TL783: softstart functionality

Ethan Tan

Prodigy 80 points

Part Number: TL783
Other Parts Discussed in Thread: LM317, , LM317HV

Can this chip use the popular LM317 soft start method?with a HV pnp BJT plus appropriate working voltage capacitor.

Targeted regulated voltage is around 250V or lesser.

over 6 years ago

0 Gerard Copeland over 6 years ago

TI__Genius 10490 points

Hi,

Yes, the same circuit with appropriately rated components can be used to implement a slow startup with the TL783. From the LM317 datasheet:

Please keep in mind that the TL783 device cannot support an output voltage of 250 V as its maximum is 125 V:

Thanks,

Gerard

0 Ethan Tan over 6 years ago in reply to Gerard Copeland

Prodigy 80 points

Hi,if not mistaken,we can operate at that voltage as long as the vi/vo voltage difference is not more than 125V.

0 Gerard Copeland over 6 years ago in reply to Ethan Tan

TI__Genius 10490 points

Hi,

The maximum input to output differential is 125 V, and the output range for this device is 1.25 V to 125 V.

Thanks,

Gerard

0 Ethan Tan over 6 years ago in reply to Gerard Copeland

Prodigy 80 points

Hi Gerard,I being seen people using the LM317 family in HV regulator application,that's why I am wondering the TL783 should do the same.Attached are some circuits for reference.

Feel free to correct me if they are wrong.Thanks!

0 Gerard Copeland over 6 years ago in reply to Ethan Tan

TI__Genius 10490 points

Hi,

The only issue I can see with the schematics is the output voltage. Although other designers may have used these devices in higher voltage applications, it is not recommended to operate these devices outside of the rated output voltage (57 V for the LM317HV and 125 V for the TL783). This is to ensure the device's longevity, consistency, and reliable performance.

Thanks,
Gerard

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TL783: softstart functionality