A source synchronous data transmission system includes a data transmitting device and a data receiving device. A dedicated data line carries a data signal from the data transmission device to the data receiving device. A dedicated clock line carries a modulated clock signal from the data transmission device to the data receiving device. The data transmission device includes a clock data driver configured to encode data into the modulated clock signal by modulating an amplitude of the modulated clock signal. Thus, the clock line of the source synchronous data transmission system carries the clock signal and additional data.

Dynamic power control embodiments concern a data processing pipeline. First and second pipeline stages respectively receive first and second clock signals. The first and second pipeline stages are configured to perform first and second operations respectively triggered by first timing edges of the first clock signal and second timing edges of the second clock signal. A clock controller is configured to generate the first and second clock signals. The clock controller is capable of operating in a first mode in which, during a first data processing cycle of the data processing pipeline, a first of the first timing edges is in-phase with a first of the second timing edges. The clock controller is also capable of operating in a second mode in which, during a second data processing cycle of the data processing pipeline, a second of the first timing edges is out of phase with a second of the second timing edges.

A memory controller component includes transmit circuitry and adjusting circuitry. The transmit circuitry transmits a clock signal and write data to a DRAM, the write data to be sampled by the DRAM using a timing signal. The adjusting circuitry adjusts transmit timing of the write data and of the timing signal such that an edge transition of the timing signal is aligned with an edge transition of the clock signal at the DRAM.

In an embodiment, an integrated circuit includes a clock tree circuit and logic circuitry that is clocked by the clocks received from the clock tree circuit. The logic circuit is powered by a first power supply voltage. The integrated circuit includes a voltage regulator that receives the first power supply voltage and generates a second power supply voltage having a magnitude that is lower than the magnitude of the first power supply voltage by a predetermined amount. The second power supply voltage may track the first power supply voltage over dynamic changes during use, either intentional changes to operating state or noise-induced changes. The second power supply voltage may be used to power at least a portion of the clock tree.

In an embodiment, an integrated circuit includes a clock tree circuit and logic circuitry that is clocked by the clocks received from the clock tree circuit. The logic circuit is powered by a first power supply voltage. The integrated circuit includes a voltage regulator that receives the first power supply voltage and generates a second power supply voltage having a magnitude that is lower than the magnitude of the first power supply voltage by a predetermined amount. The second power supply voltage may track the first power supply voltage over dynamic changes during use, either intentional changes to operating state or noise-induced changes. The second power supply voltage may be used to power at least a portion of the clock tree.

In accordance with embodiments disclosed herein, there is provided systems and methods for a serial mid-speed interface. A first component includes a phase-locked loop (PLL) to receive an input clock signal and to output an output signal, an interface controller including a clock-management state machine, and a transmitter. The interface controller is to receive the input clock signal, receive the output signal from the PLL, and generate a speed-switch packet. The transmitter is to transmit a first plurality of packets to a second component at a clock rate based on the clock signal via a mid-speed interface, transmit the speed-switch packet to the second component, and transmit a second plurality of packets to the second component at a PLL rate based on the output signal, where the PLL rate is greater than the clock rate.

In accordance with embodiments disclosed herein, there is provided systems and methods for a serial mid-speed interface. A first component includes a phase-locked loop (PLL) to receive an input clock signal and to output an output signal, an interface controller including a clock-management state machine, and a transmitter. The interface controller is to receive the input clock signal, receive the output signal from the PLL, and generate a speed-switch packet. The transmitter is to transmit a first plurality of packets to a second component at a clock rate based on the clock signal via a mid-speed interface, transmit the speed-switch packet to the second component, and transmit a second plurality of packets to the second component at a PLL rate based on the output signal, where the PLL rate is greater than the clock rate.

In some embodiments, clock input buffer circuitry and divider circuitry use a combination of externally-suppled voltages and internally-generated voltages to provide the various clock signals used by a semiconductor device. For example, a clock input buffer is configured to provide second complementary clock signals responsive to received first complementary clock signals using cross-coupled buffer circuitry coupled to a supply voltage and to drive the first complementary clock signals using driver circuitry coupled to an internal voltage. In another example, a divider circuitry may provide divided clock signals based on the second complementary clock signals via a divider coupled to the internal voltage and to drive the divided clock signals using driver circuitry coupled to the supply voltage. A magnitude of the supply voltage may be less than a magnitude of the internal voltage.

In some embodiments, clock input buffer circuitry and divider circuitry use a combination of externally-suppled voltages and internally-generated voltages to provide the various clock signals used by a semiconductor device. For example, a clock input buffer is configured to provide second complementary clock signals responsive to received first complementary clock signals using cross-coupled buffer circuitry coupled to a supply voltage and to drive the first complementary clock signals using driver circuitry coupled to an internal voltage. In another example, a divider circuitry may provide divided clock signals based on the second complementary clock signals via a divider coupled to the internal voltage and to drive the divided clock signals using driver circuitry coupled to the supply voltage. A magnitude of the supply voltage may be less than a magnitude of the internal voltage.

Embodiments of the present disclosure provide systems and methods for realizing phase synchronization updates based on an input system reference signal SYSREF without the need to synchronously distribute the SYSREF signal on a high-speed domain. In particular, phase synchronization mechanisms of the present disclosure are based on keeping a first phase accumulator in the device clock domain and using a second phase accumulator in the final digital clock domain to asynchronously transmit phase updates to the final digital clock domain. Arrival of a new SYSREF pulse may be detected based on the counter value of the first phase accumulator, which value is asynchronously transferred and scaled to the second phase accumulator downstream. In this manner, even though the SYSREF signal itself is not synchronously transferred to the second phase accumulator, the phase updates from the SYSREF signal may be transferred downstream so that the final phase may be generated deterministically.