Voltage controlled oscillator band switching system

1. A band switching apparatus, comprising:

a reference generation and comparison module to generate a positive signal based on a comparison of a loop filter voltage associated with a voltage controlled oscillator to a maximum tuning voltage and a minimum tuning voltage;

a clock pulse generation module to generate a clock pulse in response to said positive signal; and

a counter and gating module to disable band switching of said voltage controlled oscillator when a lock condition is detected and said loop filter voltage comprises a voltage between said maximum tuning voltage and said minimum tuning voltage.

2. The band switching of claim 1 , wherein said reference generation module comprises a phase-locked loop filter to provide said loop filter voltage based on an output voltage waveform of said voltage controlled oscillator.

3. The band switching apparatus of claim 1 , wherein said reference generation module comprises a first comparator to compare said loop filter voltage to a first reference voltage and a second comparator to compare said loop filter voltage to a second reference voltage.

4. The band switching apparatus of claim 1 , wherein said clock pulse generation module comprises a low-pass filter and said clock pulse comprises a time constant associated with said low-pass filter.

5. The band switching apparatus of claim 4 , wherein said clock pulse generation module comprises a logic gate to generate said clock pulse based on a first input comprising said positive signal and a second input comprising said positive signal delayed by said time constant.

6. The band switching apparatus of claim 4 , wherein said clock pulse generation module comprises a switch to short said low-pass filter to ground.

7. The band switching apparatus of claim 1 , wherein said clock pulse generation module comprises an inverter chain and said clock pulse comprises a time constant equal to a delay through said inverter chain.

8. The band switching apparatus of claim 7 , wherein said clock pulse comprises a pulse width proportional to said inverter chain.

9. The band switching apparatus of claim 1 , wherein said counter and gating module comprises a counter to output a band select word to said voltage controlled oscillator.

10. The band switching apparatus of claim 9 , wherein said counter outputs said band select word if a lock condition is not detected.

11. The band switching apparatus of claim 9 , wherein said band select word controls band switching of said voltage controlled oscillator.

12. The band switching apparatus of claim 1 , wherein said counter and gating module comprises a register to disable band switching in response to a clock edge provided by a logic gate.

13. The band switching apparatus of claim 12 , wherein said clock edge is delayed by an inverter chain.

14. A band switching method, comprising:

generating a positive signal based on a comparison of a loop filter voltage associated with a voltage controlled oscillator to a maximum tuning voltage and a minimum tuning voltage;

generating a clock pulse in response to said positive signal; and

disabling band switching of said voltage controlled oscillator when a lock condition is detected and said loop filter voltage comprises a voltage between said maximum tuning voltage and said minimum tuning voltage.

15. The band switching method of claim 14 , further comprising providing said loop filter voltage based on an output voltage waveform of said voltage controlled oscillator.

16. The band switching method of claim 14 , further comprising comparing said loop filter voltage to a first reference voltage and comparing said loop filter voltage to a second reference voltage.

17. The band switching method of claim 14 , wherein generating said clock pulse comprises delaying said positive signal by a time constant associated with a low-pass filter.

18. The band switching method of claim 14 , wherein said clock pulse comprises a time constant equal to a delay through an inverter chain.

19. The band switching method of claim 14 , further comprising outputting a band select word to said voltage controlled oscillator if a lock condition is not detected.

20. The band switching method of claim 19 , further comprising controlling band switching of said voltage controlled oscillator based on said band select word.

21. The band switching method of claim 14 , wherein disabling band switching comprises generating a clock edge in response to a detected lock condition.

22. The band switching method of claim 20 , further comprising delaying said clock edge by an inverter chain.

23. A system, comprising:

an antenna; and

an integrated circuit coupled to said antenna, said integrated circuit comprising a band switching apparatus, said band switching apparatus comprising: a reference generation and comparison module to generate a positive signal based on a comparison of a loop filter voltage associated with a voltage controlled oscillator to a maximum tuning voltage and a minimum tuning voltage;

a clock pulse generation module to generate a clock pulse in response to said positive signal; and

a counter and gating module to disable band switching of said voltage controlled oscillator when a lock condition is detected and said loop filter voltage comprises a voltage between said maximum tuning voltage and said minimum tuning voltage.

24. The system of claim 23 , wherein said integrated circuit comprises a complementary metal oxide semiconductor voltage controlled oscillator.

25. The system of claim 23 , wherein said integrated circuit comprises a phase-locked loop filter to provide said loop filter voltage based on an output voltage waveform of said voltage controlled oscillator.