Buck-boost converter

摘要: A controller ( 10 ) for a constant frequency current-mode buck-boost converter, the converter including an inductor (L), first switch (SW 1, S 1 connected between input terminal (V in of and one end diode or (D 2 ), ground, second 2, 3 output out 4 coupled other ground. current sensor is also present sensing as measure (L) current. The comprises feedback circuit deriving signal from waveform generator 31, 32 generating buck boost slope compensation ramps (RMP-BUCK, RMP-BOOST) used improving stability operation both operating modes converter. Control logic generates drive signals during every clock period to repeatedly open close switches at individual duty cycles determined on basis signal, sensed ramps. are mutually offset with respect another time, example by 50% cycle, control uses only while closed, thus avoiding need additional circuitry.