TIDA-010054: TIDA-010054

Hi Martin,

You are correct that for average current control, we need DC blocking capacitors to block the DC offset developing in the transformer when operated over extended periods. Ideally, we need a number of ceramic capacitors connected in parallel to handle the RMS currents. In TIDA-010054, we have placeholder for the capacitance and wanted to experiment the performance with and without the capacitance. But as you told we will need a bank of capacitors. Currently the series capacitor used is around 3uF and you will typically need 10 small 300nF ceramic capacitors in parallel for this application depending on your current levels.

The following link can be helpful in selecting the dc capacitor for the application.

https://electronics.stackexchange.com/questions/286566/how-do-i-calculate-the-correct-value-for-a-capacitor-block-dc

Please let me know if you have any further questions.

Thank you

Hi Harish

Thank you for your answer. If I understand correctly in TIDA-010054, you do not have peak current mode controll and you have DC blocking capacitor in placeholder on the primary side.

My next question is: Do I have to use DC blocking capacitor on the secondary side too, when the the energy is transfering from secondary side to primary side and therefore transformer is driven from secondary? Or necessary is only one DC blocking capacitor on the primary side if I will not use peak current mode control for both direction of energy transfer. 

In TIDA-010054 you dont have this capacitor.

Hi Martin,

Yes we need to have DC blocking capacitor on the secondary as well when transferring power from secondary to primary side as shown below.

In the above circuit the leakage inductance is symmetrically split between the primary and secondary sides and DC blocking capacitors are added in the primary and secondary, In other cases, to balance common mode impedance, four identical inductors instead of one inductor are used in the design but this is rarely used as shown below

Please let me know if you have any other questions.

Thank you

Hi Harish

The result from this our conversation is: If we will not use peak current mode control, we must have DC blocking capacitor on the primary and secondary side too, like it is shown on the upper schematics.

Do you agree?

Hi Martin,

Yes, you are correct.

Thank you