This paper presents a self-startup power management IC (PMIC) applicable in thermoelectric generators (TEGs). The PMIC is based on a boost converter integrated with a complete control circuitry that handles all required operations, including maximum power point tracking (MPPT). The converter supports cold self-start from low TEG voltages using three startup phases and two power-on-reset (POR) signals for smooth transitions between the phases. The PMIC is designed and fabricated in a 180-nm technology. The cold-start operation is verified at a minimum TEG voltage of 60 mV. The converter achieves a peak efficiency of 79.94% at 120-mV input voltage and 1080 mu W output power, while maintaining efficiency above 70% for a wide range of TEG voltage from 80 mV.