Low-power CMOS current-conveyor relaxation oscillators

CMOS implementation of low-power oscillators based on the modified Fabre-Normand current conveyor

“…Analysis of this circuit reveals that the real part of the roots of the system's characteristic equation is always positive and large, approximately equal to lRrnl/Lp~ [3], ensuring reliable and quick build-up of oscillations. To provide low-voltage, low-power operation, we replaced improved Wilson with simple current mirrors without affecting the circuit functionality [7]: The RC oscillator with modified Fabre-Normand circuit is shown in Figure 3. The timing capacitor C may be replaced with a quartz crystal unit to create a crystal oscillator.…”

“…The timing capacitor C may be replaced with a quartz crystal unit to create a crystal oscillator. Detailed analysis of RC and crystal oscillators realized with the Fabre-Normand circuit is given in [7].…”

“…In general, when the operating voltage is lowered, the problem of the start-up of oscillations can be aggravated [SI. However, the circuits reported in [7] have a reliable start-up even with very low supply voltages, since the oscillations startup is based on negative resistance. This paper presents the circuit design and measured performance of oscillators based on both original or modified Fabre-Normand current conveyors that were originally described in [7].…”

“…Maximum operating frequency was 103MHz and the required supply voltage was 2.7-6V. We modified the original Fabre-Normand current conveyor for low-voltage, low-power operation [7]. In general, when the operating voltage is lowered, the problem of the start-up of oscillations can be aggravated [SI.…”