Configurable, Power Supply Voltage Referenced Single-Ended Signaling with ESD Protection
AssigneeRambus Inc.
InventorsJohn W. Poulton, Frederick A. Ware, Carl W. Werner
Life of this patent
Estimating the term…
Abstract
A single-ended data transmission system transmits a signal having a signal voltage that is referenced to a power supply voltage and that swings above and below the power supply voltage. The power supply voltage is coupled to a power supply rail that also serves as a signal return path. The signal voltage is derived from two signal supply voltages generated by a pair of charge pumps that draw substantially same amount of current from a power supply.
Claims39
A circuit to be coupled to a power supply, comprising:
- first and second terminals, the second terminal to be at a power supply voltage after being coupled to the power supply;
- and
- a transmitter configured to transmit a signal via the first terminal, the signal having a voltage level that is referenced to the power supply voltage and that swings substantially symmetrically above and below the power supply voltage.
A circuit to be coupled to a power supply, comprising:
- first and second terminals, the second terminal to be at a power supply voltage after being coupled to the power supply;
- and
- a receiver amplifier including a first input and a second input coupled to the first terminal and the second terminal, respectively, the receiver amplifier configured to detect a voltage difference between a signaling voltage at the first terminal with reference to the power supply voltage at the second terminal.
A method of transmitting a signal over a transmission line using a transmitter having a first terminal coupled to the transmission line and a second terminal at a power supply voltage, the method comprising:
- receiving a first data bit of a first digital value;
- generating a first output voltage representing the first data bit for outputting to the transmission line, the first output voltage being above the power supply voltage and causing a first output current to flow out of the first terminal and into the second terminal;
- receiving a second data bit of a second digital value different from the first digital value;
- and
- generating a second output voltage representing the second data bit for outputting to the first transmission line, the second output voltage being below the power supply voltage and causing a second output current to flow out of the second terminal and into the first terminal.
A circuit, comprising:
- a first terminal, a second terminal, and a power supply terminal, the power supply terminal to be coupled to a power supply voltage;
- and
- a transmitter configurable to operate in either a single-ended signaling mode or a differential signaling mode, the transmitter in the single-ended signaling mode configured to transmit a single-ended signal via the first terminal, the single-ended signal having a signal return path through the power supply terminal and a signaling voltage that is referenced to the power supply voltage and that swings above and below the power supply voltage, the transmitter in the differential signaling mode configured to transmit a differential signal via the first and second terminals.
A circuit configurable to operate in either a first signaling mode or a second signaling mode, the circuit comprising:
- a first terminal for coupling to a first external signal transmission line, a second terminal for coupling to a second external signal transmission line, and a power supply terminal for coupling to a power supply voltage;
- an amplifier having first and second inputs;
- and
- switching circuitry configured to couple the first input of the amplifier to the first terminal and the second input of the amplifier to the power supply terminal so as to configure the circuit to operate in the first signaling mode, the switching circuitry configured to couple the first input of the amplifier to the first terminal and the second input of the amplifier to the second terminal so as to configure the circuit to operate in the second signaling mode.
A communication system, comprising:
- a circuit board having a power supply plane and at least one signal transmission line;
- a first circuit on the circuit board, the first circuit having a first terminal coupled to a signal transmission line and a second terminal coupled to the power supply plane, the first circuit to transmit a signal via the first terminal over the transmission line, the signal being referenced to a voltage of the power supply plane and having a return path through the power supply plane;
- and
- a second circuit on the circuit board, the second circuit having a third terminal coupled to the signal transmission line and a fourth terminal coupled to the power supply plane, the second circuit to receive the signal from the signal transmission line and to detect a voltage difference between a signaling voltage at the third terminal with reference to the voltage of the power supply plane.
Dependencies are inferred from the claim text.