摘要:
The function selection signal of an ALU is resistively decoupled or serially coupled to the input multiplexers of the ALU. By producing delayed function selection signals and decoupling the delayed function signals from the input multiplexers, the input multiplexers are serially activated. This need not impact the overall speed of the ALUs, since the adders are also serially activated by virtue of the carry signal ripple. However, by resistively decoupling the function selection signal from the input multiplexers, the load seen by the input driver that drives the function selection signal inputs of the multiplexer may be reduced, thereby allowing the least significant bit input multiplexer to be activated more rapidly. Moreover, resistive decoupling may be implemented by polysilicon resistors, thereby allowing metal interconnect layers in the integrated circuit to be used for other purposes.
摘要:
Impedance-matched output driver circuits include a first totem pole driver stage and a second totem pole driver stage. The first totem pole driver stage includes at least one PMOS pull-up transistor and at least one NMOS pull-down transistor therein that are responsive to a first pull-up signal and a first pull-down signal, respectively. The second totem pole driver stage has at least one NMOS pull-up transistor and at least one PMOS pull-down transistor therein that are responsive to a second pull-up signal and second pull-down signal, respectively. The linearity of the output driver circuit is enhanced by including a first resistive element that extends between the first and second totem pole driver stages. The first resistive element has a first terminal, which is electrically coupled to drain terminals of the at least one PMOS pull-up transistor and the at least one NMOS pull-down transistor in the first totem pole driver stage, and a second terminal, which is electrically coupled to source terminals of the at least one NMOS pull-up transistor and the at least one PMOS pull-down transistor in the second totem pole driver stage.
摘要:
Integrated circuit output buffers include pull-down an pull-up circuits and a control circuit that utilizes a preferred feedback circuit to facilitate a reduction in simultaneous-switching noise during pull-down and pull-up operations and also improve the impedance matching characteristics of the output buffers during DC conditions. The preferred feedback circuit also limits the degree to which external noise can influence operation of the control circuit. Each of the pull-down and pull-up circuits may comprise a respective pair of primary and secondary transistors. The pull-down circuit is preferably configured so that the primary and secondary pull-down transistors (e.g., NMOS transistors) are electrically coupled to an output signal line (through an ESD protection resistor) and a first reference signal line (e.g., Vss). The control circuit is designed to activate the pull-down circuit by turning on both the primary and secondary pull-down transistors during a leading portion of the pull-down time interval and by turning off the secondary pull-down transistor during a trailing portion of the pull-down time interval using a first feedback switch that is electrically coupled in series between the output signal line and a gate electrode of the secondary pull-down transistor so that a signal representing a potential of said output signal line can be passed through the first feedback switch to the gate electrode of the secondary pull-down transistor.
摘要:
A method and apparatus for source synchronous testing have been disclosed. In one case a data signal is delayed and a selectively activated delay is applied to a clock. This allows the clock to be positioned before the data and also after the data.
摘要:
Integrated circuit output buffers include primary and secondary pull-down transistors and an output signal line electrically coupled to a drain of the primary pull-down transistor and a drain of the secondary pull-down transistor. A preferred control circuit is also provided. The control circuit turns on the primary pull-down transistor during first and second consecutive portions of a pull-down time interval and uses a signal fed back from the output signal line to control the timing of when a gate of the secondary pull-down transistor is electrically connected to a drain of the secondary pull-down transistor during the first portion of the pull-down time interval and also control the timing of when the gate electrode of the secondary pull-down transistor is electrically connected to a source of the secondary pull-down transistor during the second portion of the pull-down time interval. A pull-down portion of the control circuit may include a gate pull-up transistor having a drain electrically connected to the drain of the secondary pull-down transistor and a source electrically connected to a gate of the secondary pull-down transistor, and a gate pull-down transistor having a drain electrically connected to the gate of the secondary pull-down transistor and a source electrically connected to a source of the secondary pull-down transistor. These gate pull-up and pull-down transistors can be utilized to selectively turn on the secondary pull-down transistor during a first leading portion of a pull-down time interval and then turn off the secondary pull-down transistor during a second trailing portion of the pull-down time interval.
摘要:
A Method and Apparatus for a Transmission Gate for Multi-GB/s Application have been disclosed. By actively biasing the gate and body of both NFET and PFET improved performance is achieved.
摘要:
Rate matching for use in data links between a source device and a sink device is provided. A rate matching device includes a first-in-first-out (FIFO) buffer having a write pointer and a read pointer; a write control having a write clock to write an input data stream from the source device onto the FIFO buffer using the write pointer; a read control having a read clock to read data from the FIFO buffer using a read pointer, insert data to an output data stream and transmitting the data stream to the sink device; a processor to provide a bit number based on the write clock period and the read clock period, wherein the read control inserts blanking data into the output data stream while the read pointer is stopped in the FIFO buffer to allow the write pointer to move ahead by the bit number provided by the processor. Some embodiments are thus able to avoid buffer overflow or underflow scenarios.
摘要:
A substrate biasing circuit may include a first pump control circuit that generates a first control signal in response to a first reference voltage and a voltage of a first substrate portion, and includes a first reference generator coupled between a temperature compensated voltage and a reference power supply voltage that varies the first reference voltage in response to the voltage of the first substrate voltage and the temperature compensated voltage. A first clamp circuit may generate a first clamp signal in response to a first limit voltage and the voltage of the first substrate portion, the first limit voltage being a scaled version of the temperature compensated voltage. A first charge pump may pump the first substrate portion in at least a first voltage direction in response to the first control signal, and is prevented from pumping in the first voltage direction in response to the first clamp signal.
摘要:
A data transmission system is provided. The data transmission system includes a source device having a source device controller and a register and a sink device having a sink device controller. The data transmission system also includes a transmission link coupling the source device and the sink device. The transmission link includes a unidirectional main line having a plurality of main link channels, a bidirectional auxiliary line configured to transmit data between the source device and the sink device at a first data rate, and a unidirectional interrupt line. The transmission link is configured to transmit data from the source device to the sink device over one of the main link lines at a second data rate and to transmit data from the sink device to the source device over the auxiliary line at the second data rate. The transmission link may comply with the DisplayPort standard, and the data may be transmitted in accordance with the USB standard.