Datasheet

t- Time=10ms/div

V (5V/div)

V (2V/div)

I (2 A/div)

PTN04050C

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SLTS251A –SEPTEMBER 2005–REVISED FEBRUARY 2011

Power-Up Characteristics

When configured per the standard application, the PTN04050C power module produces a regulated output

voltage following the application of a valid input source voltage. During power up, internal soft-start circuitry slows

the rate that the output voltage rises, thereby limiting the amount of in-rush current drawn from the input

source.Figure 15 shows the power-up waveforms for a PTN04050C, operating from a 5-V input and with the

output voltage adjusted to 12 V. The waveforms were measured with a 1-A resistive load.

Figure 15. Power-Up Waveforms

Overtemperature Protection

A thermal shutdown mechanism protects the module's internal circuitry against excessively high temperatures. A

rise in temperature may be the result of a drop in airflow, a high ambient temperature, or a sustained overcurrent

condition. If the junction temperature of the internal control IC rises excessively, the module turns its boost

operation off. Although the module is off, an output voltage of approximately (V

– 300 mV) is still present. The

module restarts boost operation when the sensed temperature decreases by approximately 10 degrees.

Note: Overtemperature protection is a last resort mechanism to prevent damage to the module. It should not be

relied on as permanent protection against thermal stress. Always operate the module within its temperature

derated limits, for the worst-case operating conditions of output current, ambient temperature, and airflow.

Operating the module above these limits, albeit below the thermal shutdown temperature, reduces the long-term

reliability of the module.

Product Folder Links: PTN04050C