I am developing a product powered by a LiPoly battery. If the battery is allowed to discharge too far, the protection circuit turns off access to the battery (@2.5V). It takes raising the battery terminals to >3.4V for the protection circuit to turn the battery back on and allow charging. The product has a small micro/radio/audio circuitry powered by the battery which draws no more than about 20mA during normal operation.
The BQ21040 is programmed to charge at 75mA. There is a load switch on the product that is enabled by the charger voltage when the product is plugged into the charger. This switch prevents the battery voltage in the product from being persistently applied to the battery charge terminal.
My problem seems to be that when the battery protection circuit is opened up and I plug the product into the charger, the charger can not/does not bring the battery terminal up enough in voltage to enable the connection in the protection circuit and thereby allow the battery to begin charging. About every 3 seconds, it looks like the BQ21040 tries 8 times in rapid succession to start up the battery charging.
Any suggestions? Is there something else you need to know in order to formulate a solution?