PIMB063T-R68MS-63 datasheet(16/29 Pages) TI1

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TPS51362

SLUSBB6A – FEBRUARY 2013 – REVISED JUNE 2013

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Out-of-Bounds Operation (OOB)

When the output voltage rises to 8% above the target value, the out-of-bound operation starts. During the OOB

operation, the controller operates in forced PWM-only mode by turning on low side FET. Turning on the low side

FET beyond the zero inductor current can quickly discharge the output capacitor thus causing VOUT to fall quickly

towards setpoint. During the operation, the cycle by cycle negative current limit is also activated to ensure the

safe operation of the internal FETs.

Overvoltage Profection (OVP) and Undervoltage Protection (UVP)

When the output voltage rises to a level 20% (typ) higher than the setpoint voltage, an overvoltage condition is

present. When a 0-V event is detected, the converter turns off the high side FET and turns on the low side FET.

The operation continues until the cycle by cycle negative current limit is reached and low side FET is turned off

and high side FET is turned on, for a minimum on-time. After the minimum on-time expires, the high side FET is

driven off and low side FET is driven on again until negative current limit is reached or VOUT is discharged to 0 V.

When the VOUT is discharged to 0 V, both high-side and low-side FETs are latched off. An OVP fault requires the

V5IN voltage to fall below POR threshold or EN reset to clear.

Undervoltage Protection (UVP)

The undervoltage protection (UVP) is set when the VOUT voltage falls below 68% (typ) of the setpoint voltage for

1msec or longer. In this fault condition, the converter turns off both high-side and low-side FETs. The UVP

function is enabled after 1.4 ms of soft start completion. An UVP fault requires 5-V UVLO or EN reset.

V5IN Undervoltage Lockout (UVLO) Protection

TPS51362 has a 5-V supply undervoltage lockout protection (UVLO) threshold. When the V5IN voltage is lower

than UVLO threshold voltage, Vout is shut off. This is a non-latch protection.

Power-On-Reset (POR)

To prevent single rail supply voltage brown-out due to output OV condition, when the output voltage is shut down

due to OVP fault, Power-on-Reset (POR) on V5IN is implemented. To reset OVP fault, V5IN voltage must fall

below POR threshold voltage of 1.7 V (typ) or EN reset to clear.

Thermal Shutdown

TPS51362 includes an internal temperature monitor. If the die temperature exceeds the threshold (published in

the EC table of this datasheet), the converter will be shutdown. This is a non-latch protection and the operation is

restarted with soft-start sequence when the device temperature is reduced by the hysteresis.

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