Datasheet

LM5046

SNVS703G –FEBRUARY 2011–REVISED MARCH 2013

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Soft-Stop Off

The Soft-Start Off (SSOFF) pin gives additional flexibility by allowing the power converter to be configured for

hard-stop during line UVLO and hiccup mode condition. If the SS OFF pin is pulled up to the 5V REF pin, the

power converter hard-stops in any fault condition. Hard-stop drives each control output to a low state

immediately. Refer to Table 2 for more details.

Table 2. Soft-Stop in Fault Conditions

Fault Condition SSSR

UVLO Soft-Stop

(UVLO<1.25V) 3x the charging rate

OVP Hard-Stop

(OVP>1.25V)

Hiccup Soft-Stop

(CS>0.75 and RES>1V) 6x the charging rate

VCC/VREF UV Hard-Stop

Internal Thermal Limit Hard-Stop

Note: All the above conditions are valid with SSOFF pin tied to GND. If SSOFF=5V, the LM5046 hard-stops in all

the conditions. The SS pin remains high in all the conditions until the SSSR pin reaches 1V.

Thermal Protection

Internal thermal shutdown circuitry is provided to protect the integrated circuit in the event the maximum rated

junction temperature is exceeded. When activated, typically at 160°C, the controller is forced into a shutdown

state with the output drivers, the bias regulators (VCC and REF) disabled. This helps to prevent catastrophic

failures from accidental device overheating. During thermal shutdown, the SS and SSSR capacitors are fully

discharged and the controller follows a normal start-up sequence after the junction temperature falls to the

operating level (140 °C).

Product Folder Links: LM5046