Connecting Battery for Secondary Power
Thought for 2 mins 59 sec
Got it: USB-C with PD at 9 V, and a 2S Li‑Ion charger. Below are clean, simple pairings that make USB the primary source and seamlessly charge/run the system. Per best practice, size your power stages to the negotiated PD voltage/current you plan to request (e.g., 9 V), and consider headroom if you may later allow 12 V.
USB-C PD sink (standalone, fixed 9 V capable)
- STUSB4500QTR - Standalone PD sink, widely used for fixed PDOs with NVM profiles.
- CYPD3177-24LQXQ - Standalone PD sink, very simple bring-up for power-only sinks.
- AP33771 - Compact PD sink controller option.
2S Li‑Ion charger with NVDC/power-path (buck‑boost, 5–12 V input capable)
- BQ25713RSNR - 1–4S NVDC buck‑boost charge controller, I2C control.
- BQ25792RQMR - Compact NVDC charger IC option.
- MP2762A - 2S NVDC buck‑boost charger with integrated FETs.
Recommended pairs
- Easiest bring-up, compact: CYPD3177-24LQXQ + BQ25792RQMR
- Flexible, proven combo: STUSB4500QTR + BQ25713RSNR
- High-current integrated FETs: STUSB4500QTR + MP2762A
Next, tell me:
- Target charge current (e.g., 2 A) and peak system load while on USB.
- Whether 9 V is fixed forever, or you might later request 12 V.
Pick a pair and I will verify the datasheets for 9 V operation and then add the controller, charger, and minimal support parts to your project.
Pick STUSB4500 + MP2762A
Pick CYPD3177 + BQ25713
Need 2A charge, 4A load
Add parts to project
Compare AP33771 vs STUSB4500
