The LT4320 based IB-CAP Power Supply is designed in a very compact size and provides unregulated symmetrical or dual voltage output, high voltage, high current for your demanding needs and is ideally suited for use in Audio Amplifier design projects.
At the output Film-Foil capacitors (KP) are placed for best Audio experience.
Recommended for Power Amplifiers up to 600W or as oversized power supply for other Audio applications with less power need.
Options
The IB-CAP power supply is available with or without smoothing capacitors. Choosing to use your own capacitors (25mm diameter or less, 10mm grid), order the option "without capacitors".
Beside that both versions are same and are delivered assambled and tested. Using the IB-CAP power supply with symmetrical output, it's simply necessary to connect two output terminals with a wire. If not connected, both rails are and work completely independetly.
"Ideal Diode Bridge" rectification
What makes this IC-CAP power supply very special, is it's rectifier:
The LT4320 is an "Ideal Diode Bridge" controller that drives four MOSFET's resulting reduced power dissipation and heat, two separate secondaries are necessary to power the IB-CAP PS (no center-tapped).
Comparing to usually used diodes with a voltage drop of ~ 1,7V, the MOSFETs with their resistance of ~ 0,012 Ohm cause a minimal voltage drop only. This makes it possible to use smaller transformers regarding their output voltage and their power rating.
Please notice, that the controller needs 9VDC to work, this should be considered choosing the transformer VAC.
Due to the controller's voltage limit, the maximum voltage must not exceed 70VDC - the ripple, the higher voltage during no-load operation and the fluctuation in the mains voltage must consider that.
The maximum voltage must also consider the capacitor's maximum voltage, which is 63V at the here offered combo. We recommend a transformer voltage of max. <40VAC for that capacitors.
Anti-transformer-ringing snubber
The IB-CAP power supply has a snubber option, which makes it possible to significantly reduce transformer ringing for both rails. Please see "Quasimodo PCB" for more information. In case of ordering this power supply with a transformer, the snubber will already be configured. In case it's ordered alone, the two film capacitors will be delivered unpublished, to measure your transformer and publish necessary parts (a resistor is necessary, it's resistance is to find out with Quasimodo).
The IB-CAP power supply can also be used without a snubber.
Filtering
Beside the 8 capacitors with 54.400uF per rail (63V version as offered here), the IB-CAP Power Supply offers a Passive RC Low Pass Filter with -3dB@50Hz (see chart above for RC-characteristic) to reach a "smooth" ripple voltage. MPAudio uses four 5W resistors per rail for enough headroom and good heat dissipation. With the RC-filter the IB-CAP power supply is the best choice for Class AB and Class A designs, as well as for any other Power Amplifier design, which might benefit of a lower ripple.
At the ouput massive "4 pins screw terminals" ensure the right contact also for devices with high current need. Alternatively wires can be soldered directly to the PCB-holes.
For best heat dissipation, a cutout is implemented below the resistors.
We recommend to use a current limiter circuit between the transformer and the IB-CAP PS.
Visit also our FAQ / Bloq to learn more aboure transformers.
The last chart contains the results during a load of 0 - 3A to demonstrate the benefit of the controller based rectification (higher VDC) and the filter (smooth ripple voltage).
Please note, that even with capacitors rated to 80V, the output voltage has to be calculated according to the controller's maximum voltage of 72V. It should also be mentioned, that the transformer's voltage is higher without load - the maximum voltage must stay below 72V in any case.