An 86% Efficiency, Wide-V SIMO DC-DC Converter Embedded in a Car-Radio IC

This paper presents a single-inductor-multiple-output (SIMO) dc-dc converter suitable for supplying a car-radio. From a single input, an automotive battery-supply (V bat ), the SIMO converter generates three regulated output voltages: V bat +6.5 V boost, 4.5 V buck, and 1.8 V floating around half V bat . A novel, reconfigurable power-stage is conceived and switched appropriately to generate the unique floating output among others. Regulated floating dual-slope (RFDS) drivers are proposed to limit the di/dt through the switches and to reduce the switching-noise. A continuous-time (CT) error-processor is implemented to generate the control-phases. The circuit withstands the 4-40 V range of car-battery variations and regulates in the 4.5-27 V range while remaining in the idle-state outside. The SIMO converter is embedded in a car-radio IC and fabricated in a 110-nm BCD process. The switching frequency is 2.4 MHz. The SIMO converter offers a peak power-efficiency of 86% at 2.7 W of output power and occupies an active area of 2.5 mm 2 . The operating temperature range is -40°C to +150°C. In a 4-channel car-radio, the proposed SIMO converter reduces the quiescent power-dissipation by up to 36% while having negligible effect on the audio performance.