Pulse width modulation circuit

• US 6,201,414 B1
• Filed: 10/28/1999
• Issued: 03/13/2001
• Est. Priority Date: 10/28/1999
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Yazdy, Mostafa R.
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): Tran, Anh Q.
• Application Number:
  US09/428,822
• Time in Patent Office: 502 Days
• Field of Search: 326/29, 326/93, 326/96, 326/99, 327/141, 327/161, 327/261, 327/276
• US Class Current: 326/93
• CPC Class Codes: H03K 7/08 Duration or width modulation ; Duty cycle modulation

Abstract

A pulse width modulation circuit utilizes a clock divider to generate a plurality of clocks to be used by a plurality of delay blocks. Each delay block has plurality of delay elements each of which receives one the plurality of clocks. Each delay block receives a delay data, selects a number of the plurality of clocks based on the delay data and activates the respective delay elements for delaying its input signal.

Claims

1. A pulse width modulation circuit comprising:

a clock dividing means for receiving a system clock and generating a plurality of clocks with different clock cycles;

a delaying means for receiving a signal and delaying said signal;

said delaying means having a plurality of delaying elements;

each of said plurality of delaying elements receiving one of said plurality of clocks;

said delaying means receiving a delay data and being responsive to said delay data for selecting a number of said plurality of clocks based on the delay data and activating said respective delaying elements; and

said delaying means being so constructed and arranged to cause the signal to pass through said activated delaying elements and bypass said inactivated delaying elements.

2. The pulse width modulation circuit recited in claim 1 further comprises synchronizing block for synchronizing said system clock with the rising edge of said signal prior to delivery to said clock dividing means.

3. The pulse width modulation circuit recited in claim 1, wherein said plurality of delaying elements are positive edge triggered D flip flops.

4. A pulse width modulation circuit comprising:

a clock dividing means for receiving a system clock and generating a plurality of clocks with different clock cycles;

a delaying means for receiving a signal having a rising edge and a falling edge and delaying said rising edge of said signal;

said delaying means having a plurality of delaying elements;

each of said plurality of delaying elements receiving one of said plurality of clocks;

said delaying means receiving a delay data and being responsive to said delay data for selecting a number of said plurality of clocks based on the delay data and activating said respective delaying elements;

said delaying means being so constructed and arranged to cause the signal to pass through said activated delaying elements and bypass said inactivated delaying elements; and

said delaying means having a reset means responsive to said falling edge of said signal for resetting said delaying means.

5. The pulse width modulation circuit recited in claim 4 further comprises synchronizing block for synchronizing said system clock with the rising edge of said signal prior to delivery to said clock dividing means.

6. The pulse width modulation circuit recited in claim 4, wherein said plurality of delaying elements are positive edge triggered D flip flops.

7. A pulse width modulation circuit comprising:

a clock dividing means for receiving a system clock and generating a plurality of clocks with different clock cycles;

a plurality of delaying means for receiving a signal and delaying said signal according to a plurality of data;

each of said delaying means having a plurality of delaying elements;

each of said plurality of delaying elements of each delaying means receiving one of said plurality of clocks;

each of said plurality of delaying means receiving one of said plurality of delay data and being responsive to said respective delay data for selecting a number of said plurality of clocks based on the delay data and activating said respective delaying elements; and

each of said delaying means being so constructed and arranged to cause the signal to pass through said respective activated delaying elements and bypass said respective inactivated delaying elements.

8. The pulse width modulation circuit recited in claim 7 further comprises synchronizing block for synchronizing said system clock with the rising edge of said signal prior to delivery to said clock dividing means.

9. The pulse width modulation circuit recited in claim 7, wherein said plurality of delaying elements are positive edge triggered D flip flops.

10. A pulse width modulation circuit comprising:

a clock dividing means for receiving a system clock and generating a plurality of clocks with different clock cycles;

a plurality of delaying means for receiving a signal having a rising edge and a falling edge and delaying said rising edge of said signal according to a plurality of data;

each of said delaying means having a plurality of delaying elements;

each of said plurality of delaying elements of each delaying means receiving one of said plurality of clocks;

each of said plurality of delaying means receiving one of said plurality of delay data and being responsive to said respective delay data for selecting a number of said plurality of clocks based on the delay data and activating said respective delaying elements; and

each of said delaying means being so constructed and arranged to cause the signal to pass through said respective activated delaying elements and bypass said respective inactivated delaying elements; and

said delaying means having a reset means responsive to said falling edge of said signal for resetting said delaying means.

11. The pulse width modulation circuit recited in claim 10 further comprises synchronizing block for synchronizing said system clock with the rising edge of said signal prior to delivery to said clock dividing means.

12. The pulse width modulation circuit recited in claim 10, wherein said plurality of delaying elements are positive edge triggered D flip flops.