme based on a value of a protection field in said transmit command.
15. The apparatus of claim 12 comprising a transmit-command generator to generate said transmit command including said one or more sub-commands.
16. The apparatus of claim 12, wherein said transmit command includes a next-frame duration value corresponding to an expected transmission duration of a packet successive to said current packet.
17. The apparatus of claim 12, wherein said transmit command includes a burst duration value corresponding to an expected transmission duration of said one or more subsequent packets.
18. The apparatus of claim 12, wherein said controller is able to determine a protection-duration value to be transmitted as part of said current packet based on said one or more burst-related sub-commands.
19. The apparatus of claim 18, wherein said one or more burst-related sub-commands comprise a next-frame duration value corresponding to an expected transmission duration of a packet successive to said current packet.
20. The apparatus of claim 18, wherein said one or more burst-related sub-commands comprise a burst duration value corresponding to an expected transmission duration of said one or more subsequent packets.
21. The apparatus of claim 20 wherein said controller is able to determine a duration remainder value corresponding to an expected duration of said burst period after said current packet is transmitted, and a protection-duration value of a packet successive to said current packet based on said duration remainder value.
22. A wireless transmission system comprising:
a wireless station including:
a controller to apply a protection scheme to one or more subsequent packets of a current packet to be transmitted during a burst period, based on one or more burst-related sub-commands of a transmit command corresponding to said current packet; and
a dipole antenna to transmit said current packet.
23. The wireless transmission system of claim 22 comprising another wireless station to receive said current packet.
24. The wireless transmission system of claim 22, wherein said controller is able to apply to said subsequent packets either one of an entire-burst protection scheme and a next-frame protection scheme.
25. The wireless transmission system of claim 22, wherein said wireless station comprises a transmit-command generator to generate said transmit command including said one or more sub-commands.
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 method of driving, with a motor control circuit, a multi-phase motor having a plurality of motor windings, the method comprising:
receiving, from outside of the motor control circuit, a selection signal;
identifying, with the motor control circuit, a set of parameter values from among a plurality of different sets of parameter values retained on the motor control circuit, wherein the plurality of different sets of parameter values is indicative of a corresponding plurality of different start-up signal characteristics of a plurality of drive signals coupled to the plurality of motor windings, wherein at least two of the plurality of different sets of parameter values are indicative of rotation of the multi-phase motor in the same direction, the identifying done in accordance with the selection signal;
determining, in accordance with the identified set of parameter values, with the motor control circuit, the start-up signal characteristics of the plurality of drive signals coupled to the plurality of motor windings, wherein the determined start-up signal characteristics of the plurality of drive signals comprise a respective ramped start-up of the electric motor during a respective ramp-up time period during a start-up mode of operation; and
generating, with the motor control circuit, the plurality of drive signals comprising the determined start-up signal characteristics to start the multi-phase motor spinning.
2. The method of claim 1, further comprising:
receiving, from outside of the motor control circuit, a motor voltage signal, wherein the identifying the set of parameter values is done in accordance with both the selection signal and the motor voltage signal.
3. The method of claim 2, wherein the generating the plurality of drive signals comprises:
generating a corresponding plurality of modulated PWM waveforms, the plurality of modulated PWM waveforms having respective duty cycles that change with time according to a sine-drive modulation envelope, wherein the sine-drive modulation envelope comprises a frequency, wherein each one of the plurality of modulated PWM waveforms has a peak duty cycle, wherein the peak duty cycle of each one of the plurality of modulated PWM waveforms is related to an amplitude of a respective one of a plurality of sinusoidal current signals carried by the plurality of motor windings, and wherein the frequency of the modulation envelope is related to a frequency of the plurality of sinusoidal current signals.
4. The method of claim 3, wherein the ramped start-up comprises a ramp-up of at least one of the peak duty cycle of the modulated PWM waveform or the frequency of the sine-drive modulation envelope, wherein time varying characteristics of at least one of the peak duty cycle or the frequency during the ramp-up time period are selected in accordance with the identified set of parameter values.
