Texas Instrument’s USB Dedicated Charging Port Controller TPS2514 is specifically designed to implement the charging schemas mentioned below. An auto-detect feature monitors USB data line voltage and automatically provides the correct electrical signatures on D+ and D– data lines. Note that the chip datasheet never mentioned Samsung or Apple in particular apparently due to the copyright issues. Instead, it mentioned 1.2V mode and different Apple charging modes as Divider 1, Divider 2 and Divider 3. There are two modifications of the chip. TPS2514 has Dividers 1 and 2 for configuration #2 and #3 when TPS2514A only Apple Divider 3 for configuration #4. Both chips support DCP and Samsung charging. Note that Divider 1 or Divider 2 is configured by flipping connection to USB data lines. In other words, it is pre-wired and there is no way do it on the fly.
The TPS2514 IC is a USB dedicated charging port (DCP) controller. An auto-detect feature monitors USB data line voltage, and automatically provides the correct electrical signatures on the data lines to charge compliant devices among the following dedicated charging schemes:
- Divider 1 DCP, required to apply 2 V and 2.7 V on the D+ and D– Lines respectively (TPS2513, TPS2514)
- Divider 2 DCP, required to apply 2.7 V and 2 V on the D+ and D– Lines respectively (TPS2513, TPS2514)
- Divider 3 DCP, required to apply 2.7 V and 2.7 V on the D+ and D– Lines respectively (TPS2513A, TPS2514A)
- BC1.2 DCP, required to short the D+ Line to the D– Line
- Chinese Telecom Standard YD/T 1591-2009 Shorted Mode, required to short the D+ Line to the D– Line
- 1.2 V on both D+ and D– Lines
With TPS2514 device implementing the USB charging adapter is simple, see the schematic below. When charging Apple devices the current is limited to 1A as it is implemented Divider 1 charging schema with D+ = 2.0 V and D− = 2.7 V. Also, try to use good quality charging cables. The one particularly bad cable I was using introduced a significant voltage drop forcing my Samsung device switching to the slow charging mode.
Read more: USB CHARGING PORT CONTROLLER USING TPS2514
