WO1994018860B1 - Method and apparatus for controlling the supply of energy to a heating load in a smoking article - Google Patents

Abstract

A method and an apparatus for controlling energy flow into a heating load array of a smoking article are provided. In response to a pressure drop in the mouthpiece of the smoking article, a selected load in the heating load array is switchably connected to a power supply. Energy delivered to the load is measured and the load is disconnected when a predetermined amount of energy has been delivered.

Claims

- 24 -AMENDED CLAIMS[received by the International Bureau on 2 September 1994 (02.09.94); original claims 1-25 replaced by amended claims 1-28 (9 pages)]

1. An apparatus for controlling delivery of energy from a power supply to a heating load (101) in a smoking article, comprising: puff sensor means (110) for sensing when a smoker draws a puff from the smoking article; switching means (108) for coupling the heating load to said power supply; energy measurement means (106, 116), coupled to the heating load, for measuring an amount of energy delivered to the heating load; control means (106) , coupled to said puff sensor means, said switching means and said energy measurement means, for enabling said switching means to connect the heating load to the power supply when said puff sensor means senses a puff and for disabling the switching means to disconnect the heating load from the power supply when a predetermined amount of energy as measured by the energy measurement means has been delivered to the heating load; and oscillator means (120) , coupled to the control means, for generating interrupt signals at a predetermined rate, wherein the control means (106) comprise a microcontroller comprising: means for maintaining the microcontroller in a stop mode; means for entering a run mode upon receipt of an interrupt from the oscillator means; and means for returning to the stop mode after entering the run mode when the puff sensor means has not sensed a puff.

2. An apparatus for controlling delivery of energy from a power supply to a plurality of heating loads (101) in a smoking article, comprising: puff sensor means (110) for sensing when a smoker draws a puff from the smoking article; switching means (108) for selectively coupling at least one of the plurality of heating loads to the power supply; energy measurement means (106, 116) coupled to the power source, for measuring an amount of energy delivered to the at least one heating load; control means (106) , coupled to the puff sensor means, the switching means and the energy measurement means, for enabling the switching means to connect the at least one heating load to the power supply when the puff sensor means senses a puff and for disabling the switching means to disconnect the at least one heating load from the power supply when a predetermined amount of energy as measured by the energy measurement means has been delivered to the at least one heating load; and oscillator means (120) , coupled to the control means, for generating interrupt signals at a predetermined rate, wherein the control means (106) comprises a microcontroller comprising: means for maintaining the microcontroller in a stop mode; means for entering a run mode upon receipt of an interrupt from the oscillator means; and means for returning to the stop mode after entering the run mode when the puff sensor means has not sensed a puff.

3. Apparatus according to claim 2, wherein the control means further comprises means for enabling the switching means to select at least one unused heating load each time the puff sensor means senses a puff, until all of the plurality of heating loads have been used. - 26 -

4. Apparatus according to claim 3, f rther comprising display means (104) , coupled to the control means, for displaying a symbol indicative of a number of unused heating loads remaining.

5. Apparatus according to any of claims 1 to 4, further comprising load sensor means (130, 134, 136), coupled to the microcontroller and the heating load, for sensing when the heating load is coupled to the power supply.

6. An apparatus for controlling delivery of energy from a power supply to a heating load (101) in a smoking article, comprising: puff sensor means (110) for sensing when a smoker draws a puff from the smoking article; switching means (108) for coupling the heating load to the power supply; energy measurement means (106, 116) , coupled to the heating load, for measuring an amount of energy delivered to the heating load; control means (106) , coupled to said puff sensor means, said switching means and said energy measurement means, for enabling said switching means to connect the heating load to the power supply when said puff sensor means senses a puff and for disabling said switching means to disconnect the heating load from the power supply when a predetermined amount of energy as measured by said energy measurement means has been delivered to the heating load; oscillator means (12) , coupled to said control means, for generating interrupt signals at a predetermined rate; wherein said control means comprises a microcontroller; and further comprising load sensor means (130, 134, 136) coupled to said microcontroller and the heating load, - 27 -

for sensing when the heating load is coupled to the power supply.

7. An apparatus for controlling delivery of energy from a power supply to a plurality of heating loads (101) in a smoking article, comprising: puff sensor means (110) for sensing when a smoker draws a puff from the smoking article; switching means (108) for selectively coupling at least one of the plurality of heating loads to the power supply; energy measurement means (106, 116), coupled to the power supply, for measuring an amount of energy delivered to the at least one heating load; control means (106) , coupled to said puff sensor means, said switching means and said energy measurement means, for enabling said switching means to connect the at least one heating load to the power supply when said puff sensor means senses a puff and for disabling said switching means to disconnect the at least one heating load from the power supply when a predetermined amount of energy as measured by said energy measurement means has been delivered to the at least one heating load; oscillator means (120) , coupled to said control means, for generating interrupt signals at a predetermined rate; wherein said control means comprises a microcontroller; and further comprising load sensor means (103, 134, 136) , coupled to said microcontroller and the plurality of heating loads, for sensing when the plurality of heating loads are coupled to the power supply.

