Dear TI Technical Support Team,
I am currently designing a long-range ToF system using the OPT3101 analog front-end. I am writing to inquire about the flexibility of the illumination modulation timing.
We are planning to use a high-power light source that has a strict thermal constraint: it requires a maximum duty cycle of 0.1% to operate safely.
1. Current Understanding of OPT3101: Based on my review of the datasheet (specifically the Timing Generator and Register 71), the OPT3101 appears to generate a continuous burst of modulation clocks (e.g., 10MHz) during the entire ILLUM_EN window (approx. 210µs per sub-frame).
This implies that during the measurement window, the light source is driven with a 50% duty cycle modulation signal continuously, resulting in thousands of consecutive pulses.
2. The Requirement: To use our target light source, we need to significantly reduce the pulse density. Ideally, we need a driving scheme that allows for long rest intervals between individual pulses (e.g., firing a 1ns ~ 100ns pulse and then resting for approx. 1µs ~ 100µs) to maintain an effective duty cycle of around 0.1%.
3. Questions:
Modulation Adjustment: Is there any register setting in the OPT3101 that allows for adjusting the pulse density or duty cycle of the modulation output signal? Pulsed Mode: Does the OPT3101 support a "low-duty pulsed mode" where the modulation clock is not continuous but intermittent within the integration window? Clarification: If the OPT3101 strictly requires a continuous wave (CW) modulation during the integration time, could you confirm that it is natively incompatible with light sources requiring very low duty cycles (like < 1%) without external circuitry?
Your confirmation would be greatly appreciated to help us finalize our component selection.
Best regards,
