Abstract: In an embodiment, a method includes: forming a first inter-metal dielectric (IMD) layer over a semiconductor substrate; forming a bottom electrode layer over the first IMD layer; forming a magnetic tunnel junction (MTJ) film stack over the bottom electrode layer; forming a first top electrode layer over the MTJ film stack; forming a protective mask covering a first region of the first top electrode layer, a second region of the first top electrode layer being uncovered by the protective mask; forming a second top electrode layer over the protective mask and the first top electrode layer; and patterning the second top electrode layer, the first top electrode layer, the MTJ film stack, the bottom electrode layer, and the first IMD layer with an ion beam etching (IBE) process to form a MRAM cell, where the protective mask is etched during the IBE process.

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 half-bridge flyback power converter includes: a first transistor and a second transistor which form a half-bridge circuit; a transformer and a resonant capacitor connected in series and coupled to the half-bridge circuit; and a switching control circuit configured to generate a first driving signal and a second driving signal to control the first transistor and the second transistor respectively for switching the transformer to generate an output voltage. The first driving signal is configured to magnetize the transformer. The second driving signal includes at most one pulse between two consecutive pulses of the first driving signal. The switching control circuit generates a skipping cycle period when an output power is lower than a predetermined threshold. A resonant pulse of the second driving signal is skipped during the skipping cycle period. The skipping cycle period is increased in response to the decrease of the output power.

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: 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: The present invention relates to a gasket structure for use in a fuel cell having a separator which defines at each of the both ends thereof a hydrogen manifold, an air manifold, an antifreezing solution manifold between the hydrogen manifold and the air manifold, the structure comprising a plurality of gasket parts a portion of which is open toward the outside of the separator so as to prevent antifreezing solution leaked from the antifreezing solution manifold from flowing into the hydrogen manifold and the air manifold.