MP3332

MP3332 Rev. 1.0

www.MonolithicPower.com

13

5/1/2018

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Assist Mode

The device enters assist mode by setting

LED_MOD to 10 and the LED1/2_EN bits to 1

(see Figure 3). The LED1 and LED2 current

sources are controlled by the LED1_EN and

LED2_EN bits respectively. The ramp-up slew

rate can be set by register TUP_I. The currents

can be disabled by switching to standby mode

or by setting the LED1_EN and LED2_EN bits

to 0.

MP3332 Assist Mode:

ILED1

ILED2

I2C

REG 0x0C/0D,

I1_TOR=XXXX

2I_TOR=XXXX

REG 0x01,

LED_MOD=10

REG 0x01,

LED1_EN=1

LED2_EN=1

Set REG 0x01,

LED1_EN to 0

LED2_EN to 0

Or Set

LED_MOD=00

Figure 3: Assist Mode

Indicator Mode

The device enters indicator mode for a lower

current output when LED_MOD is set to 01,

and LED1/2 is set to 1 (see Figure 4). In

indicator mode, the driver outputs a current in

31.5kHz PWM dimming mode. The current

amplitude is set by I1_TOR and I2_TOR, and

the duty cycle is set by the INDI_PWM register.

Set the LED1/2_EN bits to 0, or switch to

standby mode to disable indicator mode. The

LED1 and LED2 current sources are controlled

by

the

LED1_EN

and

LED2_EN

bits

respectively.

MP3332 Indicator Mode:

ILED1

ILED2

I2C

REG 0x0C/D,

I1_TOR=XXXX

I2_TOR=XXXX

REG 0x01,

LED_MOD=01

REG 0x05,

INDI_PWM=xx

REG 0x01,

LED1_EN=1

LED2_EN=1

Set REG 0x01,

LED1_EN to 0

LED2_EN to 0

Or Set

LED_MOD=00

Figure 4: Indicator Mode

If blinking function is enabled, LED1/2 turn on

for the blinking time and then turn off for the

same blinking time period. The cycle repeats

continuously in indicator mode (see Figure 5).

The blinking time is set by the TBK0/1 bits in

register 0FH.

TBlink

TBlink

LED1/2

Figure 5: Blinking Function

Flash Mode

The device can work in flash mode in the

following ways:

1. Hardware and Level Trigger Mode

In this mode, STR_MOD = 1, STR_LV = 1,

LED1/2_EN = 1, and LED_MOD = 11. The flash

current starts ramping up after STR goes high.

The currents are set by I_FL_1 and I_FL_2, and

the ramp-up time is set by TUP_I. The flash

current ends when STR is pulled low. After the

flash, LED_MOD is reset to standby mode, and

LED1/2_EN is reset to 0 if LED_SD = 0. If

LED_SD = 1, LED_MOD and LED1/2_EN are

not reset. The LED1 and LED2 current sources

are controlled by the LED1_EN and LED2_EN

bits respectively. If the flash timer set by the

register bit FL_TIM ends before STR goes low,

the

flash

current

terminates

immediately.

LED_MOD and LED1/2_EN are reset to the

default value if LED_SD is 0 and the time-out

fault bit FT_TO is set to 1 and is not cleared

until it is read back, or the input power is reset

(see Figure 6 and Figure 7).

MP3332 Hardware and Level

Sensitive Flash Mode w/o Timer-Out:

ILED1

ILED2

FL_TIMER

I2C

REG 0x01,

STR_MOD=1

STR_LV=1

LED_MOD=11

REG 0x06/7,

I1_FL=XXXX

I2_FL=XXXX

REG 0x03,

FL_TIM=XXXX

REG 0x01,

LED1_EN=1

LED2_EN=1

STR

Setting Time

Reset,

LED1_EN to 0

LED2_EN to 0

LED_MOD=00

Figure 6: Hardware and Level Trigger Flash

Mode without Timer-Out