Transformer design for CY8CLEDAC01 circuits | Cypress Semiconductor
Support & Community
Transformer design for CY8CLEDAC01 circuits
Last Updated: April 11, 2011
How is the turns ratio of the transformer using in CY8CLEDAC01 circuit determined?
The flyback circuit of CY8CLEDAC01 consists of the power MOSFET (primary switch) and the output diode (secondary switch) as the key switching components. The transformer's turns ratio (NTR) determines the voltage stress seen by these switching components. Based on the breakdown voltages of the selected output diode and FET minimum, the minimum and maximum allowed turns ratio can be computed.
In addition to the MOSFET breakdown voltage, the maximum turns ratio NTR(Max) is also determined by the switching frequency fsw. This is given by the equation below. The maximum turns ratio allowed is given by the lower of the two values.
Please refer the detailed design guidelines described in the application note AN66317 at the following link: