Power Management (PMU) Circuit
The aim of "Power Management (PMU) Circuit for Micro-power Thermoelectric Generators (TEG) with Low Voltage Startup" project is to develop efficient ultra-low-voltage PMU working for TEG input voltages as low as 200mV is proposed. Such PMU can be conceptually divided into two sections: The first is the startup block comprising an exponential-gain charge pump as well as a low-power BGR and voltage comparator that serve as a load to the pump. The second section is the PMU core charging a buffer (super-capacitor) employing a main DC/DC converter, which consists of a cascade of two Dickson-based charge pumps with a variable conversion factor and switching frequency. Feedback is provided from the load buffer by means of a current sensor to a control unit that employs a Maximum Power Point Tracking (MPPT) algorithm so as to maximize the overall power transfer efficiency at low input voltages. System simulation results demonstrate peak efficiency greater than 70% with a controller current consumption less than 2μA. The PMU core was designed and fabricated using a UMC CMOS 180nm process.