Provides USB Type-C® port chip solutions for lithium battery-powered devices

1 Introduction

USB Type-C® ports with USB Power Delivery (PD) are now becoming the standard port for charging single-cell and multi-cell battery-powered devices.

Applications such as wireless speakers, power banks , and power tools have transitioned from proprietary charging ports, traditional USB ports, and barrel jack ports to standardized USB PD ports.

USB PD provides a versatile alternative for fast and convenient charging that eliminates the need for users to carry multiple adapters or cables around - helping design engineers create smaller applications that charge faster and with fewer components.

As these applications become more feature-rich, compact, and power-hungry, there is a need to deliver more power in smaller solution sizes. At the same time, consumers are starting to expect USB Type-C on their new devices . However, implementing USB PD ports has historically been challenging for product developers.

2. Simplify the design solution

In the past, adding a USB PD port required a deep understanding of the USB specification and extensive firmware and hardware development. Several different components need to work together to facilitate USB PD support.

The two main integrated circuits (ICs) required to complete a USB PD port for charging applications are the USB PD controller IC and the battery charger IC. These ICs typically operate independently of each other and cannot work in the system without significant involvement of an external microcontroller (MCU).

This limitation also requires MCU firmware development to communicate events occurring on the USB PD port to the battery charger IC. For example, once the USB PD controller IC negotiates the new voltage and current on the USB Type-C port (or a new power contract), the microcontroller needs to read this information back from the USB PD controller and then update the battery charger's charge Current and charging voltage are based on what is connected to the USB PD port. Additionally, powering external devices from the USB PD port requires additional communication between the USB PD controller, MCU, and battery charger.

Programming the MCU to interface between the USB PD controller and the battery charger is typically not the only firmware development required when adding a USB PD. A typical PD controller IC requires some form of firmware development to configure the PD controller behavior itself, such as compiling some code or scripting functionality together. The USB PD controller must be configured to ensure that the settings on the PD controller meet your system requirements, including what voltages and currents the system can sink and what voltages and currents it can source.

3. Design using TI controllers and chargers

To help simplify the design of USB PD ports for battery-powered applications up to 45 W, the TPS25750 USB PD controller adds I 2 C host support to directly control the BQ25792 battery charger without any intervention from an external MCU. The TPS25750 USB PD controller will automatically update the charging parameters of the BQ25792 through I 2 C based on the power negotiation on the USB PD port. Therefore, no external MCU is now required and you can add a USB PD port to battery-powered applications without developing firmware.

Configuring USB PD port behavior using the TPS25750's web-based graphical user interface (GUI) requires answering a few multiple-choice questions about what your USB PD port needs to support—no complex scripting, code compilation, or firmware development required. Not only does this reduce bill of materials costs; it allows you to add USB PD without having in-depth expertise about the technology.

The TPS25750 and BQ25792 integrate all power paths required for the battery charger and USB PD controller. Figure 1 highlights how these devices simplify the implementation of USB PD ports for battery-powered systems up to 45 W. When these two ICs are used together, the USB PD port will be able to support bidirectional power supply, providing source power and sinking power, thus enabling the system to receive power from the USB port when connected to an external device such as a laptop, smartphone, headset, or AC adapter. PD port charging or charging.

In addition to these system implementation benefits, the TPS25750D and BQ25792 integrate all of the system's field-effect transistors (FETs), eliminating the need for an external MCU, allowing you to achieve very small solution sizes. Compared to non-integrated MCU-based USB PD battery charging implementations, the typical system solution size is approximately 150 mm 2 . When using the TPS2570 and BQ25792, a system solution size of approximately 55 mm2 can be achieved .

Figure 1: TPS25750D and BQ25792 USB PD battery charger implementation

Figure 2 highlights an MCU-based USB PD controller and battery charger with external FETs for applications requiring high power charging and system power typically greater than 45 W. For applications greater than 45 W, consider pairing the TPS25750 controller with the BQ25731 charger.

Figure 2: MCU-based non-integrated solution

Table 1 compares USB PD charging between integrated and non-integrated MCU based solutions.

Table 1: Comparison of integrated and non-integrated USB PD battery charger implementations

The trend of using USB PD for charging has gained more urgency recently as regulations drive the emergence of universal chargers . Updating your system to charge from USB PD is now easier than ever with the TPS25750 and BQ25792, allowing you to migrate to the latest universal charging connectors without compromising solution size.