Abstract: A LED dimming control circuit that avoids a higher output voltage than expected is provided. The LED dimming control circuit comprises an inductor, a transistor, a dimming control signal, a feedback signal, a switching control circuit, an error amplifier, and an inverted amplifier. The inductor and the transistor are coupled to a node. The switching control circuit is controlled by the dimming control signal and the feedback signal. The transistor is controlled by the switching control circuit. The output terminal of the error amplifier and the non-inverted input terminal of the error amplifier form a negative feedback path via the inverted amplifier.

Abstract: A low ripple DC to DC power converter comprises a first switch, a second switch, an inductor, a driving circuit, and an oscillating circuit. The driving circuit is used to control the first switch and the second switch based on a driving signal. The driving signal has a duty cycle. The oscillating circuit comprises a first oscillating signal and a second oscillating signal. The first oscillating signal has a first pulse width and the second oscillating signal has a second pulse width. The oscillating circuit is used to generate a pulse oscillating signal, where the frequency of the pulse oscillating signal is modulated based on the duty cycle, the first pulse width, and the second pulse width so as to reduce the ripple of the output voltage.

Abstract: A LED dimming control circuit that avoids a higher output voltage than expected is provided. The LED dimming control circuit comprises an inductor, a transistor, a dimming control signal, a feedback signal, a switching control circuit, an error amplifier, and an inverted amplifier. The inductor and the transistor are coupled to a node. The switching control circuit is controlled by the dimming control signal and the feedback signal. The transistor is controlled by the switching control circuit. The output terminal of the error amplifier and the non-inverted input terminal of the error amplifier form a negative feedback path via the inverted amplifier.

Abstract: A synchronous switching voltage converter has a first switch, a second switch, and an inductor, which are all coupled together to a switch node. A reverse current preventing circuit has a current detecting circuit, a voltage detecting circuit, a delay time adjusting circuit, and a blocking circuit. When an inductor current reduces to reach a predetermined threshold current, the current detecting circuit generates an original preventing signal. The voltage detecting circuit detects a switch voltage at the switch node. In response to the original preventing signal, the delay time adjusting circuit generates a corrected preventing signal after an adjustable delay time with respect to the original preventing signal. The adjustable delay time is adjusted on a basis of the switch voltage. In response to the corrected preventing signal, the blocking circuit turns OFF the second switch.

Abstract: An initial voltage establishing circuit has a current supplying circuit, a current adjusting circuit, a charge/discharge control circuit, and an oscillating signal generating circuit. The current supplying circuit provides a charge current and a discharge current. The current adjusting circuit adjusts the charge current and the discharge current. The charge/discharge control circuit selectively allows the charge current and the discharge current to flow through. The oscillating signal generating circuit employs the charge current and the discharge current to generate an initial voltage establishing signal such that a duty cycle of the initial voltage establishing signal gradually increases. The initial voltage establishing signal is applied to a switching voltage converter for establishing an initial output voltage.

Abstract: A switching voltage regulator has a first switch, a second switch, and an inductor, which are coupled together to a switch node. A switch control system applies a drive signal for controlling the first and the second switches. A duty cycle detecting circuit detects a duty cycle of the drive signal. When the duty cycle is larger than a predetermined threshold, the duty cycle detecting circuit generates an over-threshold signal. When the duty cycle is smaller than the predetermined threshold, the duty cycle detecting circuit generates an under-threshold signal. In response to the over-threshold signal and the under-threshold signal, an oscillating signal adjusting circuit generates an adjusting current. An oscillating signal generating circuit generates and applies an oscillating signal to the switch control system. The oscillating signal has a period adjusted by the adjusting current.

Abstract: A synchronous switching voltage converter has a first switch, a second switch, and an inductor, which are all coupled together to a switch node. A reverse current preventing circuit has a current detecting circuit, a voltage detecting circuit, a delay time adjusting circuit, and a blocking circuit. When an inductor current reduces to reach a predetermined threshold current, the current detecting circuit generates an original preventing signal. The voltage detecting circuit detects a switch voltage at the switch node. In response to the original preventing signal, the delay time adjusting circuit generates a corrected preventing signal after an adjustable delay time with respect to the original preventing signal. The adjustable delay time is adjusted on a basis of the switch voltage. In response to the corrected preventing signal, the blocking circuit turns OFF the second switch.

