A 280nW, 100kHz, 1-cycle start-up time, on-chip CMOS relaxation oscillator employing a feedforward period control scheme

A 70 MHz Temperature-Compensated On-Chip CMOS Relaxation Oscillator for Mobile Display Driver ICs

“…Several onchip oscillators have been investigated as alternative solutions [1][2][3]. A relaxation oscillator with bandgap reference (BGR) generates a stable frequency using a voltage and current reference circuit [2].…”

“…In [1], a voltage averaging feedback constantly maintains the oscillation frequency by adjusting the control signal but requires a long start-up time due to the feedback operation. A relaxation oscillator with a feedforward period controller in [3] achieves a short start-up time of one cycle period, which is suitable for intermittent operation systems, but generates a low frequency of 100 kHz. In addition, the feedforward period controller may increase the power dissipation needed to generate a frequency of tens of megahertz due to several power-consuming circuits, which include two comparators, an RS-F/F, and initial level generator, and a replica slew rate generator.…”

“…The proposed oscillator compensates for frequency variation with respect to temperature by adjusting the bias currents to control the change in delay of comparators with temperature. A BGR is used to stabilize the bias currents with respect to temperature and supply voltages, and a short start-up time is accomplished by using the stable bias currents [3]. Additional temperature compensation for the generated frequency is achieved by optimizing the resistance in the BGR after measuring the output frequency.…”

High-Robust Relaxation Oscillator with Frequency Synthesis Feature for FM-UWB Transmitters

“…The existing oscillators [11][12][13] with good PVT robustness have large power dissipation in comparison to low oscillation frequency, which causes poor figure of merit (FOM) values. The existing oscillator [14] encounters slight f OSC shift under power supply variations. Although these oscillators have better PVT feature than those [3][4][5][6], they either could not generate the desired triangular waveforms, or have no the frequency synthesis (FS) function, namely, f OSC is not linearly tuned by a digital control signal.…”

A low power low supply sensitivity current-mode relaxation oscillator

“…Ring oscillators [5] are considerably accurate, but consume several hundred microwatts. Relaxation oscillators [3,6,7,8,9] can achieve good temperature performance while operate at lower power, which is extremely suitable for low power applications.…”