An integrated circuit can comprise an output terminal, a power transistor having a first current electrode coupled to the output terminal and a second current electrode coupled to a power supply terminal, a driver having an output coupled to a control electrode of the power switch, a capacitor having a first terminal coupled to the output terminal and a second terminal coupled to a circuit node, a first low pass filter coupled between the circuit node and an input of the driver, the first low pass filter having a first cut off frequency, a set of current sources, and a second low pass filter coupled between the circuit node and an output of the set of current sources. The second low pass filter can have a second cut off frequency that is higher than the first cut off frequency.

In a method of operating a circuit, at a beginning of a first edge of a driving signal, a first transistor is turned ON to pull, at a first changing rate, a voltage of the driving signal on the first edge from a first voltage toward a second voltage. Then, in response to the voltage of the driving signal on the first edge reaching a threshold voltage between the first voltage and the second voltage, the first transistor is turned OFF and an output circuit is caused to start a second edge of an output signal in response to the first edge of the driving signal. The second edge has a slew rate corresponding to a second changing rate of the voltage of the driving signal on the first edge from the threshold voltage toward the second voltage. The second changing rate is smaller than the first changing rate.

A load control device for controlling power delivered from an AC power source to an electrical load may have a closed-loop gate drive circuit for controlling a semiconductor switch of a controllably conductive device. The controllably conductive device may be coupled in series between the source and the load. The gate drive circuit may generate a target signal in response to a control circuit. The gate drive circuit may shape the target signal over a period of time and may increase the target signal to a predetermined level after the period of time. The gate drive circuit may receive a feedback signal that indicates a magnitude of a load current conducted through the semiconductor switch. The gate drive circuit may generate a gate control signal in response to the target signal and the feedback signal, and render the semiconductor switch conductive and non-conductive in response to the gate control signal.

The present invention discloses a USB signal output circuit having reverse current prevention mechanism. A switch circuit turns on when a switch control terminal receives a first high level voltage to output a signal from a signal input terminal to a signal output terminal. A first voltage pull-low circuit includes a passive-component high-pass filter circuit and a discharging circuit. The passive-component high-pass filter circuit couples an output terminal voltage of the signal output terminal to a pull-low control terminal. The discharging circuit turns on when a voltage of the pull-low control terminal is larger than a predetermined voltage level to discharge the switch control terminal to pull the switch control terminal to a second high level voltage. A second voltage pull-low circuit pulls the switch control terminal to a low level voltage when the output terminal voltage is larger than a reference voltage and does not have a glitch.

A change rate control circuit computes a first drive speed, which is a gate drive speed of a gate of a drive-subject element, for controlling a change rate of an element voltage of the drive-subject element at a target change rate during a change period. A timing generating circuit acquires, in advance, a delay time caused when the gate is driven and determines a switching timing, at which the element voltage reaches a switching threshold voltage which is lower than a desired switching voltage by a predetermined value, during turn-off of the drive-subject element and generates a timing signal representing the switching timing. A speed change circuit changes the gate drive speed from the first drive speed to a second drive speed at the switching timing during turn-off of the drive-subject element.

A method for controlling an electrical switch using a driver waveform, wherein the driver waveform comprises: a first time period, T.sub.1, associated with a first current, I.sub.G_high; a second time period, T.sub.2, associated with a second current, I.sub.G_low; wherein: the first current of the driver waveform, I.sub.G_high, is larger than the second current of the driver waveform, I.sub.G_low; and the first time period, T.sub.1, has a first duration and the second time period, T.sub.2, has a second duration. The method comprising: determining an optimised first duration by repeatedly modifying the first duration until an overshoot in an output waveform generated by switching the electrical switch using the driver waveform is less than a threshold; determining an optimised second duration based on the optimised first duration; and switching the electrical switch using the optimised first duration and the optimised second duration.

A semiconductor device includes high-side and low-side switching elements connected in series to form a switching arm, a high-side driver IC for driving the high-side switching element, and, on a chip separate from the high-side switching element, a low-side driver IC for driving the low-side switching element. The driver IC includes a first controller for monitoring a switching voltage appearing at the node where the high-side and low-side switching elements are connected together. When a first driving control signal fed in from outside the semiconductor device instructs to turn on the high-side switching element, the first controller determines whether or not to permit the high-side switching element to be turned on based on a result of checking the switching voltage.

A switched power circuit to control a common-mode signal. The switched power circuit includes a first switch and a second switch configured to generate switch mode voltage between a first node and a second node. The switched power circuit further includes a feedback circuit that is configured to detect common-mode voltage generated between the first node and the second node by a first signal generated by the first switch and a second signal generated by the second switch, and incrementally adjust a timing parameter of the first signal to adjust the common-mode signal.

Turn-off circuits. In one aspect, the turn-off circuit includes a transistor having a gate terminal, a source terminal and a drain terminal, a first pull-down circuit connected to the gate terminal, a second pull-down circuit connected to the gate terminal, and a third pull-down circuit connected to the gate terminal. In another aspect, the first, the second and the third pull-down circuits are arranged to cause a turn off of the transistor by changing a voltage at the gate terminal at a first rate of voltage with respect to time from an on-state voltage to a first intermediate voltage, and from the first intermediate voltage to a second intermediate voltage at a second rate of voltage with respect to time, and from the second intermediate voltage to an off-state voltage at a third rate of voltage with respect to time, wherein the first rate is higher than the second rate.

A gate drive device drives a gate of each of two semiconductor switching elements constituting upper and lower arms of a half bridge circuit. The gate drive device detects a peak value of an element voltage that is a voltage of a main terminal of one of the two semiconductor switching elements, as one semiconductor switching element, or a change rate of the element voltage during a change period in which the element voltage changes. The gate drive device determines whether an energization to the one semiconductor switching element during the change period is a forward energization in which a current flows in a forward direction or a reverse energization in which the current flows in a reverse direction.