LM3492HC: Protection function

Hello Ishiwata,

Does the LM3492HC have Open LED Protection?  Yes, Page 17 of the datasheet:  "8.3.10.3 Output Current Undervoltage Indication
The LM3492HC device gives an IOUTn (n = 1, 2) undervoltage indication if the voltage of the IOUTn pin when
DIMn is high is lower than its minimum required voltage which can regulate ILED, and the voltage of the CDHC
pin reaches its maximum. These conditions remain while the device applies 508 consecutive dimming signals on
the DIMn pin. This means that the current of the LED string n does not reach the regulation value. In most cases,
the IOUT undervoltage indication can be regarded as an open fault of the LED string n. A bit pattern (see
Table 1) can be read from the COMM pin. The device does not latch off and continues to operate in the
presence of the IOUT undervoltage indication."

Page 11 of the datasheet:  "Diagnostic functions including power good indication, over-temperature indication, output current overvoltage and
undervoltage indications facilitate the interface of the device application circuit with external micro-processors
(MCUs). The device does not latch off and continues to operate in the presence of the indications. Other useful
features include thermal shutdown, VCC undervoltage lockout, and precision enable."

Page 16 of the datasheet:  "8.3.9 Overvoltage Protection
When VFB is higher than the FB pin overvoltage protection (OVP) threshold VFB-OVP (typically 2.76 V and
maximum 2.88 V), the on-period of the integrated MOSFET stop immediately, and the MOSFET keeps off until
VFB falls back below below 2.545 V (typical hysteresis 0.215 V)."

The MOSFET turns off under certain fault conditions and will resume operation once the fault/hysteresis clears such as thermal and over-voltage.  This is all described in the datasheet.  It doesn't latch off for these faults.

Best Regards,