5. The method of claim 1, wherein the generating the plurality of drive signals comprises:
generating a corresponding plurality of modulated PWM waveforms, the plurality of modulated PWM waveforms having respective duty cycles that change with time according to a sine-drive modulation envelope, wherein the sine-drive modulation envelope comprises a frequency, wherein each one of the plurality of modulated PWM waveforms has a peak duty cycle, wherein the peak duty cycle of each one of the plurality of modulated PWM waveforms is related to an amplitude of a respective one of a plurality of sinusoidal current signals carried by the plurality of motor windings, and wherein the frequency of the modulation envelope is related to a frequency of the plurality of sinusoidal current signals.
6. The method of claim 5, wherein the ramped start-up comprises a ramp-up of the peak duty cycle of the modulated PWM waveform during a ramp-up time period, wherein time varying characteristics of the peak duty cycle during the ramp-up time period are selected in accordance with the identified set of parameter values.
7. The method of claim 5, wherein the ramped start-up comprises a ramp-up of the frequency of the sine-drive modulation envelope during the ramp-up time period, wherein time varying characteristics of the frequency during the ramp-up time period are selected in accordance with the identified set of parameter values.
8. The method of claim 5, wherein the ramped start-up comprises:
a ramp-up of the peak duty cycle of the modulated PWM waveform during the ramp-up time period, wherein time varying characteristics of the peak duty cycle during the ramp-up time period are selected in accordance with the identified set of parameter values; and
a ramp-up of the frequency of the sine-drive modulation envelope during the ramp-up time period, wherein time varying characteristics of the frequency during the ramp-up time period are selected in accordance with the identified set of parameter values.
9. The method of claim 8, wherein the ramp-up time period is also selected in accordance with the identified set of parameter values.
10. The method of claim 5, wherein the ramp-up time period comprises a first ramp-up time period followed by a second different ramp-up time period.
11. The method of claim 10, wherein the ramped start-up comprises:
a ramp-up of at least the peak duty cycle of the modulated PWM waveform during the first ramp-up time period, wherein time varying characteristics of the peak duty cycle during the first ramp-up time period are selected in accordance with the identified set of parameter values, and
a ramp-up of at least the frequency of the sine-drive modulation envelope during the second ramp-up time period, wherein time varying characteristics of the frequency during the second ramp-up time period are selected in accordance with the identified set of parameter values.
12. The method of claim 11, wherein the first and second ramp-up time periods are also selected in accordance with the identified set of parameter values.
13. The method of claim 10, wherein the determined start-up signal characteristics comprise:
first ramp-up characteristics during the first ramp-up time period; and
second different ramp-up characteristics during the second ramp-up time period.
14. The method of claim 13, wherein the first ramp-up characteristics comprise first characteristics of the plurality of drive signals beginning at a time when the multi-phase motor is not spinning and ending at an end of the first ramp-up time period, wherein the first ramp-up time period comprises a first at least one cycle of the plurality of sinusoidal current signals, and wherein the second ramp-up characteristics comprise second characteristics of the plurality of drive signals beginning at a beginning of the second ramp-up time period and ending at an end of the second ramp-up time period, wherein the second ramp-up time period comprises a second at least one cycle of the plurality of sinusoidal current signals, wherein an end of the first at least one cycle is continuous in phase with a start of the second at least one cycle.
15. The method of claim 5, wherein the generating the plurality of drive signals comprises:
generating the plurality of drive signals such that, at an end of the ramp-up time period, a last one of the plurality of cycles of a selected one of the plurality of sinusoidal current signals ends at a zero current.
16. The method of claim 15, further comprising
stopping the plurality of drive signals for a coasting time period following the end of the ramp-up time period;
detecting a back EMF signal indicative of a zero back EMF voltage on a selected one of the plurality of motor windings while the plurality of drive signals are stopped, the detected back EMF signal indicative of an end of the coasting time period; and
driving the plurality of motor windings with the plurality of sinusoidal current signals in a normal mode of operation in response to the detecting, wherein, in the normal mode of operation, a first cycle of a sinusoidal current signal on the selected one of the plurality of motor windings begins at zero current and at a phase continuous with a phase of the last one of the plurality of cycles of the sinusoidal current signal on the selected one of the plurality of motor windings at the end of the ramp-up time period.
17. The method of claim 1, wherein a value of the selection signal is determined based upon a load upon the multi-phase motor.
