An integrated high-voltage buck converter realized with a low-voltage cmos process

The mantra of the microelectronics community over the past 40 years is smaller and faster. Voltage levels powering IC chips have fallen in recent years from 3.3V to 1.0V, and sub 1.0V processes are on the near horizon. Such low voltage levels make delivering clean reliable power across circuit boards problematic. One solution is to transport power at the supply voltage across a circuit board and directly to an IC chip. Then using on chip power converters reduce the voltage magnitude to the IC´s intended process voltage. However, the transistors in the power converters would be subjected to voltages larger than they are capable of supporting. Special high voltage transistors can be used but they require extra manufacturing steps and masks which are expensive. The Stacked MOSFET is a circuit consisting of several MOSFETs designed to evenly share a large voltage. This paper will show the Stacked MOSFET and its implementation into two buck converters in two different IC processes. Simulation results will be presented showing the feasibility of this solution.