US Patent 7672182 Read assist circuit of SRAM with low standby current

A SRAM memory with a read assist circuit is presented. The read assist circuit uses bitline voltage level switches, which are connected to a low power supply and a high power supply. The bitline voltage level switches have a write operation state, a read operation state, and a standby operation state. The write operation state selectively provides the high power supply to bitlines in columns selected for a write operation, and provides the low power supply to bitlines in the remaining columns. The read operation state selectively provides the low power supply to bitlines in columns selected for the read operation, and provides the low power supply to bitlines in the other columns. The standby operation state selectively provides the low power supply to bitlines in all columns when not in the read operation state or the write operation state.