A fast-response buck-boost DC-DC converter with constructed full-wave current sensor

A comparator-based current mode control buck-boost DC-DC converter with low transition noise full-wave current sensor is reported in this work. The proposed comparator-based current mode control method with on-time modulation eliminates the controller delay in constant on/off time period during load transient, which is adopted in a buck-boost DC-DC converter to achieve faster load transient responses. Benefited from the combination of SenseFET-based and filter-based current sensing, the proposed constructed current sensor is free from large spiking during state transition between high-side and low-side power transistor current sensing. Moreover, its dc accuracy will not drift due to the dc resistance (DCR) of the inductor as in the conventional filter-based inductor current sensor.