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TPS254900A-Q1 Datasheet(PDF) 20 Page - Texas Instruments |
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TPS254900A-Q1 Datasheet(HTML) 20 Page - Texas Instruments |
20 / 39 page ![]() 20 TPS254900A-Q1 SLUSCU5A – NOVEMBER 2017 – REVISED JANUARY 2018 www.ti.com Product Folder Links: TPS254900A-Q1 Submit Documentation Feedback Copyright © 2017–2018, Texas Instruments Incorporated The TPS254900A-Q1 device has two OVP thresholds; one is 6 V (typical) and the other is 6.95 V (typical). Set the OVP threshold using the external OVP_SEL pin. 8.3.5 Output and D+ or D– Discharge To allow a charging port to renegotiate current with a portable device, the TPS254900A-Q1 device uses the OUT discharge function. During mode change, the TPS254900A-Q1 device turns off the power switch while discharging OUT with a 500- Ω resistance, then turning back on the power switches to reassert the OUT voltage. When an OVP condition occurs on DP_IN or DM_IN, the TPS254900A-Q1 device enables an internal 200-k Ω discharge resistance from DP_IN to ground and from DM_IN to ground. The analog switches are also turned off. The TPS254900A-Q1 device automatically disables the discharge paths and turns on the analog switches once the OVP condition is removed. When an OVP condition occurs on OUT, the TPS254900A-Q1 device turns on an internal discharge path (see Table 2 for the discharge resistance). The TPS254900A-Q1 device automatically turns off the discharge path and turns on the power switch once the OVP condition is removed. (1) 0 = inactive, 1 = active (2) — = no discharge resistance Table 2. OUT Discharge Resistance VIN(1) EN(1) OVP(1) OUT DISCHARGE RESISTANCE(2) 0 0 0 — 0 0 1 80 k Ω 0 1 0 — 0 1 1 80 k Ω 1 0 0 500 Ω 1 0 1 500 Ω or 55 kΩ 1 1 0 — 1 1 1 55 k Ω 8.3.6 Port Power Management (PPM) PPM is the intelligent and dynamic allocation of power. PPM is for systems that have multiple charging ports but cannot power them all simultaneously. 8.3.6.1 Benefits of PPM The benefits of PPM include the following: • Delivers better user experience • Prevents overloading of system power supply • Allows for dynamic power limits based on system state • Allows every port potentially to be a high-power charging port • Allows for smaller power-supply capacity because loading is controlled 8.3.6.2 PPM Details All ports are allowed to broadcast high-current charging. The current limit is based on ILIM_HI. The system monitors the STATUS pin to see when high-current loads are present. Once the allowed number of ports asserts STATUS, the remaining ports are toggled to a non-charging port. The current limit of the non-charging port is based on the ILIM_LO setting. The non-charging ports are automatically toggled back to charging ports when a charging port deasserts STATUS. STATUS asserts in a charging port when the load current is above ILIM_LO + 30 mA for 210 ms (typical). STATUS deasserts in a charging port when the load current is below ILIM_LO – 20 mA for 3 seconds (typical). |
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