Hello. I am the system engineer from the power interface product line. Today I want to introduce a new method to support a Type-C VCONN power without using an external LDO in the TPS2583x application. This is agenda for this video. It has two sessions.

In the session one, first, I will introduce the TPS2583x. Later, I will introduce the limitation of the TPS2583x type-C VCONN power. And in the end, I will introduce a method that will use the external LDO to power the VCONN. In the session two, first, I will introduce the method that use the built-in DCDC to power the VCONN. And later, I will give the design example.

This is the overview of the TPS25831. It can support up to a 36V input voltage. They integrate a 3.5A Buck Regulator with high efficiency at 400 kHz. It can support dynamic cable compensation and also supports short to battery protection on VBUS, CC1, CC2, and on D plus, D minus.

The TPS2583x integrates an internal LDO to generate the VCC for control circuitry and the MOSFET driver. You can refer to below block. The VCONN is provided over the CC pin that is not connected to the CC wire of the cable. If Ra is detected on the other CC pin, VCONN is applied to allow a current to flow from the VCC to the CC pin, which connected to the Ra.

The limitation of the internal VCONN power is the VCC only can provide the maximum five mA current to the VCONN. If under overloaded conditions, a precision current-limit circuit will limit the VCONN output current. What will happen then?

So if the VCONN overload condition is present, the TPS2583x maintains a consistent output current. Since the VCC just can provide a maximum 5 mA current, so VCONN functionality is supported only with an external 5-V supply connected to the VCC. If the device in UFP try to sink more than 5 mA current, the VCC will be pulled down to a very low voltage.

That may cause the TPS2583x VCC to reset. So the device will reset. And it can't work properly. To solve the power limitation problem of the internal VCONN source, in the applications that the VCONN need a higher power, the VCC pin can be over-driven with an external 5-V LDO, which capable of sourcing at least 300 mA. The [INAUDIBLE] below picture.

Using this solution, the external LDO is follow a special timing sequence. That is, the external VCONN power can't be enabled before the TPS2583x is enabled. So the external VCONN power must be disabled if the TPS2583x device is disabled. In the real application, customer can connect the LDO EN pin and the TPS2583x EN pin together to meet this special timing requirement.

Above solution can solve the VCONN power problem. But it needs an external LDO and some capacitors. So it's not the optimized solution.

Below will introduce a new solution that power the VCONN through the TPS2583x DCDC converter. This method can help save the BOM cost and also minimize the solution size. In this method, it needs an external P-MOSFET and use the TPS2583x /LD_DET pin to control the MOSFET ON/OFF. And I will introduce the detail of this method in next session. Thank you.