Claims
- 1. A circuit for generating pulse width modulated signal from an analog video signal, said circuit comprising:
a pulse width modulated signal generating circuit portion; a voltage sampling circuit portion comprising:
a first switch; a voltage storage device for storing a portion of the analog video signal as a voltage value according to the first switch activated according to sample time information within a portion of time of the analog video signal; and a second switch for outputting the stored voltage value to the pulse width modulated signal generating circuit portion when activated according to a next portion of time of the analog video signal; wherein the pulse width modulated signal generating circuit portion for generating a pulse width modulated signal by comparing the outputted voltage value to a waveform, when the stored voltage value is outputted to the pulse width modulated signal generating circuit.
- 2. The circuit of claim 1, wherein the waveform is a saw tooth waveform.
- 3. The circuit of claim 1, wherein the pulse width modulated signal generating circuit portion is a Schmidt trigger with a variable threshold.
- 4. The circuit of claim 1, wherein the pulse width modulated signal generating circuit portion is a comparator.
- 5. The circuit of claim 4, wherein the comparator has an impedance greater that 1 mega ohm.
- 6. The circuit of claim 1, wherein the voltage storage device is a capacitor.
- 7. The circuit of claim 1, wherein the stored portion of the analog video signal represents display element information.
- 8. A circuit for generating pulse width modulated signal from an analog video signal, said circuit comprising:
a first circuit portion comprising:
a first subcircuit portion comprising:
a first switch; a voltage storage device for storing a portion of the analog video signal as a voltage value within a period of time according to the first switch activated according to sample time information within the period of time; and a second switch for outputting the stored voltage value when activated during a subsequent period of time; and a second subcircuit portion comprising:
a first switch; a voltage storage device for storing a next portion of the analog video signal as a voltage value within the subsequent period of time according to the first switch activated according to sample time information within the subsequent period of time; and a second switch for outputting a previously stored voltage value when activated during the period of time; and a second circuit portion for generating a pulse width modulated signal by comparing the outputted voltage values to a waveform.
- 9. The circuit of claim 8, wherein the waveform is a saw tooth waveform.
- 10. The circuit of claim 8, wherein the second circuit portion is a Schmidt trigger with a variable threshold.
- 11. The circuit of claim 8, wherein the second circuit portion is a comparator.
- 12. The circuit of claim 11, wherein the comparator has an impedance greater that 1 mega ohm.
- 13. The circuit of claim 8 wherein the voltage storage devices are capacitors.
- 14 The circuit of claim 8 wherein the stored portions of the analog video signal represent display element information.
- 15. The circuit of claim 8, wherein the first circuit portion further comprises a sequencer for enabling each pulse width modulated signal to drive a display element in a different row of display elements within a frame display period of time.
- 16. A method for generating pulse width modulated signal from an analog video signal, said method comprising:
storing a portion of the analog video signal as a voltage value according to a switch activated according to sample time information within a portion of time of the analog video signal; outputting the stored voltage value according to a switch activated according to a next portion of time of the analog video signal; and converting the outputted voltage value into a pulse width modulated signal by comparing the outputted voltage value to a waveform.
- 17. The method of claim 16, wherein the waveform is a saw tooth waveform.
- 18. The method of claim 16, wherein converting is performed by a Schmidt trigger with a variable threshold.
- 19. The method of claim 16, wherein converting is performed by a comparator.
- 20. The method of claim 19, wherein the comparator has an impedance greater that 1 mega ohm.
- 21. The method of claim 16, wherein storing is performed by a capacitor.
- 22. The method of claim 16, wherein the stored portion of the analog video signal represents display element information.
- 23. A method for generating pulse width modulated signal from an analog video signal, said method comprising:
storing a portion of the analog video signal as a voltage value within a first circuit portion within a period of time according to a switch activated according to sample time information within the period of time; outputting a previously stored voltage value within a second circuit portion according to a switch activated during the period of time; storing a next portion of the analog video signal as a voltage value within the second circuit portion within a subsequent period of time according to a switch activated according to sample time information within the subsequent period of time; outputting the stored voltage value, that was stored within the first circuit portion according to a switch activated during the subsequent period of time; converting the outputted voltage values from the first and second circuit portions into pulse width modulated signals by comparing the outputted voltage value to a waveform.
- 24. The method of claim 23, wherein the waveform is a saw tooth waveform.
- 25. The method of claim 23, wherein converting is performed by a Schmidt trigger with a variable threshold.
- 26. The method of claim 23, wherein converting is performed by a comparator.
- 27. The method of claim 26, wherein the comparator has an impedance greater that 1 mega ohm.
- 28. The method of claim 23, wherein storing is performed by a capacitor.
- 29. The method of claim 23, wherein the stored portion of the analog video signal represents display element information.
- 30. The method of claim 23, further comprising:
enabling each pulse width modulated signal to drive a display element in a different row of display elements within a frame display period of time.
Parent Case Info
[0001] The present invention is related to the following co-pending U.S. patent applications Ser. No. ______ entitled “Method of Gray Scale Generation For Displays Using a Binary Weighted Clock;” Ser. No. ______ entitled “Method of Gray Scale Generation For Displays Using a Register and a Binary Weighted Clock;” and Ser. No. ______ entitled “Method of Gray Scale Generation For Displays Using a Sample and Hold Circuit With Discharge;”