摘要:
Disclosed is a current booster or kicker for an output amplifier of a programmable logic control or other integrated circuit. The current booster includes a control mechanism and an auxiliary voltage supply. When a change in output state is initiated, the control mechanism connects the auxiliary voltage supply to the output of the output amplifier. After a change in output state in completed, the control mechanism disconnects the auxiliary voltage supply from the output of the output amplifier. In this way, the output amplifier can drive a relatively high capacitance load at a relatively high slew rate.
摘要:
A programmable logic device is equipped for low voltage differential signaling (“LVDS”) by providing an LVDS input buffer and/or an LVDS output buffer on the device. I/O pins on the device that are used together in pairs for LVDS can alternatively be used individually for other types of signaling. The LVDS buffers are constructed to give good performance and to meet LVDS specifications despite variations due to temperature, manufacturing process inconsistency, and power supply changes.
摘要:
A programmable input/output circuit for a programmable logic device input/output pin can be configured in a standard I/O mode, or in a reference voltage mode. The circuit includes a tristatable, but otherwise standard I/O buffer as well as a reference voltage clamp circuit. In reference voltage mode, the I/O circuit is tristated, and the reference voltage clamp circuit passes a reference voltage from the I/O pin to a reference voltage bus. In standard I/O mode, the I/O buffer is operational. The reference voltage clamp circuit isolates the I/O pin from the reference voltage bus and may include undervoltage and overvoltage protection to prevent disturbance of the reference voltage bus by an out-of-range I/O signal.
摘要:
A programmable logic device is equipped for low voltage differential signaling (“LVDS”) by providing an LVDS input buffer and/or an LVDS output buffer on the device. I/O pins on the device that are used together in pairs for LVDS can alternatively be used individually for other types of signaling. The LVDS buffers are constructed to give good performance and to meet LVDS specifications despite variations due to temperature, manufacturing process inconsistency, and power supply changes.
摘要:
A circuit provides a programmable phase shift feature, where the phase shift is programmably selectable by a user. This circuitry may be incorporated in a programmable logic device (PLD) or field programmable gate array (FPGA) to provide additional programmability features. The programmable phase shift circuitry may be implemented within a phase locked loop (PLL) or delay locked loop (DLL) circuit. In an implementation, the programmable phase shift circuitry is implemented using two programmable counters.
摘要:
A programmable logic device is equipped for low voltage differential signaling (“LVDS”) by providing an LVDS input buffer and/or an LVDS output buffer on the device. I/O pins on the device that are used together in pairs for LVDS can alternatively be used individually for other types of signaling. The LVDS buffers are constructed to give good performance and to meet LVDS specifications despite variations due to temperature, manufacturing process inconsistency, and power supply changes.
摘要:
An input buffer circuit has a plurality of selectively enabled differential amplifier circuits, where each differential amplifier is configured for compatibility with a particular differential I/O standard and its corresponding input operating range. For example, the input buffer may have two differential amplifiers suitable for receiving LVDS differential input signals over a wide input operating range, and another differential amplifier suitable for receiving the PCML differential input signals. One or more control signals are provided to the input buffer, e.g., programmably, to selectively enable the required differential amplifier(s) for a given I/O standard.
摘要:
A programmable I/O element for an I/O terminal of a logic array is suitable for operating according to high speed 110 modes such as double data rate and zero bus turnaround. The I/O element may include an input block with two registers for registering input signals from the terminal upon alternate clock edges. In addition or alternatively, it may include an output block with two registers that separately register output signals from the array on the same clock edge and a multiplexer that alternately outputs those signals. For bidirectional terminals, the multiplexer output is connectable to the I/O terminal via an output buffer, and an output enable block provides an enable signal to a gating input of the output buffer. Programmable delays may be included in the input, output, and output enable paths, in particular to provide a slower turn-on time than turn-off time for the output buffer.
摘要:
Techniques and circuitry are used to more rapidly configuring programmable integrated circuits. Configuration data is input into a programmable integrated circuit in parallel via parallel inputs (705), and this data is also handled internally in parallel. The configuration data will be stored in a data register (722). This data register includes two or more serial register chains, each chain being made up of a serial chain of registers. The configuration data is input into the two of more chains of the data registers in parallel. Circuitry is also provided to handle redundancy.
摘要:
An input buffer circuit has a plurality of selectively enabled differential amplifier circuits, where each differential amplifier is configured for compatibility with a particular differential I/O standard and its corresponding input operating range. For example, the input buffer may have two differential amplifiers suitable for receiving LVDS differential input signals over a wide input operating range, and another differential amplifier suitable for receiving the PCML differential input signals. One or more control signals are provided to the input buffer, e.g., programmably, to selectively enable the required differential amplifier(s) for a given I/O standard.