A circuit for controlling a switching mode power supply having a power switch, having: a feedback pulse circuit, configured to receive a feedback signal, and to provide a feedback pulse signal; a load determining circuit, configured to receive the feedback signal, and to provide a load determining signal; a light load pulse circuit, configured to receive the load determining signal and a frequency regulating signal, and to provide a light load pulse signal; a frequency regulating circuit, configured to receive the load determining signal, the light load pulse signal and a normal load pulse signal, and to provide the frequency regulating signal; and a selecting circuit, configured to receive the load determining signal, the feedback pulse signal and the light load pulse signal, and to provide an on control signal and the normal load pulse signal; wherein the on control signal controls an on operation of the power switch.

The present invention provides a switched-mode power converter with regulation demand pulses sent across a galvanic isolation barrier.

System and method for regulating a power conversion system. A system controller for regulating a power conversion system includes a first controller terminal and a second controller terminal. Additionally, the system controller is configured to receive an input signal at the first controller terminal, and generate a drive signal at the second controller terminal based at least in part on the input signal to turn on or off a transistor in order to affect a current associated with a secondary winding of the power conversion system. Moreover, the system controller is further configured to determine whether the input signal is larger than a first threshold at a first time, in response to the input signal being determined to be larger than the first threshold at the first time, determine whether the input signal is smaller than a second threshold at a second time.

A control circuit for an isolated power converter includes a first sensing circuit that senses a secondary side output voltage and produces a pulse wave modulation (PWM) signal having a duty cycle that is proportional to a value of the secondary side output voltage. The PWM is transferred across the converter isolation barrier to the primary side, and a primary side circuit receives the PWM signal and outputs a control signal. A controller determines the value of the secondary side output voltage from the control signal and uses the value to control primary side power switching devices of the isolated power converter to regulate the secondary side output voltage at a selected value.

A power converter controller includes an analog to digital converter (ADC) to generate a digital representation of a feedback signal of a power converter, the feedback signal being received from a compensator of the power converter and being based on an output voltage of the power converter. A nonlinear gain block of the power converter controller receives the digital representation of the feedback signal and generates a transformed digital representation of the feedback signal using a nonlinear function. A switch control block of the power converter controller controls an on-time of a primary-side switch of the power converter based on the transformed digital representation of the feedback signal.

A driver unit for programming an output current of a driver with an output stage for providing the output current and a primary control stage with a control input for controlling the output current has been provided. The driver unit includes a programmable memory unit for storing data corresponding a target value of the output current, a programming signal circuit configured to provide electric signals for writing the data in the programmable memory unit as well as a controller circuit with a controller. The controller is operatively connected to the programmable memory unit and is configured to read out the data stored in the programmable memory unit and generate a controller output signal for adjusting the output current of the driver, based on the data stored in the programmable memory unit.

System controller and method for regulating a power converter. For example, the system controller includes a first controller terminal and a second controller terminal. The system controller is configured to receive an input signal at the first controller terminal and generate a drive signal at the second controller terminal based at least in part on the input signal to turn on or off a transistor in order to affect a current associated with a secondary winding of the power converter. Additionally, the system controller is further configured to determine whether the input signal remains larger than a first threshold for a first time period that is equal to or longer than a first predetermined duration.

An insulated power supply circuit includes a power input circuit including a switching control circuit and a switching element connected to a corresponding winding of a transformer, and power output circuits of two systems each including a regulator connected to a corresponding winding. By the control circuit controlling ON/OFF of the switching element in accordance with an output condition change command signal, which is generated based on a load condition at an output destination of each regulator, a voltage corresponding to an estimated value of a preset excitation level is generated, to thereby change the excitation level of the winding. Each regulator receives an output voltage generated in a corresponding winding in response to the change in excitation level.

System and method for controlling turning on a first transistor and turning off a second transistor. For example, a system for controlling turning on a first transistor and turning off a second transistor includes: a logic signal generator configured to: process information associated with a first voltage related to a second voltage of a first auxiliary winding, the first auxiliary winding being coupled to a primary winding, a secondary winding, and a second auxiliary winding; generate a third voltage based on at least information associated with the first voltage, the third voltage indicating a first voltage difference from a drain terminal to a source terminal of a first transistor related to the primary winding; process information associated with the third voltage and a reference voltage; and change a logic signal from a first logic level to a second logic level.

A flyback power converter converts an input power on a primary side into an output power on a secondary side. On the secondary side, the output power is monitored to provide a representative signal representing a characteristic of the output power. A count is kept unchanged when a clock ticks if the representative signal is within a first range defined in accordance with a target value, that the representative signal is going to be regulated at. The count is changed in response to the clock if the representative signal is within a second range different from the first range. In response to the count, a driving current is generated to control a coupler, which generates a compensation signal on the primary side that controls power transmitted from the primary side to the secondary side.