This article presents an adaptive match-line (ML) discharge scheme for low-power, high-performance, and compact ternary content addressable memory (TCAM). In the proposed TCAM, the transposed cell topology enables the selectively controlled ML pull-down path and compact array area. By employing the adaptive ML discharge and ML boosting scheme, unnecessary ML discharge and redundant search-line (SL) switching are eliminated for low-cost TCAM search operation. In order to minimize ML voltage swing at a wide voltage range, a timing calibration scheme is also adopted in the proposed TCAM. A 128 $\times $ 64 test chip implemented with 65-nm CMOS technology shows that the proposed adaptive ML discharge improves up to 69% of search delay and saves 37% of search energy compared with the conventional approach at 1.1 V, 100 MHz. The measurement result shows energy efficiency of 0.6 fJ/bit/search and 8% improvement of figure-of-merit (FoM) (energy/bit/search) compared with the state-of-the-art works.
28 June 2024 in IEEE Transactions on Power Electronics
This letter proposes an n-type output capacitorless low-dropout regulator (LDO) with high power supply rejection (PSR) and fast transient response. To enhance both the performances, a multiple-feedback loop structure is proposed. The LDO obtained a PSR of –40 dB (–25 dB) at 1 MHz with load currents of 100 mA (600 mA). The LDO achieved an undershoot of 116 mV when the load changes from 1 to 600 mA, while consuming a quiescent current of 27.5 μA. The chip was fabricated in the 180-nm CMOS process with an area of 0.063 mm 2 .
This paper presents a segmented match-line (ML) and charge-sharing based search scheme for low-cost ternary contents addressable memory (TCAM). In the proposed TCAM, a first-round search operation is performed on half cells located in even columns. During the first-round search, most of the mismatch cases are filtered out while remaining few mismatched cases that is misrecognized as the matched case. To complete the search operation in a low-power manner, a charge-sharing between the segmented MLs is used for the second-round search operation. The proposed 16KB 16T-NOR TCAM macro has been implemented using a 28nm CMOS technology. Numerical results show that the proposed TCAM improves sensing delay up to 5.6x faster and saves search energy-delay-product by 83% compared to the conventional approaches.
Recently, wireless charging technologies for large moving objects, such as electric vehicles and robots, have been actively researched. The power transmitting and receiving coils in most large moving objects are structurally separated by a given distance, which exposes a high output power to the outside world. If a foreign metal object enters the area between these two coils during wireless power transfer, fire hazards or equipment damage may occur. Therefore, we propose a method for detecting foreign metal objects in the gap between the transmitting and receiving coils in a wireless high-power transfer system. A resonant detection coil set is used to exploit the change induced in electrical characteristics when a foreign metal object is inserted. The mutual inductance of the foreign metal object changes the impedance of the detection coil set. We developed a simple circuit to detect both the magnitude and phase change of the voltage signal according to the altered impedance. Additionally, we implemented a prototype of a wireless power transfer system with a detection system to verify that even small foreign metal objects can be detected effectively.