OFF time, tFASTTRIP(dly). At Overload current level in the range of IFASTTRIP < IOUT < ISCP, the fast-trip comparator

response is 3.2 µs (typical).

9.3.4.2.1 Start-Up With Short-Circuit On Output

When the device is started with short-circuit on the output, the current begins to limit at I(OL). Due to high

power dissipation of VIN x I(OL) within the device the junction temperature increases. Subsequently, the thermal

regulation control loop limits the load current to regulate the junction temperature at T(J_REG), 145°C (typical)

for a duration of t(Treg_timeout), 1.25 sec (typical). Subsequent operation of the device depends on the MODE

configuration (auto-retry or latch off) setting as per the Table 9-1. FLT gets asserted after t(Treg_timeout) and

remains asserted till the output short-circuit is removed. Figure 9-9 illustrates the behavior of the device in this

condition.

VIN

FLTb

IIN

VIN = 24 V

RILIM = 3 kΩ

Figure 9-9. Start-Up With Short on Output

9.3.5 Output Power Limiting, PLIM (TPS16632 Only)

In TPS16630, with a fixed overcurrent limit threshold the maximum output power limit increases linearly with

supply input. Electrical Industrial process control equipment such as PLC CPU must comply with standards

like IEC61010-1 and UL1310 for fire safety which require limited energy and power circuits. Limiting the output

power becomes a challenge in such high power applications where the operating supply voltage range is wide.

The TPS16632 integrate adjustable output power limiting functionality that simplifies the system design requiring

compliance in accordance to this standard.

Connect a resistor from PLIM to GND as shown in Figure 9-10 to set the output power limiting value. If

output power limiting is not required, then connect PLIM to GND directly. This connection disables the PLIM

functionality.

During an over-power load event, the TPS16632 limits the output power at the programmed value set by PLIM

resistor. This limit indirectly results in the device operation in current limiting mode with steady state output

voltage and current set by the load characteristics and PLIM = VOUT × IOUT. Figure 7-8 shows the output power

limit and current limit characteristics of TPS16632 with 100-W power limit setting. The maximum duration for the

device in power limiting mode is 162 msec (typical), tCL_PLIM(dly). After this time, the device operates either in

auto-retry or latch off mode based on MODE pin configuration in Table 9-1.

P(PLIM) = 1 × R(PLIM)

(5)

Here, P(PLIM) is output power limit in watts, and R(PLIM) is the power limit setting resistor in kΩ.

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TPS1663

SLVSET9F – SEPTEMBER 2018 – REVISED FEBRUARY 2023

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