A Sub-10-$\mu\hbox{W}$ Digitally Controlled Oscillator Based on Hysteresis Delay Cell Topologies for WBAN Applications

Abstract

This brief presents an all digitally controlled oscillator (DCO) design with two newly proposed hysteresis delay cells (HDCs) for wireless body area network applications. According to circuit topologies, the two HDCs are defined as on-off and cascaded HDCs that provide various propagation delay values. These HDCs form a simple oscillator structure based on a power-of-2 delay stage DCO (P2-DCO) architecture. Each delay stage provides half of the delay of the previous delay stage in descending order, enabling low-power and small-area features. The P2-DCO is verified in a 90-nm CMOS technology for wide operating frequencies with area of 80 μm × 80 μm and least significant bit resolution of 2.05 ps. With a supply voltage of 1.0 V, the measured dynamic power values are 5.4 and 166 μW at 3.4 and 163.2 MHz, respectively. Index Terms-Digitally controlled oscillator (DCO), hysteresis delay cell (HDC).

A micropower biomedical signal processor for mobile healthcare applications

“…As the PLL power is usually dominated by the DCO, the power efficient hysteresis delay cells (HDC) with power-oftwo delay architecture [10] are thereby applied for DCO power reduction. These HDCs generate various delays while consuming constrained current because of the hysteresis effect.…”

A Low-Power All-Digital on-Chip CMOS Oscillator for a Wireless Sensor Node

“…To reduce redundant power consumption by the system, WSN designs usually adopt the sleep/wakeup scheme for power management [6]. However, the status change from sleep to wakeup itself consumes power.…”

A portable high-frequency digitally controlled oscillator (DCO)

“…Most of these DCOs employ one or more of the techniques illustrated in Figure 1 to change the delay. These techniques are; current-starved inverters as delay stages [1][2][3]9,12], inverters with switched shunt MOS capacitors [4][5][12][13], and multiplexors to select the number of delay stages (path selection) [1,[6][7][8][9][10][11]. The current starvation and path selection methods are seldom used on their own and are usually combined with other techniques (e.g.…”

“…The current starvation and path selection methods are seldom used on their own and are usually combined with other techniques (e.g. [1,9]). This is because current starvation has very limited range and path selection has very limited resolution.…”