Device-mismatch-insensitive current divider
In this paper, a new iterative process for current division is presented and a circuit implementing the process proposed. In this process, each iteration consists of two phases and each phase involves only one signal sampling. By means of this process, the accuracy of the current division is made insensitive to the device mismatch. The circuit implementing the process is simple and the step of adjustment per iteration is variable, so that an accurate adjustment can quickly be reached after a few iterations. Also, in this circuit, the effect of the switching noise is reduced by applying a simple and effective technique.
Very accurate current divider
This letter presents a new current divider principle based on CMOS dynamic current sources. The proposed method is characterised by very accurate current division without any matching requirements or component trimmings. Among the different applications of this new principle, the D/A conversion field is probably the most important.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.