Abstract: A switching control circuit for a power supply circuit generating an output voltage from an AC voltage. The power supply circuit includes an inductor receiving a first rectified voltage corresponding to the AC voltage, and a transistor controlling an inductor current flowing through the inductor. The switching control circuit controls switching of the transistor, and comprises: an identification circuit identifying whether an effective value of the AC voltage is a first or second level; a first comparator circuit comparing the inductor current with a first current value and a second current value, respectively when the effective value is the first level and the second level; and a driver circuit driving the transistor based on the inductor current and the output voltage. The driver circuit turns off the transistor in response to the inductor current exceeding the first current value or the second current value as a result of comparison.

Abstract: An integrated circuit for a power supply circuit that includes a state-indicating circuit, which is a first or second circuit when the power supply circuit is of a non-isolated or isolated type, as the case may be. The integrated circuit including a voltage generation circuit that generates, at a first terminal, a voltage that is (1) lower than a first level, when the first circuit is coupled to the first terminal, (2) higher than a second level, when the second circuit is coupled to the first terminal, and (3) higher than the first level and lower than the second level, when no state-indicating circuit is coupled to the first terminal, and a determination circuit that determines that the power supply circuit is of the non-isolated or isolated type, when the voltage at the first terminal is lower or higher than the second level, as the case may be.

Abstract: Recently, it is desired to improve responsiveness in case where a drop in the output voltage is prevented. A power supply control device is provided, comprising a switch control unit for controlling an ON/OFF state of a switching device of a boosting chopper using an oscillation wave, a voltage acquisition unit for acquiring DC output voltage corresponding to an output of the boosting chopper, and an oscillation control unit for reducing a change speed of the oscillation wave during at least a part of a period during which the switching device is in an ON state, in response to a drop in the DC output voltage.

Abstract: An integrated circuit for a power supply circuit that includes a state-indicating circuit, which is a first or second circuit when the power supply circuit is of a non-isolated or isolated type, as the case may be. The integrated circuit including a voltage generation circuit that generates, at a first terminal, a voltage that is (1) lower than a first level, when the first circuit is coupled to the first terminal, (2) higher than a second level, when the second circuit is coupled to the first terminal, and (3) higher than the first level and lower than the second level, when no state-indicating circuit is coupled to the first terminal, and a determination circuit that determines that the power supply circuit is of the non-isolated or isolated type, when the voltage at the first terminal is lower or higher than the second level, as the case may be.

Abstract: A power factor correction circuit includes an error signal generation unit configured to output an error signal obtained by amplifying a difference between an output voltage and a referential voltage. A pulse width modulation unit is configured to receive the error signal to generate a pulse width modulation signal to control an on-time of a switching element. An input interruption detection unit is configured to detect an interruption state of an AC input voltage. When the input interruption detection unit detects an input interruption state, the input interruption detection unit causes the pulse width modulation unit to shorten the on-time of the switching element.

Abstract: A power supply circuit, including a rectifier circuit, an inductor having a voltage from the rectifier circuit applied thereto, a transistor for controlling a current flowing through the inductor, and an integrated circuit that performs switching of the transistor. The integrated circuit includes a signal generating circuit that generates a drive signal that reaches first and second logic levels to respectively turn on and off the transistor, a buffer circuit that generates first and second voltages for turning on and off the transistor based on the drive signal at the first and second logic levels, respectively, a detection circuit that detects elapse of a time period from when the drive signal reaches the first logic level to a predetermined timing before the drive signal reaches the second logic level, and a determination circuit that determines whether the terminal is short-circuited when the time period has elapsed since the drive signal reaches the first logic level.

Abstract: A switching control circuit for controlling a power supply circuit that includes an inductor to which an input voltage is applied and through which an inductor current flows, and a transistor configured to control the inductor current. The switching control circuit includes first and second error voltage output circuits that output first and second error voltages, based respectively on a feedback voltage corresponding to the output voltage and a reference voltage, and on an error signal corresponding to a difference between the level of the output voltage and a second level, when the power supply circuit is of a non-isolated type and an isolated type, respectively. The switching control circuit further includes a drive circuit that switches the transistor based on the inductor current, and on the first and second error voltage when the power supply circuit is of the non-isolated type and an isolated type, respectively.

