IPS2050H datasheet(14/32 Pages) STMICROELECTRONICS

14 / 32 page

Figure 9. Thermal protection plot, TC > TCSD

OUTX

TCASE

TCSD

TCR

TJX

OUTY

LIM

FAULT

VINX

VINY

7.3

Overload

The IC integrates two independent overload protection circuits (one for each output channel) 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-X) is triggered, then the current limitation control circuitry is activated to limit output current to the

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

The IC allows the user to set both single and dual activation thresholds for each channel. See the following

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

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

by RON * IOUT2, but when the current limitation circuit is activated, power dissipation increases and can be

calculated by VDS * ILIM-X, where VDS is the voltage drop between OUTX and VCC pins of the IC. In order to

protect the IC against thermal stress, the overtemperature protection is always active and retains the highest

priority.

7.3.1

Overload protection with dual threshold

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

activation thresholds IPKH-X and IPKL-X.

The IPKH-X is active only in the limited time frame between the L-H transition of the INX signal and the DPKX delay

defined by the following design rule:

DPKX 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-X is triggered within the DPKX time frame, then the output current is limited to ILIMH-X.

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

IPS2050H, IPS2050H-32, IPS2050HQ, IPS2050HQ-32

Overload

DS13779 - Rev 3

page 14/32

IPS2050H Datasheet(PDF) 14 Page - STMicroelectronics