An UltraLow Power CyclebyCycle Current Limiter Suitable for SwitchingMode Power Supply with 2.2 MHz Frequency A high performance, low power cyclebycycle current limiter is proposed in this paper, which can prevent switchingmode power supply from damage under over current or short circuit conditions. With the clamping effect formed by feedback loop with operational amplifier, the output current can be proportionally sampled and transferred to a voltage relative to ground. In order to further reduce power consumption, the sampling loop with low bias current is only enabled during the on time of highside transistors. Besides, an assistant clamping circuit is presented to accelerate the settling time of every cycle for highspeed applications. Whatu0027s more, a sourceinput comparator with voltage clamper is adopted to judge the status of output current, which can realize reference level and comparison at the same time for further speed improvement with lower power requirement. The proposed current limiter is implemented in a standard 0.18xc2xb5m CMOS process, whose verification results within a 3A, 2.2MHz Buck converter show that a 39ns response time with 8.6MHz bandwidth is realized with only 2xc2xb5A onstate and zero offstate current consumption.

Digital Low Power Mode Control Technique for HighFrequency Synchronous DCDC Buck Converters This paper presents a low power mode control technique for digitally controlled synchronous buck converters optimized for the heavy load regulation. The proposed control mode achieves compact area and low complexity thanks to an efficient logic partitioning and reuse of the digital controller. The inductor peak current is controlled with a predictive algorithm that does not require current sensing. A prototype of a digitally controlled synchronous 5xe2x80x940.9 V, 1.5 A buck DCDC converter that embeds the low power control technique is implemented. A custom IC in a 28nm CMOS process has been designed for the digital controller and the gate drivers. Experimental results indicate that the high efficiency range is extended, obtaining an efficiency improvement up to 43% at light load.