12V Automotive LED Driver IC TLD2142-1EP LITIX™ Basic+ Short-circuit Fault Management

Open online SPICE simulator circuit link: atv_12v_LED_lighting_driver_TLD2142-1EP_FAULT_short_circuit_fault_management_V1.tsc


12V Automotive LED Driver IC TLD2142-1EP LITIX™ Basic+
Short-circuit fault management

{ Please double click here to enter design criteria }

{ Number of Thermal Model }
THERMAL_MODEL := 1;

The LITIX™ Basic+ TLD2142-1EP is a single channel high-side driver IC with
integrated output stage. It is designed to control LEDs with a current up to 240
mA. In typical automotive applications the device is capable of driving 3 red
LEDs with a current up to 180 mA and even above, if not limited by the overall
system thermal properties. Practically, the output current is controlled by an
external resistor or reference source, independently from load and supply voltage
changes.

This setup is showing the short circuit fault management with D pin connected to
an external capacitor. A short circuit event is applied on the output between 1ms and 3ms.
During start-up, the output capacitor is charged with a current in order to rise
the output voltage above short circuit detection threshold in less than tfault.
The same current is flowing also after short circuit event is applied for the duration of tfault.
When the fault has been detected, IOUT(fault) current is flowing out of the affected channel.
When the voltage on D pin rises above VD(th), IN_SET goes in a weak pull-down.
For more information please consult chapter 6.2.1 and Figure 19 from datasheet.

The Ambient temperature of the entire chip can be set from VTAMB voltage source.
Junction temperature can be monitored on TJ output pin.
TJ is always TAMB + temperature due to self-heating of the device considering
the main sources of power dissipation (power device, logic, internal regulator).

Thermal model description:
THERMAL_MODEL=1: P=1W; T=85°C; PCB type: 1s0p 300mm2
THERMAL_MODEL=2: P=1W; T=85°C; PCB type: 1s0p 600mm2
THERMAL_MODEL=3: P=1W; T=85°C; PCB type: 1s0p footprint
THERMAL_MODEL=4: P=1W; T=85°C; PCB type: 2s2p
where: P=power injected in chip; T=ambient temperature

Observations:
1. It is required to let the TJ pin open (no external connection)
2. The convention is 1V=1°C

{=== How to change SPICE convergence parameters ===}

Change the convergence-speed-accuracy trade-off with "Analysis -> Analysis Parameters..."
1) How to improve Accuracy
To speed up the simulation, the TR maximum time step [s] can be adjusted (default value = 10Gs).
- high values may produce less accuracy during signal transition
- a general rule is to have the ratio between test duration (End display) and TR maximum time step
in the range of 1k to 10k
2) How to improve Convergence
The SPICE model is not guaranteed to converge in every test situation with the default simulator settings.
Increasing gradually the following analysis parameters may help achieving the convergence:
Important: exceeding indicated values may impact results accuracy.
- DC absolute current error [A] from 1n (default) to 10n
- DC absolute voltage error [V] from 1u (default) to 10u
- DC relative error [%] from 1m (default) to 10m

- Change simulation time:
"Analysis->Transient: Start - End Display"
- Double click on the green window to enter design criteria
- Click on "Run" and Simulate Transient




Product info: TLD2142-1EP
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Demoboard: BASICPLUS DEMOBOARD