2
\$\begingroup\$

enter image description here

What is the maximum voltage that appears on a boot-strap capacitor? For example, in this circuit, does \$C_B\$ ever charge to a voltage level near \$600V \pm V_{cc}\$ ? Or does it charge to \$V_{cc}\$ at most?

\$\endgroup\$
1
\$\begingroup\$

In normal circumstances the voltage on the boot pin will be about 12 to 15 volts higher than the voltage on the source pin and this is due to the charge on the boot capacitor. As this cap connects between boot and source this is the voltage seen across it normally.

However, if your circuit shuts down with a load connected to the high voltage and source the cap will need to be rated at the full power rail because one side will be taken to the high power rail by the load and the other will decay to 0 volts.

The reverse voltage rating on the diode needs to be at the full power rail by the way.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.