Multi-level power-domain voltage regulation

Abstract

An integrated circuit has at least two power domains. A first power domain has circuitry coupled between a first power supply terminal and a second power supply terminal. A second power domain has circuitry coupled between a third power supply terminal and a fourth power supply terminal. A complementary voltage regulator includes N-type and P-type voltage regulators. The N-type voltage regulator is coupled between the first and third power supply terminals and controls a first voltage level at the second power supply terminal. The P-type voltage regulator is coupled between the third and fourth power supply terminals and controls a second voltage level at the third power supply terminal. The N-type voltage regulator produces a mid-level supply voltage to the P-type regulator and a 'ground' for the circuits in the first power domain. The P-type regulator circuit produces a 'ground' for the N-type regulator and a mid-level supply voltage for the circuits in the second power-domain. Thus, a current consumed by the first power-domain is reused in the second power domain, thus enhancing power efficiency.