Abstract: A brushless motor drive device has a signal synthesizing circuit for converting a plurality of sensing signals into a plurality of drive signals so as to determine an amplitude of each of the drive signals in accordance with a current error signal. The sensing signals are generated by a sensing circuit in response to variations in a magnetic field of a brushless multi-phase motor. The current error signal is representative of a difference between a current command signal and a motor drive current. The signal synthesizing circuit is characterized by including a calibrating circuit for adjusting the current error signal in accordance with an amplitude of any of the sensing signals. The calibrating circuit includes a differential amplifying circuit, a rectifying circuit, a filtering circuit, and a dividing circuit.

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 dimming control circuit generates a dimming control signal for determining brightness of at least one light-emitting diode. The dimming control signal has a plurality of bright-dark cycles, each of which consists of a bright phase and a dark phase. The bright phase starts with an adaptive rising portion. The adaptive rising portion restricts the brightness of the at least one light-emitting diode to increase gradually from zero.

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 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: For applying a driving voltage to a motor, an H-bridge circuit is constructed by a first and a second linear unit and a first and a second switching unit. An error amplifier generates an error signal representative of a difference between the driving voltage detected by a voltage detecting circuit and a command voltage signal. A state control circuit synchronously controls the first and second switching units and a feedback circuit. Through the feedback circuit, the error signal is selectively applied to the first or second linear unit such that one is operated in a linear mode and the other is operated in a nonconductive mode, thereby controlling the driving voltage to become proportional to the command voltage signal. The state control circuit further controls a brake circuit for transforming the error signal into a brake signal to operate the first and second linear units simultaneously in a conductive mode.

Abstract: A motor control circuit includes a detector circuit, a comparator circuit, a sifter circuit, and a driver circuit. The detector circuit is coupled to a plurality of coils of a motor for generating a detection signal. The detection signal is in association with a terminal voltage of a selected-to-be-floated coil of the plurality of coils. Based on comparison between the detection signal and a reference voltage, the comparator circuit generates a comparison signal. The sifter circuit receives in sequence a first-time crossing and a second-time crossing from the comparison signal, and generates an indication signal in response to the second-time crossing. The driver circuit controls a commutation of the motor in response to the indication signal.

Abstract: In a pulse frequency modulated (PFM) voltage regulator, a PFM switching signal is provided for converting a DC voltage source to an output voltage. The output voltage is detected. When the output voltage is lower than a predetermined target voltage, a duty cycle of the PFM switching signal is reduced. For example, a minimum OFF-time of the PFM switching signal may be prolonged or a constant ON-time of the PFM switching signal may be shortened. In other words, a period of delivering energy to a capacitor from an inductor may be prolonged or a period of storing energy in the inductor may be shortened. Therefore, a ripple of the output voltage is effectively reduced when the PFM voltage regulator is operated in a heavy loading condition.

Abstract: A voltage detection unit generates a detection voltage signal representative of a potential difference caused by a current to be detected. A reference current generation unit generates a first reference current and a second reference current having a linear relationship therebetween. In response to the detection voltage signal and the first reference current, a transfer unit determines a first operation voltage. Furthermore, the transfer unit determines a second operation voltage and a transfer current in response to the first operation voltage and the second reference current. The second operation voltage is substantially equal to the first operation voltage. A detection current signal having a linear relationship with the current to be detected is generated through subtracting at least the second reference current from the transfer current.

Abstract: A Hall sensing circuit generates a positional detection signal representative of a positional relationship between a rotor and a phase coil of a motor. A signal synthesizing circuit transforms the positional detection signal to a driving signal. Based on a comparison of the driving signal and a high-frequency reference signal, a pulse signal is generated for controlling a switching circuit to drive the motor. A current error signal is supplied through feedback to adjust a relative relationship between an amplitude of the drive signal and an amplitude of the high-frequency reference signal, thereby changing a duty ratio of the pulse signal. A duty-ratio limiting circuit is provided to limit the duty ratio of the pulse signal for ensuring a reliable rotation of the motor.

