BOOST CONVERTER WITH A PULSE FREQUENCY MODULATION MODE FOR OPERATING ABOVE AN AUDIBLE FREQUENCY

摘要

The embodiments discussed herein relate to systems, methods, and apparatus for executing a pulse frequency modulation (PFM) mode of a boost converter in order to ensure that a switching frequency of the boost converter is a above an audible frequency threshold. In this way, a user operating a display device that is controlled by the boost converter will not be disturbed by audible noises generated at the display device. The PFM mode enforces an audible frequency threshold by using control circuitry designed to increase or decrease the frequency of a pulse signal depending on how the frequency of the pulse signal changes over time. The control circuitry can apply an additional load to the boost converter in order to increase the frequency of the pulse signal when the frequency is approaching the audible frequency threshold.

主权项

1. A control circuit for a display device, the control circuit comprising:
a boost circuit configured to output a switching signal to a subsystem of the display device based on a minimum frequency threshold; and a timing circuit configured to detect pulses in the switching signal, wherein, when the timing circuit does not detect a pulse in the switching signal before a cycle period of the timing circuit expires, the cycle period restarts and timing circuit causes the boost circuit to output a supplemental pulse to ensure that a frequency of the switching signal stays above the minimum frequency threshold.