High speed differential pre-driver using common mode pre-charge
AssigneeIntel Corporation
InventorsRonald W. Swartz, Yoon San Ho
Life of this patent
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Abstract
In general, the embodiments introduce a pre-charge state between an idle state (when no data in being transmitted) and an active state (when data is being transmitted). In the pre-charge state, both differential signals are pre-charged to the common mode voltage, which is also the crossover voltage. Similarly, an additional pre-charge state is inserted between the active state and the idle state when the signals transition from active to idle. Because both signals for each bit, including the first and last bits, are being driven from the same voltage level, the quality of the first and last bits are improved to be similar in quality to the middle bits.
Claims23
A method, comprising:
- causing a differential driver circuit to enter an idle state, the differential driver circuit including a first and a second output transistor;
- causing the differential driver circuit to enter a precharge state;
- and
- causing the differential driver circuit to enter an active state.
An apparatus, comprising:
- a first output transistor to steer current to a first output pin when an appropriate potential is applied to a first output transistor gate;
- a second output transistor to steer current to a second output pin when an appropriate potential is applied to a second output transistor gate;
- and
- a pre-driver circuit to apply approximately identical potentials to the first output transistor gate and the second transistor gate to enable the first and second output transistors to steer approximately the same amount of current to the first and second output pins, respectively.
A system, comprising:
- a first device including an output circuit, the output circuit including
- a first output transistor to steer current to a first output pin when an appropriate potential is applied to a first output transistor gate, a second output transistor to steer current to a second output pin when an appropriate potential is applied to a second output transistor gate, and
- a pre-driver circuit to apply approximately identical potentials to the first output transistor gate and the second transistor gate to enable the first and second output transistors to steer approximately the same amount of current to the first and second output pins, respectively;
- and
- a second device couple to the first device via a interconnect, the interconnect implemented using differential signaling.
Dependencies are inferred from the claim text.