The Si9139 is current-mode PWM and PSM converter controller, with two high current, high efficiency synchronous buck controllers and an adjustable buck-boost controller whose output can be set between 1.24 V and 20 V with an external resistor divider. Designed for fixed and portable devices, it offers a total of five power outputs (three tightly regulated dc/dc converter outputs, a precision 3.3-V reference and a 5-V LDO output. Individually controlled power-up sequencing, power-good signal with delay, internal frequency