DLPS039F December 2015 – April 2019 TPS99000-Q1
The excessive brightness BIST uses a secondary photodiode connected to TIA2 to detect over-brightness conditions in the output image of the HUD.
The output of TIA2 is compared to a programmable threshold. If the output exceeds the threshold, the DLPC230-Q1 software will log an error. TIA2 can be used in a high bandwidth or low bandwidth configuration for this BIST.
The low bandwidth mode provides an RC filter low-passed value of the TIA2 output. The resistor element of the filter is embedded in the TPS99000-Q1, while the capacitor is an external component. If the low bandwidth input is used, the value of the capacitor should be expected such that the time constant is longer than the frame time.
The hardware controls for the threshold are not synchronized to the dimming functionality of the TPS99000-Q1. Therefore, this feature may need to be enabled or disabled, or the thresholds may need to be adjusted based on the dimming level of the HUD.