Reference design provides USB PD fast charging, bidirectional Type-C operation and power-path management for single-cell portable devices.
Monolithic Power Systems has developed a USB Power Delivery reference design for charging single-cell lithium-ion batteries in portable electronic devices. The design complies with USB PD 3.0 specifications and combines a high-current switching battery charger with a USB Power Delivery controller. It is intended for applications such as smartphones, tablets and other mobile devices requiring fast charging and bidirectional USB Type-C functionality.
The reference design operates from an input voltage range of 5 V to 16 V and supports common fixed USB Power Delivery voltage profiles. The charger can sustain input voltages of up to 22 V and provides a high-efficiency buck charging architecture with a maximum charging capability of 4.5 A. The design can achieve up to 18 W of USB Power Delivery fast charging and offers an efficiency of more than 90 per cent.
A bidirectional dual-role USB Type-C port is incorporated into the design. When connected to a USB power source, the port operates in charging mode to charge the battery. When a compatible USB PD sink device is connected, the system can operate as a power source and provide a 5 V USB On-The-Go output. The design supports battery discharge currents of up to 9 A, enabling the battery to supply power to connected devices.
The reference design uses narrow-voltage DC power-path management to control power delivery between the input source, battery and system load. An I²C interface allows several operating parameters to be configured, including charge voltage, charge current and input regulation settings. The system specifications list a configurable 4.2 V battery charge voltage and a 3 A charge current, while the USB On-The-Go output is regulated at approximately 5.1 V with a configurable current limit.
Protection and thermal-management features are also included to support reliable battery charging and system operation. These include configurable battery-temperature protection, thermal regulation, thermal shutdown and input and system over-voltage protection. The reference design provides engineers with a platform for evaluating USB Power Delivery charging and bidirectional Type-C power functionality in compact battery-powered products.
Monolithic Power Systems provides supporting resources and additional information for evaluating this reference design. The company’s website contains further technical details about the design and its implementation. To read more about this reference design, click here.
