关于BQ24040/BQ24090 ISET 和ISET2管脚的使用问题 ?

芯片手册对于ISET和ISET2的描述如下:

ISET:  Programs the Fast-charge current setting. External resistor from ISET to VSS defines fast charge current value. Range is 10.8k (50mA) to 540 Ω (1000mA).

ISET2:Programming the Input/Output Current Limit for the USB or Adaptor source: High = 500mAmax, Low = ISET, FLOAT = 100mA max.

我的疑问如下:在ISET2 = HIGH时,输入/输出电流最大为500mA,这时如果设置RISET = 540 Ω (1000mA) ,ISET2已经限制了最大电流,怎么实现快速充电电流的1000mA ?