Other Parts Discussed in Thread: LM2576
We are using BQ24075 in our design. We use 950mAh battery in our design.
This battery acts as a backup in case the mains 12 volts power is cut by user. BQ24075 is always ON with supplied external power input. We use 12v to 4.5 DC-Dc converter LM2576 to provide input power to the device and hence BQ24075.
We choose BQ24075 in our design due to its ability to manage power paths efficiently however we are unable to see that working.
Here are our observations.
1. If we disconnect the main power of device (IN of BQ24075) when the battery is fully charged, then the device works flawlessly till the battery dies down completely(6 hours approx)
2. After the battery is fully drained and the device is fully off, if we connect the supply again (IN of BQ24075) the battery charging starts.
The battery voltage starts increasing from 3.3v to 4.17 or 4.19v.
3. We expect the device to turn on when the battery voltage reaches 4 volts or higher. But the device never gets full power.
4. Our device requires 2A max peak current and hence a battery supplement mode is necessary either when using USB charging or 12V charging.
But the switch-over from charging to Battery or capacity to provide enought current is not seen until we disconnect the main power. That means the main supply needs to be manually disconnected from the BQ24075.
Can you please let us know what could be the issue in switching the DPPM mode or providing enough current to the load ?
