12V Automotive LED Driver IC LITIX™ Power Flex TLD5542-1QV - test bench Multi-Float-Switch jump from 8 to 5 LEDs

Open online SPICE simulator circuit link: atv_lighting_TLD5542-1QV_testbench_MFS.TSC

Model Parameters:

Multi Float Switch - Transient with TLD5542-1QV

Low Beam
5LEDs

High Beam
3LEDs

- frequency: specify directly the controller frequency [200kHz to 700kHz]
MFS feature related parameters (to disable the feature for other test-benches, make t_SOMFS longer than total simulation time)
- LED_initial: number of LEDs before performing the jump; this number must be the same with the number of LEDs connected
at the output; the range is between 2 and 16
- LED_after: number of LEDs after the jump; this number must be the same with the number of LEDs that will remain connect
at the output; the range is between 1 and 15
- t_PREP: time until Ccomp is discharged; give the compensation capacitors enough time to discharge, otherwise spikes will still
appear at the output
- t_SOMFS: time when MFS routine will start; for other test benches, keep this parameter higher than simulation time to deactivate
the feature

- Double click on the green window to enter design criteria
- Click on "Run" and Simulate Transient

This test bench shows the Multi Float Switch (MFS) feature. The controller performs special routines in order to minimize
the current overshoots in dynamic load applications when the number of LEDs is decreased (i.e. High Beam to Low Beam
front light change). Parameters LED_initial, LED_after, t_PREP and t_SOMFS must be set accordingly before the simulation
is started. After the internal operations for MFS are complete (when EOMFS pin is released high), the pair of switches S1 and
Vled_sw disconnect the LEDs from the output. Timing is essential to have a proper transition. With the right settings of the
timing parameters, the overshoot of the output current will be minimized. Please refer to the AppNote on the device for more
details on the MFS routine and the calculation of the timings.The setup is configured for a jump from 8 LEDs to 5 LEDs.

Notes:
BODY_DIODE is not a real diode but a Voltage Controlled Current Source which models the threshold and ON/OFF states
resistance. RCOMP is a placeholder for further adjustment of the resistor for stability purpose. Keep unchanged otherwise.
S2G is a virtual pin used for monitoring short to ground fault if VFB<0.563V for at least 8 clock cycles. During start-up,
the detection is ignored until VSOFT_START>1.75V.