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I've been trying to get a -24V output out of the following circuit, but the voltage readings I've been getting are below 0.3V. The input voltage comes from a battery with a maximum voltage of 29.6V and a minimum voltage of 24V.
Hello Katelyn,
Thank you for your support.
The voltage measure at VCC is 7.5V. Nothing significant was observed at SW, which is a problem. What could be causing this?
Yours truly,
Louis-Normand
Hello Katelyn,
Sorry for the late reply, I was out of the office last week.
I removed the R9 resistor and took a couple oscilloscope captures, that are here attached. It doesn't seem like much has changed.
drive.google.com/.../1ULh9hokaVSaH4EPvhhF_IZpIuZeJ4K_f
I also tried using the circuit calculator, but the switching frequency is limited in the spreadsheet. My circuit had been designed with a 300kHz frequency in mind.
Best Regards,
Louis-Normand
Hello,
Thank you for sharing the screen captures. It seems this device is not switching under these conditions.
Looking at the schematic again there is not a bulk input capacitor. This could be causing your issue. Could you add a Cin of 47uF to VIN to -VOUT, and add the Cin of 10uF from VIN to ground?
Thanks,
Katelyn
Hello,
I want to follow up with you. Did you get a chance to trying adding the additional capacitance from VIN to Ground and VIN to VOUT?
Thank you,
Katelyn
Hello,
Due to inactivity, I am going to close this thread. Please feel free to respond to this post in order to reopen the thread.
Thanks,
Katelyn