Synopsys, Inc.

Vaibhav Verma

Prashant Dubey

Amit Khanuja

Sanjeev Kumar Jain

Sanjay Kumar Yadav

Pritender Singh

Sachin Taneja

Gaurav Ahuja

A circuit detects values stored in bit cells of a memory circuit, for example, a memory circuit with single ended sensing. The circuit injects a charge into a bit line coupled to a bit cell to detect the value stored in the bit cell. A level detector detects the voltage level of the bitline as the charge in injected in the bitline. The sensing circuit determines the bit value stored during the charge injection phase. If the bitline voltage reaches above a high threshold voltage level as the charge in injected in the bitline, the circuit determines that the bit cell stores a first bit value (for example, bit value 1.) If the bitline voltage stays below a low threshold voltage level as the charge in injected in the bitline, the circuit determines that the bit cell stores a second bit value (for example, bit value 0).

Sensing scheme for high speed memory circuits with single ended sensing

Embodiments relate to preventing or mitigating excessive drop in the negative voltage level of a bitline of memory bitcells by controlling the delay of a trigger signal for initiating injection of negative charge into the bitline. A write assist circuit causes negative charge to drop gradually in response to receiving a data input indicating a negative value of the bitline. When supply voltage is high, the timed delay of trigger signal is reduced, thereby causing negative charge to be injected into the bitline while bitline voltage remains at a higher voltage level and before the bitline voltage drops close to ground voltage. Since the negative charge is injected while the bitline voltage level is relatively high, the bitline is prevented from being pulled down to an excessively negative voltage level even when the supply voltage is relatively high.

Controlling timing of negative charge injection to generate reliable negative bitline voltage

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Haryana, India

Vaibhav Verma