CMOS Image Sensor Readout with Replica Delay Noise Control

The patent applies preliminary action by pre-charging the bit lines before reading data from the counter array. The sense amplifier array is precharged to a known voltage level before the actual read operation, ensuring that the readout can proceed at high speed without waiting for line charging during the critical read window. This preliminary preparation enables high-speed readout while maintaining power efficiency by concentrating power consumption in controlled precharge phases rather than during continuous high-speed operation.

The patent uses a replica delay circuit that creates a copy of the clock signal timing to replicate and match the timing of sense amplifier operations with counter array operations. This copying approach allows the system to maintain synchronized operation between the counter array and sense amplifiers, enabling effective ADC integration while managing power noise through precise timing replication rather than direct high-power conversion operations during sensitive readout phases.

The patent applies preliminary action by pre-charging the bit lines to a definite voltage level before the sense amplifier begins its high-speed differentiation operation. This precharge ensures that when the sense amplifier operates at high speed to detect small voltage differences from the counter array, the bit lines start from a known, stable state, thereby maintaining adequate noise margin even during high-speed operation. The precharge phase prepares the system for fast sensing without compromising the voltage margins needed for reliable detection.