We propose a ring oscillator (RO) based current-to-voltage-to-frequency (I-V-F) converting current transducer with a cascade bias circuit. The I-V-F converting scheme guarantees highly stable biasing against RO, with a rail-to-rail output operation. This device was fabricated using National NanoFab Center (NNFC) 180 nm complementary metal-oxide-semiconductor (CMOS) technology, which achieves a current resolution of 1 nA in a measurement range up to 200 nA. A noise floor of 11.8 pA/√Hz, maximum differential nonlinearity (DNL) of 0.15 in 1 nA steps, and rail-to-rail output with a 1.8 V power supply is achieved. The proposed transducer can be effectively applied to bio-sensing devices requiring a compact area and low power consumption with a low current output. The fabricated structure can be applied to monolithic-three-dimensional integration with a bio-sensing device.

中文翻译：

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基于带有级联偏置电路的电流-电压-频率转换环形振荡器的电流测量传感器。

我们提出了一种具有级联偏置电路的基于环形振荡器（RO）的电流-电压-频率（IVF）转换电流传感器。IVF转换方案通过轨到轨输出操作确保了对RO的高度稳定偏置。该设备是使用国家纳米工厂中心（NNFC）180 nm互补金属氧化物半导体（CMOS）技术制造的，该技术在高达200 nA的测量范围内实现了1 nA的电流分辨率。噪声本底为11.8 pA /√Hz，最大差分非线性（DNL）为1 nA步长为0.15，具有1.8 V电源的轨至轨输出。提出的换能器可以有效地应用于需要紧凑的面积和低功耗，低电流输出的生物传感设备。