Abstract: An integrated circuit for digitally controlling a critical mode power factor correction (PFC) circuit according to one or more embodiments may include: an output voltage detector and a switching current detector; an A/D converter and a sample and hold circuit that perform analog-to-digital conversion of an output signal of the output voltage detector and the switching current detector; an arithmetic unit that performs calculation based on the output signal of the A/D converter and generates a pulse signal to turn on/off a switching device of the PFC circuit; a correction value calculator that calculates, based on a switching frequency of the PFC circuit, a correction value for linearly correcting the output signal of the A/D converter; and an adder that adds the correction value to the output signal of the A/D converter to correct the output signal of the A/D converter and inputs the corrected output signal to the arithmetic unit.

Abstract: A method may include detecting an output voltage of the output smoothing capacitor in the bridgeless interleaved power factor correction circuit of a critical mode, comparing the detected output voltage with a reference voltage, controlling the first and the second half-bridge circuits included in the bridgeless interleaved power factor correction circuit of the critical mode to be on and off based on an error signal between the output voltage and the predetermined reference voltage, measuring ON time of a synchronous rectification switch operation of the first half-bridge circuit by measuring a time period between OFF timing of an active switch of the first half-bridge circuit and output of a differentiation signal generated by a differentiation circuit included in the bridgeless interleaved power factor correction circuit of the critical mode; and assigning the measured time to next ON time of the synchronous rectification switch operation of the second half-bridge circuit.

Abstract: An integrated circuit for digitally controlling a critical mode power factor correction (PFC) circuit according to one or more embodiments may include: an output voltage detector and a switching current detector; an A/D converter and a sample and hold circuit that perform analog-to-digital conversion of an output signal of the output voltage detector and the switching current detector; an arithmetic unit that performs calculation based on the output signal of the A/D converter and generates a pulse signal to turn on/off a switching device of the PFC circuit; a correction value calculator that calculates, based on a switching frequency of the PFC circuit, a correction value for linearly correcting the output signal of the A/D converter; and an adder that adds the correction value to the output signal of the A/D converter to correct the output signal of the A/D converter and inputs the corrected output signal to the arithmetic unit.

Abstract: A method may include detecting an output voltage of the output smoothing capacitor in the bridgeless interleaved power factor correction circuit of a critical mode, comparing the detected output voltage with a reference voltage, controlling the first and the second half-bridge circuits included in the bridgeless interleaved power factor correction circuit of the critical mode to be on and off based on an error signal between the output voltage and the predetermined reference voltage, measuring ON time of a synchronous rectification switch operation of the first half-bridge circuit by measuring a time period between OFF timing of an active switch of the first half-bridge circuit and output of a differentiation signal generated by a differentiation circuit included in the bridgeless interleaved power factor correction circuit of the critical mode; and assigning the measured time to next ON time of the synchronous rectification switch operation of the second half-bridge circuit.

Abstract: Embodiments of this disclosure provide a control apparatus and method for a current resonance circuit and a current resonance power supply. The control method includes: performing integration on a resonance current of the current resonance circuit or a switching current of one or more switching elements to generate an integration signal; generating a feedback signal of the current resonance circuit; comparing the integration signal with the feedback signal, and generating a measurement signal according to a comparison result; performing digital filtering on the measurement signal; and according to the measurement signal after filtering, generating a pulse width modulation signal controlling the switching elements.

Abstract: A device and method for calculating switching time. The device includes: a digital calculator configured to calculate a next on time according to an output voltage signal and an inductor current signal detected during an on period of a switching element and calculate a next off time according to the next on time, an input voltage signal and the output voltage signal; and a signal generator configured to generate a pulse width modulation signal for controlling the switching element, according to the next on time and the next off time. Therefore, a digital controlling manner is provided, not only the number of components and the cost are decreased, but also detection accuracy is improved with a simple structure.

Abstract: A device and method for calculating switching time. The device includes: a digital calculator configured to calculate a next on time according to an output voltage signal and an inductor current signal detected during an on period of a switching element and calculate a next off time according to the next on time, an input voltage signal and the output voltage signal; and a signal generator configured to generate a pulse width modulation signal for controlling the switching element, according to the next on time and the next off time. Therefore, a digital controlling manner is provided, not only the number of components and the cost are decreased, but also detection accuracy is improved with a simple structure.

