Solid-state switch driven by thermovoltaic generator

Abstract

This invention relates to a high-transimpedance solid-state switch manufactured by micromachining technology. A thermopile is formed by a thin-film structure capable of producing sufficient thermoelectrical voltage to drive a MOS transistor on and off, functioning like a switch. The driving thermoelectric voltage is generated by Joule's heat released by a thin-film heater disposed nearby a thermopile hot junction to generate a substantial temperature difference related to its cold junction. These elements can be monolithically integrated, wherein the heater and hot junctions are disposed on a thermal pad formed by micromachining having high thermal isolation. This invention has the following advantages: 1) the input and output ends are thermally coupled, thus are electrically isolated (very high transimpedance), therefore a small input power is able to control the MOS device having high output voltage and power; 2) the solid-state switch is a micromachined monolithic structure which is batch-producible, rather than the single-unit production for traditional mechanical switch; 3) when the present switch is ON/OFF, it is unnecessary to employ the charge leakage circuit essential for the current 'photoelectric-coupling MOS solid state switch', therefore the chip area is reducible; 4) the input of the switch for driving the heater can be designed to be high or low, AC or DC voltage, according to the necessity; 5) package of this invention may utilize the standard 'dual-in-line' structure, which is simpler and less costly compared with the photo-coupled switch whose package is 3-dimensional.