LM317HVT versus LM317 Regulators for 9K Power Supply

Is there any benefit to using hte LM317HVT version regulator instead of the LM317?    I'm using the regulator in Keiths 9K power supply for 48V phantom power.

The HVT is rated for higher voltage and the normal 317 seems to be rated up to 37V output which isn't even the 48V that I need.

It looks like they are directly swappable and I was just wondering what you guys have used?  Would the HVT be better? Will it get as hot as the regular 317 i wonder...?

They're both rated 1.5Amps.

The voltage rating is the DIFFERENCE between Vout and Vin. The HVT has a higher voltage differential.

You can swap it with an LM317T. The price difference is minimal between the 2 models.

In 48v applications, the HVT is a better choice. Although in normal operation, the input-output differential voltage is smaller than 37v, in case of short-circuit or in transient operation (start-up) it may be higher. The HVT offers better resilience in these circumstances.

Will it get as hot as the regular 317 I wonder..?

Click to expand...

The main dissipation is given by the input-output voltage difference times output current. This is obviously independent of the regulator chip but rather a question of the surround circuitry, in particular the transformer secondary voltage (or the voltage multiplier design if there is any).

Samuel

in many power supplies is used the normal LM317 for the 48V power and not its HV version.
Often,  back of the LM317 there are 60-70V that's more the difference between Vout and Vin
of the LM317, but, in these circuits, this voltage  (Vout-Vin of the 317) isn't never exceeded, so to use the HV version is needless.

ppa said:

in many power supplies is used the normal LM317 for the 48V power and not its HV version.
Often,  back of the LM317 there are 60-70V that's more the difference between Vout and Vin
of the LM317, but, in these circuits, this voltage  (Vout-Vin of the 317) isn't never exceeded, so to use the HV version is needless.

Click to expand...

This is true for steady-state operation, but at start-up, the output voltage is zero, and the input voltage is almost instantly reaching its nominal value. During this period, the regulator may suffer. same if a short-circuit happens at the output.

again, it's commonly used for 48v regulation, but if you're worried, use a soft-start circuit ahead of it...

abbey road d enfer said:

ppa said:

in many power supplies is used the normal LM317 for the 48V power and not its HV version.
Often,  back of the LM317 there are 60-70V that's more the difference between Vout and Vin
of the LM317, but, in these circuits, this voltage  (Vout-Vin of the 317) isn't never exceeded, so to use the HV version is needless.

Click to expand...

This is true for steady-state operation, but at start-up, the output voltage is zero, and the input voltage is almost instantly reaching its nominal value. During this period, the regulator may suffer. same if a short-circuit happens at the output.

Click to expand...

The problem is carging the cap used to increase the +48V power supply S/N value,
the LM317 at start-up operation carge this cap, if this cap carging is too slow the LM317's Vout-Vin may exceed the 37V. If the circuit was designed fine there are no problems.