TPS92513: 输出没有电压

Hi Customer,

Please refer to my comments below:

• For 24V input voltage, you should not use a 20V-rating Schottky diode D20. Please check if your Schottky diode D20 is broken or not.
• Could you provide your LED spec (like voltage and current)?
• For components marked with "NL", does this mean the components are not installed?
• Is there any switching behavior at the PH pin?

Best Regards,

Steven

感谢你的支持，1.经过检查肖特基二极管没有损坏，这种情况下也需要换高耐压的肖特基二极管吗？ 2.我们的led规格是24v的视觉光源，我们这也有3v的发光二极管，如果led规格不适合，我们可以使用多个发光二极管串联。3.对于标有“NL”的元件，你的判断没有错，代表未安装这些元器件。4.ph引脚上没有任何的开关行为

Hi Customer,

Please refer to my comments below:

• Yes. You do need a higher-voltage-rating Schottky diode D20.
• It looks like you are triggering "BOOT UVLO". Please refer to Section 8.4.3 Maximum Duty Cycle and Bootstrap Voltage (BOOT) from the datasheet. 24V input voltage is too low for a 24V-LED. You can try LED with lower forward voltage or try higher input voltage and see if it helps. 

Best Regards,

Steven

输出没有电压已经解决了，我们二极管焊反了；但是现在有个新的问题，就是刚上电的时候led是熄灭状态，当我们用pwm调整占空比以后，led正常发光；但是当我们关闭pwm时，led有微弱的亮光，这是什么导致的；我们已经用示波器看过波形，确定已经没有pwm波了

Hi Customer,

Please check if there is any reverse current on the diode D18 that may flow into the LED.

Best Regards,

Steven

没有，尽管我们把D18去掉，依然有这样的现象，有没有什么方式可以让它停止工作

这个芯片如果是24v输入的话，最低输出电压能达到多少？我使用0.02%占空比的pwm，c33两端依然有19v的电压

Hi Customer,

May I understand what is the forward voltage of the LED you are using now? You can provide the I-V curve if possible.

Best Regards,

Steven

24v的正向电压，I-V曲线我没有资料；只有个淘宝链接：m.tb.cn/h.5Bbdmij

Hi Customer,

Sorry but I cannot open the link you posted.

Again, 24V input voltage is too low for a 24V-LED with TPS92513.

Best Regards,

Steven