MP3331-2A SYNCHRONOUS BOOST FLASH LED DRIVER WITH I

MP3331 Rev. 1.02

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14

5/3/2016

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Figure 7: Hardware and Edge Sensitive Mode

3. Software and edge sensitive mode

In this mode, STR_MOD = 0, LED_EN = 1, and

LED_MOD = 11. The current is set by I_FL, and

the ramping up time is set by TUP_I. The flash

current ends when the flash timer set by

FL_TIM ends. If LED_SD = 0, the LED_MOD is

reset to standby mode, and LED_EN is set to 0

after the flash. If LED_SD = 1, the LED_MOD,

and LED_EN are not reset (see Figure 8).

Figure 8: Software and Edge Sensitive Mode

Torch Mode to Flash Mode

During torch mode, the device can change to

flash mode from torch mode directly when STR

goes from low to high (if STR_MOD = 1). After

the flash, the operation is the same as

described in the “Flash Mode” section (see

Figure 9).

Figure 9: Torch Mode to Flash Mode

Assist Mode to Flash Mode

During assist-light mode, the device can

change to flash mode from assist-light mode

directly when STR goes from low to high (if

STR_MOD = 1). After the flash, the operation is

the same as described in the “Flash Mode”

section (see Figure 10).

Figure 10: Assist Mode to Flash Mode

5V DC Output Mode

If 5V_MOD is set to 1, the device works in a

fixed 5V DC output mode, and the control loop

is taken over by the voltage loop. Note that the

LED current sources can still output current if

the mode conditions are met (as described

above). Care must be taken to ensure thermal

temperatures are ok because the 5V powers

the

LED

directly.

To

avoid

this,

it

is

recommended to set LED_EN to 0 during the

5V DC mode (see Figure 11).