Abstract: The present invention includes: a series circuit formed of a reactor Lr, a primary winding P of a transformer T, and a capacitor C2; a full-wave rectifier/smoothing circuit D1, D2, C3 configured to perform full-wave rectification and smoothing on a voltage generated in a secondary winding S of the transformer thereby to extract a DC voltage; a control circuit FF1 configured to set a first ON time of the first switch element Q1 and a second ON time of the second switch element Q2 to the same predetermined time thereby to alternately turn on and off the first switch element and the second switch element; and a first ON time controller I1, 16, C7 configured to set one of the first ON time and the second ON time, shorter than the predetermined time, under light-load conditions, based on the DC voltage detected by a detector 11.

Abstract: The present invention includes: a series circuit formed of a reactor Lr, a primary winding P of a transformer T, and a capacitor C2; a full-wave rectifier/smoothing circuit D1, D2, C3 configured to perform full-wave rectification and smoothing on a voltage generated in a secondary winding S of the transformer thereby to extract a DC voltage; a control circuit FF1 configured to set a first ON time of the first switch element Q1 and a second ON time of the second switch element Q2 to the same predetermined time thereby to alternately turn on and off the first switch element and the second switch element; and a first ON time controller I1, I6, C7 configured to set one of the first ON time and the second ON time, shorter than the predetermined time, under light-load conditions, based on the DC voltage detected by a detector 11.

Abstract: A power factor correction circuit includes: an ON time setting unit, which sets an ON time period of the switching element based on the output voltage; a bottom detection unit, which detects a bottom when a voltage between both ends of the switching element is damped-oscillated while the switching element is being turned off; and a bottom skip controller, which causes the switching element to perform quasi-resonant if a ratio of the ON time period set by the ON time setting unit to a regeneration period of a current flowing through the reactor while the switching element is being turned off is less than or equal to a predetermined value, and turns on the switching element at a timing when a next bottom is reached after one bottom skipped from an initial bottom if the ratio is greater than the predetermined value.

Abstract: The present invention includes: a series circuit formed of a reactor Lr, a primary winding P of a transformer T, and a capacitor C2; a full-wave rectifier/smoothing circuit D1, D2, C3 configured to perform full-wave rectification and smoothing on a voltage generated in a secondary winding S of the transformer thereby to extract a DC voltage; a control circuit FF1 configured to set a first ON time of the first switch element Q1 and a second ON time of the second switch element Q2 to the same predetermined time thereby to alternately turn on and off the first switch element and the second switch element; and a first ON time controller I1, l6, C7 configured to set one of the first ON time and the second ON time, shorter than the predetermined time, under light-load conditions, based on the DC voltage detected by a detector 11.

Abstract: A current resonant power source apparatus includes a series circuit (Lr, P, C2) connected between switch elements Q1 and Q2 and a capacitor C1, a full-wave rectifying and smoothing circuit (D1, D2, C3) for providing a DC voltage, a control circuit of Q1 and Q2, a voltage detector 11 of the DC voltage, a current detector of the primary winding P, a soft-start time constant setting unit, and an ON time controller. If a voltage generated to a time constant is smaller than a set voltage, the ON time controller sets an ON time for Q1 and Q2 according to the DC voltage and soft-start signal, and if it is equal to or greater than the set voltage, sets one of the first and second ON times according to the current from the current detector.

Abstract: A power factor correction circuit includes: an ON time setting unit, which sets an ON time period of the switching element based on the output voltage; a bottom detection unit, which detects a bottom when a voltage between both ends of the switching element is damped-oscillated while the switching element is being turned off; and a bottom skip controller, which causes the switching element to perform quasi-resonant if a ratio of the ON time period set by the ON time setting unit to a regeneration period of a current flowing through the reactor while the switching element is being turned off is less than or equal to a predetermined value, and turns on the switching element at a timing when a next bottom is reached after one bottom skipped from an initial bottom if the ratio is greater than the predetermined value.

