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TPD2S300

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SLVSDL1 – APRIL 2017

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Table 6. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

20 V

24 V

VBIAS nominal capacitance

0.1 µF

Dead battery charging

100 W

TPD2S300 VPWR power source

3.3-V LDO from TPS65987

TPD2S300 VM power source

3S or 4S Battery

Maximum ambient temperature requirement

85°C

8.2.2.2 Detailed Design Procedure

8.2.2.2.1

VBIAS Capacitor Selection

This VBIAS capacitor requirements for this application are identical to the Smart-Phone application; see the

VBIAS Capacitor Selection section for more details.

8.2.2.2.2

Dead Battery Operation

For this application, we want to support 100-W dead battery operation; when the laptop is out of battery, we still

want to charge the laptop at 20 V and 5 A. This means that the USB PD Controller must receive power in dead

dead battery condition. The TPS65987 can also provide power to its flash during this condition through its

LDO_3V3 pin.

The TPD2S300s OVP FETs remain OFF when it is unpowered in order to insure in a dead battery situation

proper protection is still provided to the PD controller in the system, in this case the TPS65987. However, when

the OVP FETs are OFF, this isolates the TPS65987's dead battery resistors from the USB Type-C ports CC pins.

connector's CC pins, the TPD2S300 integrates dead battery resistors on its C_CCx pins, and exposes them

when the device is unpowered.

provides power to the TPS65987, turning the PD controller on, and allowing the battery to begin to charge.

USB PD negotiation is required to accomplish this, so the TPS65987 needs to be able to communicate on the

CC pins. This means the TPD2S300 needs to be turned on in dead battery mode as well so the TPD65987's PD

controller can be exposed to the CC lines. To accomplish this, it is critical that the TPD2S300 is powered by the

TPD2S300 is turned on simultaneously. Additionally, for low resistance VCONN support, the VM pin needs to be

connected to the 3S battery, so TPD2S300 needs to be able to receive this voltage in the dead battery condition

as well.

It is critical that the TPS65987's dead battery resistors are present; once the TPD2S300 receives power,

line in order to guarantee the power adaptor stays connected. If RD is not present and the voltage on CC

Also, it is important that the TPS65987's dead battery resistors are present so it properly boots up in dead

battery operation with the correct voltages on its CC pins.

Once this process has occurred, the TPS65987 can start negotiating with the power adaptor through USB PD for

higher power levels, allowing 100-W operation in dead battery mode.

For more information on the TPD2S300 dead battery operation, see the CC Dead Battery Resistors Integrated

for Handling Dead Battery Use Case in Mobile Devices section in the description section of the datasheet. Also,

see Figure 22 for a waveform of the CC line when the TPD2S300 is turning on and exposing the TPS65987's

dead battery resistors to the USB Type-C connector.