Abstract: A control circuit for an isolated power supply is disclosed, the control circuit includes a secondary-side drive signal generator, a secondary-side transistor switch turn-off detector and a primary-side control signal generator. The primary-side control signal generator is configured to: determine a second turn-on instant referring to an turn-off instant of the secondary-side synchronous rectification transistor from the turn-off acknowledgement signal; determine a first turn-on instant referring to a supposed turn-on instant for the primary-side transistor switch from the feedback signal of the output voltage of the isolated power supply; and determine the turn-on instant for the primary-side transistor switch from the second turn-on instant or the first turn-on instant whichever is later, and responsively generate the primary-side transistor switch control signal.

Abstract: Isolated power supply control circuits, isolated power supply and control method thereof are disclosed, the control circuit for controlling an isolated power supply includes a secondary-side control signal generator and a primary-side control signal generator. The secondary-side control signal generator produces a secondary-side transistor switch control signal containing information about a turn-off instant of a secondary-side synchronous rectification transistor, which serves as a second turn-on instant. The primary-side control signal generator derives, from a feedback signal, a supposed turn-on instant for a primary-side transistor switch, which serves as a first turn-on instant. The primary side turn-on signal generator further derives a turn-on instant for the primary-side transistor switch from the second or first turn-on instant whichever is later and responsively generates a primary-side transistor switch control signal.

Abstract: A control circuit, system and method for switched-mode power supply are disclosed, the control circuit is for driving a first switch to convert an input voltage into an output voltage. The control circuit includes an on-time control unit, which receives a first signal characterizing switching frequency of first switch and a second signal characterizing current flowing through first switch and responsively generates a signal indicative of a turn-off instant for first switch. When a peak value of the current flowing through the first switch drops below a predefined value, the on-time control unit determines the turn-off instant for the first switch based on the first signal so that the switching frequency of the first switch is maintained at a target frequency. This design can effectively avoid the generation of audible noise, stabilize the output voltage against load changes while maintaining desirable efficiency, and ensure operational safety of the switched-mode power supply.

Abstract: A control circuit, system and method for switched-mode power supply are disclosed, the control circuit is for driving a first switch to convert an input voltage into an output voltage. The control circuit includes an on-time control unit, which receives a first signal characterizing switching frequency of first switch and a second signal characterizing current flowing through first switch and responsively generates a signal indicative of a turn-off instant for first switch. When a peak value of the current flowing through the first switch drops below a predefined value, the on-time control unit determines the turn-off instant for the first switch based on the first signal so that the switching frequency of the first switch is maintained at a target frequency. This design can effectively avoid the generation of audible noise, stabilize the output voltage against loading changes while maintaining desirable efficiency, and ensure operational safety of the switched-mode power supply.

Abstract: A control circuit, a control chip and a power supply device are disclosed by the present invention. The control circuits are used for control of a constant-voltage closed-loop which causes a voltage of a voltage feedback signal obtained from an output voltage to approach a voltage of a reference voltage signal obtained from a base voltage and thereby achieves a constant-voltage output. In addition, when a sampled current obtained from an output current is higher than a predetermined current, or when output power is higher than a predetermined power, the control circuit increases the voltage feedback signal or decreases the reference voltage signal, causing the constant-voltage closed loop to decrease the output voltage and the output current and thereby achieving a limited output current and limited output power.

Abstract: An operation circuit and a chip pertaining to the field of integrated circuit design technology are disclosed by the present application. The circuit includes a capacitor charging/discharging module and an error amplification module electrically connected to the capacitor charging/discharging module. The capacitor charging/discharging module is configured to receive a first signal and a third signal that are external to the capacitor charging/discharging module and to output a feedback signal. The error amplification module is configured to receive the feedback signal and a second signal that is external to error amplification module and to output, based on the received feedback and second signals, a target signal to the capacitor charging/discharging module. In a steady state, values of the target, first, second and third signals satisfy a predefined mathematical relationship.

