7.3.3 IR Mode

In IR mode, the target LED current is equal to the value stored in the LED Flash Brightness Register (0x03 bits [7:0]). When IR mode is enabled by the Enable Register (0x01) setting mode M1, M0 (bits [1:0]) to 01, the boost converter turns on and sets the output equal to the input (pass mode). In IR mode, toggling the STROBE pin enables and disables the LED current source. The STROBE pin can only be set to be Level sensitive, as all timing of the IR pulse is externally controlled. In IR mode, the current source does not control the ramp rate of the LED output. The current transitions immediately from off to on and then on to off.

1. If needed, the DC/DC boost will turn on when the LED current is delivered (Strobe Pin = High). When the Strobe Pin goes low, the output voltage will return to V_IN (Pass Mode)

Figure 29. IR Mode with Boost

1. In pass mode, the boost stays disabled and V_OUT = V_IN when the Strobe Pin is high or low

Figure 30. IR Mode Pass Only

1. When the flash timer elapses, the device goes into stand-by regardless of strobe state

Figure 31. IR Mode Time-out