LM3560 Datasheet, PDF (23/42 Pages) Texas Instruments – LM3560 Synchronous Boost Flash Driver w/ Dual 1A High-Side Current Sources (2A Total Flash Current)

FIGURE 16. VLED Monitor Manual Mode
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FLAGS REGISTER AND FAULT INDICATORS
Eight fault flags are available in the LM3560. These include a
Flash Timeout, a Thermal Shutdown, an LED Failure Flag
(LED Shorted or Output going OVP indicating LED open), an
LED Thermal Flag (NTC threshold tripping), a VIN Monitor
Flag, and a VIN Flash Monitor Flag. Additionally, two LED in-
terrupt flag bits (TX1 interrupt and TX2 interrupt) are set when
the corresponding interrupt is activated. Reading back a '1'
indicates the flagged event has happened. A read of the Flags
Register resets these bits.
FLASH TIMEOUT
The Timeout or (TO flag), (bit [0] of the Flags Register) reads
back a '1' if the LM3560 is active in Flash mode and the Time-
out period expires before the Flash pulse is terminated. The
flash pulse can be terminated before the Timeout period ex-
pires by pulling the STROBE pin low (with Enable Register bit
[5] = 0), or by writing a (0,0) to bit [1:0] of the Enable Register.
The TO flag is reset to '0' by pulling HWEN low, removing
power to the LM3560, or reading the Flags Register.
THERMAL SHUTDOWN FLAG
When the thermal shutdown threshold is tripped a '1' gets
written to bit [1] of the Flags Register (Thermal Shutdown bit).
The LM3560's flash, torch, or privacy modes cannot be
restarted until the Flags Register has been read back, or when
the device is shut down and started up again.
LED FAULT
The LED Fault flag (bit 2 of the Flags Register) reads back a
'1' if the part is active in Flash or Torch mode and either LED1
or LED2 experience an open or short condition. An LED open
condition is signaled if the OVP threshold is crossed at the
OUT pin while the device is in Flash, Torch, or Privacy mode.
An LED short condition is signaled if the voltage at LED1 or
LED2 goes below 500 mV while the device is in Flash, Torch,
or Privacy mode. In an LED open condition there is a 2µs
deglitch time from when the output voltage crosses the OVP
threshold to when the LED Fault Flag is triggered. In an LED
short condition there is a 250µs deglitch time from when the
LED voltage falls below 500 mV until the LED Fault Flag is
set. The LED Fault Flag can only be reset to '0' by pulling
HWEN low, cycling power, or by removing the fault condition
and reading back the Flags Register.
TX1 AND TX2 INTERRUPT FLAGS
The TX1 and TX2 interrupt flags (bits [3] and [4]) indicate an
interrupt event has occurred on the respective TX inputs. Bit
3 will read back a '1' if TX1 is in TX mode and there has been
a TX1 event since the last read of the Flags Register. Bit 4
will read back a '1' if TX2 is in TX mode and there has been
a TX2 event since the last read of the Flags Register. A read
of the Flags Register automatically resets these bits. A TX
event on TX1 or TX2, can be a high-to-low transition or a low-
to-high transition depending on the setting of the TX1 and TX2
polarity bits (see Configuration Register 1 Bits [6:5]).
LED THERMAL FAULT (NTC Flag)
The NTC flag (bit [5] of the Flags Register) reads back a '1' if
the LM3560 is active in Flash or Torch mode, the device is in
NTC mode, and the voltage at LEDI/NTC has fallen below
V_TRIP (1V typical). When this has happened, and the LM3560
has been forced into Torch mode or LED shutdown (depend-
ing on the state of Configuration Register 2 bit [1), the Flags
Register must be read, and V_LEDI/NTC must go above 1V in
order to place the device back in normal operation. (see NTC
MODE section for more details).
VIN FLASH MONITOR FAULT
The VIN Flash Monitor Flag (bit [6] of the Flags Register)
reads back a '1' if the VIN Flash Monitor is enabled and VIN
falls below the programmed VIN Flash Monitor threshold. This
flag must be read back in order to resume normal operation
after the LED current has been forced to the lower flash cur-
rent setting.
VIN MONITOR FAULT
The VIN Monitor Flag (bit [7] of the Flag Register) reads back
a '1' when the VIN Monitor is enabled and VIN falls below the
programmed VIN Monitor threshold. This flag must be read
back and VIN must go above the VIN Monitor Threshold in
order to resume normal operation after the LED current has
been forced to Torch mode or turned off due to a VIN Monitor
event.
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