Abstract:
A method, algorithm, architecture, circuit and/or system that compensates for frequency difference in oversampled CDRs. The oversampled CDR uses a programmable divider whose division ratio is changed, for one or more cycles, from its usual division ratio, when accumulated phase movement in either direction exceeds a threshold. Accordingly, the elasticity buffer in oversampled CDRs can be made much smaller or entirely eliminated, resulting in less area, and reduced or eliminated dependence of max allowed burst size on ppm difference. The threshold can be kept programmable, and more than half unit interval, to provide robustness towards high frequency jitter.
Abstract:
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.
Abstract:
A data receiving device may include an envelope detector that may include first and second inputs configured to receive a differential input signal, a first pair of detectors coupled to the first input and configured to generate first and second detector outputs, and a second pair of detectors coupled to the second input and configured to generate third and fourth detector outputs. The envelope detector may also include a logic circuit configured to generate a reset based upon the first and third detectors. The data receiving device may also include a receiver circuit coupled to the envelope detector and configured to generate an output based upon the second and fourth detectors along with the reset, and a first bit detection circuit coupled to the receiver circuit.
Abstract:
A method, algorithm, architecture, circuit and/or system that compensates for frequency difference in oversampled CDRs. The oversampled CDR uses a programmable divider whose division ratio is changed, for one or more cycles, from its usual division ratio, when accumulated phase movement in either direction exceeds a threshold. Accordingly, the elasticity buffer in oversampled CDRs can be made much smaller or entirely eliminated, resulting in less area, and reduced or eliminated dependence of max allowed burst size on ppm difference. The threshold can be kept programmable, and more than half unit interval, to provide robustness towards high frequency jitter.
Abstract:
A power harvesting circuit includes a new transmitter topology that ensures that no junction of thin oxide transistors forming the power harvesting circuit will experience a voltage across junctions of the transistors that is more than a maximum tolerable junction voltage. A supplemental power feed circuit operates to provide a supplemental feed current to components in a transmitter circuit when power harvested from a receiver circuit is insufficient to adequately power these components of the transmitter circuit, which may occur during high frequency operation of communications channels coupling the transmitter and receiver circuits. The supplemental power feed circuit also operates to sink a shunt current when power harvested from the receiver circuit is more than is needed to power the components in the transmitter circuit.
Abstract:
A PWM receiver circuit receives and demodulates pulse width modulated (PWM) data signals without requiring synchronization such that no synchronization preamble need be provided with the PWM data signal. Embodiments may consume less power since there is no need to repeatedly synchronize a PLL, counter or other circuitry to the PWM data signal. Furthermore, the PWM receiver circuit operates in view of or is “tolerant” to jitter in the frequency of the PWM signal and also to a relatively wide range of intentional variation in the frequency. Interleaved operation of parallel PWM receiver circuits are utilized in some embodiments. In one embodiment currents are integrated during low and high portions of the duty cycle of the PWM data signal and the difference in the respective voltages generated through such integration used to demodulate the PWM data signal.