Abstract: A power supply circuit that generates an output voltage from an AC voltage. The power supply circuit includes a rectifier circuit that rectifies the AC voltage, an inductor receives a rectified voltage from the rectifier circuit, a transistor that controls an inductor current flowing through the inductor, and an integrated circuit that performs switching of the transistor. The integrated circuit includes an error output circuit that outputs an error between a feedback voltage and a reference voltage, a target value generating circuit that generates a target value of the inductor current based on the error, an adjustment circuit that adjusts the target value, first and second comparison circuits that compare the inductor current with a predetermined value and with the target value, respectively, and a drive circuit that turns on the transistor when the inductor current reaches the predetermined value, and turns off the transistor when the inductor current reaches the target value.

Abstract: A switching control circuit for controlling a power supply circuit that includes an inductor to which an input voltage is applied and through which an inductor current flows, and a transistor configured to control the inductor current. The switching control circuit includes first and second error voltage output circuits that output first and second error voltages, based respectively on a feedback voltage corresponding to the output voltage and a reference voltage, and on an error signal corresponding to a difference between the level of the output voltage and a second level, when the power supply circuit is of a non-isolated type and an isolated type, respectively. The switching control circuit further includes a drive circuit that switches the transistor based on the inductor current, and on the first and second error voltage when the power supply circuit is of the non-isolated type and an isolated type, respectively.

Abstract: A power factor correction circuit includes an error signal generation unit configured to output an error signal obtained by amplifying a difference between an output voltage and a referential voltage. A pulse width modulation unit is configured to receive the error signal to generate a pulse width modulation signal to control an on-time of a switching element. An input interruption detection unit is configured to detect an interruption state of an AC input voltage. When the input interruption detection unit detects an input interruption state, the input interruption detection unit causes the pulse width modulation unit to shorten the on-time of the switching element.

Abstract: A power supply circuit that generates an output voltage from an AC voltage. The power supply circuit includes a rectifier circuit that rectifies the AC voltage, an inductor receives a rectified voltage from the rectifier circuit, a transistor that controls an inductor current flowing through the inductor, and an integrated circuit that performs switching of the transistor. The integrated circuit includes an error output circuit that outputs an error between a feedback voltage and a reference voltage, a target value generating circuit that generates a target value of the inductor current based on the error, an adjustment circuit that adjusts the target value, first and second comparison circuits that compare the inductor current with a predetermined value and with the target value, respectively, and a drive circuit that turns on the transistor when the inductor current reaches the predetermined value, and turns off the transistor when the inductor current reaches the target value.

Abstract: A power factor correction circuit including: an error signal generation unit configured to output a signal obtained by amplifying an error between the output voltage of a boost chopper and a referential voltage; an oscillation unit configured to output a triangular wave signal; a zero current detection unit configured to detect zero current in an inductor current of the boost chopper; a drive signal generation unit configured to generate a drive signal for the switching element based on a zero current detection signal, the error signal, and the triangular wave signal; and an input interruption detection unit configured to detect an interruption state of an AC input voltage based on the zero current detection signal. When the input interruption detection unit detects an input interruption state, the oscillation unit controls a slope of the triangular wave signal to be larger than the slope when no input interruption state is detected.

Abstract: A power supply circuit, including a rectifier circuit, an inductor having a voltage from the rectifier circuit applied thereto, a transistor for controlling a current flowing through the inductor, and an integrated circuit that performs switching of the transistor. The integrated circuit includes a signal generating circuit that generates a drive signal that reaches first and second logic levels to respectively turn on and off the transistor, a buffer circuit that generates first and second voltages for turning on and off the transistor based on the drive signal at the first and second logic levels, respectively, a detection circuit that detects elapse of a time period from when the drive signal reaches the first logic level to a predetermined timing before the drive signal reaches the second logic level, and a determination circuit that determines whether the terminal is short-circuited when the time period has elapsed since the drive signal reaches the first logic level.

