13.5V low side over-temperature protection with HITFET™ BTF3050TE

Open online SPICE simulator circuit link: atv_bp_18V_low_side_BTF3050TE_protection_OT.tsc

HITFET™ Automotive Smart Low-Side Switch BTF3050TE:
Protection Features - Thermal Shutdown With Restart

{1. click here to set circuit parameters}
{2. click on "Run" to calculate components}
{3. click on "OK" and Simulate Transient }

{Switching slew rate adjustment: }
R_SRP:= 58k {use 5k ... 70k}
{normal operation, see datasheet section 5.5}

{Thermal model number: }
ThermalModel:= 3 {use 1 ... 4}

{Current increasing trigger time t_on/off [s]: }
t_on:= 2m {use 1m ... 10m}
t_off:= 20m {use t_on+15m ... 25m}

{Do NOT change the values below. }
{Fault condition reset trigger time [s]: }
tFault_reset_on:= t_off + 2m
tFault_reset_off:= tFault_reset_on + 0.1m

Thermal model description:
THERMAL_MODEL=1: 1s0p PCB 300\e(mm,2)
THERMAL_MODEL=2: 1s0p PCB 600\e(mm,2)
THERMAL_MODEL=3: 1s0p PCB min. footprint
THERMAL_MODEL=4: 2s2p PCB

The BTF3050TE is a 50 mOhm single channel Smart Low-Side Power Switch providing
embedded protective functions. Infineon’s HITFET™ protected low-side switches drive
resistive, capacitive as well as inductive loads. The target applications of the BTF3050TE
are replay replacement, small motors and solenoids.

This circuit demonstrates the protection feature thermal shutdown with restart of the
BTF3050TE. Once the junction temperature is reaching out the thermal shut down junction
temperature, the device is shut down, the current is limited and a logic high at pin SRP is
triggered as a latched fault signal. The device will turn on again, if the input is still high,
after the measured temperatrure has dropped below the thermal hysteresis.

The SRP pin can be pulled down to a smaller voltage than the threshold VSRP(RESET) of
1.8V (typ.) for at least 100 µs to clear the latched fault signal.

The switch SW_par is used to increase
the current and thus the junction temperature.