Original question:
SN6505A: Spread Spectrum Range & Cycle/Maximum Turns Ratio/Dead Time
When increasing the temperature of driver upto 85'C ,the D1,D2 dead time current drastically increases to 2A-4A AND Output voltages decreases.
During higher temperature the Driver Transformer behavior becomes abnormal.
Driver :SN6505A
Transformer used is :760390014
Hi Vijaykumar, and welcome to E2E!
At temperatures above 85dC, many Schottky diodes' reverse leakage current increases into the millamp range, and this is not acceptable for push-pull topologies. A possible solution to this issue is to simply replace the Schottky diodes with low-leakage ones like RB168MM-40. Please do let us know if this is or isn't helpful, and meanwhile feel free to refer to the E2E thread below for context from a similar issue:
Have a great day,
Manuel Chavez
Hi Vijaykumar,
Another potential reason for collapse of an isolated power supply comes from the transformer's V-t product. At Vcc = 5V, the SN6505A should be paired with transformers having V-t products of 20V-μs and greater. The transformer used here, 760390014, has a V-t product of 11V-μs which is definitely too low for SN6505A. In this case, SN6505B can be used since it requires a V-t product of only 8Vμs or greater.
Alternatively, the transformer can be replaced to one with a V-t product of 20Vμs or greater to use with the SN6505A. If you'd like assistance selecting a transformer, please let me know the desired operating voltages and turns ratio.
Below is a similar thread occurring in parallel for reference:
Best,
Manuel Chavez
PSA: Original post edited to include SN6505B option
