The TCPP01-M12 protects USB Type-CTM ports against over-voltage on VBUS and CC lines as well as electrostatic discharges on the connector pins, among other things. TCPP stands for Type-C Port Protection, and the TCPP01-M12 is unique because it works as a companion chip for our STM32 MCUs with built-in USB-C Power Delivery (UCPD) controllers on sink configurations. Moreover, using an STM32G0, STM32G4, or an STM32L5, and the TCPP01-M12 is significantly more cost-effective than competing solutions. The TCPP01-M12 also distinguishes itself thanks to a null quiescent current when unplugged and using the device in a sink configuration. However, the ST component is polyvalent, and it is possible to use it in a product that acts as a source as long as engineers add a few discrete components.
TCPP01-M12: Why USB-C Needs Protection and How the Industry Deals with this Challenge
The press1 hailed 2019 as the year when USB-C reached critical adoption, which means that consumers can more easily encounter poor quality chargers that don’t control their voltage as precisely as they should. For example, if a sink device (charging) requests only 5 V, but a source product (charger) remains at 20 V, due to a hardware or software defects, the product receiving the charge without adequate protection could suffer severe damages on its VBUS line. Engineers must also guard against electrostatic discharges or electrical overstresses that can damage the internal circuitry. Moreover, since the USB Type-C connector is so small, it’s essential to protect it against a possible short between the CC and VBUS lines, which could damage the USB controller.
Until now, it was common to find the protection circuit inside a controller dedicated to USB-C Power Delivery. However, by supporting USB-C PD with an embedded module inside an MCU and a companion Type-C port protection device, we can lower the bill of material and facilitate the transition from micro-B devices, without requiring an expensive USB-C PD ASIC controller. One of the reasons the MCU and TCPP01-M12 bundle is such a compelling financial proposition is that the latter device integrates the VBUS gate driver, which enables the use of more affordable N-MOSFET, instead of the more expensive P-MOSFET.
TCPP01-M12: What Protects the USB-C Port and What Mechanisms Improve Efficiency
Another advantage of using the TCPP01-M12 with a microcontroller that embarks a Power Delivery controller is that it offers a flexible architecture. Engineers can separate the low voltage MCU domain and high voltage power path and benefit from all the protections needed. Additionally, the QFN12 package of the TCPP01-M12 can sit really close to the USB Type-C connector itself to maximize protection. Similarly, the fact that the device is compliant with programmable power supplies means that the sink device starts at 3.3. V and increases its request voltage by 20 mV increments until it matches the characteristics of the battery, thus offering quick charging capabilities while safeguarding the system.
The TCPP01-M12 also improves the overall efficiency, compared to competing solutions, by offering a low RDSon and a null quiescent current. The last feature is possible because the device receives power from the GPIO pin of the MCU rather than an internal low-dropout regulator. As a result, when the user unplugs a cable, the TCPP01-M12 doesn’t consume any energy at all. The is particularly crucial for companies looking to create tiny products with particularly small batteries, and that must thus limit the system’s consumption as much as possible. Many engineers may underestimate it, but when a product is as little as a pen, every microamp counts.
Serving the Industry with a Better Approach to USB-C PD
Until now, the USB-C PD standard was extremely demanding. Engineers had to review half a thousand pages to understand the protocol, and teams had to do almost everything from scratch. However, ST will now include the TCPP01-M12 on all its new development boards with a USB-C port, and designers can get our schematics to reuse them in their design. We are also inaugurating the arrival of the X-Nucleo-USBPDM1, a Nucleo expansion board that features the TCPP01-M12, and a load switch that enables the creation of a sink PPS USB-C Power Delivery application of up to 100 W when associated with the NUCLEO-G071RB or the NUCLEO-G474RE development boards.
The device is present on the NUCLEO-L552ZE-Q that features an ultra-low-power STM32L552ZE and a Type-C connector on sink mode. The TCPP01-M12 uses a QFN12 package with a 500 µm pitch, which remains more common for PCB assembly and thus more accessible. We even offer an application note to guide engineers looking to build a prototype with our Nucleo boards, STM32CubeMX, and STM32CubeMonUCPD.
