NCP1608BOOSTGEVB

NCP1608BOOSTGEVB NCP1608 100 W Boost Evaluation Board User s Manual NCP1608BOOSTGEVB Diode Bridge Diode Bridge I L I L V V V in in drain + + L L + + + V AC Line AC Line out V drain The power switch is ON The power switch is OFF With the power switch voltage being about zero, the The inductor current flows through the diode. The inductor input voltage is applied across the inductor. The induct- voltage is (V V ) and the inductor current linearly decays out in or current linearly increases with a (V /L) slope. with a (V V )/L slope. in out in Inductor (V V )/L Critical Conduction Mode: out in V /L Current in Next current cycle starts I L(peak) when the core is reset. V drain V out V in If next cycle does not start then V rings towards V drain in Figure 2. Schematic and Waveforms of an Ideal CrM Boost Converter Features of the NCP1608 The NCP1608 is an excellent controller for robust For detailed information on the operation of the medium power CrM boost PFC applications due to its NCP1608, please refer to NCP1608/D at www.onsemi.com. integrated safety features, low impedance driver, high A CrM boost pre-converter featuring the NCP1608 is precision error amplifier, and low standby current shown in Figure 3. consumption. V in L V out D N :N B ZCD LOAD R ZCD (Ballast, SMPS, etc.) V CC R NCP1608 out1 + 8 + 1 C in V FB CC C bulk EMI M 7 AC Line 2 Filter Control DRV 6 3 Ct GND R out2 5 4 CS ZCD C C COMP t R sense Figure 3. CrM Boost PFC Stage Featuring the NCP1608 The FB pin senses the boost output voltage through the A combination of resistors and capacitors connected resistor divider formed by R and R . The FB pin between the Control and ground pins forms a compensation out1 out2 includes overvoltage protection (OVP), undervoltage network that limits the bandwidth of the converter. For high protection (UVP), and floating pin protection (FPP). This PF, the bandwidth is set to less than 20 Hz. A capacitor pin is the input to the error amplifier. The output of the error connected to the Ct pin sets the maximum on time. The CS amplifier is the Control pin. pin provides cyclebycycle overcurrent protection. The