Power Management Controller for Drivers

• US 20100158278A1
• Filed: 12/19/2008
• Published: 06/24/2010
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Lu, Mary Xiao-Hua, Skov, James, Crespi, Lorenzo, Larsen, Christian, Elkhatib, Mouna
• Granted Patent: US 8,325,940 B2
• Time in Patent Office: Days
• US Class Current: 381/120
• CPC Class Codes: H03F 1/305 in case of switching on or off of a power supply
• CPC Class Codes: H03F 2200/03 the amplifier being designed for audio applications
• CPC Class Codes: H03F 2200/249 A switch coupled in the input circuit of an amplifier being controlled by a circuit, e.g. feedback circuitry being controlling the switch
• CPC Class Codes: H03F 2200/414 A switch being coupled in the output circuit of an amplifier to switch the output on/off
• CPC Class Codes: H03F 3/187 in integrated circuits
• CPC Class Codes: H03G 3/348 Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A driver controller comprising a state machine for controlling transitions between a plurality of states. An output switch for providing a low impedance path to ground during transition periods. An output stage for decoupling output signal from driver amplifier during the transition periods.

Claims

1. A driver controller comprising:

a state machine for controlling transitions between a plurality of states;

an output switch coupled to the state machine for providing a low impedance path to ground during transition periods; and

an output stage coupled to the state machine for controlling signal processing during the transition periods.

2. The driver controller of claim 1 wherein the state machine comprises a port controller for receiving a plurality of state variables and determining state transitions based on the state variables.

3. The driver controller of claim 1 wherein the state machine comprises a port controller for receiving external mute state data, digital to analog converter state data, high definition audio interface control data, and personal computer beep data and determining state transitions between a reset state, a mute state and an enabled state based on the state variables.

4. The driver controller of claim 1 further comprising an output stage controller coupled to the output stage and the state machine, the output stage controller for receiving control data from the state machine and providing status data to the state machine.

5. The driver controller of claim 1 further comprising a charge pump coupled to the output stage controller and the output stage, the charge pump for providing a negative voltage to the output stage in response to control data received from the output stage controller.

6. The driver controller of claim 1 further comprising:

an amplifier for amplifying an input signal; and

a reference current generator coupled to the amplifier and the output stage for providing current to the amplifier and the output stage controller.

7. The driver controller of claim 1 further comprising:

an amplifier for amplifying an input signal; and

a reference current generator coupled to the amplifier and the output stage for providing a constant current to the amplifier and an adjustable current the output stage controller.

8. The driver controller of claim 1 further comprising:

a clock coupled to the state machine; and

power on reset circuitry coupled to the state machine, wherein the clock and the power on reset circuitry are for controlling power up of the state machine.

9. A driver controller comprising:

means for controlling transitions between a plurality of states; and

an output stage coupled to the means for controlling transitions between a plurality of states, the output stage for controlling signal processing during transition periods.

10. The driver controller of claim 9 wherein the means for controlling transitions between a plurality of states comprises a state machine.

11. The driver controller of claim 9 wherein the means for controlling transitions between a plurality of states comprises a port controller coupled to one or more external devices.

12. The driver controller of claim 9 further comprising an output stage controller coupled to the output stage, the output stage controller for receiving control data from the state machine and providing status data to the state machine.

13. The driver controller of claim 9 further comprising an output stage enable switch coupled to the output stage, the output stage enable switch for disconnecting the output stage from an output node.

14. The driver controller of claim 9 further comprising:

personal computer beep detection circuitry coupled to the means for controlling transitions between a plurality of states; and

a multiplexer coupled to the personal computer beep detection circuitry for multiplexing an audio signal and a personal computer beep signal.

15. A method for controlling a driver comprising:

determining a first driver state based on a plurality of first driver state variables;

receiving one or more second state variables; and

transitioning from the first driver state to a second driver state in response to the one or more second state variables.

16. The method of claim 15 wherein determining the first driver state based on the plurality of first driver state variables comprises determining a driver reset state based on an amplifier state variable and an output stage state variable.

17. The method of claim 15 wherein determining the first driver state based on the plurality of first driver state variables comprises determining a driver mute state based on an output switch state variable and an output stage state variable.

18. The method of claim 15 wherein determining the first driver state based on the plurality of first driver state variables comprises determining an enabled state based on a driver state variable and a digital to analog converter state variable.

19. The method of claim 15 further comprising:

receiving one or more third state variables; and

transitioning from the second driver state to a third driver state in response to the one or more third state variables.

20. The method of claim 15 further comprising:

receiving one or more third state variables; and

transitioning from the second driver state to one of the first driver state or a third driver state in response to the one or more third state variables.