Rapidly transient response with the flexible mode and high-efficiency buck-boost converter

A novel current sensing technique with a rapidly transient and flexible mode buck-boost converter is presented. The converter can work in an appropriate mode according to the input voltage (V_IN) and inductor current (I_L), with smooth transition and flexible working modes achieved. The average current sensing (AVCS) circuit has an accurate measurement of I_L. The transient response time is also decreased. The current sensing converter is implemented in the Silterra 0.18μm COMS process. Experimental results show 95％ peak efficiency at an output current 1A with 4.2V V_IN, so that the converter can extend the battery life. The output transient with the load current altering from 0 to 2A is 6mV and the recovery time is 60μs.