Masahiro Kano

Targeting DNa topoisomerase II with podophyllotoxin aza-analogue

Abstract Oxidation of a cytotoxic podophyllotoxin aza-analogue 2 into the quinone 3 succeeded in acquiring DNA topoisomerase II inhibitory activity at a concentration of 25 μM due to stabilization of the cleavable complex.

Analysis and design of a triangular active charge injection for stabilizing resonant power supply noise

This paper proposes an analysis of the active charge injection for a resonant power supply noise by controlling the number of canceling capacitors so that the core supply voltage does not become lower than the voltage at the beginning of the canceling charge injection. Based on this analysis, we propose a circuit that injects adequate amount of charge in accordance with the injection time and the amount of the voltage drop whose code comes from an on-chip voltage drop detector. The proposed circuit is composed of a voltage drop detector, a finite state machine (FSM) that controls the injection and canceling capacitor circuit. The injection controller FSM enables the robust operation against the variation of the current consumed in the core circuit. The post-layout simulation indicates that our proposed circuit reduces the resonant power supply noise by about 30%, and also reduce 71% silicon area compared to the area of passive decoupling capacitors for the same amount of the noise reduction.

Resonant power supply noise cancelling with noise detector based in DLL and vernier TDC

This paper proposes an active resonant power supply noise cancelling with fast voltage drop sensor using the combination of delay-locked loop (DLL) and vernier time-to-digital converter (TDC). Also, we propose the capacitor selector circuit realizing the active insertion of capacitors in less silicon area. These components enable one clock noise detection with fine resolution. Simulation results show that our noise sensor detects 54 mV voltage drop in one clock cycle and cancels 28% of the supply noise by the active charge injection. The proposed circuits use the silicon area about 27 times more effectively than conventional passive decaps.

Resonant power supply noise reduction using a triangular active charge injection

This paper shows the efficacy of a triangular active charge injection for resonant power supply noise reduction by measuring a real silicon chip. Based on the analysis of a triangular active charge injection, our circuit composed of a voltage drop detector, a finite state machine (FSM) and canceling capacitors injects the adequate amount of charge into the supply line of the LSI so that the core supply voltage does not become lower than the voltage at the beginning of the canceling charge injection. The measurement result indicates that our circuit realizes 14% noise reduction with passive decap to mitigate spike noises and consumes 25.2 mW in steady state by 0.182 mm2 silicon area.

Improvement of power integrity with Die-Attached STO thin film capacitors

This paper demonstrates that our Die-Attached STO thin film decoupling capacitor is effective for reduction of the resonant power supply noise of LSIs. Shmoo plots shows improvement of operable frequency and power supply voltage reduction, as results of the improved power integrity realized by our STO thin film capacitors.

Resonant power supply noise reduction using on-die decoupling capacitors embedded in organic interposer

This paper demonstrates an on-die STO thin film decoupling capacitor used for resonant power supply noise reduction. The on-die STO capacitor consists of STO whose dielectric constant is about 20 and is sandwitched by Cu films in an organic interposer on which we can also draw connection wires by Cu deposition. The capacitor was attached directly on our test chip using ball banding technique through PADs connection. Our experimental results using a real silicon chip shows that our on-die STO capacitor achieved significant resonant supply noise reduction. This result also shows that we can reduce the power supply noise without chip area penalty, and also it enables us to modify the noise characteristics even after the chip fabrication process.