Abstract: A Totem Pole PFC circuit includes at least one fast-switching leg, a slow-switching leg, and a control unit. Each fast-switching leg includes a fast-switching upper switch and a fast-switching lower switch. The slow-switching leg is coupled in parallel to the at least one fast-switching leg, and the slow-switching leg includes a slow-switching upper switch and a slow-switching lower switch. The control unit receives an AC voltage with a phase angle, and the control unit includes a current detection loop, a voltage detection loop, and a control loop. The control loop generates a second control signal assembly to respectively control the slow-switching upper switch and the slow-switching lower switch. The control loop controls the second control signal assembly to follow the phase angle, and dynamically adjusts a duty cycle of the second control signal assembly to turn on or turn off the slow-switching upper switch and the slow-switching lower switch.

Abstract: An input device with a page turning functionality is used with a set of communication cards, and includes a casing, a clip provided to hold the communication cards together, a processor, a touchpad, a memory, a speaker and a target page reminding device. When at least one communication block on a communication card is pressed, the processor generates a target page signal. The target page reminding device will remind a user to turn to the corresponding page according to the target page signal.

Abstract: A learning device with page indicators includes a case, a touch pad, an electronic control unit and multiple page indicators. When each learning card is placed on the touch pad, the position next to the page actuating mark of each learning card has one corresponding page indicator. When the page actuating mark is touched, the corresponding page indicator is activated.