On-chip temperature sensor with high tolerance for process and temperature variation

A reliable temperature sensor circuit that is robust against wafer or chip process and sensing temperature variation is introduced. The circuit includes a reference voltage generator and a constant current bias voltage generator in order to compensate for process and sensing temperature variations. This method eliminates post-production adjustments by circuits such as fuses or non-volatile memory devices. It reduces adjustment test costs and silicon area for these devices, their test control circuits and the interface circuits. Temperature measurement variation of less than 0.6°C by the proposed circuit with a simple low-power structure was verified. The circuit is implemented for a refresh cycle control in 1.5 times of the PAD space on a low-power pseudo-SRAM type DRAM product with a 0.175-μm CMOS bulk process.