High speed bus system

A high speed bus system for coupling at least one master device to at least one slave device, said bus comprising at least one low impedance transmission line for transmission of signals, said master device and said slave device coupled to the at least one transmission line;

• each master device and slave device comprising at least a bus driver and bus receiver;
• said bus driver comprising current mode source to drive current along the transmission line at a low, small swing voltage,
• said bus receiver comprising a plurality of sampler/amplifier circuits which sample the received signal and amplify the signal from the small swing voltage level to a large swing voltage level compatible with the device coupled to the receiver, each of said sampler/amplifier circuits operating on alternate clocks to increase the throughput of the receiver, each of said sampler/amplifier circuits comprising,
• a first stage circuit for sampling the received signal, said first stage comprising a differential amplifier having a gain close to unity,
• a second stage circuit comprising a sense amplifier for amplifying the received signal to a voltage level compatible with the device coupled to the receiver, said second stage electrically isolated from the first stage, and
• means for transferring the sampled received signal from the first stage to the second stage;
• whereby the parasitic capacitive charge that is back injected onto the transmission line by the first stage circuit is minimized by maintaining a small swing signal at the first stage and transferring the sampled small swing signal to the isolated second stage prior to amplifying the small swing signal to a large swing signal and the signal received by the bus receiver is output rapidly in a form compatible with the device coupled to the bus receiver.

In a high speed bus system for coupling at least one master device to at least one slave device, said bus comprising at least one transmission line for transmission of signals, said master device and said slave device coupled to the at least one transmission line a method for transmitting signals between a transmitting device and a receiving device of the master and slave devices, said method comprising the steps of:

• driving a signal on the bus utilizing a current mode source to drive current along the transmission line at a small swing voltage;
• sampling the signal at a first stage of the receiver device;
• transferring the sampled signal to a second stage of the receiver device, said second stage electrically isolated from the first stage;
• amplifying the sampled received signal from the small swing voltage to a large swing voltage level compatible with a device coupled to the receiver;
• whereby parasitic capacitive charge that is back injected onto the transmission line by the first stage circuit is minimized by maintaining a small swing signal at the first stage and transferring the sampled small swing signal to the isolated second stage prior to amplifying the small swing signal to a large swing signal and the signal received by the bus receiver is output rapidly in a form compatible with the device coupled to the bus receiver.

A high speed bus configuration for coupling at least one master device to at least one slave device, said bus comprising:

• at least one transmission line, said master device coupled to a first end of the transmission line, said slave device coupled to the transmission line at a point between the first end and a second end of the transmission line;
• a termination resistor located at the second end of the transmission line, said resistor having an impedance equivalent to the impedance of the transmission line whereby signals which travel to the second end of the transmission line are absorbed;
• said slave device communicating to the master device by producing a drive current which is divided at the output of the slave device to generate first and second 1/2 swing signals, the first 1/2 swing signal propagating towards the second end of the transmission line and said second 1/2 swing signal propagating towards the first end of the transmission line;
• said terminating resistor absorbing the first 1/2 swing signal, said second 1/2 swing signal reaching the first end of the transmission line and reflecting back towards the second end of the bus, said master devices located at the first end of the bus receiving a full swing signal resulting from the sum of the first 1/2 swing signal and reflected first 1/2 swing signal;
• whereby the power dissipation along the bus is minimized without increasing the time of flight delay (t.sub.f) of the bus and the effectiveness of the master and slave devices as bus drivers is increased.