18. A motor control circuit for driving a multi-phase motor having a plurality of motor windings, the motor control circuit comprising a start-up control module configured to:
receive, from outside of the motor control circuit, a selection signal;
identify set of parameter values from among a plurality of different sets of parameter values retained on the motor control circuit, wherein the plurality of different sets of parameter values is indicative of a corresponding plurality of different start-up signal characteristics of a plurality of drive signals coupled to the plurality of motor windings, wherein at least two of the plurality of different sets of parameter values are indicative of rotation of the multi-phase motor in the same direction, the identifying done in accordance with the selection signal; and
determine, in accordance with the identified set of parameter values, the start-up signal characteristics of the plurality of drive signals coupled to the plurality of motor windings, wherein the determined start-up signal characteristics of the plurality of drive signals comprise a respective ramped start-up of the electric motor during a respective ramp-up time period during a start-up mode of operation; wherein the motor control circuit is configured to:
generate the plurality of drive signals comprising the determined start-up signal characteristics to start the multi-phase motor spinning.
19. The motor control circuit of claim 18, wherein the start-up control module is further configured to:
receive a motor voltage signal, and to identify the set of parameter values in accordance with both the selection signal and the motor voltage signal.
20. The motor control circuit of claim 19, wherein the motor control circuit is configured to generate the plurality of drive signals by:
generating a corresponding plurality of modulated PWM waveforms, the plurality of modulated PWM waveforms having respective duty cycles that change with time according to a sine-drive modulation envelope, wherein the sine-drive modulation envelope comprises a frequency, wherein each one of the plurality of modulated PWM waveforms has a peak duty cycle, wherein the peak duty cycle of each one of the plurality of modulated PWM waveforms is related to an amplitude of a respective one of a plurality of sinusoidal current signals carried by the plurality of motor windings, and wherein the frequency of the modulation envelope is related to a frequency of the plurality of sinusoidal current signals.
21. The motor control circuit of claim 20, wherein the ramped start-up comprises a ramp-up of at least one of the peak duty cycle of the modulated PWM waveform or the frequency of the sine-drive modulation envelope, wherein time varying characteristics of at least one of the peak duty cycle or the frequency during the ramp-up time period are selected in accordance with the identified set of parameter values.
22. The motor control circuit of claim 18, wherein the motor control circuit is configured to generate the plurality of drive signals by:
generating a corresponding plurality of modulated PWM waveforms, the plurality of modulated PWM waveforms having respective duty cycles that change with time according to a sine-drive modulation envelope, wherein the sine-drive modulation envelope comprises a frequency, wherein each one of the plurality of modulated PWM waveforms has a peak duty cycle, wherein the peak duty cycle of each one of the plurality of modulated PWM waveforms is related to an amplitude of a respective one of a plurality of sinusoidal current signals carried by the plurality of motor windings, and wherein the frequency of the modulation envelope is related to a frequency of the plurality of sinusoidal current signals.
23. The motor control circuit of claim 22, wherein the ramped start-up comprises a ramp-up of the peak duty cycle of the modulated PWM waveform during a ramp-up time period, wherein time varying characteristics of the peak duty cycle during the ramp-up time period are selected in accordance with the identified set of parameter values.
24. The motor control circuit of claim 22, wherein the ramped start-up comprises a ramp-up of the frequency of the sine-drive modulation envelope during the ramp-up time period, wherein time varying characteristics of the frequency during the ramp-up time period are selected in accordance with the identified set of parameter values.
25. The motor control circuit of claim 22, wherein the ramped start-up comprises:
a ramp-up of the peak duty cycle of the modulated PWM waveform during the ramp-up time period, wherein time varying characteristics of the peak duty cycle during the ramp-up time period are selected in accordance with the identified set of parameter values; and
a ramp-up of the frequency of the sine-drive modulation envelope during the ramp-up time period, wherein time varying characteristics of the frequency during the ramp-up time period are selected in accordance with the identified set of parameter values.
26. The motor control circuit of claim 25, wherein the ramp-up time period is also selected in accordance with the identified set of parameter values.
27. The motor control circuit of claim 22, wherein the ramp-up time period comprises a first ramp-up time period followed by a second different ramp-up time period.
