XCL303/XCL304 Series ■OPERATIONAL EXPLANATION This IC consists of a standard voltage reference, error amp, ramp wave circuit, oscillator circuit, PWM comparator, PWM/PFM controller, Pch driver transistor, current sensing circuit, UVLO circuit, VREF startup circuit and etc. Control method is a current mode control method which allows for the use of low ESR ceramic capacitors. L1 L2 Inductor AVDD Phase Current Sense PVDD FB Compensation Current Limiter AVDD Error Amp PWM Comparator - VREF - PWM/PFM Buffer VREF VIN start up + Controller Logic Driver Controller + Each L X Circuit CE CE Controller Logic RAMP Wave Oscillator Generatar PVDD AVDD VIN UVLO GND XCL303/XCL304 Series block diagram 8/24