8. Apparatus according to claim 7, wherein said control means further comprises means for enabling said switching means to select at least one unused heating - 28 -

load each time said puff sensor senses a puff, until all of the plurality of heating loads have been used.

9. Apparatus according to claim 7 or 8, further comprising display means, coupled to said control means, for displaying a symbol indicative of a number of unused heating loads remaining.

10. Apparatus according to any of claims 6 to 9, wherein the microcontroller (106) comprises: means for maintaining the microcontroller in a stop mode; means for entering a run mode upon receipt of an interrupt from the oscillator means; and means for returning to the stop mode after entering the run mode when the puff sensor means has not sensed a puff.

11. Apparatus according to any of claims 1 to 10, wherein the control means (106) comprises means for enabling the switching means so that the predetermined amount of energy is delivered from the power supply to the heating load or the at least one heating load within a predetermined period of time.

12. Apparatus according to claim 11, wherein the control means (106) further comprises: means for dividing the predetermined period of time into a plurality of intervals, each of the intervals being a duration substantially equal to a predetermined fraction of the period of time; and means for enabling the switching means so that a corresponding fraction of the predetermined amount of energy is delivered from the power supply to the heating load or the at least one heating load during each of the plurality of intervals. - 29 -

13. Apparatus according to any of claims 1 to 5 or 10, wherein the microcontroller further comprises means for returning to the stop mode after entering the run mode when the puff sensor means senses a puff and the predetermined amount of energy has been delivered from the power supply to the heating load or the at least one heating mode.

14. Apparatus according to any of claims 1 to 5 or 10, wherein the microcontroller further comprises: means for disabling the puff sensor means when the microcontroller enters the stop mode; and means for enabling the puff sensor means when the microcontroller receives an interrupt signal from the oscillator.

15. Apparatus according to claims 5, 6 or 7, wherein the microcontroller comprises means, responsive to the load sensor means, for enabling the microcontroller to enter a dormant mode when the heating load or the at least one heating load is not coupled to the power supply.

16. Apparatus according to claim 15, wherein the means for enabling the microcontroller to enter a dormant mode comprises: means for disabling the oscillator; and means for causing the microcontroller to enter a stop mode.

17. Apparatus of claim 16 further comprising wake-up logic means (130) , coupled to the microcontroller, for generating an interrupt signal when the, or the at least one, heating load (101) is coupled to the power supply. - 30 -

18. Apparatus according to claim 17, wherein the microcontroller further comprises: means for receiving the interrupt signal from the wake-up logic means; means for enabling the microcontroller to enter a run mode upon receipt of the interrupt signal from the wake-up logic means; and means for enabling the oscillator means upon receipt of the interrupt signal from the wake-up logic means.

19. Apparatus according to claim 11, wherein the control means comprises means for determining that the power supply has sufficient stored energy to deliver the predetermined amount of energy to the heating load within the predetermined period of time.

20. Apparatus according to claim 19, further comprising display means (104) for displaying an error symbol when the power supply has insufficient stored energy to deliver the predetermined amount of energy to the heating load (101) or the at least one heating load (101) within the predetermined period of time.

21. Apparatus according to any of claims 1 to 20, wherein: the energy measurement means comprises an analog-to-digital converter (116) to measure a voltage that is applied to the heating load and to provide a digital representation of the measured voltage; and the microcontroller comprises means for monitoring the digital representation of the measured voltage, for determining a duration that the measured voltage is applied to the heating load (101) or the at least one heating load (101) , and for calculating energy delivered to the heating load while the measured voltage is applied to the heating load (101) or at least one heating load (101) from the measured voltage, - 31 -

the determined duration and a predetermined resistance of the heating load or the at least one heating load.

22. Apparatus of claim 20, wherein the analog- to-digital converter (116) is provided by the microcontroller.

23. Apparatus according to any preceding claim, wherein the puff sensor means (110) comprises a pressure transducer that senses a pressure drop in a mouthpiece of the smoking article.

24. A method for controlling energy flow in a smoking article, comprising: sensing the presence of a heating load in the smoking article; sensing when a puff is drawn on the smoking article; and delivering a predetermined amount of energy to the heating load in response to a sensed puff, the delivery step further comprising: maintaining the delivery step in a stop mode; generating interrupt signals at a predetermined rate; initiating a run mode upon receipt of a generated interrupt signal; returning to the stop mode when no heating load is sensed; and delivering the predetermined amount of power from a battery when a heating load and a puff are sensed.

25. The method of claim 24, wherein the step of delivering the predetermined amount of energy comprises delivering the predetermined amount of energy to the heating load within a predetermined period of time. - 32 -

26. A method for determining when a battery in a smoking article has insufficient stored energy, comprising: measuring the amount of energy delivered to the heating load of the smoking article within a predetermined period of time; and comparing the measured amount of energy to an expected amount of energy to determine if the measured amount of energy is less than the expected amount of energy, which indicates that the battery has insufficient stored energy.

27. The method of claim 24, further comprising returning to the stop mode after the delivery step.

28. A smoking article including apparatus for controlling delivery of energy from a power supply to one or more heating loads according to any of claims 1 to 23.