IPS1025H datasheet(14/32 Pages) STMICROELECTRONICS

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7.3

Overload

The IC integrates an overload protection circuit consisting of an output current sensing section and an output

current limitation section.

When the output channel is ON, the sensing circuitry monitors the current supplied to the load: if the activation

threshold (IPK) is triggered, then the current limitation control circuitry is activated to limit output current to the

current limitation level (ILIM) and FLT2 pin is activated until the overload condition is removed.

See the following sections for details and Table 9 / Table 10 for specific activation thresholds and limitation levels.

Note that while the output channel operates below its activation threshold, the power dissipation can be calculated

by RON * IOUT 2, but when the current limitation circuit is activated, power dissipation increases and can be

calculated by VDS * IOUT, where VDS is the voltage drop between the OUT and VCC pins of the IC. In order to

protect the IC against thermal stress, the over-temperature protection is always active and retains the highest

priority.

7.3.1

Overload protection with dual threshold

This case is activated when the pin IPD is connected to GND by a capacitor (CPD) and the IC works with two

activation thresholds IPKH and IPKL.

The IPKH is active only in the limited time frame between the L-H transition of the IN signal and the DPK delay

defined by the following design rule:

DPK µs = 215×CPD nF

The above design rule is valid in the range 470 pF ≤ CPD ≤ 470 nF (see Table 9 / Table 10).

If the IPKH is triggered within the DPK time frame, then the output current is limited to ILIMH.

After DPK has elapsed, the IC operates with IPKL activation threshold and ILIML limitation level, respectively.

IPS1025H, IPS1025H-32, IPS1025HQ, IPS1025HQ-32

Overload

DS13780 - Rev 3

page 14/32

IPS1025H Datasheet(PDF) 14 Page - STMicroelectronics