Hi Dear,
May I ask if TI has a solution where a single boost chip can achieve positive and negative output?
For example, with a 4.2V input and a 5V output obtained through a boost chip, can negative 5V be obtained by adding some capacitor isolation or other discrete components after 5V?
Hi Anna,
Our solution is to build a charge pump circuit using the boost switch. The circuit is depicted in the figure below.
The circuit works like this:
1.During Toff, the high voltage on SW pin will charge the fly capacitor CCHG through the RCHG and D2. Meanwhile Cout2 supply the load.
2.During Ton, Cchg charges COUT2 negatively through RCHG and D3.
For more details about this design, you can check the application note below:
Best Regards,
Travis
