Other Parts Discussed in Thread: TIDA-00200
Dear Sir/Madam,
With the TIDA-00200 Reference Design, I am now testing the channel 1 of the LM5032 chip with the Channel 2 disabled purposely without the feedback loop (I just want to see how the LM5032 performs).
I applied a 1.3V voltage to the UVLO pin and a 7.7V voltage to the VCC pin. The RT pin is connected to a 86.6 kohm resistor to ground while the DCL pin is connected to a 200 kohm to ground as suggested by the TIDA-00200 design. I did not apply any voltage to the CS1 pin. I apply an external voltage source to the pin 2 of the Opto-Coupler (I did not solder the feedback Opamp of U3A to the board). When I adjust the voltage source connected to the pin2 of the Opto-Coupler, I can see the PWM signal's Duty Cycle at the OUT1 pin of LM5032 varying accordingly. However, the maximum duty cycle I can achieve is 50% no matter how I tune the magnitude of the voltage at the pin2 of the Opto-Coupler.
I checked the datasheet of LM5032, it says as long as RDCL is larger than RT, the Max Duty Cycle should be 80%. As in my case, the Max D is 50%, is it because I did not apply any voltage to the CS1 pin? Can you please help me on this?
Thanks
Lin
