Battery Charger Solutions for 100W Multi-Source Power Systems

In 100W class portable applications, the adoption of multi-source power inputs continues to grow. How can charging architectures balance efficiency and stability while managing multiple inputs, dynamic load variations, and real time system control?

1. Multiple input sources

Systems may support USB-C PD, AC adapters, and 2 to 4 cell battery packs simultaneously. Wide voltage variation requires a flexible buck-boost topology to ensure seamless power delivery.

2. Stable power under dynamic load

During input drop or load spikes, voltage droop is a key risk. NVDC power path enables instant battery support to keep the system stable.

3. Real time system control

To enable real time control, the MCU requires visibility of charging and power status. An SMBus interface reports key parameters for accurate monitoring and control.

To address these challenges, Richtek introduces the RT9478 / RT9478M 4 switch bi-directional buck-boost NVDC battery charger controllers, delivering

✅ High efficiency with low standby consumption

Up to 97% efficiency in Buck mode with 18µA low battery quiescent current to extend battery life.

✅ Flexible protection configuration

Multiple VSYS OVP settings minimize false triggering in 4 cell battery applications, enhancing overall system reliability.

✅ Optimized design flexibility

Supports 1.2MHz, 800kHz, and 720kHz operation. Lower frequency improves efficiency, while higher frequency reduces inductor size for greater design flexibility.