ok turns out - from what i am reading of the datasheets - that the bq24193 can cope with running from 3.3v, it looks like it doesn't mind: the limit of the I2C and other pins is 6V.

the bq27542 is a different matter (i thought it was 1.8v, it's not: it's 2.5v).  it has its own 2.5v LDO on-board but the maximum input voltage is 2.5v for its I2C and HDQ (status / IRQ pin).  sooo what i've done is, connect the 2.5v output (REG25) to the level-shifter, and the other side to VREFTTL.

i updated the schematics pdfs.

l.

arm-netbook mailing list arm-netbook@lists.phcomp.co.uk
http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook
Send large attachments to arm-netbook@files.phcomp.co.uk