Datasheet TCPP01-M12 (STMicroelectronics) - 9

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TCPP01-M12 USB charging system scalability 5.4 USB charging system scalability
Thanks to its simple implementation and system compliancy with both legacy USB charging and latest USB power delivery specification, USB-C applications using TCPP01-M12 can simply migrate from legacy USB charging (see Figure 19) to USB power delivery charging (see Figure 20) by simply swapping their STM32 from general purpose (for example: STM32L0) to general purpose + UCPD (example: STM23G0) and remove C1/C2 and add R5/R6 in the PCB to take benefit of the USB-C power delivery. Empty PCB footprints can be planned earlier in the design to allow this system scalability.
5.5 How to handle dead battery (DB) condition with the TCPP01-M12
Dead battery use case happens when a battery-operated sink (consumer or UFP) application has its battery fully depleted. In this case TCPP01-M12 enters into dead battery operation. Dead battery behavior is basically a pull down (Rd) or a voltage clamp when a USB type-C source voltage is applied to CC. It is interpreted as a request by the sink to receive VBUS. It thus facilitates the charging of equipment with a fully depleted battery: • It must be present in most cases • It must not be present in the case of a (pure) type-C Source, for example a wall charger The DB/ or 'dead battery resistor management' pin is a pulled-down active-low TCPP01-M12 input. The DB/ pin can be used in two ways: • The DB/ pin is connected to VCC or • The DB/ pin is driven by an MCU GPIO As long as the DB/ pin is low or high-impedance (an internal 5 kΩ pull-down sets the level to ‘0’), the dead-battery resistors are connected and CC switches are open (OFF state). When the DB/ pin is tied to VCC, the DB/ resistors are disconnected and CC OVP switches are closed (ON state). DB/ usage in SINK (SNK) applications: • After system power-up, the DB/ pin must be kept at 0. In this case Rd is enabled at TCPP01-M12 level. • Once Rd is enabled in the UCPD (USB-C power delivery controller), the DB/ pin must be set to the logic level '1' For DB/ usage in SRC or Source mode, the DB/ pin must be tied to VCC.
Table 8. Dead battery logic states TCPP01-M12 TCPP01-M12 TCPP01-M12 TCPP01-M12 TCPP01-M12 CC1/CC2 OVP FET VCC DB/ DB clamp present DB function state state
0 0 Yes Open Activated 0 1 Yes Open Activated 1 0 Yes Open Activated 1 1 No Closed Inactivated Note: When STM32-UCPD boots, Rd seen on CC lines are coming from TCPP01-M12. When STM32-UCPD has wake-up, Rd from TCPP01-M12 are disconnected and STM32-UCPD set Rd on CC lines from UCPD IP
DS12900
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Rev 1 page 9/25
Document Outline Cover image Product status / summary Features Applications Description 1 Pinout and functions 2 TCPP01-M12 simplified internal block diagram 3 Characteristics 4 Typical electrical characteristics curves 5 Application 5.1 General information 5.2 Electrical hazards related to USB Type-C 5.2.1 CC lines short to VBUS 5.2.2 Defective charger 5.2.3 Electrostatic discharge (ESD) 5.3 USB Type-C protection 5.4 USB charging system scalability 5.5 How to handle dead battery (DB) condition with the TCPP01-M12 5.6 Application example for USB type-C power delivery for sink (consumer), PPS compliant, without battery 5.6.1 ESD capacitor (C3) 5.6.2 CC line capacitance (C1, C2) 5.6.3 Sense resistor (R1, R2) 5.6.4 N-channel MOSFET (T1) 5.6.5 Complementary products for USB dataline protection for pins DP, DM, SSRX, SSTX 5.7 Typical USB-C battery powered application 5.8 Typical USB-C source application 5.9 Sink-source application example based on STM32G0 (with two UCPD ports) 6 PCB design recommendations 7 Package information 7.1 QFN12 package information 8 Ordering information Revision history