Methods and apparatus for actuator control
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.
1. An actuator control circuit, comprising:
a driver circuit connected to the actuator and configured to supply a drive signal to the actuator; and
an induced voltage detection circuit connected to:
a first output terminal of the driver circuit; and
the actuator;
wherein the induced voltage detection circuit is configured to: generate a replica voltage, wherein the replica voltage is a replica of a DC component of an output voltage of the driver circuit; and
output an induced voltage of the actuator according to:
the output voltage of the driver circuit; and
the replica voltage.
2. The actuator control circuit according to claim 1 , wherein the induced voltage detection circuit comprises:
an output voltage replica circuit configured to replicate the DC component of the 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.
3. The actuator control circuit according to claim 2 , wherein the induced voltage detection circuit further comprises a switch connected to the first output terminal of the driver circuit and a second output terminal of the driver circuit, and configured to selectively connect the driver circuit to the differential amplifier circuit via one of the first output terminal and the second output terminal of the driver circuit.
4. The actuator control circuit according to claim 2 , wherein the differential amplifier circuit is further directly connected to the first output terminal of the driver circuit.
5. The actuator control circuit according to claim 2 , 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.
6. The actuator control circuit according to claim 1 , further comprising a feedback control circuit connected to:
an output terminal of the induced voltage detection circuit; and
the driver circuit.
7. The actuator control circuit according to claim 1 , wherein the induced voltage detection circuit comprises:
a replica circuit connected to the actuator and configured to generate the replica voltage; and
a differential amplifier circuit connected to the replica circuit.
8. The actuator control circuit according to claim 7 , wherein 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.
9. The actuator control circuit according to claim 8 , wherein a non-inverting terminal of the differential amplifier circuit is connected to the replica circuit at a node located between the variable resistor and the second transistor.
10. A method for detecting an induced voltage in an actuator operated by a driver circuit, comprising:
receiving, at a terminal of a differential amplifier circuit, an output voltage from the driver circuit;
generating a replica voltage, wherein the replica voltage is a replica of a DC component of an output voltage of the driver circuit; and
generating, with the differential amplifier circuit, a difference signal according to at least one of the replica voltage and the output voltage;
wherein the difference signal represents the induced voltage.
11. The method according to claim 10 , wherein generating the difference signal comprises:
receiving the output voltage at an inverting terminal of the differential amplifier circuit; and
receiving the replica voltage at a non-inverting terminal of the differential amplifier circuit.
12. The method according to claim 10 , wherein generating the replica voltage comprises: generating a current that is proportional to a driver current.
13. The method according to claim 10 , wherein generating the replica voltage comprises:
generating a first signal according to:
a high reference voltage;
a low reference voltage; and
a resistance code; and
generating a second signal according to:
the first signal; and
a third signal representing position information.
14. An imaging system capable of detecting an induced voltage in 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 drive circuit connected to the actuator and comprising:
a first output terminal; and
a second output terminal; and
an induced voltage detection circuit connected to:
at least one of the first and second output terminals of the driver circuit; and
the actuator;
wherein the induced voltage detection circuit is configured to:
generate a replica voltage, wherein the replica voltage is a replica of a DC component of an output voltage of the driver circuit; and
output an induced voltage of the actuator according to:
an output voltage of the driver circuit; and
the replica voltage.
15. The imaging system according to claim 14 , wherein the induced voltage detection circuit comprises: an output voltage replica circuit configured to replicate the DC component of the 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.
16. The imaging system according to claim 15 , wherein the induced voltage detection circuit further comprises a switch connected to the first output terminal of the driver circuit and the second output terminal of the driver circuit, and configured to selectively connect the driver circuit to the differential amplifier circuit via one of the output terminals of the driver circuit.
17. The imaging system according to claim 15 , 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.
18. The imaging system according to claim 14 , wherein the induced voltage detection circuit comprises:
a replica circuit connected to the actuator and configured to generate the replica voltage; and
a differential amplifier circuit connected to the replica circuit.
19. The imaging system according to claim 18 , wherein the replica circuit comprises:
a first transistor connected to a supply voltage at a first terminal of the first transistor;
a second transistor connected to a second terminal of the first transistor;
a variable resistor connected between the first and second transistors.
20. The imaging system according to claim 19 , wherein a non-inverting terminal of the differential amplifier circuit is connected to the replica circuit at a node located between the variable resistor and the second transistor.