Abstract: A switching control circuit for use in controlling a resonant flyback power converter generates a first driving signal and a second driving signal. The first driving signal is configured to turn on the first transistor to generate a first current to magnetize a transformer and charge a resonant capacitor. The transformer and charge a resonant capacitor are connected in series. The second driving signal is configured to turn on the second transistor to generate a second current to discharge the resonant capacitor. During a power-on period of the resonant flyback power converter, the second driving signal includes a plurality of short-pulses configured to turn on the second transistor for discharging the resonant capacitor. A pulse-width of the short-pulses of the second driving signal is short to an extent that the second current does not exceed a current limit threshold.

Abstract: A resonant flyback power converter includes: a first transistor and a second transistor which are configured to switch a transformer and a resonant capacitor for generating an output voltage; and a switching control circuit generating first and second driving signals for controlling the first and the second transistors. The turn-on of the first driving signal magnetizes the transformer. The second driving signal includes a resonant pulse having a resonant pulse width and a ZVS pulse during the DCM operation. The resonant pulse is configured to demagnetize the transformer. The resonant pulse has a first minimum resonant period for a first level of the output load and a second minimum resonant period for a second level of the output load. The first level is higher than the second level and the second minimum resonant period is shorter than the first minimum resonant period.

Abstract: A resonant flyback power converter includes: a first and a second transistors which form a half-bridge circuit for switching a transformer and a resonant capacitor to generate an output voltage; a current-sense device for sensing a switching current of the half-bridge circuit to generate a current-sense signal; and a switching control circuit generating a first and a second driving signals for controlling the first and the second transistors. The turn-on of the first driving signal controls the half-bridge circuit to generate a positive current to magnetize the transformer and charge the resonant capacitor. The turn-on of the second driving signal controls the half-bridge circuit to generate a negative current to discharge the resonant capacitor. The switching control circuit turns off the first transistor when the positive current exceeds a positive-over-current threshold, and/or, turns off the second transistor when the negative current exceeds a negative-over-current threshold.

Abstract: A resonant flyback power converter includes: a first transistor and a second transistor which are configured to switch a transformer and a resonant capacitor for generating an output voltage; and a switching control circuit generating first and second driving signals for controlling the first and the second transistors. The turn-on of the first driving signal magnetizes the transformer. During a DCM (discontinuous conduction mode) operation, the second driving signal includes a resonant pulse for demagnetizing the transformer and a ZVS (zero voltage switching) pulse for achieving ZVS of the first transistor. The resonant pulse is skipped when the output voltage is lower than a low-voltage threshold.

Abstract: The present disclosure provides an operating method of a dopamine transporter check system, and the operation method includes steps as follows. A scan image of a subject's brain is obtained from a scan machine, and the scan image is a three-dimensional image. The scan image is aligned to a standard brain space to obtain a standardized scan image. Intensity normalization is performed on the standardized scan image. The standardized scan image after the intensity normalization is converted into a two-dimensional image. A plurality of image data are got from at least one region of interest in the two-dimensional image, and the at least one region of interest includes a left caudate, a left putamen, a right caudate and a right putamen. A dopamine neuron loss degree measurement and evaluation model based on the image data is established through a transfer learning.

Abstract: The present disclosure provides an operating method of a dopamine transporter check system, and the operation method includes steps as follows. A scan image of a subject's brain is obtained from a scan machine, and the scan image is a three-dimensional image. The scan image is aligned to a standard brain space to obtain a standardized scan image. Intensity normalization is performed on the standardized scan image. The standardized scan image after the intensity normalization is converted into a two-dimensional image. A plurality of image data are got from at least one region of interest in the two-dimensional image, and the at least one region of interest includes a left caudate, a left putamen, a right caudate and a right putamen. A dopamine neuron loss degree measurement and evaluation model based on the image data is established through a transfer learning.