Adjustable efuse regulator
Publication Date: 2011-Jan-25
The IP.com Prior Art Database
Described is a regulator which provides a programmable voltage on the chip to an integrated circuit based on an external reference voltage.
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A voltage is required to be provided to the efuse macros of approximately 1 volt. This is accomplished by providing a fixed reference voltage to an operational amplifier (op-amp). The output of the op-amp provides the voltage to various circuits such as the e-fuse macros. To reliably blow the fuses, this voltage is desired to be as close to the chosen voltage as possible. Process variation and device tracking and resistive losses cause the op-amp output to have uncertainty and a wider than desired range of voltage at the e-fuse macro. The wire from the module IO to the input of the op-amp is fairly long and resistive, so the wire cannot conduct much current.
A method of moving the output of the op-amp voltage is described. The invention provides for the op-amp to be adjusted digitally without modifications to the board or system needed. The invention does not load the input to the op-amp.
A resistor is placed in the feedback of the op-amp and a set of PMOS switched current sources and NMOS switched current sources are added to the input of the op-amp. Because the op-amp will force both voltages at its inputs to be equal by toggling the controls to the current sources, the output voltage of the op-amp will be moved by the product of the current multiplied by the resistor in the feedback. This allows the output voltage of the op-amp to be adjusted by logic on the chip to get the optimum voltage for the e-fuses. One could also fix the current and switch in varying...