JAJSJH4D december 2010 – september 2020 BQ24133
PRODUCTION DATA
N-type MOSFETs are used as input ACFET(Q1) and RBFET(Q2) for better cost-effective and small-size solution, as shown in Figure 22. Normally, there is a total capacitance of 50 µH connected at PVCC node: 10-µF capacitor for buck converter of BQ24133 and 40-µF capacitor for system side. There is a surge current during Q1 turnon period when a valid adapter is inserted. Decreasing the turnon speed of Q1 can limit this surge current in desirable range by selecting a MOSFET with relative bigger CGD and/or CGS. If Q1 turns on too fast, we must add external CGD and/or CGS. For example, 4.7-nF CGD and 47-nF CGS are adopted on EVM while using NexFET CSD17313 as Q1.