Methods and apparatus for actuator control

Patent metadata

Field	Value
Publication number	US-10574914-B2
Application number	US-201816002214-A
Country	US
Kind code	B2
Filing date	Jun 7, 2018
Priority date	Oct 27, 2017
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

Various embodiments of the present technology may comprise methods and apparatus for actuator control. The methods and apparatus may comprise various circuits and/or systems to detect an induced voltage and various signal processing functions to utilize the induced voltage to control the actuator. The apparatus for actuator control may comprise an induced voltage detection circuit and adjust the actuator position according to the detected induced voltage.

First claim

The invention claimed is:

1. An actuator control circuit, comprising:
a driver circuit connected to the actuator and configured to apply a drive signal to the actuator;
an induced voltage detection circuit connected to the driver circuit and the actuator and configured to detect an induced voltage of the actuator while the driver circuit is ON; and
a feedback control circuit connected between the induced voltage detection circuit and the driver circuit and configured to:
receive an induced voltage signal from the induced voltage detection circuit according to the induced voltage;
generate a feedback signal according to the induced voltage, wherein the feedback signal is digitally filtered; and
provide continuous feedback control to the driver circuit via the feedback signal.

2. The actuator control circuit according to claim 1 , further comprising: an adder circuit connected to an output terminal of the feedback control circuit and configured to receive the feedback signal and a control signal.

3. The actuator control circuit according to claim 2 , further comprising:
a digital-to-analog converter connected to:
an output terminal of the adder circuit; and
an input terminal of the driver circuit.

4. The actuator control circuit according to claim 1 , wherein:
the feedback control circuit comprises an analog-to-digital converter and a digital filter connected in series; and
the digital filter comprises: a band-pass filter and a feedback compensation filter connected in series.

5. The actuator control circuit according to claim 1 , wherein the induced voltage detection circuit comprises an output voltage replica circuit configured to generate a replica voltage that is equal to an output voltage of the driver circuit.

6. The actuator control circuit according to claim 5 , wherein the output voltage replica circuit comprises:
a first digital-to-analog converter (DAC) configured to receive:
a high reference voltage;
a low reference voltage; and
a resistance code; and

a second DAC connected to an output terminal of the first DAC and an input terminal of a differential amplifier circuit.

7. The actuator control circuit according to claim 1 , wherein the induced voltage detection circuit comprises a replica circuit configured to generate a replica voltage; and
the replica circuit comprises:
a first transistor connected to a supply voltage at a first terminal;
a second transistor connected to a second terminal of the first transistor;
a variable resistor connected between the first and second transistors.

8. A method for suppressing resonance vibrations of an actuator controlled with a driver circuit, comprising:
selectively coupling one of a plurality of driver circuit output terminals to an induced voltage detection circuit; wherein the driver circuit output terminals are connected to the actuator;
detecting an induced voltage of the actuator while the driver circuit is ON; and
continuously controlling the actuator according to the induced voltage.

9. The method according to claim 8 , further comprising converting the induced voltage from an analog signal to a digital signal.

10. The method according to claim 9 , further comprising: filtering the digital signal; and
summing the digital signal with a current code.

11. The method according to claim 10 , further comprising: converting the sum of the digital signal and the current code to an analog driver signal.

12. The method according to claim 11 , further comprising: operating the driver circuit according to the analog driver signal.

13. The method according to claim 8 , wherein continuously controlling the actuator comprises: utilizing a feedback control circuit to adjust a current through the driver circuit.

14. An imaging system having an actuator, comprising:
an image sensor coupled to an image signal processor, wherein the image sensor transmits image data to the image signal processor; and
a control circuit, coupled to the image signal processor and configured to receive a target position from the image signal processor, comprising:
a driver circuit coupled to the actuator;
an induced voltage detection circuit, connected to the driver circuit and the actuator, and configured to detect an induced voltage of the actuator; and
a feedback control circuit, connected between the induced voltage detection circuit and the driver circuit, and configured to:
receive an induced voltage signal according to the induced voltage;
digitally filter the induced voltage signal; and
generate a feedback signal according to the digitally filtered induced voltage signal;

wherein:
the induced voltage detection circuit detects the induced voltage while the driver circuit is ON; and
the feedback control circuit provides continuous feedback control to the driver circuit via the feedback signal.

15. The imaging system according to claim 14 , further comprising:
an adder circuit connected to an output terminal of the feedback control circuit and configured to receive the feedback signal and a control signal.

16. The imaging system according to claim 15 , further comprising:
a digital-to-analog converter connected to:
an output terminal of the adder circuit and
an input terminal of the driver circuit.

17. The imaging system according to claim 14 , wherein the feedback control circuit comprises an analog-to-digital converter and a digital filter connected in series.

18. The imaging system according to claim 14 , wherein the induced voltage detection circuit comprises:
an output voltage replica circuit configured to generate a replica voltage that is equal to an output voltage of the driver circuit; and
a differential amplifier circuit connected to an output terminal of the output voltage replica circuit, wherein the differential amplifier circuit outputs the induced voltage.

19. The imaging system according to the claim 18 , wherein the output voltage replica circuit comprises:
a first digital-to-analog converter (DAC) configured to receive:
a high reference voltage;
a low reference voltage; and
a resistance code; and

a second DAC connected to an output terminal of the first DAC and an input terminal of the differential amplifier circuit.

20. The imaging system according to claim 14 , wherein:
the induced voltage detection circuit comprises a replica circuit configured to generate a replica voltage; and
the replica circuit comprises:
a first transistor connected to a supply voltage at a first terminal;
a second transistor connected to a second terminal of the first transistor; and
a variable resistor connected between the first and second transistors.

Assignees

• Semiconductor Components Ind Llc

Inventors

• Tabuchi Yoshihisa
• Noda Atsushi

Classifications

• H03F2203/45116

  Feedback coupled to the input of the differential amplifier · CPC title

• H03F2203/45528

  the FBC comprising one or more passive resistors and being coupled between the LC and the IC · CPC title

• G03B5/00

  Adjustment of optical system relative to image or object surface other than for focusing · CPC title

• G03B2205/0015

  by displacing one or more optical elements normal to the optical axis · CPC title

• H03F2200/129

  there being a feedback over the complete amplifier · CPC title