Circuit Implementation of Switchable Pins in Chip Multiprocessor

Transistor scaling and voltage scaling promote the development of VLSI chip design and modern portable devices. However, transistor scaling brings dark silicon to chips. Lowering supply voltage also results in many transistors to work in near threshold voltage region in which transistors are very sensitive to voltage variation. The paper analyzes the influence of IR drop in a chip multiprocessor (CMP) architecture. Based on our previous work, we focus on the circuit implementation of the proposed switch able pin in CMP using I/O pads with on-chip low cost control circuit, and to let the microprocessor work in data mode or power mode according to various requirements. Using six of eight traditional data pins in an 8-bit RISC microprocessor as switch able pins, the entire current in power mode can be boosted by 72% compared to normal data mode. For data transmission, relative signal-to-noise ratio (rSNR) are tested and the performance of the DRAM is also discussed.