Vaporization device systems and methods
Vaporization devices and methods of operating them are described. In particular, apparatuses with a resistive heating element, electrical circuitry for measuring a voltage between the resistive heating element and a reference resistor, and a microcontroller for controlling a temperature of the resistive heating element in response to a determined resistance are described. The electrical circuitry may comprise the reference resistor, a first switch operable to interrupt the flow of current from the power source through the resistive heating element, a second switch operable to add the reference resistor in series with the resistive heating element when the flow of current from the power source through the resistive heating element is interrupted by operation of the first switch, and a voltage divider configured to measure a voltage between the resistive heating element and the reference resistor.
1. An apparatus comprising:
a detachable cartridge comprising a storage compartment configured to hold a vaporizable material, a resistive heating element configured to cause vaporization of the vaporizable material when supplied with a flow of current, and a mouthpiece configured for passage of an aerosol formed from the vaporization;
a device body comprising:
a power source configured to supply the flow of current;
a cartridge receptacle configured to form a separable coupling with the detachable cartridge when the detachable cartridge is inserted into the cartridge receptacle;
electrical circuitry comprising a reference resistor having a reference resistance, a first switch operable to interrupt the flow of current from the power source through the resistive heating element, a second switch operable to provide the reference resistor in series with the resistive heating element when the flow of current from the power source through the resistive heating element is interrupted by operation of the first switch, and a voltage divider configured to determine a voltage between the resistive heating element and the reference resistor; and
a microcontroller configured to perform operations comprising:
operating the first switch to interrupt the flow of current supplied from the power source through the resistive heating element to cause the vaporization of the vaporizable material and concurrently operating the second switch to add the reference resistor in series with the resistive heating element;
determining a resistance of the resistive heating element based on the voltage measured by the voltage divider when the microcontroller concurrently operates the first switch and the second switch; and
controlling a temperature of the resistive heating element in response to the determined resistance by adjusting power supplied to the resistive heating element.
2. The apparatus of claim 1 , wherein the microcontroller is further configured to perform operations comprising:
determining that the determined resistance exceeds a threshold resistance indicative of the resistive heating element being dry; and
turning the power source off in response to determining that the determined resistance exceeds the threshold resistance.
3. The apparatus of claim 1 , further comprising:
a pressure sensor configured to detect when a user is puffing on the mouthpiece, wherein the electrical circuitry is configured to supply, in response to detecting the user puffing on the mouthpiece, the flow of current from the power source through the resistive heating element.
4. The apparatus of claim 1 , wherein the microcontroller comprises a proportional-integral-derivative control law, the microcontroller configured to monitor whether the determined resistance exceeds a resistance value indicating that the resistive heating element has reached a setpoint temperature value.
5. The apparatus of claim 4 , wherein the microcontroller is further configured to perform operations comprising:
monitoring an amount of power required to keep the resistive heating element at the setpoint temperature value; and
turning the power source off in response to detecting that the amount of power is below a threshold power level.
6. The apparatus of claim 4 , wherein the microcontroller is further configured to perform operations comprising:
preventing, during a time period in which the determined resistance exceeds the resistance value, the flow of current from the power source to the resistive heating element.
7. The apparatus of claim 4 , wherein the setpoint temperature value is between 200° C. and 400° C.
8. The apparatus of claim 1 , wherein operating the first switch to interrupt the flow of current through the resistive heating element comprises activating the first switch at fixed intervals.
9. The apparatus of claim 8 , wherein activating the first switch at fixed intervals comprises activating the first switch for approximately one millisecond per every one hundred milliseconds.
10. The apparatus of claim 1 , wherein
the detachable cartridge further comprises two first contacts; and
the device body further comprises two second contacts disposed within the cartridge receptacle, wherein the two second contacts are configured to electrically couple with the two first contacts to complete an electrical circuit comprising the power source and the resistive heating element.
11. An apparatus comprising:
a detachable cartridge comprising a fluid storage compartment that holds a vaporizable material, a wick, a resistive heating element, and a condensation chamber;
a device body comprising a power source, the device body and the detachable cartridge configured to form a separable coupling when connected;
wherein the apparatus further comprises:
electrical circuitry comprising a reference resistor having a reference resistance, a first switch operable to interrupt a flow of current from the power source through the resistive heating element configured when the detachable cartridge is coupled with the device body to cause vaporization of the vaporizable material when supplied with the flow of current, a second switch operable to provide the reference resistor in series with the resistive heating element when the flow of current from the power source through the resistive heating element is interrupted by operation of the first switch, and a voltage divider configured to determine a voltage between the resistive heating element and the reference resistor; and
a microcontroller configured to perform operations comprising:
operating the first switch to interrupt the flow of current supplied from the power source through the resistive heating element to cause the vaporization of the vaporizable material and concurrently operating the second switch to add the reference resistor in series with the resistive heating element;
determining a resistance of the resistive heating element based on the voltage measured by the voltage divider when the microcontroller concurrently operates the first switch and the second switch; and
controlling a temperature of the resistive heating element in response to the determined resistance by adjusting power supplied to the resistive heating element.
12. The apparatus of claim 11 , wherein the microcontroller is further configured to perform operations comprising:
determining that the determined resistance exceeds a threshold resistance indicative of the resistive heating element being dry; and
turning the power source off in response to determining that the determined resistance exceeds the threshold resistance.
13. The apparatus of claim 11 , further comprising:
a pressure sensor configured to detect when a user is puffing on the apparatus, wherein the electrical circuitry is configured to supply, in response to detecting the user puffing on the apparatus, the flow of current from the power source through the resistive heating element.
14. The apparatus of claim 11 , wherein the microcontroller comprises a proportional-integral-derivative control law, the microcontroller configured to monitor whether the determined resistance exceeds a resistance value indicating that the resistive heating element has reached a setpoint temperature value.
15. The apparatus of claim 14 , wherein the microcontroller is further configured to perform operations comprising:
preventing, during a time period in which the determined resistance exceeds the resistance value, the flow of current from the power source to the resistive heating element.
16. The apparatus of claim 14 , wherein the setpoint temperature value is between 200° C. and 400° C.
17. The apparatus of claim 11 , wherein operating the first switch to interrupt the flow of current through the resistive heating element comprises:
activating the first switch at fixed intervals, wherein activating the first switch at fixed intervals comprises activating the first switch for approximately one millisecond per every one hundred milliseconds.
18. The apparatus of claim 11 , wherein the device body further comprises:
a cartridge receptacle configured to receive the detachable cartridge, wherein the detachable cartridge is configured to electrically couple the power source and the resistive heating element, when the detachable cartridge is received within the cartridge receptacle.