1 to 1.8V output, 3 to 5.5V input Buck converter

STAR4001 was designed in a TSMC 65nm LP process with 5V tolerant devices used for the output stage. The block provides a stepped-down voltage of 1V - 1.9V efficiently from a wide input voltage range of 2.97V - 5.5V. The converter integrates power switches and a hysteretic controller which is used to achieve closed loop feedback control of the output voltage. This makes the buck IP quickly respond to load and line transients. As a result, dynamic behavior of the regulator is significantly improved compared to other architectures.

Several sub-components have been incorporated into the design including a digital to analog converter (DAC), digital hysteretic controller, instrumentation amplifier, clocked comparator, clocking circuit, testbus circuitry, reference generator, and master bias circuit. The behavior of STAR4001 is digitally configurable. The converter utilizes two distinct modes of operation: Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) in order to optimize efficiency based on the load requirement. Furthermore, a dedicated soft start circuit has been included to reduce stress on the input voltage supply.