Adaptive open-load overvoltage control method and circuit

A method of overvoltage protection, comprising:

• setting an overvoltage limit for a power supply circuit to a first value that is higher than a safety limit defined for the power supply circuit;
• detecting that an output voltage of the power supply circuit reaches the overvoltage limit;
• in response to detecting that the output voltage reaches the overvoltage limit, changing the overvoltage limit to a second value that is lower than the safety limit and deactivating the power supply circuit;
• waiting for a first predetermined time period after the deactivation of the power supply circuit, and then determining whether the output voltage of the power supply has discharged to below a third value, the third value being lower than the safety limit;
• responsive to determining that the output voltage has discharged to below the third value, reactivating the power supply circuit;
• determining whether the output voltage of the power supply circuit reaches the second value of the overvoltage limit after each occurrence of reactivating the power supply circuit;
• and
• deactivating the power supply circuit for each occurrence of the output voltage reaching the second value.

A power supply circuit configured to provide power to a load and configured to provide overvoltage protection at an output of the power supply circuit, the power supply circuit comprising a voltage source and a controller configured to control the voltage and current output from the power supply, the controller including an overvoltage protection circuit operable to:

• set an overvoltage limit for the power supply circuit to a first value that is higher than a safety limit defined for the power supply circuit;
• detect that an output voltage of the power supply circuit reaches the overvoltage limit;
• in response to detecting that the output voltage reaches the overvoltage limit, change the overvoltage limit to a second value that is lower than the safety limit and deactivate the power supply circuit;
• subsequently reactivate the power supply circuit;
• determine whether the output voltage of the power supply circuit reaches the second value of the overvoltage limit after each occurrence of reactivation of the power supply circuit;
• and
• deactivate the power supply circuit for each occurrence of the output voltage reaching the second value.