|
|
|
|
|
|
|
|
| ( 1 of 1 ) |
| United States Patent | 7,183,823 |
| Gibson , et al. | February 27, 2007 |
In the proposed method of generating a pulsed output signal from a periodic ramp signal and a reference voltage, the linear range of duty cycles of the pulsed output signal is significantly extended to minimum values. The ramp signal and the reference voltage are applied to inputs of a comparator and the output signal is taken from an output of the comparator. The ramp signal has a ramp that extends between a minimum voltage level and a maximum voltage level. The duty cycle of the pulse signal is controlled by varying the reference voltage between the minimum and maximum voltage levels. The ramp has an initial start section extending from the minimum voltage level and a main section extending between the initial section and the maximum voltage level. The ramp slope has a constant value over the main ramp section and a value greater than the constant value over the initial section. In the initial section of the ramp the slope is varied in a manner to compensate for non-linearity of the comparator in an operating range where the reference voltage is close to the minimum voltage level of the ramp signal. It is also preferred to insert a short blanking period before the actual ramp of the waveform. The method can be used in switched mode power converters and in class-d amplifiers.
| Inventors: | Gibson; Neil (Freising, DE), Scoones; Kevin (Munich, DE) |
|---|---|
| Assignee: |
Texas Instruments Incorporated
(Dallas,
TX)
|
| Family ID: | 35062163 |
| Appl. No.: | 11/080,882 |
| Filed: | March 15, 2005 |
| Document Identifier | Publication Date | |
|---|---|---|
| US 20050248378 A1 | Nov 10, 2005 | |
| Mar 20, 2004 [DE] | 10 2004 016 073 | |||
| Current U.S. Class: | 327/170; 363/15 |
| Current CPC Class: | H03F 3/217 (20130101); H03K 7/08 (20130101); H03K 5/06 (20130101) |
| Current International Class: | H03K 5/12 (20060101) |
| Field of Search: | ;327/170-175 ;363/15,34,71,21.12 ;323/282,283 |
| 3393363 | July 1968 | Forster |
| 6057675 | May 2000 | Tateishi |
| 6208216 | March 2001 | Nasila |
| 6208516 | March 2001 | Fangonilo et al. |
| 6825644 | November 2004 | Kernahan et al. |
| 2247123 | Feb 1992 | GB | |||
| 98/27648 | Jun 1998 | WO | |||
|
|