MOTOR DRIVE CIRCUIT

• US 20130222309A1
• Filed: 02/28/2013
• Published: 08/29/2013
• Est. Priority Date: 02/28/2012
• Status: Abandoned Application

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Sun, Weiming, Liao, Qing, Huang, Lei
• Application Number:
  US13/780,559
• Publication Number:
  US 20130222309A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: H02P 25/032 Reciprocating, oscillating or vibrating motors
• CPC Class Codes: H02P 31/00 Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00

Abstract

This document discusses, among other things, apparatus and methods for a motor drive, such as a haptic motor drive. In an example, a motor drive can include a low dropout (LDO) regulator configured to receive a supply voltage and to provide a regulated voltage, a power switch circuit configured to receive the supply voltage and to receive the regulated voltage from the LDO regulator, and a level shift circuit configured to receive power from the power switch circuit, to receive an input signal, and to provide an output signal to a a voltage difference generating circuit based on the input signal and the power from the power switch circuit. In certain states of the motor drive, the power switch circuit can couple either the regulated voltage or the supply voltage to the level shift circuit.

Claims

1. A motor drive circuit, comprising:

a low dropout (LDO) regulator configured to receive a supply voltage and to provide a regulated voltage;

a power switch circuit configured to receive the supply voltage and to receive the regulated voltage from the LDO regulator; and

a level shift circuit configured to receive power from the power switch circuit, to receive an input signal, and to provide an output signal to a a voltage difference generating circuit based on the input signal and the power from the power switch circuit,

wherein the power switch circuit includes a first state and a second state,

wherein the power switch circuit is configured to provide the regulated voltage from the LDO regulator to the level shift circuit in the first state, and

wherein the power switch circuit is configured to provide the supply voltage to the level shift circuit in the second state.

2. The motor drive circuit of claim 1, including an overdrive circuit configured to control the state of the power switch.

3. The motor drive circuit of claim 1, including the voltage difference generating circuit, the voltage difference generating circuit configured to receive power from the supply voltage and to provide at least a portion of the power to a motor.

4. The motor drive circuit of claim 3, wherein the voltage difference generating circuit is configured to provide the at least a portion of the power using the output signal of the level shift circuit.

5. The motor drive circuit of claim 3, wherein the voltage difference generating circuit includes an amplifier.

6. The motor drive of claim 3, wherein the voltage difference generating circuit includes an AB amplifier.

7. An electronic device comprising:

a touchscreen configured to provide an indication of a touch event associated with the touch screen; and

a motor drive circuit configured to receive the indication and to provide a drive signal to a haptic actuator, the motor drive circuit including;

a low dropout (LDO) regulator configured to receive a supply voltage and to provide a regulated voltage;

a power switch circuit configured to receive the supply voltage and to receive the regulated voltage from the LDO regulator; and

a level shift circuit configured to receive power from the power switch circuit, to receive an input signal, and to provide an output signal to a a voltage difference generating circuit based on the input signal and the power from the power switch circuit,

wherein the power switch circuit includes a first state and a second state,

wherein the power switch circuit is configured to provide the regulated voltage from the LDO regulator to the level shift circuit in the first state, and

wherein the power switch circuit is configured to provide the supply voltage to the level shift circuit in the second state.

8. The electronic device of claim 7, including an overdrive circuit configured to control the state of the power switch;

and

the voltage difference generating circuit, the voltage difference generating circuit configured to receive power from the supply voltage and to provide at least a portion of the power to a motor; and

to provide the at least a portion of the power using the output signal of the level shift circuit.

9. The electronic device of claim 8, including the haptic actuator;

10. The electronic device of claim 9, wherein the haptic actuator includes an eccentric rotating mass motor.

11. The electronic device of claim 7, including a wireless transceiver configured to communicate over a wireless network in response to the indication.

12. A method for driving a haptic motor, the method comprising;

receiving a drive command at a motor drive coupled to the haptic motor;

coupling a level shift circuit to a supply voltage of the motor drive to initiate motion of the haptic motor in response to the drive command; and

coupling the level shift circuit to a low drop-out regulator of the motor drive to maintain motion of the haptic motor.

13. The method of claim 12, including:

receiving a halt command at the motor drive; and

coupling the level shift circuit to the supply voltage to stop the motion of the haptic drive.

14. The method of claim 13, wherein receiving the drive command includes receiving a high logic signal from an overdrive circuit of the motor drive at the level shift circuit;

and

providing a first voltage having a first polarity to the haptic motor, wherein the first voltage is near the supply voltage.

15. The method of claim 14, wherein receiving the drive command includes receiving a pulse width modulated signal at the motor drive.

16. The method of claim 14, wherein receiving the halt command includes receiving a low logic signal from the overdrive circuit at the level shift circuit;

and

providing the first voltage having a second polarity to the haptic motor, wherein the second polarity is opposite the first polarity.

17. The method of claim 13, including:

receiving a first indication of a first touch event from a touch control;

providing the drive command in response to the first touch event using a processor coupled to the touch screen;

receiving an second indication of a second touch event from the touch control; and

providing the halt command in response to the second indication using the processor.

18. The method of claim 17 wherein the touch control includes a touch screen.

19. The method of claim 13, including:

receiving a first indication of a first touch event from a pushbutton; and

providing the drive command in response to the first touch event using a processor coupled to the touch screen.

20. The method of claim 17 wherein a touch screen includes the pushbutton.