The present disclosure is directed to a pulse frequency modulation (PFM) control method for a boost converter and apparatus for carrying out the method. A boost converter includes an inductor and a transistor coupled thereto. A control circuit is arranged to control the transistor to cause current pulsed to be sourced through the inductor. When operating in a PFM mode, the control circuit may control the timing of pulses such that, at the beginning of a specified time period, current pulses may be sourced with no spacing between successive pulses. After a desired number of pulses have been sourced, no pulses are sourced for the remainder of the specified time period. Nevertheless, the number of pulses sourced over the time period corresponds to a desired average frequency of pulses.

There is provided a DC-DC converter which is safe and secure, but yet with low power consumption. The DC-DC converter is configured such that an overcurrent protection circuit is operated intermittently only for a predetermined period of time based on a signal output from an output control circuit to turn on a switching element.

A control method of a power converter including a first stage converter and a second stage converter is provided. The first stage converter converts an input voltage into an intermediate voltage. The second stage converter converts the intermediate voltage into an output voltage to power a load. If a loading amount of the load is larger than a first threshold value, the intermediate voltage is adjusted to increase a voltage difference between the intermediate voltage and the output voltage, so that a change of the intermediate voltage is in a negative correlation with a change of the loading amount. If the loading amount is smaller than a second threshold value, the intermediate voltage remains be unchanged or the intermediate voltage is adjusted, so that the change of the intermediate voltage is in positive correlation with the change of the loading amount.

A display apparatus is provided. The display apparatus includes a display configured to display an image, an image signal provider circuit configured to provide an image signal to the display, and a power supply configured to generate driving power and to supply the generated driving power to the image signal provider, wherein the power supply controls an operation time of a power factor compensation (PFC) circuit which performs power factor compensation of the display apparatus based on a size of an output load receiving the driving voltage.

An integrated circuit for a power supply circuit configured to generate an output voltage at a target level. The power supply circuit includes a transistor configured to control an inductor current flowing through an inductor. The integrated circuit includes a load detection circuit outputting a detection voltage corresponding to a power consumption of a load and corresponding to an operation mode of the power supply circuit, based on the inductor current, a driver circuit driving the transistor according to the operation mode of the power supply circuit, and a control circuit configured to control the driver circuit to switch the power supply circuit to a second mode upon the detection voltage reaching a first level with a decrease in the power consumption of the load, and to a first mode upon the detection voltage reaching a second level with an increase in the power consumption of the load.

A DC-DC voltage converter and associated control method capable of dynamically adjusting upper boundary of the inductor current are provided. The DC-DC voltage converter is electrically connected to an input terminal having an input voltage and an output terminal having an output voltage. The DC-DC voltage converter converts the input voltage to the output voltage, and the DC-DC voltage converter operates in a pulse frequency modulation mode. The DC-DC voltage converter includes an inductor and a converting circuit, which are electrically connected to each other. An inductor current flows through the inductor. The converting circuit adjusts the inductor current according to a setting signal so that the inductor current is less than or equivalent to an upper boundary of the inductor current.

A primary-side controller comprises a feedback (FB) terminal coupled to a light-receiving element of a photocoupler so as to receive a feedback signal from the photocoupler, and a current detection (CS) terminal that receives a current detection signal that corresponds to a voltage drop across a sense resistor R.sub.S. The primary-side controller includes a current mode modulator that generates a control pulse based on the voltage at the FB terminal and the voltage at the CS terminal. The primary-side controller is configured to be switchable between a normal mode and a burst mode. When the electrical state of the DC/DC converter satisfies a predetermined condition, a burst mode adjustment circuit inhibits transition to the burst mode, or otherwise forces transition from the burst mode to the normal mode.

An embodiment PFC control circuit includes a first terminal providing a drive signal to an electronic switch of a boost converter, a second terminal receiving a feedback signal indicative of an output voltage generated by the boost converter, and a third terminal connected to a compensation network. An error amplifier generates a current as a function of the voltage at the second terminal and a reference voltage, wherein an output of the error amplifier is coupled to the third terminal. A driver circuit generates the drive signal as a function of the voltage at the third terminal, and selectively activates or deactivates the generation of the drive signal as a function of a burst mode enable signal. A detection circuit generates the burst mode enable signal as a function of the voltage at the second terminal.

A power converter is provided. A driver circuit is connected between a controller circuit and a switch circuit. The switch circuit is connected to an inductor. The inductor is connected in series with a first capacitor and grounded through the first capacitor. A first comparison input terminal of a first comparator is connected to an output terminal between the inductor and the first capacitor. A second comparison input terminal of the first comparator is grounded through a second capacitor. The controller circuit outputs a control signal for controlling the driver circuit to drive the switch circuit according to a comparison signal outputted by the first comparator. A reference current source provides a reference current to the second capacitor. A first terminal of a first resistor is connected to the second capacitor. A second terminal of the first resistor is coupled to a reference potential.

According to an aspect, a power supply system includes a power stage, a power supply controller configured to control operations of the power stage, a metering circuit configured to sense measured conditions of the power stage, and a system performance controller configured to be coupled to the power supply controller and the metering circuit. The system performance controller is configured to set or adjust a control parameter for the power stage based on standby power of the power stage. The system performance controller includes a standby power computation circuit configured to compute the standby power of the power stage based on the measured conditions, and a control manipulation module configured to modify the control parameter until the standby power achieves a threshold condition.