IVFM ENABLE

LEVEL STROBE

VIN PROFILE for Stop and Hold Mode

O/P Current Profile in

Stop and Hold Mode

Dotted line shows O/P Current Profile with

IVFM Disabled

Set Target Flash Current

IVFM-D

SET RAMP FROM

THE RAMP

REGISTER USED

11

LM36011

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7.4 Device Functioning Modes

7.4.1 Start-Up (Enabling The Device)

At turnon the LED current source steps through each FLASH or TORCH level until the target LED current is

flash and the target LED torch currents are set by the LED Flash Brightness Register (0x03 bits [6:0]) and LED

Torch Brightness Register (0x04 bits [6:0]) respectively.

7.4.2 Input Voltage Flash Monitor (IVFM)

The LM36011 has the ability to adjust the flash current based upon the voltage level present at the IN pin

utilizing the input voltage flash monitor (IVFM). The adjustable threshold IVFM-D ranges from 2.9 V to 3.6 V in

100-mV steps and is set by Configuration Register (0x02) bits [7:5]. Additionally, the IVFM-D threshold sets the

input voltage boundary that forces the LM36011 to stop ramping the flash current during start-up.

Figure 19. IVFM Mode

7.4.3 Fault/Protections

Upon a fault condition, the LM36011 sets the appropriate flag(s) in the Flags Register (0x05) and switches into

stand-by mode obtained by clearing the mode M1, M0 (bits [1:0]) of the Enable Register (0x01). The LM36011

fault status can be re-checked. If the fault(s) is still present, the LM36011 re-sets the appropriate flag bits and

enters stand-by again.

7.4.3.1 Input Voltage Flash Monitor (IVFM)

When the input voltage crosses the IVFM-D value, programmed by Configuration Register (0x02) bits [7:5], the

LM36011 sets the IVFM flag (bit [6]) of Flags Register (0x05).

7.4.3.2 LED Short Fault

(0x05) is set, if the LED output experiences a short condition. An LED short condition occurs if the voltage at the

LED pin goes below 500 mV (typical). There is a deglitch time of 256 µs before the LED short flag is valid The

LED short fault can be reset to 0 by removing power to the LM36011, or setting the software reset field (Register

0x06 bit [7]) to a 1, or by reading back the Flags Register.