Optical image stabilization synchronization of gyroscope and actuator drive circuit
Various embodiments provide an optical image stabilization circuit that synchronizes its gyroscope and drive circuit using gyroscope data ready signals and gyroscope reset signals. In response to a gyroscope data ready signal, the optical image stabilization circuit synchronously obtains position measurements of a camera lens when power drive signals are not transitioning from one power level to another power level, and synchronously transitions the power drive signals simultaneously with gyroscope reset signals. By synchronizing the gyroscope and the drive circuit, the gyroscope and other onboard sensing circuits are isolated from noise generated by the drive circuit.
1. A method of driving a lens for movement relative to a camera housing in which the lens is located, the method comprising:
receiving a reset signal from a gyroscope that is positioned within the camera housing, the reset signal being active indicating that the gyroscope is in a non-measuring state;
outputting a power drive signal at a first power level to drive an actuator that moves the lens;
transitioning, concurrently with the reset signal being active, the power level of the power drive signal from the first power level to a second power level;
outputting the power drive signal at the second power level; and
obtaining position data of a position of the lens from a position sensor while the power drive signal is at the first power level and prior to the step of transitioning between the first and second power levels.
2. The method according to claim 1 , wherein the camera housing is a smartphone.
3. The method according to claim 1 , further comprising:
transitioning the power level of the power drive signal from the second power level to a third power level; and
obtaining additional position data of a position of the lens from the position sensor while the power drive signal is at the third power level.
4. The method according to claim 1 , further comprising:
calculating power drive signal data of another power drive signal concurrently with the outputting of the power drive signal at the first power level and the obtaining of the position data.
5. The method according to claim 1 , further comprising:
receiving a data ready signal from the gyroscope, the data ready signal indicating that movement data of a movement of the camera housing is ready for processing, the outputting of the power drive signal at the first power level being in response to the data ready signal.
6. A method of driving a lens for movement relative to a camera housing in which the lens is located, the method comprising:
receiving a plurality of reset signals from a gyroscope that is located in the same housing as the lens, the plurality of reset signals having a first frequency, each of the plurality of reset signals indicating that a gyroscope is in a non-measuring state;
outputting a power drive signal to drive an actuator that moves the lens, the power of the power drive signal being constant for a first period time, having a transition from one power level to another power level within a single cycle of the power drive signal, and then being constant for a second period of time, the transition being synchronised with a reset signal of the plurality of reset signals; and
obtaining position data of the lens from a position sensor located adjacent to the lens and in the same housing, the timing of the obtaining of the position data being selected to occur while the power of the power drive signal is at a constant power.
7. The method according to claim 6 , wherein the camera housing is a smartphone.
8. The method according to claim 6 , further comprising:
counting the plurality of reset signals; and
tracking the power drive signal based on the counting of the plurality of reset signals.
9. The method according to claim 6 , wherein the power drive signal has a second frequency that is greater than 20 kHz.
10. The method according to claim 6 , wherein the power drive signal has a second frequency that is greater than the first frequency.
11. The method according to claim 6 , further comprising:
receiving a data ready signal from the gyroscope, the data ready signal indicating that movement data of the camera housing is ready for processing, the outputting of the power drive signal and the obtaining of the position data being in response to the data ready signal.
12. A method, comprising:
receiving a reset signal from a gyroscope, the reset signal being active indicating the gyroscope is in a non-measuring state;
outputting a power drive signal to an actuator, the power drive signal having a transition from one power level to another power level, the transition of the power drive signal being synchronized to be concurrent with the reset signal being active; and
obtaining position data from a position sensor, the obtaining of the position data being synchronized with the power drive signal to not be during the transition of the power drive signal.
13. The method according to claim 12 , further comprising:
receiving a data ready signal from the gyroscope, the data ready signal indicating that movement data is ready, the obtaining of the position data being in response to the data ready signal.
14. The method according to claim 12 , further comprising:
moving a camera lens based on the power drive signal.
15. The method according to claim 12 , wherein the outputting of the power drive signal and the obtaining of the position data are performed concurrently.