Hi -
I am migrating a design from BQ24090 from TI due to the package size. I want to move down to a smaller package with a minimum of external components. The chip should charge a Li-Po battery (just one), and optionally power the system while charging.
With the TI chip I connect the system load in parallel with the battery. This is suggested on the spec sheet. However no similar reference design is printed on the freescale chargers I looked at (such as MC34673). The power comes from a USB port, if that matters. The microcontroller must know if the device is plugged into the USB port (/PPR pin provides this functionality so no problem there).
I should also specify that I have an LDO regulator downstream of the battery, so strictly speaking it's the LDO that is in parallel with the battery, and system load is powered from that (however _some_ peripherals such as motors etc. are powered directly from VBAT).
So the question is, let's say I use MC34673. I just connect EN to VIN, BAT to the regulator input, leave FAST disconnected, and connect PPR to a microcontroller input pin.
Ahia or nisch nisch?
Take a look at the FRDM-FXS-MULTI schematics here: Re: FRDM-FXS-MULTI Schematics
It pretty much does what you are requesting.