Abstract: A frequency-locked circuit for a variable frequency topology is configured to trigger a Pulse Width Modulation (PWM) controller to lock a frequency of a driving signal outputted by the PWM controller. The frequency-locked circuit includes an AC wave generating circuit and a comparator. The AC wave generating circuit receives and converts the driving signal to generate an AC wave signal. The comparator is electrically connected to the AC wave generating circuit and receives the AC wave signal. The comparator compares the AC wave signal with a reference signal to generate a comparison output signal. In response to determining that the AC wave signal is greater than the reference signal, the comparison output signal triggers the PWM controller to convert the driving signal from one voltage level to another voltage level so as to lock the frequency. The one voltage level is different from the another voltage level.

Abstract: A power supply apparatus (10) suppressing a transient voltage is applied to an input voltage (50). The power supply apparatus (10) includes a power supply circuit (20), a feedback signal generation circuit (30) and a feedback signal control circuit (40). If the power supply circuit (20) stops receiving the input voltage (50), the feedback signal control circuit (40) controls the feedback signal generation circuit (30) to discharge so that the feedback signal generation circuit (30) controls the power supply circuit (20) to decrease an output voltage (60), so that when the power supply circuit (20) receives the input voltage (50) again, the power supply circuit (20) avoids generating an output overvoltage condition for the output voltage (60).

Abstract: A power supply apparatus (10) suppressing a transient voltage is applied to an input voltage (50). The power supply apparatus (10) includes a power supply circuit (20), a feedback signal generation circuit (30) and a feedback signal control circuit (40). If the power supply circuit (20) stops receiving the input voltage (50), the feedback signal control circuit (40) controls the feedback signal generation circuit (30) to discharge so that the feedback signal generation circuit (30) controls the power supply circuit (20) to decrease an output voltage (60), so that when the power supply circuit (20) receives the input voltage (50) again, the power supply circuit (20) avoids generating an output overvoltage condition for the output voltage (60).