看数据手册6.3.5.1LDO Regulator Description这部分说明,供电小于4.5V的情况直接接到VIN,大于4.5V的情况需要接到VPWR,同时需要一个外置P-MOS(型号已在6.3.5.3External Components标出),通过LDOG连接与内部的误差放大器一起构成一个LDO,降压给VIN用。注意不论供电电源低于4.5还是高于4.5,所有SW的供电电源都是由VIN提供的。另外还可参考一下Figure 36. Typical Application Schematic,大致的原理连接都标出了,VIN*的NOTE里也做了相关说明:
Notes:*: The PF3000 can also be powered through VIN directly (ie. 3.7V Li-ion Battery application). In this case, the Front-End LDO regulator is not used : the external MOSFET has to be unpopulated and VPWR pin must be connected to GND. The capacitors on VPWR can be removed and only a 2.2uF capacitor on VIN to ground is necessary in this case.
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