A resistorless MOSFET-only current reference for energy harvesting applications

This work presents a resistorless MOSFET-only current reference on a standard $\\boldsymbol{0.13 \\mu \\mathrm{m}}$ CMOS process. The proposed architecture makes full use of subthreshold and deep triode MOSFETs to avoid the employment of any passive component. The current reference is based on the sum of proportional-to-absolute-temperature and complementary-to-absolute-temperature and a current-adder to result in a constant current. The current reference output produces an average current of 41.5 nA at 2 V of power supply, with a 0.19 ${\\mathbf{nA}/^{\\circ}\\mathrm{C}}$ for a temperature range of −10 to $\\boldsymbol{60 ^{\\circ}\\mathrm{C}}$. The temperature coefficient demonstrated seems reasonable and capable of providing bias current for other circuits within the PMC. The proposed architecture can be employed in power management circuits for energy harvesting systems and be used on wireless sensor networks and implantable medical devices.