Method of controlling a switching converter in burst mode and related controller for a switching converter

A controller suitable for a switching converter, the controller comprising:

• an input terminal configured to receive an error signal, representative of a difference between a regulated DC voltage or current and a nominal output voltage or current;
• a switching controller configured to control in a burst mode a switching stage to increase the regulated DC voltage or current by performing switching cycles synchronously with active edges of a clock signal for switching an energy tank circuit of the converter between a positive voltage line and a negative voltage line, or to decrease the regulated DC voltage or current when an error signal, representative of a difference between the regulated DC voltage or current and the nominal output voltage or current, surpasses a burst-stop threshold,
• means for:
• sensing a difference between the error signal and the burst-stop threshold at a beginning of a burst period;
• determining an integer first number based on the difference between the error signal and the burst-stop threshold at a beginning of a burst period;
• if the error signal has surpassed the burst-stop threshold:
• causing the switching controller to set the switching stage in a high impedance state at a new active edge of the clock signal,
• causing the switching controller to keep the switching stage in the high impedance state for a number of cycles of said clock signal equal to the first number, and
• causing the switching controller to re-enable the switching stage to switch the energy tank circuit until an end of the burst period.

A resonant switching converter configured to output in operation a regulated DC voltage or current, comprising:

• an energy tank circuit;
• a feedback path configured to generate in operation an error signal;
• and
• a controller circuit configured to:
• receive said error signal,
• control in a burst mode a switching stage to increase the regulated DC voltage or current by performing switching cycles synchronously with active edges of a clock signal for switching the energy tank circuit of the converter between a positive voltage line and a negative voltage line, or to decrease the regulated DC voltage or current when the error signal, representative of a difference between the regulated DC voltage or current and the nominal output voltage or current, surpasses a burst-stop threshold,
• sense a difference between the error signal and the burst-stop threshold at a beginning of a burst period;
• determine an integer first number based on the difference between the error signal and the burst-stop threshold at a beginning of a burst period;
• if the error signal has surpassed the burst-stop threshold:
• set the switching stage in a high impedance state at a new active edge of the clock signal,
• keep the switching stage in the high impedance state for a number of cycles of said clock signal equal to the first number, and
• re-enable the switching stage to switch the energy tank circuit until an end of the burst period.

A controller suitable for a switching converter with an energy tank circuit the controller comprising:

• an input terminal configured to receive an error signal, representative of a difference between a regulated DC voltage or current and a nominal output voltage or current;
• a switching controller configured to control a switching stage of the switching converter;
• a sense circuit configured to sense a difference between the error signal and a burst-stop threshold at a beginning of a burst period and determine an integer first number based on the difference between the error signal and the burst-stop threshold at a beginning of a burst period;
• and
• a comparator configured to determine if the error signal has surpassed the burst-stop threshold and cause the switching controller to set the switching stage in a high impedance state at a new active edge of a clock signal;
• the switching controller being configured to keep the switching stage in the high impedance state for a number of cycles of said clock signal equal to the first number, and to re-enable the switching stage to switch the energy tank circuit until an end of the burst period.