Abstract: A switch driving circuit is provided, wherein the switch driving circuit has a function of periodically updating a simultaneous OFF time prepared to soft-switch an upper switch and a lower switch of a switching output circuit, and is configured to monitor how an output power or an input power of the switching output circuit is changed depending on previous updating of the simultaneous OFF time to determine new updated contents.

Abstract: A switching power supply includes: a switching output circuit generating an output voltage from an input voltage according to ON/OFF control of an output transistor by a pulse width modulation (PWM) signal; a first voltage generating circuit generating a first voltage based on a difference between the output voltage and a predetermined reference voltage; a second voltage generating circuit generating a triangular second voltage; a comparing circuit generating a comparison signal by comparing the first voltage and the second voltage; a clock oscillating circuit generating a clock signal; and a logic circuit generating a PWM signal in response to the clock signal and the comparison signal, wherein the second voltage generating circuit generates the second voltage by adding a first slope voltage having a first slope and a second slope voltage having a second slope according to current flown through the switching output circuit.

Abstract: A switching power supply includes: a switching output circuit generating an output voltage from an input voltage according to ON/OFF control of an output transistor by a pulse width modulation (PWM) signal; a first voltage generating circuit generating a first voltage based on a difference between the output voltage and a predetermined reference voltage; a second voltage generating circuit generating a triangular second voltage; a comparing circuit generating a comparison signal by comparing the first voltage and the second voltage; a clock oscillating circuit generating a clock signal; and a logic circuit generating a PWM signal in response to the clock signal and the comparison signal, wherein the second voltage generating circuit generates the second voltage by adding a first slope voltage having a first slope and a second slope voltage having a second slope according to current flown through the switching output circuit.

Abstract: A switch driving circuit is provided, wherein the switch driving circuit has a function of periodically updating a simultaneous OFF time prepared to soft-switch an upper switch and a lower switch of a switching output circuit, and is configured to monitor how an output power or an input power of the switching output circuit is changed depending on previous updating of the simultaneous OFF time to determine new updated contents.

Abstract: A switching power control circuit includes an analog-to-digital converter (ADC) configured to convert an analog direct current (DC) voltage into a digital voltage; a digital compensator configured to set a gain and phase characteristics of the digital voltage output from the ADC and output a digital compensation value; and a pulse generating circuit configured to generate at least one driving signal based on the digital compensation value, wherein the pulse generating circuit is switched by an ON/OFF signal for turning on or off an output of the driving signal from the pulse generating circuit and a control scheme selection signal for selecting a predetermined driving signal from the driving signal.

Abstract: A switching power control circuit includes an analog-to-digital converter (ADC) configured to convert an analog direct current (DC) voltage into a digital voltage; a digital compensator configured to set a gain and phase characteristics of the digital voltage output from the ADC and output a digital compensation value; and a pulse generating circuit configured to generate at least one driving signal based on the digital compensation value, wherein the pulse generating circuit is switched by an ON/OFF signal for turning on or off an output of the driving signal from the pulse generating circuit and a control scheme selection signal for selecting a predetermined driving signal from the driving signal.

Abstract: Provided is an electronic circuit including an upper control unit and a lower control unit. The upper control unit performs a logic transition of a gate signal so as to off-latch an upper switch by using the fall edge of a drive signal as a trigger and release the off-latch of the upper switch by using the rise edge of a monitor signal as a trigger. The lower control unit performs a logic transition of the gate signal so as to off-latch a lower switch by using the rise edge of the drive signal as a trigger and release the off-latch of the lower switch by using the rise edge of a monitor signal as a trigger.

Abstract: A temperature protection circuit comprises means adapted to compare the temperature being monitored with each of threshold temperatures and judging that the temperature being monitored reaches a threshold temperature when the temperature being monitored is maintained at the threshold temperature or more for a predetermined confirmation period, means adapted to set a longer confirmation period as the threshold temperature compared with the temperature being monitored is lower, means adapted to generate one of corresponding temperature protection signals (Sarm, Slmt, Stsd1, Stsd2) according to the judgment of which threshold temperature the temperature being monitored reaches. With this constitution, temperature protection operation can be preformed with high accuracy and high safety without unnecessarily narrowing the range of the operating temperature of an IC to be protected.

Abstract: Provided is an electronic circuit including an upper control unit and a lower control unit. The upper control unit performs a logic transition of a gate signal so as to off-latch an upper switch by using the fall edge of a drive signal as a trigger and release the off-latch of the upper switch by using the rise edge of a monitor signal as a trigger. The lower control unit performs a logic transition of the gate signal so as to off-latch a lower switch by using the rise edge of the drive signal as a trigger and release the off-latch of the lower switch by using the rise edge of a monitor signal as a trigger.

Abstract: A temperature protection circuit comprises means adapted to compare the temperature being monitored with each of threshold temperatures and judging that the temperature being monitored reaches a threshold temperature when the temperature being monitored is maintained at the threshold temperature or more for a predetermined confirmation period, means adapted to set a longer confirmation period as the threshold temperature compared with the temperature being monitored is lower, means adapted to generate one of corresponding temperature protection signals (Sarm, Slmt, Stsd1, Stsd2) according to the judgment of which threshold temperature the temperature being monitored reaches. With this constitution, temperature protection operation can be preformed with high accuracy and high safety without unnecessarily narrowing the range of the operating temperature of an IC to be protected.

Abstract: An overcurrent detection circuit that detects an overcurrent state of a transistor that outputs a current to a load is provided with a start-up monitoring portion that distinguishes between a start-up state and a steady state, an overcurrent monitoring portion that monitors an overcurrent state of the transistor, and an output voltage monitoring portion that detects whether the output voltage to the load is normal or abnormal. The overcurrent monitoring portion changes an overcurrent detection level while referring to information from the start-up monitoring portion and the overcurrent monitoring portion.