28. The motor control circuit of claim 27, wherein the ramped start-up comprises:
a ramp-up of at least the peak duty cycle of the modulated PWM waveform during the first ramp-up time period, wherein time varying characteristics of the peak duty cycle during the first ramp-up time period are selected in accordance with the identified set of parameter values, and
a ramp-up of at least the frequency of the sine-drive modulation envelope during the second ramp-up time period, wherein time varying characteristics of the frequency during the second ramp-up time period are selected in accordance with the identified set of parameter values.
29. The motor control circuit of claim 28, wherein the first and second ramp-up time periods are also selected in accordance with the identified set of parameter values.
30. The motor control circuit of claim 27, wherein the determined start-up signal characteristics comprise:
first ramp-up characteristics during the first ramp-up time period; and
second different ramp-up characteristics during the second ramp-up time period.
31. The motor control circuit of claim 30, wherein the first ramp-up characteristics comprise first characteristics of the plurality of drive signals beginning at a time when the multi-phase motor is not spinning and ending at an end of the first ramp-up time period, wherein the first ramp-up time period comprises a first at least one cycle of the plurality of sinusoidal current signals, and wherein the second ramp-up characteristics comprise second characteristics of the plurality of drive signals beginning at a beginning of the second ramp-up time period and ending at an end of the second ramp-up time period, wherein the second ramp-up time period comprises a second at least one cycle of the plurality of sinusoidal current signals, wherein an end of the first at least one cycle is continuous in phase with a start of the second at least one cycle.
32. The motor control circuit of claim 22, wherein the generating the plurality of drive signals comprises:
generating the plurality of drive signals such that, at an end of the ramp-up time period, a last one of the plurality of cycles of a selected one of the plurality of sinusoidal current signals ends at a zero current.
33. The motor control circuit of claim 32, wherein the start-up control module is further configured to:
stop the plurality of drive signals for a coasting time period following the end of the ramp-up time period; and
detect a back EMF signal indicative of a zero back EMF voltage on a selected one of the plurality of motor windings while the plurality of drive signals are stopped, the detected back EMF signal indicative of an end of the coasting time period; wherein the motor control circuit is further configured to:
drive the plurality of motor windings with the plurality of sinusoidal current signals in a normal mode of operation in response to the detecting, wherein, in the normal mode of operation, a first cycle of a sinusoidal current signal on the selected one of the plurality of motor windings begins at zero current and at a phase continuous with a phase of the last one of the plurality of cycles of the sinusoidal current signal on the selected one of the plurality of motor windings at the end of the ramp-up time period.
34. The motor control circuit of claim 18, wherein a value of the selection signal is determined based upon a load upon the multi-phase motor.
35. A method of driving, with a motor control circuit, a multi-phase motor having a plurality of motor windings, the method comprising:
receiving, from outside of the motor control circuit, a selection signal;
identifying, with the motor control circuit, a set of parameter values from among a plurality of sets of parameter values retained on the motor control circuit, the identifying done in accordance with the selection signal;
determining, in accordance with the identified set of parameter values, with the motor control circuit, start-up signal characteristics of a plurality of drive signals coupled to the plurality of motor windings, wherein the determined start-up signal characteristics of the plurality of drive signals comprise a ramped start-up of the electric motor during a ramp-up time period during a start-up mode of operation;
generating, with the motor control circuit, the plurality of drive signals comprising the determined start-up signal characteristics to start the multi-phase motor spinning; and
receiving, from outside of the motor control circuit, a motor voltage signal, wherein the identifying the set of parameter values is done in accordance with both the selection signal and the motor voltage signal.
36. A motor control circuit for driving a multi-phase motor having a plurality of motor windings, the motor control circuit comprising a start-up control module configured to:
receive, from outside of the motor control circuit, a selection signal;
identify set of parameter values from among a plurality of sets of parameter values retained on the motor control circuit, the identifying done in accordance with the selection signal; and
determine, in accordance with the identified set of parameter values, start-up signal characteristics of a plurality of drive signals coupled to the plurality of motor windings, wherein the determined start-up signal characteristics of the plurality of drive signals comprise a ramped start-up of the electric motor during a ramp-up time period during a start-up mode of operation; wherein the motor control circuit is configured to:
generate the plurality of drive signals comprising the determined start-up signal characteristics to start the multi-phase motor spinning, wherein the start-up control module is further configured to:
receive a motor voltage signal, and to identify the set of parameter values in accordance with both the selection signal and the motor voltage signal.