Abstract: An operation circuit and a chip pertaining to the field of integrated circuit design technology are disclosed by the present invention. The circuit includes a capacitor charging/discharging module and an error amplification module electrically connected to the capacitor charging/discharging module. The capacitor charging/discharging module is configured to receive first, second and third signals external to the capacitor charging/discharging module, and to output a reference signal and a feedback signal. The error amplification module is configured to receive the reference and feedback signals and output a target signal to the capacitor charging/discharging module based on the received reference and feedback signals. The first, second and third signals are all analog signals, and in a steady state, values of the target, first, second and third signals satisfy a predefined mathematical relationship.

Abstract: An output short-circuit protection method, a power management chip and a switched-mode power supply are disclosed. When current accumulation has occurred in a power transistor, the number of consecutive current pulses during which the current accumulation occurred is counted. Upon the number of consecutive current pulses reaches a preset value, a regulation interval spanning switching periods is triggered, for at least some of the switching periods, the leading-edge blanking time is shortened or cancelled. In this way, an excessively large current flowing through the power transistor is prevented. Compared with existing fault response measures for power management chips, restart of the power supply and adjustment of the system timing are not needed, allowing easier implementation. Further, the automatic restart during chip start up due to false triggering as found in the existing measures for power management chips is circumvented.

Abstract: A control circuit, system and method for switched-mode power supply are disclosed, the control circuit is for driving a first switch to convert an input voltage into an output voltage. The control circuit includes an on-time control unit, which receives a first signal characterizing switching frequency of first switch and a second signal characterizing current flowing through first switch and responsively generates a signal indicative of a turn-off instant for first switch. When a peak value of the current flowing through the first switch drops below a predefined value, the on-time control unit determines the turn-off instant for the first switch based on the first signal so that the switching frequency of the first switch is maintained at a target frequency. This design can effectively avoid the generation of audible noise, stabilize the output voltage against loading changes while maintaining desirable efficiency, and ensure operational safety of the switched-mode power supply.

Abstract: Isolated power supply control circuits, isolated power supply and control method thereof are disclosed, the control circuit for controlling an isolated power supply includes a secondary-side control signal generator and a primary-side control signal generator. The secondary-side control signal generator produces a secondary-side transistor switch control signal containing information about a turn-off instant of a secondary-side synchronous rectification transistor, which serves as a second turn-on instant. The primary-side control signal generator derives, from a feedback signal, a supposed turn-on instant for a primary-side transistor switch, which serves as a first turn-on instant. The primary side turn-on signal generator further derives a turn-on instant for the primary-side transistor switch from the second or first turn-on instant whichever is later and responsively generates a primary-side transistor switch control signal.

Abstract: The present disclosure provides a light state regulation controller, control system and control method. The controller comprises a peak current comparator, a PWM controller, a power switch, a state detector and a state machine. The peak current comparator produces a PWM turn-off signal according to a comparison result between a peak current sampling signal and a reference voltage. The PWM controller outputs a PWM control signal and the reference voltage under the control of the PWM turn-off signal and a state control signal, wherein the state control signal controls the state of the PWM control signal. The state detector detects a state change in the PWM control signal or an equivalent signal for the PWM control signal, and outputs a state input signal. The state machine produces a plurality of states according to the state input signal, and outputs the state control signal reflecting the plurality of states.

Abstract: The present disclosure provides a light state regulation controller, control system and control method. The controller comprises a peak current comparator, a PWM controller, a power switch, a state detector and a state machine. The peak current comparator produces a PWM turn-off signal according to a comparison result between a peak current sampling signal and a reference voltage. The PWM controller outputs a PWM control signal and the reference voltage under the control of the PWM turn-off signal and a state control signal, wherein the state control signal controls the state of the PWM control signal. The state detector detects a state change in the PWM control signal or an equivalent signal for the PWM control signal, and outputs a state input signal. The state machine produces a plurality of states according to the state input signal, and outputs the state control signal reflecting the plurality of states.