A low-power wide tuning-range CMOS current-controlled oscillator

• A new current-controlled oscillator for detecting a wide current range is proposed.
• The circuit can detect and convert low currents in the range of femto-amperes.
• The math behind the circuit operation is extracted.
• It is robust against supply voltage, temperature, and process parameter variations.
• The circuit is compact, low-power, and it is compatible with technology scaling.

This paper presents a low-power, small-size, wide tuning-range, and low supply voltage CMOS current-controlled oscillator (CCO) for current converter applications. The proposed oscillator is designed and fabricated in a standard 180-nm, single-poly, six-metal CMOS technology. Experimental results show that the oscillation frequency of the CCO is tunable from 30 Hz to 970 MHz by adjusting the control current in the range of 100 fA to 10 µA, giving an overall dynamic range of over 160 dB. The operation of the circuit is nearly independent of the power supply voltage and the circuit operates at supply voltages as low as 800 mV. Also, at this voltage, with control currents in the range of sub-nano-amperes, the power consumption is about 30 nW. These features are promising in sensory and biomedical applications. The chip area is only 8.8×11.5 µm2.