Abstract: An IC includes an internal circuit that switches between on-state and off-state in response to an external signal and also includes an oscillator circuit that is externally synchronized. The IC further includes a state holding circuit that, when pulses for synchronizing the oscillator circuit are inputted to a standby pulse input terminal, applies, to the internal and the oscillator circuits, as an operation signal, a voltage obtained by rectifying pulses outputted from a comparator, and, when a constant voltage for non-operation is applied to the standby pulse input terminal for a given time period, applies, to the internal and oscillator circuits, as a non-operation signal, a constant voltage outputted from the comparator.

Abstract: A switching regulator type power supply apparatus that converts an input voltage and then feeds the voltage thus converted to a smoothing circuit, and that operates in such a way that an output from the smoothing circuit becomes equal to a predetermined output voltage includes a control circuit for generating a control signal by a PWM scheme so that the output becomes equal to the predetermined output voltage, and a switching element that is switched by the control signal so as to convert the input voltage and feed the voltage thus converted to the smoothing circuit. Here, based on an external signal for turning on/off an output of the output voltage, a supply path for supplying an operating power to elements constituting the control circuit is switched between a conducting state and a non-conducting state.

Abstract: An excess current detecting circuit detects an excess current status of a power MOS transistor, which outputs a current to a load from a drain electrode, and outputs the excess current detection signal. The excess current detecting circuit is provided with: a detection MOS transistor wherein a source electrode and a gate electrode are connected to a source electrode and a gate electrode of the power MOS transistor, respectively, a constant current circuit connected with a drain electrode of the detection MOS transistor for flowing a prescribed constant current to the detection MOS transistor, and a comparator for outputting the excess current detection signal based on the results of the comparison between a potential of the drain electrode of the power MOS transistor and a potential of the drain electrode of the detection MOS transistor.

Abstract: An overcurrent detection circuit (35) that detects an overcurrent state of a transistor (2) that outputs a current to a load (25) is provided with a start-up monitoring portion (31) that distinguishes between a start-up state and a steady state, an overcurrent monitoring portion (33) that monitors an overcurrent state of the transistor (2), and an output voltage monitoring portion (34) that detects whether the output voltage to the load (25) is normal or abnormal. The overcurrent monitoring portion (31) changes an overcurrent detection level while referring to information from the start-up monitoring portion (31) and the overcurrent monitoring portion (33).

Abstract: Provided is a semiconductor integrated circuit device having an output portion that outputs via a switch element a predetermined voltage to the outside from a voltage output terminal through a voltage output line and a control portion that performs predetermined control based on a control signal inputted from outside to a signal input line or a signal input terminal that is so arranged as to be adjacent to a voltage output line or a voltage output terminal. To achieve a highly-reliable semiconductor integrated circuit device that is prevented from being broken even when the voltage output terminal and a terminal adjacent thereto are short-circuited, there is provided a voltage detection portion that detects that a voltage higher than a reference voltage is inputted to the signal input line or the signal input terminal and feeds the resultant signal to the output portion as a voltage detection signal, and the output portion opens the switch element when the voltage detection signal is provided thereto.

Abstract: A power supply device produces a predetermined voltage from a supply voltage through a voltage follower composed of a plurality of transistors. The voltage follower has a function of preventing backflow current. The voltage follower has one end connected to the supply voltage and another end connected to a capacitor. A constant voltage generating circuit produces a constant voltage from the voltage across the capacitor. A switch circuit is connected between the supply voltage and the control electrode of one of the transistors constituting the voltage follower other than the first-stage transistor thereof. A voltage drop detecting circuit detects a drop below a predetermined level in the voltage across the capacitor, and turns on the switch circuit on detecting such a drop.

Abstract: A stabilized DC power supply device that maintains an output voltage thereof at a constant level despite a fluctuation arising in a power supply voltage fed thereto comprises a control circuit that compares the output voltage with a reference voltage so as to output a control signal by which the output voltage is maintained at a predetermined level, and a ripple cancellation circuit that amplifies an undulating component included in the power supply voltage at a predetermined gain and that feeds out a resulting signal as an undulation compensation signal for correcting the output voltage, wherein the undulation compensation signal for correcting the output voltage is superimposed on the reference voltage so as to prevent an undulation arising in the power supply voltage from appearing in the output voltage.

Abstract: A stabilized DC power supply device that maintains an output voltage thereof at a constant level despite a fluctuation arising in a power supply voltage fed thereto comprises a control circuit that compares the output voltage with a reference voltage so as to output a control signal by which the output voltage is maintained at a predetermined level, and a ripple cancellation circuit that amplifies an undulating component included in the power supply voltage at a predetermined gain and that feeds out a resulting signal as an undulation compensation signal for correcting the output voltage, wherein the undulation compensation signal for correcting the output voltage is superimposed on the reference voltage so as to prevent an undulation arising in the power supply voltage from appearing in the output voltage.

Abstract: A power supply device produces a predetermined voltage from a supply voltage through a voltage follower composed of a plurality of transistors. The voltage follower has a function of preventing backflow current. The voltage follower has one end connected to the supply voltage and another end connected to a capacitor. A constant voltage generating circuit produces a constant voltage from the voltage across the capacitor. A switch circuit is connected between the supply voltage and the control electrode of one of the transistors constituting the voltage follower other than the first-stage transistor thereof. A voltage drop detecting circuit detects a drop below a predetermined level in the voltage across the capacitor, and turns on the switch circuit on detecting such a drop.