12V Automotive LED Driver IC TLD2131-3EP LITIX™ Basic+ Single LED Short-circuit Fault Management

Open online SPICE simulator circuit link: atv_12v_LED_lighting_driver_TLD2131-3EP_SLS_single_short_fault_management_V1.TSC


12V Automotive LED Driver IC TLD2131-3EP LITIX™ Basic+
Single LED Short fault management

The LITIX™ Basic+ TLD2131-3EP is a triple channel high-side driver IC
with integrated output stages. It is designed to control LEDs with a current
up to 80 mA. In typical automotive applications the device is capable of
driving 3 red LEDs per chain (total 9 LEDs) with a current up to 60 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 Single LED Short fault management with D and
DS pins connected to external capacitors. A short circuit event is applied on
a single LED on CH1 at 1ms and removed at 4ms. The SLS_REF resistor
has been calculated in order to detect the fault when the output voltage drops
with 1 LED forward voltage.
Play with different RSLS_REF and monitor the ERRN activity:
- if RSLS_REF is too low, the device cannot detect 1 LED short
- if RSLS_REF is too high, the device requires more initial LEDs
in order to operate in normal condition
For more information please consult section 6.3.4 and Figure 24from datasheet.

{ Please double click here to enter design criteria }

{ Number of Thermal Model }
THERMAL_MODEL := 1;
{ Model Parameter CORNER_CASE }
CORNER_CASE := 0;

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

It is possible to perform worst case analysis using
the model parameter CORNER_CASE:
CORNER_CASE = -1 { worst case minimum }
CORNER_CASE = 0 { typical }
CORNER_CASE = 1 { worst case maximum }

Electrical Characteristics of the device dependent
on CORNER_CASE parameter:
VIN_SET(ref)
KSLS_REF
BSLS = f(VOUT)
KALL = f(IIN_SET)

- 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: TLD2131-3EP
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Demoboard: BASICPLUS DEMOBOARD