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STROBE

(Level/Edge Bit

Set to Edge)

LED

Current

Timeout Duration

32 Ps

LM3559

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SNVS624B – JUNE 2011 – REVISED JUNE 2016

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Device Functional Modes (continued)

Figure 35. LED Current for Strobe (Edge Triggered, Enable Register Bit [5] = 1)

After the flash pulse terminates; either by a flash timeout, pulling STROBE low or disabling it via the I2C-

compatible interface, LED1 and LED2 turn completely off. This happens even when torch is enabled via the I2C-

compatible interface, and the flash pulse is turned on by toggling STROBE. After a flash event ends, the EN1,

EN0 bits (bits [1:0] of the Enable Register) are automatically reset with 0, 0. The exception occurs when the

privacy terminate bit is low (bit [3]) in the Privacy Register. In this case, the specific current source that is

enabled for privacy mode turns back on after the flash pulse if privacy mode had been enabled before the flash

pulse.

8.4.4 Torch Mode

In torch mode the current sources LED1 and LED2 each provide 8 different current levels (Table 3). Torch mode

is activated by setting Enable Register bits [1:0] to (1, 0). Once torch mode is enabled, the current sources ramp

up to the programmed torch current level by stepping through all of the torch currents at (32 µs/step) until the

programmed torch current level is reached.

8.4.5 Privacy-Indicate Mode

The current sources (LED1 and/or LED2) can also be used as a privacy indicator before and after flash mode.

Privacy-indicate mode is enabled by setting the Enable Register bit [1:0] to (0,1). Additionally, the Privacy

both), whether or not the privacy-indicate mode turns off at the end of the flash pulse, and contains the 8

intensity levels for the privacy indicator.

The intensity of the LEDs in privacy indicate mode is set by PWM’ing the lowest torch current level (28.125 mA).

Bits [2:0] of the Privacy Register allow for 8 different duty cycles of 10%, 20%, 30%, 40%, 50%, 60%, 70%, and

80%. See Table 14 for Privacy Register bit settings. Figure 36 details the timing for the privacy-indicate mode on

ILED1 or ILED2.

LM3559 датащи(PDF) 21 Page - Texas Instruments