XTPS55285VALR datasheet(13/45 Pages) TI1

13 / 45 page

6.3 Feature Description

6.3.1 VCC Power Supply

An internal LDO to supply the TPS55285 outputs regulated 5.2V voltage at the VCC pin. When VIN is less than

VOUT, the internal LDO selects the power supply source by comparing VIN to a rising threshold of 6.2V with 0.3V

hysteresis. When VIN is higher than 6.2V, the supply for LDO is VIN. When VIN is lower than 5.9V, the supply for

LDO is VOUT. When VOUT is less than VIN, the internal LDO selects the power supply source by comparing VOUT

to a rising threshold of 6.2V with 0.3V hysteresis. When VOUT is higher than 6.2V, the supply for LDO is VOUT.

When VOUT is lower than 5.9V, the supply for LDO is VIN. Table 6-1 shows the supply source selection for the

internal LDO.

Table 6-1. VCC Power Supply Logic

VIN

VOUT

INPUT for VCC LDO

VIN > 6.2V

VOUT > VIN

VIN

VIN < 5.9V

VOUT > VIN

VOUT

VIN > VOUT

VOUT > 6.2V

VOUT

VIN > VOUT

VOUT < 5.9V

VIN

6.3.2 Default Output Enable(OE) bit Status

By placing different resistors between the MODE pin and the AGND pin, the TPS55285 selects default Output

Enable (OE) bit value. Output Enable (OE) bit is logic bit to control device output in 06H register.

If default Output Enable (OE) bit is set to 0, when VIN and EN/UVLO pins exceed UVLO threshold, the device

doesn't switch until Output Enable (OE) bit is set to 1 in 06H register.

If default Output Enable (OE) bit is set to 1, the FB bit in 04H register is also set to 1 automatically to select

external feedback network. Once VIN and EN/UVLO pins exceed UVLO threshold, the device starts switching

with 282mV VREF. External feedback resistors is needed in this case.

Table 6-2. I2C Target Address and Default OE bit

Resistor Value (kΩ)

I2C TARGET ADDRESS

DEFAULT OUTPUT ENABLE (OE)

BIT

75H

24.9

75H

6.3.3 Input Undervoltage Lockout

When the input voltage is below 2.4V, the TPS55285 is disabled. When the input voltage is above 3V, the

TPS55285 can be enabled by pulling the EN pin to a high voltage above 1.3V.

www.ti.com

TPS55285

SLVSI72 – FEBRUARY 2025

Submit Document Feedback

Product Folder Links: TPS55285

XTPS55285VALR Datasheet(PDF) 13 Page - Texas Instruments

XTPS55285VALR Datasheet(HTML) 13 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Datasheet Download

Link URL