Integrated charge-control single-inductor dual-output (SIDO) switching converters are presented. These converters work in pseudo-continuous conduction mode (PCCM) in achieving a larger current handling capability than DCM (discontinuous conduction mode) converters while retaining a low cross-regulation. By monitoring the charges delivered to the two loads directly, charge-control converters achieve good line and load regulation, with minimized cross regulation, and automatic over-current protection. _dc...[ Read more ]

Integrated charge-control single-inductor dual-output (SIDO) switching converters are presented. These converters work in pseudo-continuous conduction mode (PCCM) in achieving a larger current handling capability than DCM (discontinuous conduction mode) converters while retaining a low cross-regulation. By monitoring the charges delivered to the two loads directly, charge-control converters achieve good line and load regulation, with minimized cross regulation, and automatic over-current protection.

An integrated charge-control SIDO non-inverting flyback converter has been implemented using a 0.35μm process. It occupied an area of 2709μmx2347μm. The switching frequency was 1MHz and the supply voltage was 1.8V. The inductor current ramps up to a predefined reference current level (I_dc) in the first clock phase and discharges to the two output nodes in two subsequent phases. The inductor current then freewheels in the last clock phase. It delivers 80mA to a first output voltage of 2.4V, and 80mA to a second output voltage of 1.6V, while achieving an efficiency of 87%. Steady state and transient measurements showed no cross-regulation between the two converters. A novel scheme of charge monitoring and feedback control was implemented that minimized the free-wheeling duration within a switching cycling, thus reducing the reference current to a lower value. Charge control was also employed in a SIDO step-up/step-down converter. This new topology eliminates one switch compared to a conventional design, and validity is verified by HSPICE simulation.