Electrically operated aerosol-generating device with continuous power regulation
An aerosol-generating device is provided, including an electrical power source; an electrical heater; and a power control circuit connected between the power source and the heater, the circuit including a power measuring unit configured to determine a power supplied to the heater from the power source and to output a power measurement voltage proportional to power supplied to the heater, a voltage comparator connected to the power measuring unit and configured to output a voltage difference signal based on a difference between the power measurement voltage and a reference voltage, and a power regulator connected between the power source and the heater and responsive to the voltage difference signal, the power regulator being configured to adjust a current or a voltage supplied to the heater in order to return the voltage difference signal to within a predetermined range or in order to minimize the voltage difference signal.
1. An aerosol-generating device, comprising:
an electrical power source;
an electrical heater; and
a power control circuit connected between the electrical power source and the electrical heater, wherein the power control circuit is an analog circuit and comprises:
a power measuring unit configured to determine a power supplied to the electrical heater from the electrical power source and to output a power measurement voltage proportional to power supplied to the electrical heater,
a voltage comparator connected to the power measuring unit and configured to output a voltage difference signal based on a difference between the power measurement voltage and a reference voltage, and
a power regulator connected between the electrical power source and the electrical heater and responsive to the voltage difference signal, the power regulator being configured to adjust a current or a voltage supplied to the electrical heater in order to return the voltage difference signal to within a predetermined range or in order to minimize the voltage difference signal,
wherein the power measuring unit, the voltage comparator, and the power regulator are all implemented using analog circuit components.
2. The aerosol-generating device according to claim 1 , wherein the power regulator is further configured to adjust the current supplied to the electrical heater only if the voltage difference signal is outside of the predetermined range.
3. The aerosol-generating device according to claim 1 , wherein the power regulator comprises a bipolar junction transistor having a base connected to an output of the voltage comparator.
4. The aerosol-generating device according to claim 1 , wherein the power measuring unit comprises a multiplier unit configured to multiply a voltage applied to the electrical heater with a voltage indicative of the current applied to the electrical heater to provide the power measurement voltage.
5. The aerosol-generating device according to claim 1 , wherein the power measuring unit comprises a current measurement unit configured to provide an output voltage indicative of the current applied to the electrical heater.
6. The aerosol-generating device according to claim 1 , further comprising a microcontroller configured to provide the reference voltage.
7. The aerosol-generating device according to claim 6 , wherein the microcontroller is further configured to vary the reference voltage during operation of the aerosol-generating device.
8. The aerosol-generating device according to claim 7 , wherein the microcontroller is further configured to vary the reference voltage based on a detected number of user inhalations.
9. The aerosol-generating device according to claim 7 , wherein the microcontroller is further configured to vary the reference voltage based on time following activation of the aerosol-generating device.
10. The aerosol-generating device according to claim 1 , wherein the aerosol-generating device is a handheld device.
11. The aerosol-generating device according to claim 1 , wherein the electrical heater is removably coupled to the power control circuit and is configured to allow for replacement of the electrical heater.
12. The aerosol-generating device according to claim 1 ,
wherein the aerosol-generating device is configured to generate an aerosol for user inhalation, and, in use, user inhalation draws air past the electrical heater, and
wherein the aerosol-generating device comprises a memory and is configured to record changes in current or voltage supplied to the electrical heater as an indication of user inhalation.
13. A method for regulating a supply of power to an electrical heater in an electrically heated aerosol-generating system, the aerosol-generating system comprising an electrical power source, an electrical heater, and a power control circuit connected between the electrical power source and the electrical heater, wherein the power control circuit is an analog circuit, and wherein the power measuring unit, the voltage comparator, and the power regulator are all implemented using analog circuit components, the method comprising:
determining a power supplied to the electrical heater from the electrical power source and generating a power measurement voltage proportional to power supplied to the electrical heater;
generating a voltage difference signal based on a difference between the power measurement voltage and a reference voltage; and
adjusting a current or a voltage supplied to the electrical heater in order to maintain the voltage difference signal within a predetermined range or in order to minimize the voltage difference signal.