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LT4320 based active rectifier

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#161
#165
Dear all,
Here is the schematics THT and SMD boards.
I have given a rough indication of type of MOSFETS suitable for the application.
While this isnt a strict requirement use particular mosfet, do follow the guidelines given in the below post by me .
LT4320 based active rectifier
and very comprehensively by Tibi
LT4320 based active rectifier


I still would like to retain the optional pads for electro cap just in case of someone's implementation makes it far away from main filter caps.
Also, retained is the optional led indicator for smd, but I would recommend LED+ resistor only for low-medium voltage application (12-35V) where dissipation through resistor can be controlled well within the rated power. https://www.mouser.in/datasheet/2/392/n_catalog_partition24_en-948804.pdf
As informed by Tibi, there no absolute need for either electro cap or LED indicator.

Regards
Prasi
 

Attachments

  • schema-ideal BR_SMD_New SO-8 mosfet.png
    schema-ideal BR_SMD_New SO-8 mosfet.png
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  • SCH-TO-220-LT4320 RECTIFIER.png
    SCH-TO-220-LT4320 RECTIFIER.png
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#167
Hello Rainfallsky,
At an appropriate time when the boards are about to be delivered , I will send out a Paypal invoice to every subscriber. Thats when one needs to make the payment.
Inbox is now good to go. Sorry for the inconvenience.
Regards
Prasi

P.S. 500 PM storage capacity and still it gets full. I need to find a way to retrieve DIYA xml export so that I can refer old PMs when required.
 
#176
I am not EE too just trying to understand things in a subject where I floating. )
But snubber is definately for dumping transformer secondary so it wont ring.
I just remembered Mark Johnson article in Linear Audio where he tests a lot of diodes.
Introduction was that in PSU diode switch-off generates a current spikes (dl/dt).
Large spikes stimulate transformer oscillatory ringing. (very simplified)
Part of conclusion was that in the end all diodes more or less produce transformer ringing. (thats how I understand it)
What I wanted to ask, does LT4320+FETs active rectifier produce same thing (ringing)?
 
#179
On the SLB PSU which uses the LT4320, the rectified output is a clean sawtooth with no switch noise or ringing - this is because the MOSFETs are time phased to switch at zero crossover. Whereas diodes switch at 0.6v. There is also minimal heat if low RDson MOSFETs are used. I measure 35C for 4.4A current with no heatsinks. If the active bridge is used with a properly designed CRC (note that you do *not* want low ESR caps here to reduce the ripple current which can overheat a bulk cap). and in my case 15,000uF // 0.2R // 15,000uF and a CFP Cap MX, the output ripple was measured at sub mV rms for 4A SE Class A amp load. See yellow trace below. After seeing measured performance of the LT4320 and hearing how clean it sounds, plus fact that it generates no heat - the classic Si diode bridge is dead to me for high current Class A applications. There is no going back - It is just better in every way. I have a bunch of CRC and CRCRC PSU boards that use TO220 diodes. Not sure if I will ever use them now unless I adapt them to use LT4320 active bridge.

755128d1557282091-slb-smooth-butter-active-rect-crc-cap-mx-class-power-supply-gb-f24d7a01-4828-4e07-ab9b-cca3c862e232-jpeg
 
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