Abstract: An initial voltage establishing circuit has a current supplying circuit, a current adjusting circuit, a charge/discharge control circuit, and an oscillating signal generating circuit. The current supplying circuit provides a charge current and a discharge current. The current adjusting circuit adjusts the charge current and the discharge current. The charge/discharge control circuit selectively allows the charge current and the discharge current to flow through. The oscillating signal generating circuit employs the charge current and the discharge current to generate an initial voltage establishing signal such that a duty cycle of the initial voltage establishing signal gradually increases. The initial voltage establishing signal is applied to a switching voltage converter for establishing an initial output voltage.

Abstract: A switching voltage regulator has a first switch, a second switch, and an inductor, which are coupled together to a switch node. A switch control system applies a drive signal for controlling the first and the second switches. A duty cycle detecting circuit detects a duty cycle of the drive signal. When the duty cycle is larger than a predetermined threshold, the duty cycle detecting circuit generates an over-threshold signal. When the duty cycle is smaller than the predetermined threshold, the duty cycle detecting circuit generates an under-threshold signal. In response to the over-threshold signal and the under-threshold signal, an oscillating signal adjusting circuit generates an adjusting current. An oscillating signal generating circuit generates and applies an oscillating signal to the switch control system. The oscillating signal has a period adjusted by the adjusting current.

Abstract: Through operated alternately between a charging phase and a discharging phase, a charge pump converts an input voltage source into a drive voltage for being supplied to a light emitting diode. A current setting unit determines a reference current. A current regulating unit has a current regulating terminal and a feedback detecting terminal. The current regulating terminal is coupled to the light emitting diode so as to control a current flowing through the light emitting diode to be proportional to the reference current. The feedback detecting terminal provides a feedback signal representative of a current regulation characteristic voltage. Based on a difference between the feedback signal and a reference voltage source, an error amplifier generates an error signal. A variable resistance unit is coupled between the input voltage source and the charge pump for adjusting a variable resistance in response to the error signal.

Abstract: Through operated alternately between a charging phase and a discharging phase, a charge pump converts an input voltage source into a drive voltage for being supplied to a light emitting diode. A current setting unit determines a reference current. A current regulating unit has a current regulating terminal and a feedback detecting terminal. The current regulating terminal is coupled to the light emitting diode so as to control a current flowing through the light emitting diode to be proportional to the reference current. The feedback detecting terminal provides a feedback signal representative of a current regulation characteristic voltage. Based on a difference between the feedback signal and a reference voltage source, an error amplifier generates an error signal. A variable resistance unit is coupled between the input voltage source and the charge pump for adjusting a variable resistance in response to the error signal.

Abstract: A switching circuit operates with a first operating state and a second operating state. During the first operating state, the switching circuit allows a switching current to linearly increase. During the second operating state, the switching circuit allows the switching current to linearly decrease. A control circuit is coupled to the switching circuit for controlling the switching circuit to operate with the first operating state or the second operating state. A setting circuit generates a threshold signal for the control circuit to ensure that during the first operating state the switching current linearly increases to become higher than or equal to a current value set by the threshold signal. Thereby, the switching current is prevented from linearly decreasing to reverse polarity during the second operating state.

Abstract: An input switching unit selectively couples a first terminal of an inductor with an input voltage and a ground potential. An output switching unit selectively couples a second terminal of the inductor with an output voltage and the ground potential. A first pulse generating circuit generates a first pulse signal with a first duty ratio, which is modulated in response to the output voltage. A second pulse generating circuit generates a second pulse signal with a second pulse signal with a second duty ratio, which is a constant larger than zero and smaller than one. When the first duty ratio is larger than a predetermined threshold duty ratio, a mode control circuit applies the first pulse signal to control one of the input switching unit and the output switching unit and applies the second pulse signal to control another of the input switching unit and the output switching unit.