Abstract: A power factor correction circuit including: an error signal generation unit configured to output a signal obtained by amplifying an error between the output voltage of a boost chopper and a referential voltage; an oscillation unit configured to output a triangular wave signal; a zero current detection unit configured to detect zero current in an inductor current of the boost chopper; a drive signal generation unit configured to generate a drive signal for the switching element based on a zero current detection signal, the error signal, and the triangular wave signal; and an input interruption detection unit configured to detect an interruption state of an AC input voltage based on the zero current detection signal. When the input interruption detection unit detects an input interruption state, the oscillation unit controls a slope of the triangular wave signal to be larger than the slope when no input interruption state is detected.

Abstract: Recently, it is desired to improve responsiveness in case where a drop in the output voltage is prevented. A power supply control device is provided, comprising a switch control unit for controlling an ON/OFF state of a switching device of a boosting chopper using an oscillation wave, a voltage acquisition unit for acquiring DC output voltage corresponding to an output of the boosting chopper, and an oscillation control unit for reducing a change speed of the oscillation wave during at least a part of a period during which the switching device is in an ON state, in response to a drop in the DC output voltage.

Abstract: An inverting amplifier creates a voltage C using a reference voltage (voltage B) as a reference point. An adder composed of two input inverting amplifier circuits ultimately creates a voltage D by carrying out weighted addition of the voltage A and the voltage C. By using the voltage D created by an input front-end circuit, the internal functions of the control IC can prevent the operating points and control amounts for each function from being different relative to the input voltage and make it possible to distinguish voltage within the control IC from zero voltage when the lowest input voltage is received.

Abstract: An inverting amplifier creates a voltage C using a reference voltage (voltage B) as a reference point. An adder composed of two input inverting amplifier circuits ultimately creates a voltage D by carrying out weighted addition of the voltage A and the voltage C. By using the voltage D created by an input front-end circuit, the internal functions of the control IC can prevent the operating points and control amounts for each function from being different relative to the input voltage and make it possible to distinguish voltage within the control IC from zero voltage when the lowest input voltage is received.

Abstract: An integrated control circuit for controlling a switching power supply, a switching power supply incorporating the same, and a method of controlling the switching power supply, where the control IC includes a current comparator that detects current flowing through a switching device, a flip-flop circuit that controls the ON-period of the switching device, an averaging circuit that converts the peak load current value to a time-average, a comparator that detects an overloaded state from the load current, a delay circuit that sets a time from detecting the overcurrent state to stopping the switching operation, a latch circuit that stops the switching operation for a period of time, a first reference voltage supply used in the current comparator, which has a higher voltage value than a second reference voltage supply used in the comparator.

Abstract: An integrated control circuit for controlling a switching power supply, a switching power supply incorporating the same, and a method of controlling the switching power supply, where the control IC includes a current comparator that detects current flowing through a switching device, a flip-flop circuit that controls the ON-period of the switching device, an averaging circuit that converts the peak load current value to a time-average, a comparator that detects an overloaded state from the load current, a delay circuit that sets a time from detecting the overcurrent state to stopping the switching operation, a latch circuit that stops the switching operation for a period of time, a first reference voltage supply used in the current comparator, which has a higher voltage value than a second reference voltage supply used in the comparator.

Abstract: An integrated circuit for controlling a switching power supply includes a signal input terminal in addition to a switching input terminal that is also provided in a conventional integrated circuit and is a terminal to switch IC operation modes using an external control signal. The switching input terminal signal is made valid when the signal input terminal voltage is higher than a threshold voltage, such that mode switching using an external control signal is enabled. When the signal input terminal voltage is lower than the threshold voltage, mode switching is automatically conducted by switching a MOSFET ON or OFF using output signals of portions of a comparator connected to a feedback terminal to which an output voltage of a power supply device is applied.