An active discharge circuit discharges an X capacitor and includes a sensor circuit that generates a sensor signal indicative of an AC voltage at the X capacitor. A processing unit generates a reset signal as a function of a comparison signal. A comparator circuit generates the comparison signal by comparing the sensor signal with a threshold. A timer circuit sets a discharge enable signal to a first logic level when the timer circuit is reset via a reset signal. The timer circuit determines the time elapsed since the last reset and tests whether the time elapsed exceeds a given timeout value. If the time elapsed exceeds the given timeout value, the timer circuit sets the discharge enable signal to a second logic level. A dynamic threshold generator circuit varies the threshold of the comparator circuit as a function of the sensor signal.

An active discharge circuit discharges an X capacitor and includes a sensor circuit that generates a sensor signal indicative of an AC voltage at the X capacitor. A processing unit generates a reset signal as a function of a comparison signal. A comparator circuit generates the comparison signal by comparing the sensor signal with a threshold. A timer circuit sets a discharge enable signal to a first logic level when the timer circuit is reset via a reset signal. The timer circuit determines the time elapsed since the last reset and tests whether the time elapsed exceeds a given timeout value. If the time elapsed exceeds the given timeout value, the timer circuit sets the discharge enable signal to a second logic level. A dynamic threshold generator circuit varies the threshold of the comparator circuit as a function of the sensor signal.

A voltage spike measurement circuit for a power switch includes a rectifier unit, a capacitive divider unit and a discharge unit, the rectifier unit configured to receive a voltage signal at both ends of a power switch and output a rectified signal; the capacitive divider unit includes at least two capacitors connected in series and configured to receive the rectified signal, divide the rectified signal based on a capacitance ratio of the at least two capacitors, and output a divider signal to a digital signal processor to calculate a voltage spike measurement value of the power switch; and the discharge unit connected in parallel to the capacitive divider unit.

A voltage spike measurement circuit for a power switch includes a rectifier unit, a capacitive divider unit and a discharge unit, the rectifier unit configured to receive a voltage signal at both ends of a power switch and output a rectified signal; the capacitive divider unit includes at least two capacitors connected in series and configured to receive the rectified signal, divide the rectified signal based on a capacitance ratio of the at least two capacitors, and output a divider signal to a digital signal processor to calculate a voltage spike measurement value of the power switch; and the discharge unit connected in parallel to the capacitive divider unit.

A startup control method for a DC/DC converter is used for starting the DC/DC converter with energy transferred from a low-voltage side to a high-voltage side, and includes: acquiring a voltage spike measurement value of a power switch at the low-voltage side; determining a duty cycle or a frequency of a driving signal according to the voltage spike measurement value and a preset voltage; and outputting the driving signal to a power switch at the high-voltage side, thereby charging a clamping capacitor of the power switch at the low-voltage side. The startup control method for a DC/DC converter of the disclosure can improve a reverse charging power of the converter to the maximum extent and reduce the time needed for charging a bus capacitor during a reverse startup process while ensuring voltage stress on the power switch not to exceed a limit.

A startup control method for a DC/DC converter is used for starting the DC/DC converter with energy transferred from a low-voltage side to a high-voltage side, and includes: acquiring a voltage spike measurement value of a power switch at the low-voltage side; determining a duty cycle or a frequency of a driving signal according to the voltage spike measurement value and a preset voltage; and outputting the driving signal to a power switch at the high-voltage side, thereby charging a clamping capacitor of the power switch at the low-voltage side. The startup control method for a DC/DC converter of the disclosure can improve a reverse charging power of the converter to the maximum extent and reduce the time needed for charging a bus capacitor during a reverse startup process while ensuring voltage stress on the power switch not to exceed a limit.

A semiconductor device having a switch circuit and an integrated circuit. The switch circuit includes serially-connected first and second switching devices respectively on a power supply side and a ground side thereof, and first and second free-wheeling diodes connected respectively in parallel with the first and second switching devices. The integrated circuit performs switching of the second switching device, and including a detection circuit that detects a load current flowing through a load of the switch circuit, and a drive circuit that controls magnitude of a current flowing to the gate terminal of the second switching device, to thereby charge a gate capacitance of the second switching device according to a detection result of the detection circuit, when a received drive signal is at one logic level, and turns off the second switching device when the received drive signal is at another logic level.

Some embodiments described herein include an apparatus having a processor communicatively coupled to a memory. The processor is configured to monitor, at a characteristic controller, a first characteristic of an electronic device. The processor is then configured to receive side-channel signature analysis of the electronic device from a signature analyzer. The processor is configured to determine if the first characteristic of the electronic device has changed or will change in a predefined period of time based on the side-channel signature analysis. The processor is then configured to adjust a second characteristic of the electronic device and/or filtering characteristics such that the side-channel signature analysis reflects predefined side-channel behavior.

Some embodiments described herein include an apparatus having a processor communicatively coupled to a memory. The processor is configured to monitor, at a characteristic controller, a first characteristic of an electronic device. The processor is then configured to receive side-channel signature analysis of the electronic device from a signature analyzer. The processor is configured to determine if the first characteristic of the electronic device has changed or will change in a predefined period of time based on the side-channel signature analysis. The processor is then configured to adjust a second characteristic of the electronic device and/or filtering characteristics such that the side-channel signature analysis reflects predefined side-channel behavior.

Certain aspects of the present disclosure are generally directed to circuitry and techniques for adjusting an audio signal to avoid undesirable system behavior under low alternating-current (AC) line voltage and high volume conditions. For example, certain aspects provide an apparatus for audio amplification. The apparatus generally includes an amplifier, a supply voltage generation circuit having an input coupled to an input voltage node of the apparatus and an output coupled to a supply voltage terminal of the amplifier, the supply voltage generation circuit having a transformer, a primary winding of the transformer being coupled to the input voltage node, a peak voltage detector circuit configured to detect a peak voltage at a secondary winding of the transformer, and a controller circuit configured to adjust an input audio signal of the amplifier based on the detected peak voltage.