TPS16632 datasheet(17/42 Pages) TI1

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ILIM

VIN

FLTb

IIN

VOUT

VIN

VOUT

FLTb

TPS1663

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SLVSET9C – SEPTEMBER 2018 – REVISED MARCH 2019

Product Folder Links: TPS1663

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Feature Description (continued)

9.3.3 Overvoltage Protection (OVP)

The TPS1663x incorporate circuitry to protect the system during overvoltage conditions. The TPS16630 features

an accurate ± 2% adjustable over voltage cut off functionality. A voltage more than V(OVPR) on OVP pin turns off

the internal FET and protects the downstream load. To program the OVP threshold externally, connect a resistor

divider from IN supply to OVP terminal to GND as shown in Figure 17. The TPS16632 features an internally fixed

39 V maximum overvoltage clamp V(OVC) functionality. The TPS16632 clamps the output voltage to V(OVC), when

the input voltage exceeds 40 V. During the output voltage clamp operation, the power dissipation in the internal

MOSFET is PD = (V(IN) – V(OVC)) × I(OUT). Excess power dissipation for a prolonged period can increase the

device temperature. To avoid this, the internal FET is operated in overvoltage clamp for a maximum duration of

tOVC(dly), 162 msec (typical). After this duration, the internal FET is turned OFF and the subsequent operation of

the device depends on the MODE configuration (Auto-Retry or latch OFF) setting as per the Table 1.

Figure 18 illustrates the overvoltage cut-off functionality and Figure 19 illustrates the overvoltage clamp

functionality. FLT is asserted after a delay of 617 µs (typical) after entering in overvoltage clamp mode and

remains asserted until the overvoltage fault is removed.

TPS16630

OVP Setting at 33 V

Figure 18. Overvoltage Cut-off Response at 33-V Level

TPS16632

COUT = 10 µF, FLT

connected to VOUT

RLOAD = 30 Ω

Figure 19. Overvoltage Clamp Response

9.3.4 Overload and Short Circuit Protection

The device monitors the load current by sensing the voltage across the internal sense resistor. The FET current

is monitored during start-up and normal operation.

9.3.4.1 Overload Protection

The TPS1663x devices feature accurate overload current limiting and fast short circuit protection feature. If the

load current exceeds the programmed current limit IOL, the device regulates the current through it at IOL

eventually reducing the output voltage. The power dissipation across the device during this operation will be

(VIN–VOUT) x IOL and this could heat up the device and eventually enter into thermal shutdown. The maximum

duration for the over current through the FET is tCL_PLIM(dly), 162 msec (typical). If the thermal shutdown occurs

before this time the internal FET turns OFF and the device operates either in auto-retry or latch off mode based

on MODE pin configuration in Table 1. Set the current limit using Equation 4

where

•

I(OL) is the overload current limit in Ampere

TPS16632 数据表(PDF) 17 Page - Texas Instruments

TPS16632 数据表(HTML) 17 Page - Texas Instruments

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