Abstract: Embodiments of the invention may include: a series circuit connected to a junction of a first switch element and a second switch element connected in series across ends of a DC power supply, and to one end of the DC power supply, and formed of a primary winding of a transformer and a capacitor; a rectifier/smoothing circuit configured to rectify and smooth a voltage generated in a secondary winding of the transformer thereby to extract a DC voltage; a control circuit configured to alternately turn on and off the first switch element and the second switch element; a voltage detector configured to detect a voltage of the DC power supply; and a duty controller configured to, under a light-load condition, set a duty ratio between the first switch element and the second switch element closer to 50% as a value of the voltage detected by the voltage detector becomes larger.

Abstract: The present invention includes: a series circuit connected to a junction of a first switch element and a second switch element connected in series across ends of a DC power supply, and to one end of the DC power supply, and formed of a primary winding of a transformer and a capacitor; a rectifier/smoothing circuit configured to rectify and smooth a voltage generated in a secondary winding of the transformer thereby to extract a DC voltage; a control circuit configured to alternately turn on and off the first switch element and the second switch element; a voltage detector configured to detect a voltage of the DC power supply; and a duty controller configured to, under a light-load condition, set a duty ratio between the first switch element and the second switch element closer to 50% as a value of the voltage detected by the voltage detector becomes larger.

Abstract: A current resonant power source apparatus includes a series circuit (Lr, P, C2) connected between switch elements Q1 and Q2 and a capacitor C1, a full-wave rectifying and smoothing circuit (D1, D2, C3) for providing a DC voltage, a control circuit of Q1 and Q2, a voltage detector 11 of the DC voltage, a current detector of the primary winding P, a soft-start time constant setting unit, and an ON time controller. If a voltage generated to a time constant is smaller than a set voltage, the ON time controller sets an ON time for Q1 and Q2 according to the DC voltage and soft-start signal, and if it is equal to or greater than the set voltage, sets one of the first and second ON times according to the current from the current detector.

Abstract: A drive circuit drives a normally-on high-side switch Q1 and a normally-off low-side switch Q2 that form a series circuit connected in parallel with a DC power source. The drive circuit includes a controller 10 that outputs a control signal to turn on/off the high- and low-side switches, a rectifier D2 having a first end connected to a connection point of the high- and low-side switches, a capacitor C2 that is connected to a second end of the rectifier and a first end of the DC power source and serves as a power source for the controller, and a driver (A1, AND1, Q3, Q4) that turns on/off the high- and low-side switches according to the control signal from the controller and a voltage from the capacitor.

Abstract: The present invention includes: a series circuit formed of a reactor Lr, a primary winding P of a transformer T, and a capacitor C2; a full-wave rectifier/smoothing circuit D1, D2, C3 configured to perform full-wave rectification and smoothing on a voltage generated in a secondary winding S of the transformer thereby to extract a DC voltage; a control circuit FF1 configured to set a first ON time of the first switch element Q1 and a second ON time of the second switch element Q2 to the same predetermined time thereby to alternately turn on and off the first switch element and the second switch element; and a first ON time controller I1, I6, C7 configured to set one of the first ON time and the second ON time, shorter than the predetermined time, under light-load conditions, based on the DC voltage detected by a detector 11.

Abstract: A drive circuit drives a normally-on high-side switch Q1 and a normally-off low-side switch Q2 that form a series circuit connected in parallel with a DC power source. The drive circuit includes a controller 10 that outputs a control signal to turn on/off the high- and low-side switches, a rectifier D2 having a first end connected to a connection point of the high- and low-side switches, a capacitor C2 that is connected to a second end of the rectifier and a first end of the DC power source and serves as a power source for the controller, and a driver (A1, AND1, Q3, Q4) that turns on/off the high- and low-side switches according to the control signal from the controller and a voltage from the capacitor.

Abstract: A device for driving switching elements is provided with a potential detector 29 which provides drive circuit 30 with signals in response to differences among potentials at junctions 17 to 20 of first and third resistors 13, 15, third resistor 15 and first control MOS-FET 8, second and fourth resistors 14, 16 and fourth resistor 16 and second control MOS-FET 9 so that drive circuit 30 supplies drive signals to a gate terminal of a first MOS-FET 1 based on potentials in first and second series circuits 11 and 12. When appropriate resistance values are selected for first to fourth resistors 13 to 16, potential detector 29 precisely detects the potential at each junction 17 to 20 to produce detection signals and prevent malfunction of drive circuit 30 even upon occurrence of abnormal signals or noises resulted from abrupt potential rise.