Optical image stabilization actuator driver power distribution control

Patent metadata

Field	Value
Publication number	US-9964777-B2
Application number	US-201514976937-A
Country	US
Kind code	B2
Filing date	Dec 21, 2015
Priority date	Dec 21, 2015
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

Various embodiments provide an optical image stabilization circuit including a drive circuit having a power waveform generator and a power waveform conversion circuit. The power waveform generator generates a power waveform. The power waveform conversion circuit converts the power waveform to a power drive signal. An actuator is then driven by the power drive signal to move a lens accordingly and compensate for any movements and vibrations of a housing of the lens.

First claim

The invention claimed is:

1. A system, comprising:
a lens located in a housing;
an actuator configured to move the lens;
a position sensor configured to measure a position of the lens and generate position data of the measured position of the lens;
a gyroscope configured to measure movement of the housing and generate movement data of the measured movement of the housing;
a microcontroller configured to determine a power input parameter based on the position data and the movement data;
a drive circuit, including:
a power waveform generator configured to generate a power waveform, the power waveform having a first amplitude value for a first time duration, a second amplitude value for a second time duration, and a third amplitude value for a third time duration, the first, second, and third amplitude values each being determined by the power input parameter, the power waveform generator configured to calculate an initial amplitude value of the power waveform, a minimum amplitude value of the power waveform, a maximum amplitude value of the power waveform, and timings of the minimum and maximum amplitude values using the power input parameter; and
a power waveform conversion circuit, including:
a digital to analog converter configured to convert the power waveform to a voltage signal by converting the first, second, and third amplitude values to first, second, and third voltages, respectively;
a voltage to current converter circuit configured to convert the voltage signal to a current signal, the drive circuit being coupled to and configured to drive the actuator with the current signal to move the lens.

2. The system of claim 1 , wherein the digital to analog converter is configured to dynamically adjust the voltage signal to minimize an offset error.

3. The system of claim 1 , wherein the voltage to current converter circuit applies a gain to the voltage signal.

4. The system of claim 1 , wherein the first time duration is the same length as the second time duration, and the third time interval is twice as long as the second time duration.

5. The system of claim 1 , wherein the power waveform generator is further configured to set the first amplitude value to the initial amplitude value, set the second amplitude value and the third amplitude value to the maximum amplitude value or the minimum amplitude value based on the calculated timings of the minimum and maximum amplitude values.

6. A system, comprising:
a lens located in a housing;
an actuator configured to move the lens;
a position sensor configured to measure a position of the lens and generate position data of the measured position of the lens;
a gyroscope configured to measure movement of the housing and generate movement data of the measured movement of the housing;
a drive circuit, including:
a power waveform generator configured to:
generate a power waveform based on the position data and the movement data; and
calculate an initial amplitude value of the power waveform, a minimum amplitude value of the power waveform, a maximum amplitude value of the power waveform, and timings of the minimum and maximum amplitude values using a power input parameter; and
a power waveform conversion circuit, including:
a digital to analog converter configured to convert the power waveform to a voltage signal;
a voltage to current converter circuit configured to convert the voltage signal to a current signal, the drive circuit being configured to drive the actuator with the current signal to move the lens.

7. The system of claim 6 , wherein the digital to analog converter is configured to dynamically adjust the voltage signal to minimize an offset error.

8. The system of claim 6 , wherein the voltage to current converter circuit applies a gain to the voltage signal.

9. The system of claim 6 , wherein the power waveform has a first amplitude value for a first time duration, a second amplitude value for a second time duration, and a third amplitude value for a third time duration, the first amplitude value being set to the initial amplitude value, the second amplitude value and the third amplitude value being set to the maximum amplitude value or the minimum amplitude value based on the calculated timings of the minimum and maximum amplitude values.

10. The system of claim 9 , wherein the first time duration is the same length as the second time duration, and the third time interval is twice as long as the second time duration.

11. A drive circuit, comprising:
a power waveform generator configured to:
receive a power input parameter;
generate a power waveform based on the power input parameter; and
calculate an initial amplitude value of the power waveform, a minimum amplitude value of the power waveform, a maximum amplitude value of the power waveform, and timings of the minimum and maximum amplitude values using the power input parameter; and
a power waveform conversion circuit, including:
a digital to analog converter configured to convert the power waveform to a voltage signal; and
a voltage to current converter circuit configured to convert the voltage signal to a current signal, the drive circuit being configured to drive an actuator with the current signal to move a lens.

12. The drive circuit of claim 11 , wherein the digital to analog converter is configured to dynamically adjust the voltage signal to minimize an offset error.

13. The drive circuit of claim 11 , wherein the voltage to current converter circuit applies a gain to the voltage signal.

14. The drive circuit of claim 11 , wherein the power waveform has a first amplitude value for a first time duration, a second amplitude value for a second time duration, and a third amplitude value for a third time duration, the first amplitude value being set to the initial amplitude value, the second amplitude value and the third amplitude value being set to the maximum amplitude value or the minimum amplitude value based on the calculated timings of the minimum and maximum amplitude values.

15. The drive circuit of claim 14 , wherein the first time duration is the same length as the second time duration, and the third time interval is twice as long as the second time duration.

Assignees

• St Microelectronics Inc

Inventors

• Lysinger Mark A
• Tai Chih-Hung
• Worley James L
• Nallamothu Pavan

Classifications

• H04N23/685

  performed by mechanical compensation · CPC title

• H04N23/55 Primary

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• H02P7/025

  the DC motors being of the moving coil type, e.g. voice coil motors · CPC title

• G02B27/646 Primary

  compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68) · CPC title

• H02K41/0356

  moving along a straight path · CPC title