A low power UART design based on asynchronous techniques

pre-printAbstract-Universal Asynchronous Receiver Transmitter (UART) implements serial communication between peripherals and remote embedded systems. The UART protocol is defined based on fixed frequencies with a sampling method to achieve robustness under reasonable frequency variations between systems. Such design specifications are natural for clocked domains. This work investigates whether this simple clocked hardware protocol can be advantageously implemented using asynchronous design techniques. A full duplex clocked and asynchronous UART are implemented and compared. The asynchronous design results in average power of about one fourth that of the clocked design under standard operating modes

Physical design of low power operational amplifier

A CMOS single output two stage operational amplifier is presented which operates at 3 V power supply at 0.18 micron (i.e., 180 nm) technology. It is designed to meet a set of provided specifications. The unique behavior of the MOS transistors in sub- threshold region not only allows a designer to work at low input bias current but also at low voltage. This op-amp has very low standby power consumption with a high driving capability and operates at low voltage so that the circuit operates at low power. The op-amp provides a gain of 20.4dB and a -3db bandwidth of 202 kHz and a unity gain bandwidth of 2.15MHz for a load of 5 pF capacitor. This op-amp has a PSRR (+) of 85.0 dB and a PSRR (-) of 60.0 dB. It has a CMRR (dc) of -64.4 dB, and an output slew rate of 12.465 v/µs. The power consumption for the op-amp is 1.18mW. The presented op-amp has a Input Common Mode Range(ICMR) of -1V to 2.4V. The op-amp is designed in the 180 nm technology using the umc 180 nm technology library. The layout for the above op-amp had been designed and the post layout simulations are compared with the schematic simulations. The proposed op-amp is a simple two stage single ended op-amp. The input stage of the op-amp is a differential amplifier with an NMOS pair. The second stage of the op-amp is a simple PMOS common source amplifier. The second stage is used to increase the voltage swing at the output. The op-amp uses a -3v Vdd and a -3v Vss and consumes a power of around 0.6mW (as per post layout simulations)

Atypical presentation of scrub typhus encephalitis with cerebral hemorrhage

Scrub typhus, an arthropod borne infection caused by the rickettsial organism Orientia tsutsugamushi, is a fairly common disease in north-eastern sub-Himalayan India, particularly the forest areas, and is known to manifest with varied presentations ranging from non-specific fever to severe multi-organ complications. Hemorrhagic manifestations described in the literature are mostly gastrointestinal and genitourinary, secondary to vasculitis and/or thrombocytopenia, but reports of cerebral hemorrhage have been extremely rare. We report a case from sub-Himalayan eastern India where a 23 years old male tea plantation worker presented with recurrent convulsions with magnetic resonance imaging (MRI) brain showing multiple parenchymal hemorrhages with encephalitis involving both the cerebral hemispheres. Although patient developed fever and acute kidney injury later in the course, these were not the presenting complaints despite fever being the most consistent sign of a scrub typhus infection. We suggest consideration of scrub typhus as a differential diagnosis of a cerebral hemorrhage in endemic regions

Atypical presentation of scrub typhus encephalitis with cerebral hemorrhage

International audienceScrub typhus, an arthropod borne infection caused by the rickettsial organism Orientia tsutsugamushi, is a fairly common disease in north-eastern sub-Himalayan India, particularly the forest areas, and is known to manifest with varied presentations ranging from non-specific fever to severe multi-organ complications. Hemorrhagic manifestations described in the literature are mostly gastrointestinal and genitourinary, secondary to vasculitis and/or thrombocytopenia, but reports of cerebral hemorrhage have been extremely rare. We report a case from sub-Himalayan eastern India where a 23 years old male tea plantation worker presented with recurrent convulsions with magnetic resonance imaging (MRI) brain showing multiple parenchymal hemorrhages with encephalitis involving both the cerebral hemispheres. Although patient developed fever and acute kidney injury later in the course, these were not the presenting complaints despite fever being the most consistent sign of a scrub typhus infection. We suggest consideration of scrub typhus as a differential diagnosis of a cerebral hemorrhage in endemic regions