Motor controller with enhanced noise immunity unbuffered hall sensors

1. A circuit for use with an unbuffered Hall sensor, comprising:

a first circuit coupleable to said unbuffered Hall sensor said first circuit providing first output signals when the magnitude of signals from said Hall sensor is within a first predetermined voltage magnitude range:

a first time dependent circuit coupled to said first circuit, said first time dependent circuit generating second output signals if said fast output signals have a predetermined relationship for a first predetermined time period; and

a lockout timer circuit coupled to said first time dependent circuit, said lockout timer circuit preventing changes in said first output signals occurring within a lockout time period from effecting generation of said second output signals.

2. A circuit in accordance with claim 1 , comprising:

a motor driver circuit controlled by said second output signals.

3. A circuit in accordance with claim 2 , comprising:

an integrated circuit having said first circuit, said first time dependent circuit, said lockout timer circuit and said motor driver circuit formed thereon.

4. A circuit in accordance with claim 3 , comprising:

a pair of first terminals coupled to said first circuit and coupleable to a Hall sensor; and

a pair of second terminals coupled to said motor driver circuit and coupleable to a motor.

5. A commutation circuit comprising:

a pair of terminals coupleable to a Hall sensor;

zero crossing detection circuitry coupled to said pair of terminals;

a timer coupled to said zero crossing detection circuitry;

a commutation latch coupled to said zero crossing detection circuitry via said timer to generate commutation output signals when said Hall sensor output signals are in a predetermined state for a predetermined period of time;

a lockout timer coupled to said commutation latch and said timer to lock out a change in said commutation output signals for a second predetermined period of time to prevent noise signals superimposed on said Hall sensor output signals from affecting said generating of said commutation output signals; and

motor driver circuitry coupled to said commutation latch to receive said commutation output signals.

6. A commutation circuit in accordance with claim 5 , comprising:

an integrated circuit having said zero crossing detection circuitry, said timer, said commutation latch, said lockout timer and said motor drive circuitry formed thereon.

7. A commutation circuit in accordance with claim 5 , wherein:

said timer comprises a shift register.

8. A method of interfacing a Hall sensor to a commutation circuit comprising:

receiving output signals from said Hall sensor;

detecting when said Hall sensor output signals are within a predetermined range;

determining said predetermined range to be a zero crossing voltage range;

generating commutation output signals when said Hall sensor output signals are in a predetermined state for a predetermined period of time;

locking out a change in said commutation output signals for a second predetermined period of time; and

selecting said second predetermined period of time to prevent noise signals superimposed on said Hall sensor output signals from affecting said generating of said commutation output signals.