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: Integrated circuits such as programmable logic devices are provided that have circuit blocks such as memory blocks. The integrated circuits may be tested to determine whether the circuit blocks contain defects. If defective circuitry is identified, switching circuitry in the circuit blocks can be configured to switch redundant circuitry into use. Repairs may be made by loading repair data into fuses on the integrated circuit. Each circuit block may have an associated control circuit with a unique address. A master block repair controller may be used to route repair data to each control circuit over a shared bus using the unique addresses of the control circuits. Each control circuit may have register circuitry into which addresses and repair data are loaded. Testing circuitry may be used to supply test signals. Multiplexing circuitry can selectively route either the test signals or repair data to the control circuits over the shared bus.

Abstract: A sensing circuit senses the programmed state of fuses such as polysilicon (poly) fuses. In a preferred embodiment, the sensing circuit comprises first and second amplifier stages, a fuse and a reference resistor wherein the fuse and the reference resistor are connected, respectively, to first and second inputs of the first amplifier stage. The first and second amplifier stages are differential amplifiers and the output of the second amplifier stage is buffered. Circuitry for programming the fuse is part of the sensing circuit.