System including preemphasis driver circuit and method
View Patent ↗A system including a preemphasis driver circuit and a method. One embodiment includes an output terminal, a main driver coupled between the input terminal and the output terminal and an auxiliary driver coupled to the output terminal, wherein at least one unclocked delay element is coupled between the input terminal and the auxiliary driver.
1. A system comprising:
a preemphasis driver circuit comprising:
a main driver driven by an input signal;
an auxiliary driver, both to drive at least one loaded transmission line in parallel;
wherein the input signal is differentiated using at least one unclocked delay element to drive the auxiliary driver; and
wherein an output level of the main driver is calibratable, and wherein the main driver comprises a plurality of driver fingers to allow a binary coding of the output level of the main driver by placing the driver fingers a corresponding number of times.
2. The system of claim 1 , wherein the at least one unclocked delay element is an RC-circuit.
3. The system of claim 1 , wherein the at least one unclocked delay element is an inverter.
4. The system of claim 1 , wherein the main driver and the auxiliary driver are based on the same schematic and the same layout cell.
5. The system of claim 1 , wherein the least one unclocked delay element is configured to generate preemphasis pulses whose duration is self-adjusting to process-voltage-temperature variations.
6. The system of claim 1 , wherein the driver fingers comprise at least one logic gate for calibrating the output level of the main driver by gating the driver fingers.
7. The system of claim 6 , wherein the preemphasis driver circuit is configured to keep its output level constant by a driver calibration bus controlling the logic gates of the driver fingers.
8. The system of claim 7 , wherein the preemphasis driver circuit comprises a differential input terminal and is configured as a pull-up/pull-down driver comprising a symmetrical schematic and layout structure for the pull-up and the pull-down part of the preemphasis driver circuit based on a corresponding schematic and layout cell for the main drivers and the auxiliary drivers of the pull-up and the pull-down part of the preemphasis driver circuit.
9. A method for operating a system including preemphasizing an input signal to drive an output terminal, the method comprising:
driving the output terminal by the input signal using a main driver and an auxiliary driver in parallel;
wherein the input signal is differentiated using at least one unclocked delay element to drive the auxiliary driver,
wherein the process of driving the output terminal by the input signal using the main driver comprises calibrating an output level of the main driver; and
wherein the process of calibrating the output level of the main driver comprises using a plurality of driver fingers to allow a binary coding of the output level of the main driver by placing the driver fingers a corresponding number of times.
10. The method of claim 9 , wherein the main driver and the auxiliary driver are based on the same schematic and the same layout cell.
11. The method of claim 9 , wherein the at least one unclocked delay element is an inverter.
12. The method of claim 9 , wherein the process of calibrating the output level of the main driver comprises using at least one logic gate in each of the plurality of driver fingers for gating the driver fingers.
13. The method of claim 12 , wherein the process of calibrating the output level of the main driver comprises keeping an output level at the output terminal constant by a driver calibration bus controlling the logic gates of the driver fingers.