Heater control circuitry for vaporizer device
A vaporizer device may include a controller and a heater control circuitry. The controller may generate, based at least on a temperature of a heating coil in a cartridge coupled with the vaporizer device, an output signal for controlling a discharge of a battery of the vaporizer device. The battery may be discharged to the heating coil to increase the temperature of the heating coil and cause a vaporization of a vaporizable material contained in the cartridge. The heater control circuitry may determine the temperature of the heating coil. The heater control circuitry may further control, based on the output signal from the controller, the discharge of the battery to the heating coil. The heater control circuitry may be powered by a voltage rail coupled to a voltage regulator configured to regulate an output voltage of the battery.
1. A vaporizer device, comprising:
a controller configured to generate, based at least on a temperature of a heating coil in a cartridge coupled with the vaporizer device, an output signal for controlling a discharge of a battery of the vaporizer device, the battery being discharged to the heating coil to increase the temperature of the heating coil, and the increase in the temperature of the heating coil causing a vaporization of a vaporizable material contained in the cartridge; and
a heater control circuitry configured to determine the temperature of the heating coil, the heater control circuitry further being configured to control, based at least on the output signal from the controller, the discharge of the battery to the heating coil, the heater control circuitry being powered by a voltage rail coupled to a voltage regulator configured to regulate an output voltage of the battery, wherein the heater control circuitry includes a switch controlling the discharge of the battery to the heating coil, and wherein the output signal from the controller controls a state of the switch.
2. The vaporizer device of claim 1 , wherein the heater control circuitry comprises:
one or more resistors having known resistances, the one or more resistors forming at least one voltage divider with the heating coil;
a differential amplifier configured to determine a voltage differential across the at least one voltage divider, the voltage differential across the at least one voltage divider corresponding to the temperature of the heating coil; and
a diode disposed between the battery and the voltage rail, the diode configured to prevent an over voltage across the one or more resistors having known resistances by at least preventing the battery from discharging to the voltage rail.
3. The vaporizer device of claim 2 , wherein a cathode of the diode is coupled to a drain of the switch.
4. The vaporizer device of claim 3 , wherein the output signal from the controller comprises a pulse width modulation signal, and wherein the controller controls the state of the switch by at least adjusting a duty cycle of the pulse width modulation signal.
5. The vaporizer device of claim 2 , wherein the at least one voltage divider includes a first voltage divider and a second voltage divider, and wherein the first voltage divider and the second voltage divider form a Wheatstone bridge.
6. The vaporizer device of claim 5 , wherein the Wheatstone bridge includes at least a fourth resistor having a known resistance, and wherein the fourth resistor is coupled with at least one of a first resistor, a second resistor, and a third resistor to adjust a range of the voltage differential across the at least one voltage divider.
7. The vaporizer device of claim 5 , wherein the first voltage divider includes a first resistor coupled in series with a second resistor, and wherein the second voltage divider includes a third resistor coupled in series with the heating coil.
8. The vaporizer device of claim 5 , wherein the heater control circuitry includes a first test node coupled to a first node between a first resistor and a second resistor in the first voltage divider, wherein the heater control circuitry further includes a second test node coupled to a second node between the heating coil and a third resistor, and wherein outputs from the first test node and/or the second node are used for determining a correction factor for the known resistances of the first resistor, the second resistor, or the third resistor.
9. The vaporizer device of claim 5 , wherein the temperature of the heating coil corresponds to a thermal coefficient of resistance of the heating coil and the known resistances of a first resistor, a second resistor, and a third resistor.
10. The vaporizer device of claim 5 , wherein the heater control circuitry further includes the switch coupled to a node between the heating coil and a third resistor, and wherein the state of the switch controls a flow of current from the voltage rail to the second voltage divider.
11. The vaporizer device of claim 10 , wherein the switch is disposed between the battery and the voltage rail to further prevent the over voltage across the one or more resistors having known resistances by at least preventing the battery from discharging to the voltage rail.
12. The vaporizer device of claim 5 , wherein the heater control circuitry further includes the switch disposed at a junction between the voltage rail, the second voltage divider, and the differential amplifier, wherein the switch is configured to prevent the heater control circuitry from being back powered by the diode when the heater control circuitry is not being powered by the voltage rail, and wherein the switch prevents the heater control circuitry from being back powered by at least preventing a backflow of current from the diode from entering the differential amplifier.
13. The vaporizer device of claim 2 , wherein the controller is further configured to determine an additional voltage associated with a Seebeck effect of the heating coil being formed from two or more metals, and wherein the voltage differential across the at least one voltage divider is adjusted based on the additional voltage in order to determine the temperature of the heating coil.
14. The vaporizer device of claim 1 , wherein the heater control circuitry includes a diode and a resistor forming an interrupt request line, wherein the diode is coupled to a positive terminal for coupling the heating coil to the heater control circuitry, and wherein a presence or an absence of a signal on the interrupt request line indicate whether the cartridge is coupled to the vaporizer device.
15. The vaporizer device of claim 14 , wherein the heater control circuitry includes a first test node coupled to the positive terminal for coupling the heating coil to the heater control circuitry and a second test node coupled to a negative terminal for coupling the heating coil to the heater control circuitry, and wherein outputs from the first test node and the second test node determine a correction factor for the signal across the heating coil.
16. The vaporizer device of claim 1 , wherein an output of the heater control circuitry comprises an analog signal, and wherein the controller includes an analog-to-digital converter for converting the analog signal from the heater control circuitry.
17. The vaporizer device of claim 1 , wherein the heater control circuitry includes a suppressor disposed between a power supply to the heater control circuitry and the switch controlling a flow of current from the power supply to the heater control circuitry, and wherein the suppressor is configured to suppress a high frequency noise present in an electrical signal from the power supply.
18. The vaporizer device of claim 17 , wherein the suppressor comprises a resistor, a zero-ohm resistor, or a ferrite bead.
19. The vaporizer device of claim 17 , wherein the heater control circuitry includes a reservoir capacitor connecting the power supply to ground, wherein the reservoir capacitor remains charged while the heater control circuitry is powered off, and wherein the reservoir capacitor prevents a voltage drop across the voltage rail when the heater control circuitry is powered on by at least supplying an in-rush current to the heater control circuitry.
20. The vaporizer device of claim 19 , wherein the suppressor and the reservoir capacitor comprise a low-pass filter configured to reject the high frequency noise present in the electrical signal from the power supply.
21. The vaporizer device of claim 1 , wherein the heater control circuitry includes a high-pass filter coupled with the output signal from the controller, wherein the high-pass filter is configured to prevent the battery from being constantly discharged to the heating coil, and wherein the high-pass filter includes a diode configured to provide a fast-discharge path for the high-pass filter when the high-pass filter produces a negative charge when the output signal from the controller transitions from high to low.