Search

Renal infarction is a rare emergency and the estimated incidence is extremely low according to the literature. In addition, simultaneous bilateral renal infarction was only about 20% in these rare cases. Herein we reported a case of acute renal failure related to bilateral renal infarction and successfully treated by endovascular therapy including angioplasty and catheter-directed thrombolysis. His renal function also significantly improved after the intervention. This rare case reminds physician that early endovascular therapy might improve renal function and result in better renal outcome for patients with simultaneous bilateral renal infarction.

In this paper, a new compensation scheme and a corre-sponding pass element structure for a CMOS low-dropout regulator (LDO) are presented. The proposed approach effectively alleviates the strict stability constraint on the ESR of the output capacitor. Stability of a CMOS LDO with the conventional compensation requires the effective series resistance (ESR) of the output capacitor in a tunnel-like region. With the proposed design approach, an LDO can be stable using an output capacitor without ESR. A 2.5V/150mA LDO has been implemented using a 0.5-μm 1P2M CMOS process. The experimental results illustrate that the proposed LDO is stable with an output capacitor of 0.33μF and no ESR.

In the world of portable wireless electronics, battery life and therefore power efficiency are key parameters, and RF power amplifiers (PAs) are severe limiting agents in this regard because of their power-intensive demands. Spectral density is also critical to extend the effective bandwidth of a wireless transmitter, which is why linear PAs are popular, in spite of their inherently low power efficiency levels. An asynchronous power-tracking scheme is therefore proposed to more efficiently power-condition the supply of linear RF PAs and extend overall battery life performance. The RF supply is comprised of a high power but slow-responding voltage regulator with a lower power but fast-responding parallel nonlinear clamping circuit. Simulations with a SiGe HBT class-A RF PA show that the proposed circuit consumes 10-15% less total power and achieves 1.5% better overall power efficiency than the state-of-the-art power-tracking scheme while meeting the same error-vector magnitude (EVM) performance.

Power management is an essential component of any electrical system, and nowadays a limiting factor in the miniaturization of portable electronic devices. Not only are the battery and power components difficult to integrate but their performance requirements in mobile environments are more stringent. And although point-of-load (PoL) regulation techniques and monolithic controllers are industry standards today, more integration is indispensable. To address these issues, system-in-package (SiP) self-renewable energy source and storage devices are proposed alongside an array of circuit techniques designed to circumvent the shortcomings of such a miniaturized environment, like smart load-sharing schemes, customizable and self-adaptive PoL regulators, active inductor and capacitor multipliers, and robust self-calibrating and self-stabilizing dc-dc converters. On their own, each seeks to push the limits of integration while maintaining and many times improving performance. As a whole, they promise the birth of a new generation of ICs.

A CMOS low dropout regulator (LDO) with a new pole-zero pairs cancellation compensation scheme is presented. LDO using this proposed compensation technique provides stable output voltage with any load capacitor. The only constraint on the equivalent series resistance (ESR) of the load capacitor is that it should be less than the load resistance. It is especially suitable for system-on-chip integration applications and board size reduction.