Abstract: A light loading control circuit operates a switching circuit of a buck-boost voltage converter alternately in a plurality of phase cycles and a sleep period. Each phase cycle has a rising phase, a falling phase, and a maintaining phase. In the rising phase, the switching circuit is operated to increase an inductor current. In the falling phase, the switching circuit is operated to decrease the inductor current. In the maintaining phase, the switching circuit is operated to keep the inductor current approximately constant. The sleep period prevents two terminals of an inductor from being respectively coupled to two selected from a group consisting of an input voltage, an output voltage, and a ground potential.

Abstract: An input switching unit selectively couples a first terminal of an inductor with an input voltage and a ground potential. An output switching unit selectively couples a second terminal of the inductor with an output voltage and the ground potential. A first pulse generating circuit generates a first pulse signal with a first duty ratio, which is modulated in response to the output voltage. A second pulse generating circuit generates a second pulse signal with a second pulse signal with a second duty ratio, which is a constant larger than zero and smaller than one. When the first duty ratio is larger than a predetermined threshold duty ratio, a mode control circuit applies the first pulse signal to control one of the input switching unit and the output switching unit and applies the second pulse signal to control another of the input switching unit and the output switching unit.

Abstract: A light loading control circuit operates a switching circuit of a buck-boost voltage converter alternately in a plurality of phase cycles and a sleep period. Each phase cycle has a rising phase, a falling phase, and a maintaining phase. In the rising phase, the switching circuit is operated to increase an inductor current. In the falling phase, the switching circuit is operated to decrease the inductor current. In the maintaining phase, the switching circuit is operated to keep the inductor current approximately constant. The sleep period prevents two terminals of an inductor from being respectively coupled to two selected from a group consisting of an input voltage, an output voltage, and a ground potential.

Abstract: A drive circuit applies a drive voltage through an outputs terminal to a switching element. The drive circuit includes a supplying circuit, an amplifying circuit, a detecting circuit, and an adjusting circuit. In response to a control signal, the supplying circuit generates a first drive current. The amplifying circuit generates and applies a second drive current, which is larger than the first drive current, to the output terminal for changing the drive voltage. The detecting circuit is coupled to the output terminal for generating a detection signal representative of the drive voltage. Based on the detection signal, the adjusting circuit implemented by a differential comparator dynamically adjusts the first drive current.

Abstract: A drive circuit applies a drive voltage through an output terminal to a switching element. The drive circuit includes a supplying circuit, an amplifying circuit, a detecting circuit, and an adjusting circuit. In response to a control signal, the supplying circuit generates a first drive current. The amplifying circuit generates and applies a second drive current, which is larger than the first drive current, to the output terminal for changing the drive voltage. The detecting circuit is coupled to the output terminal for generating a detection signal representative of the drive voltage. Based on the detection signal, the adjusting circuit implemented by a differential comparator dynamically adjusts the first drive current.

Abstract: A light-load power transistor and a heavy-load power transistor are connected in parallel between an input voltage and an output voltage. The light-load power transistor has a smaller current driving capability, i.e. a smaller dimension of a current path. During a light-load mode, only is the light-load power transistor activated to reduce the current consumption caused by an error amplifier, thereby enhancing the efficiency. When a detection current signal is higher than a threshold current signal, the heavy-load power transistor is additionally activated through a gate control circuit by a mode selection circuit, thereby achieving a sufficient current driving capability.

Abstract: A light-load power transistor and a heavy-load power transistor are connected in parallel between an input voltage and an output voltage. The light-load power transistor has a smaller current driving capability, i.e. a smaller dimension of a current path. During a light-load mode, only is the light-load power transistor activated to reduce the current consumption caused by an error amplifier, thereby enhancing the efficiency. When a detection current signal is higher than a threshold current signal, the heavy-load power transistor is additionally activated through a gate control circuit by a mode selection circuit, thereby achieving a sufficient current driving capability.