This paper presents a new system approach to an on-chip voltage source based on integrated thermoelectric generator (TEG) elements. The proposed architecture employs a novel active TEG array (ATA) system. The ATA system is able to control the TEG's harvested electrical energy, without using a DC/DC integrated converter. This makes it possible to cut power losses due to the non-ideality of the converter efficiency and to reduce the chip area. Commonly, the reduced efficiency of DC/DC converters was compensated for by adding TEG elements, thus enlarging the chip area. The proposed novel approach to designing an energy harvesting integrated voltage source was implemented to support ultra-low power systems for biomedical applications such as wearable wireless body sensors. The voltage source was simulated in a 0.18 ¿m standard CMOS process, supplying 1.8V±0.18V. The simulation results are presented.