TPS92513HV: How many LED in series can be driven by TPS92513 with 60V input and 500mA current?

Hello Kazuya,

From the datasheet:

"The TPS92513 is designed to operate up to 100% duty cycle as long as the BOOT to PH voltage is greater than
at least 2 V. If the BOOT capacitor voltage drops below 2 V, then the BOOT UVLO circuit turns off the MOSFET,
which allows the BOOT capacitor to be recharged. The current required from the BOOT capacitor to keep the
MOSFET on is quite low. Therefore, many switching cycles occur before the BOOT capacitor is refreshed. In this
way, the effective duty cycle of the converter is quite high."

This part will run near 100% duty cycle, the boot capacitor will just need the switch node to cycle for boot refresh every so often.  This is a buck converter so Vout will need to be slightly lower than Vin.

If the LED has a Vf of 3.0 volts it would almost support 20 LEDs however there are a lot of considerations such as LED Vf tolerance, thermal (colder generally means higher Vf), etc.

So in short the output can be almost 60V.

Best Regards,