Abstract: Methods and systems for detection and monitoring of power supply voltage and voltage reference circuitry are provided. In one embodiment of the invention, a first signal is set to be proportional to a power supply voltage in response to a determination from control circuitry that an output voltage of bandgap voltage reference circuitry is less than a first threshold voltage. The first signal is set to a logic low level in response to a determination from control circuitry that the output voltage of the bandgap voltage reference circuit is greater than the first threshold voltage, wherein the first threshold voltage is less than a bandgap reference voltage. A value of a reset signal is determined based at least in part on the first signal.

Abstract: An encoder is provided for converting thermometer code data with bubbles to binary format. An integrated circuit may have circuitry such as digital phase-locked loop circuitry. A thermometer code data word may be used as a control signal for the circuitry. It may be desirable to monitor the thermometer code data word for testing or for downstream processing by control logic on the integrated circuit. The encoder performs thermometer code to binary encoding without requiring that the thermometer code be error corrected to remove bubbles. A bubble detection circuit may be used to detect when the thermometer code data contains bubbles. The encoder may use carry look-ahead adders and pipeline stages.

Abstract: A sensing circuit for comparing current flow through a reference resistance with current flow through a resistive device under test (DUT) such as a fuse. The sensing circuit includes a comparator having a first PMOS transistor and a first NMOS transistor connected in series between a first input and a first node and a second PMOS transistor and a second NMOS transistor connected in series between a second input and the first node. The first PMOS and NMOS transistors are cross-coupled with the second PMOS and NMOS transistors. Specifically, a first output is connected to the first node to the gates of the second PMOS and second NMOS transistors and a second output is connected to the second node and to the gates of the first PMOS and first NMOS transistors. The reference resistance is connected to one of the inputs and the DUT is connected to the other input.

Abstract: Circuits, methods, and systems for implementing an Analog to Digital Converter (ADC) in an Integrated Circuit (IC) are provided. An IC includes an analog modulator, a digital filter coupled to the analog modulator, and a decimator coupled to the digital filter. The analog modulator includes one or more discrete integrators and a feedback path. A first discrete integrator from the one or more discrete integrators is operable to receive an analog input of the ADC. The feedback path couples an output of the analog modulator to at least one of the one or more discrete integrators. Further, the decimator is operable to produce the output of the ADC, and the IC is operable to receive an IC configuration file that specifies how the discrete integrators are connected in the analog modulator, parameters of the digital filter, and parameters of the decimator.

Abstract: Circuitry on an integrated circuit is provided that may be used to program fuses such as polysilicon fuses. Fuse programming may be performed using an elevated power supply voltage. Other circuitry on the integrated circuit may be powered using a standard power supply voltage that is less than the elevated power supply voltage. Fuse sensing may be performed using the standard power supply voltage. A control block may be used to produce a fuse programming control signal. Power-on-reset circuitry may monitor the elevated power supply voltage and may produce a corresponding elevated power supply voltage power-on-reset signal indicative of whether the elevated power supply voltage is valid. The power-on-reset circuitry may also produce a standard power supply power-on-reset signal indicative of whether the standard power supply voltage is valid. The power-on-reset signals may be used in controlling fuse programming and fuse sensing.

Abstract: An encoder is provided for converting thermometer code data with bubbles to binary format. An integrated circuit may have circuitry such as digital phase-locked loop circuitry. A thermometer code data word may be used as a control signal for the circuitry. It may be desirable to monitor the thermometer code data word for testing or for downstream processing by control logic on the integrated circuit. The encoder performs thermometer code to binary encoding without requiring that the thermometer code be error corrected to remove bubbles. A bubble detection circuit may be used to detect when the thermometer code data contains bubbles. The encoder may use carry look-ahead adders and pipeline stages.

Abstract: Power-on-reset circuitry is provided for integrated circuits such as programmable logic device integrated circuits. The power-on-reset circuitry may use comparator-based trip point voltage detectors to monitor power supply voltages. The trip point detectors may use circuitry to produce trip point voltages from a bandgap reference voltage. Controller logic may process signals from the trip point detectors to produce a corresponding power-on-reset signal. The power-on-reset circuitry may contain a noise filter that suppresses noise from power supply voltage spikes. Normal operation of the power-on-reset circuitry may be blocked during testing. The power-on-reset circuitry may be disabled when the bandgap reference voltage has not reached a desired level. The power-on-reset circuitry may be sensitive or insensitive to the power-up sequence used by the power supply signals.

Abstract: Power-on-reset circuitry is provided for integrated circuits such as programmable logic device integrated circuits. The power-on-reset circuitry may use comparator-based trip point voltage detectors to monitor power supply voltages. The trip point detectors may use circuitry to produce trip point voltages from a bandgap reference voltage. Controller logic may process signals from the trip point detectors to produce a corresponding power-on-reset signal. The power-on-reset circuitry may contain a noise filter that suppresses noise from power supply voltage spikes. Normal operation of the power-on-reset circuitry may be blocked during testing. The power-on-reset circuitry may be disabled when the bandgap reference voltage has not reached a desired level. The power-on-reset circuitry may be sensitive or insensitive to the power-up sequence used by the power supply signals.

Abstract: The present invention includes techniques for programming and verifying data in a programmable circuit. Programmable circuits such as PLDs may include a plurality of rows and columns of memory cells. Data is programmed into memory elements associated with the rows and columns. Subsequently, the programmed data may be extracted for verification. A first word line may be selected by first word line address bits in row shift registers. Data programmed into the first word line is loaded into column shift registers for verification during one or more verify steps. During a program step, data is programmed into memory elements in a second word line that is selected by the first word line address bits. The present invention also provides a technique for shifting program data bits into the column shift registers at the same time that verify data bits are shifted out of the column shift registers.

Abstract: The invention provides a high-speed buffer that may used at the input of an integrated circuit, such as an input buffer. This buffer may be configured for use as a standard buffer with a single switching threshold, such as a TTL-to-CMOS buffer, or used as a Schmitt trigger with hysteresis, which as at least two switching thresholds. The integrated circuit may be a programmable logic device (PLD) or field programmable gate array (FPGA), but in other embodiments, the integrated circuit may be other types of devices such a microprocessors, ASICs, or memories.