NB669, 24V, HIGH CURRENT SYNCHRONOUS BUCK CONVERTER WITH LDO

NB669 Rev. 1.01

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14

7/23/2013

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EN Comparator

EN

NB669

VIN

Figure 8—Adjustable UVLO

Thermal Shutdown

Thermal shutdown is employed in the NB669.

The junction temperature of the IC is internally

monitored. If the junction temperature exceeds

the threshold value (typical 150ºC), the converter

shuts off. This is a non-latch protection. There is

about 25ºC hysteresis. Once the junction

temperature drops to about 125ºC, it initiates a

SS.

Output Discharge

NB669 discharges the output when EN is low, or

the controller is turned off by the protection

functions (UVP & OCP, OCP, OVP, UVLO, and

thermal shutdown). The part discharges outputs

using an internal 6Ω MOSFET.