Hi,
I'm interested in clarifying what appears to be some conflicting statements in the datasheet regarding the buck converter inside the BQ24165/6/7 battery charger (literature number: SLUSAP4B).
On this chip there are three input pins that control the USB charging rate as specified in the datasheet page 17, table 1. Here it states just above the table that:
"Driving IUSB1, IUSB2, and IUSB3 all high places the bq24165/6/7 in High Impedance mode where the buck converter is shutdown regardless if an input is connected to USB or IN."
However in the pin description table on page 8 it is stated that:
"Table 1 shows the settings for these inputs. USB1, USB2 and USB3 have no effect on the IN input."
And on the description of "INPUT SOURCE CONNECTED" on page 16, it states that:
"When a source is connected to IN or USB, and the bq24165/6/7 is enabled, the buck converter starts up."
What I am trying to understand is the behaviour of the buck converter when I want to disable drawing power from the USB input but still allow drawing power from an AC/DC adapter, given one is present and functioning correctly. Table 1, seems to suggest that there are two combinations of IUSB[3..1] that will select a high impedance mode that won't draw any current from the USB supply: IUSB[3..1] = "011" and IUSB[3..1] = "111".
But it also says that setting this high impedance mode will shutdown the buck, which is also required for the AC/DC adapter input, or is it? An alternative understanding would be that IUSB[3..1] = "111" causes the buck to shutdown while IUSB[3..1] = "011" just disables the USB input...
Any clarification on these points would be excellent!
Cheers!