I. Introduction
Due to efficiency, high quality solid-state lighting requires multi-color LED drivers. To achieve a small and cost efficient solution for these applications the single-inductor multiple-output (SIMO) LED driver has been developed [1]. This architecture depicted in Fig. 1 requires only a single inductor and no output capacitors for driving four LED strings of different forward voltages. Therefore, one high-side (HS) 5 V gate-oxide transistor M0 for charging the inductor and four low-side (LS) 20 V gate-oxide transistors which select the active LED string have to be controlled individually. Hence, in total five gate drivers are required which have to be very area efficient to keep the size of the whole ASIC as small as possible. In addition, the SIMO LED driver consists of a high-side shunt current sensing circuit and a digital current and color control.