Motor controller with flexible protection modes

1. A motor controller for use in a motor system, comprising:

a mode select circuit for setting the motor controller in one of an internal protection mode and an external protection mode;

a fault detection circuit for detecting whether the motor system is operating in a normal operation state or a fault state;

a protection logic circuit coupled to said mode select circuit and said fault detection circuit, wherein if the motor system is operating in said fault state, said protection logic circuit outputs a protection signal in said internal protection mode, and keeps said protection signal inactive while activating an external diagnostic signal in said external protection mode; and

a motor control circuit for controlling a motor of the motor system in response to a speed control signal when said protection signal is inactive, and in response to said protection signal when said protection signal is active.

2. The motor controller of claim 1 wherein said fault state comprises a plurality of fault conditions, and said fault detection circuit provides a plurality of fault detection signals each corresponding to one of said plurality of fault conditions.

3. The motor controller of claim 2 wherein said mode select circuit comprises at least one system register for setting said one of said internal protection mode and said external protection mode independently for each of said plurality fault conditions.

4. The motor controller of claim 2 wherein said mode select circuit comprises a system register having a bit for setting the motor controller into said one of said internal protection mode and said external protection mode for all of said plurality fault conditions.

5. The motor controller of claim 1 wherein said mode select circuit comprises:

a one time programmable (OTP) memory for storing an initial value of a mode signal, wherein said mode signal indicates said internal protection mode or said external protection mode; and

a system register for loading said initial value of said mode signal in response to a reset operation, and thereafter providing an output thereof to said protection logic circuit.

6. The motor controller of claim 5 wherein said mode select circuit further comprises:

a serial interface circuit having an input for receiving external data, and an output coupled to said OTP memory and to said system register for providing said external data for programming said OTP memory and said system register.

7. The motor controller of claim 6 wherein said serial interface circuit is a serial peripheral interface (SPI) slave.

8. The motor controller of claim 1 wherein said mode select circuit further includes at least one bit for specifying an action to be taken in response to said fault state, and said protection signal includes said at least one bit.

9. The motor controller of claim 8 wherein said at least one bit selects one of a self-recovery state and a latched off state.

10. The motor controller of claim 1 wherein:

said mode select circuit, said protection logic circuit, and said motor control circuit are combined on a single monolithic integrated circuit.

11. A motor system comprising:

a motor controller having a normal operation state and a fault state, wherein:

in said normal operation state, said motor controller provides a plurality of gate driver signals in response to a speed control signal and at least one feedback signal, and

in said fault state, said motor controller operates in a selected one of an internal protection mode and an external protection mode, wherein in said internal protection mode said motor controller takes a predetermined action, and in said external protection mode said motor controller activates a diagnostic signal without taking said predetermined action.

12. The motor system of claim 11 further comprising:

a motor driver responsive to said plurality of gate driver signals for providing a plurality of motor phase drive signals in response to said plurality of gate driver signals, and for providing said at least one feedback signal; and

a motor for rotating in response to said plurality of gate driver signals.

13. The motor system of claim 11 wherein said predetermined action comprises a selected one of an auto recovery operation and a latch off operation.

14. The motor system of claim 11 wherein said motor controller comprises:

a mode select circuit for setting said motor controller in one of said internal protection mode and said external protection mode;

a fault detection circuit for detecting whether the motor system is operating in said normal operation state or said fault state;

a protection logic circuit coupled to said mode select circuit and said fault detection circuit, wherein if the motor system is operating in said fault state, said protection logic circuit outputs a protection signal in said internal protection mode, and keeps said protection signal inactive while activating an external diagnostic signal in said external protection mode; and

a motor control circuit for controlling a motor of the motor system in response to a speed control signal when said protection signal is inactive, and in response to said protection signal when said protection signal is active.

15. The motor system of claim 14 wherein said fault detection circuit detects that the motor system is in said fault state in response to a plurality of fault conditions.

16. The motor system of claim 15 wherein said mode select circuit comprises at least one system register for setting said one of said internal protection mode and said external protection mode for each of said plurality fault conditions.

17. The motor system of claim 15 wherein said mode select circuit comprises a system register having a bit for setting the motor controller into said one of said internal protection mode and said external protection mode for all of said plurality fault conditions.

18. The motor system of claim 15 wherein said mode select circuit further includes at least one bit for specifying an action to be taken in response to said fault state, wherein said at least one bit selects one of a self-recovery state and a latched off state.

19. The motor system of claim 11 further comprising:

an upper control unit having an input for receiving said diagnostic signal, and an output coupled to said motor controller for providing said speed select signal.

20. A method for use in a motor system comprising:

controlling an operation of a motor in response to at least one control input signal;

detecting a fault condition of the motor system, and in response to detecting the fault condition:

determining whether the motor system is in an internal protection mode or an external protection mode;

taking a predetermined action in said internal protection mode; and

activating a diagnostic signal without taking said predetermined action in said external protection mode.

21. The method of claim 20 wherein said taking said predetermined action in said internal protection mode comprises:

determining whether the motor system is in a latched mode;

performing an auto recovery operation if the motor system is not in said latched mode; and

latching off the motor system if the motor system is in said latched mode.

22. The method of claim 20 wherein said detecting a fault condition of the motor system comprises detecting a plurality of fault conditions.

23. The method of claim 22 wherein said determining whether the motor system is in said internal protection mode or said external protection mode comprises determining whether the motor system is in a corresponding internal protection mode or a corresponding external protection mode for each of said plurality of fault conditions.

24. The method of claim 22 wherein said determining whether the motor system is in said internal protection mode or said external protection mode comprises determining whether the motor system is in said internal protection mode or said external protection mode for all of said plurality of fault conditions.