6

Protection and diagnostic

The IC integrates several protections to ease the design of a robust application.

6.1

Undervoltage lock-out

The device turns off if the supply voltage falls below the turn-off threshold (VUV(off)). Normal operation restarts

after VCC exceeds the turn-on threshold (VUV(on)). Turn-on and turn-off thresholds are defined in Table 4. Supply.

6.2

Overtemperature

The power stage of each channel is turned off as its internal junction temperature (TJ) exceeds the

shutdown threshold (TJSD). Normal operation restarts when TJ comes back below the reset threshold (see

Table 8. Protection and diagnostic). The internal fault signal is set when the channel is OFF due to thermal

protection. The thermal fault is reported both on the FLT pin and on the INx pin of the corresponding LOADx in

fault. Note that the FLT pin reports the logic OR of the four output channels faults.

Figure 8. Thermal protection signalization behavior on FLT

MCUx

VINx

TJ

____

FLT

TJSD

TJHYS

6.3

Current limitation and cut-off

The load current flows through the integrated power stage and it is internally limited by the specific ILIM threshold

that can be set by an external resistor (RILIM) placed between ILIM and SGND ground plane. The design rule for

the RILIM resistor is:

Equation 1:

(1)

ILIM = 60/RILIM[kΩ]

The above design rule is valid in the range 30 kΩ ≤ RILIM ≤ 120 kΩ. For 0 ≤ RILIM < 30 kΩ, the current is internally

limited up to 3 A (typical). For RILIM > 120 kΩ the current is anyway limited but the linearity is not guaranteed.

IPS4260L

Protection and diagnostic

DS12305 - Rev 5

page 13/29