A Novel Start-Up Technique for Time-Based Boost Converters with Seamless PFM/PWM Transition

Time-based techniques are proven to reduce the area of the compensation networks of DC-DC converters when compared to their voltage mode counterparts. To maximize the converter efficiency both at heavy and light load, the converter controller also needs to seamlessly switch from a PWM to a PFM control. While buck converters are inherently stable during start-up, boost converters might enter a latched-up state and thus require a dedicated start-up controller, which often makes use of bulky components increasing the overall area. To overcome this issue, we present a start-up mechanism for time-based boost converters. The proposed solution makes use of the time-based feedback loop and seamless PFM/PWM transition circuit to implement the start-up functionality without requiring any extra circuitry or off-chip components.