4results about How to "Extended on-time" patented technology

The present application provides a slope compensation circuit and a backlight display device. The slope compensation circuit includes a first current generation module, a first current mirror module, a second current generation module and a second current mirror module. The first current generation module is electrically connected to the first current mirror module, and the second current generation module is electrically connected to the first current mirror module and the second current mirror module respectively. The first current generation module generates a first current, and the first current mirror module outputs a mirror current according to the first current. The mirror current has a linear function relationship with the conduction time of the switching transistor. The second current generation module generates a second current according to the mirror current, and the second current mirror module outputs a slope compensation current according to the second current. The slope compensation current has a quadratic function relationship with the conduction time of the switching transistor. The present application effectively solves the problem that when the conversion ratio of the existing slope compensation circuit is extremely large and the conduction time of the switching transistor is significantly extended, the linearly increasing compensation current is difficult to meet the compensation intensity requirement.

A control circuit for controlling a switching regulator includes a timer, a comparator, a driver circuit, and a controller. The timer is configured to generate an input signal indicative of whether a predetermined time has elapsed since a drive signal was enabled. The comparator is configured to compare a feedback voltage to a reference voltage to generate a comparison signal. The driver circuit is controlled by a control signal to generate the drive signal based on one of the input signal and the comparison signal. The control signal is indicative of whether a mode has been enabled. When the mode is enabled, the driver circuit is configured to generate the drive signal based on the input signal. The controller is configured to generate the control signal based on a result of comparing the feedback voltage to another reference voltage higher than the reference voltage in response to the input signal being enabled.

The utility model relates to the field of switching circuits, in particular to a PMOS (P-channel Metal Oxide Semiconductor) switching circuit, which is characterized in that a source electrode of a PMOS tube Q1 is connected with an input voltage end Vi n, and a drain electrode is connected with a load output end Vout; a base electrode of the triode Q2 receives the switching signal through a control signal end PWR, and an emitting electrode of the triode Q2 is grounded; the first divider resistor R1 is connected between the grid electrode of the PMOS tube Q1 and an input voltage end Vi n; the second divider resistor R2 is connected between the grid electrode of the PMOS tube Q1 and the collector electrode of the triode Q2; the first capacitor C1 is connected between the grid electrode and the source electrode of the PMOS tube Q1; the resistance value ratio of the first divider resistor R1 to the second divider resistor R2 is 1: 3 to 1: 5, the capacitance value of the first capacitor C1 is 10 nF to 100 nF, and the load capacitance C2 does not exceed 470 [mu] F. The voltage division ratio of R1 / R2 is matched with the capacitor C1, so that the conduction time of the PMOS is prolonged, the instantaneous charging current peak value of the load capacitor C2 is remarkably reduced, voltage drop is avoided, and the stability of the system is guaranteed.

The utility model relates to the technical field of medium-frequency induction heating technology metal smelting, and particularly discloses a contactor auxiliary starting device for an electric induction furnace, which comprises a rectifying circuit, a switch follow current circuit, a vacuum contactor control circuit, a starting feedback voltage detection circuit and a running state indication circuit, the input end of the rectifying circuit is electrically connected to a workshop power supply grid, and the rectifying circuit is electrically connected with the switch follow current circuit; the vacuum contactor control circuit is powered by a workshop control power supply VCC1, and the vacuum contactor control circuit is electrically connected with the switch follow current circuit; and the starting feedback voltage detection circuit is electrically connected with the vacuum contactor control circuit and is in signal connection with the post-stage circuit. According to the invention, the conduction time of the fly-wheel diode can be delayed when the electric induction furnace is started, so that the resonant load can obtain enough excitation energy at the initial stage of oscillation establishment, and after oscillation is stable, the fly-wheel diode plays a role again, so that the influence on oscillation establishment caused by premature conduction of the fly-wheel diode is avoided.