malli_1729
Full Member level 5
Hi!
I am new to this forum.
I have a design in which i have difficulty in understanding one part of it. I am attaching the partial circuit of it.
I am just giving small description about the circuit i attached.
This circuit basically a Flyback converter. In the attached diagram the Left hand side is Rectified and filtered AC signal from mains and has secondary winding of the transformer on right side which shown as a block. From it feedback is given to NCP1027(Swither) through Opto coupler.
The HV pin of NCP1027 is just a Drain connection of internal MOSFET and Source of it is connected to GND. As far as i know the Purpose of the circuit(R18,TVS2,D10 and D12) is to Clamp the voltage when over voltage above some 650V comes. TVS2 has clamping voltage as 648V and reverse srandoff voltage as 400V.Here i don't know what's the purpose these 2 diodes D10 and D12. I believe we can directly connect TVS2 to GND instead of connecting to GND through these diodes.
if anybody can share thier ideas regarding these diodes D10 and D12 why they have placed these instead of GNDing the TVS2 Directly .
It will be very helpful to me.
Thank you.
I am new to this forum.
I have a design in which i have difficulty in understanding one part of it. I am attaching the partial circuit of it.
I am just giving small description about the circuit i attached.
This circuit basically a Flyback converter. In the attached diagram the Left hand side is Rectified and filtered AC signal from mains and has secondary winding of the transformer on right side which shown as a block. From it feedback is given to NCP1027(Swither) through Opto coupler.
The HV pin of NCP1027 is just a Drain connection of internal MOSFET and Source of it is connected to GND. As far as i know the Purpose of the circuit(R18,TVS2,D10 and D12) is to Clamp the voltage when over voltage above some 650V comes. TVS2 has clamping voltage as 648V and reverse srandoff voltage as 400V.Here i don't know what's the purpose these 2 diodes D10 and D12. I believe we can directly connect TVS2 to GND instead of connecting to GND through these diodes.
if anybody can share thier ideas regarding these diodes D10 and D12 why they have placed these instead of GNDing the TVS2 Directly .
It will be very helpful to me.
Thank you.