Abstract: A charge pump is driven by at least one clock signal, for converting a supply voltage source into a pumping voltage. The pumping voltage is a function of an amplitude of the at least one clock signal such that an absolute value of the pumping voltage is larger when the amplitude of the at least one clock signal is larger. The amplitude of the at least one clock signal is so modulated as to gradually change from an activation value during an amplitude modulation period. The amplitude modulation period lasts longer than a period of the at least one clock signal by one or more metric orders. The charge pump is activated by the at least one clock signal with the amplitude of the activation value. Thereafter, the charge pump is controlled in such a way that the absolute value of the pumping voltage gradually changes along with the modulation of the amplitude of the at least one clock signal.

Abstract: First and second clocks are applied to first and second capacitors, respectively. First and second former-stage clocks are applied to first and second former-stage capacitors, respectively. A first switch couples the second former-stage capacitor with the first capacitor. A second switch couples the first former-stage capacitor with the second capacitor. A first reverse current preventing circuit couples a control electrode of the first switch alternately with the second capacitor and the second former-stage capacitor. A second reverse current preventing circuit couples a control electrode of the second switch alternately with the first capacitor and the first former-stage capacitor. Falling edges of the first and second clocks occur earlier than falling edges of the first and second former-stage clocks, respectively. Rising edges of the first and second former-stage clocks occur earlier than rising edges of the first and second clocks, respectively.

Abstract: In a pulse frequency modulated (PFM) voltage regulator, a PFM switching controller is provided to generate a PFM switching signal for converting a DC voltage source to an output voltage. A minimum OFF-time controller provides the PFM switching signal with a minimum OFF-time. In response to the output voltage, a feedback circuit generates a feedback signal. When the output voltage is lower than a predetermined target voltage, an OFF-time prolonging circuit prolongs the minimum OFF-time in response to the feedback signal. In other words, a time of delivering energy to a capacitor from an inductor may be prolonged by the OFF-time prolonging circuit. Therefore, a ripple of the output voltage is effectively reduced when the PFM voltage regulator is operated in a heavy loading condition.

Abstract: For applying a driving current to a motor, an H-bridge circuit is constructed by a first and a second switching unit and a first and a second linear unit. An error amplifier generates an error signal representative of a difference between the driving current detected by a current detecting circuit and a command current signal. A state control circuit synchronously controls the first and second switching units and a feedback circuit. Through the feedback circuit, the error signal is selectively applied to the first or second linear unit such that one is operated in a linear mode and the other is operated in a nonconductive mode, thereby controlling the driving current to become proportional to the command current signal. The state control circuit further controls a brake circuit for transforming the error signal into a brake signal to operate the first and second linear units simultaneously in a conductive mode.

Abstract: A Hall sensing circuit generates a positional detection signal representative of a positional relationship between a rotor and a phase coil of a motor. A signal synthesizing circuit transforms the positional detection signal to a driving signal. Based on a comparison of the driving signal and a high-frequency reference signal, a pulse signal is generated for controlling a switching circuit to dive the motor. A current error signal is supplied through feedback to adjust a relative relationship between an amplitude of the drive signal and an amplitude of the high-frequency reference signal, thereby changing a duty ratio of the pulse signal. A duty-ratio limiting circuit is provided to limit the duty ratio of the pulse signal for ensuring a reliable rotation of the motor.

Abstract: The DC-DC converter of the present invention sets the soft start function in the error amplifier. With soft start added, the error amplifier's output voltage will follow the slowly ascending soft start voltage when the DC-DC converter is enabled. Then the soft start looses control over the error amplifier when the soft start voltage exceeds the steady state value of the error amplifier's output voltage. And meanwhile, the amplifier's input will take over the control. By doing so, the present invention significantly eradicates or reduces jitters caused by the output voltage of the error amplifier and the DC-DC converter.

Abstract: A switching DC-to-DC converter includes multiple power supply channels, coupled in parallel between a DC voltage source and ground, for converting the DC voltage source into multiple DC output voltages that are separate from each other. An oscillator outputs multiple oscillating signals to render each of the multiple power supply channels make at least one switching transition differently in the time domain from others of the multiple power supply channels, thereby improving transient noise. The multiple oscillating signals include two triangular wave signals with a phase difference of 180 degrees and two pulse wave signals with a-phase difference of 180 degrees. Rising edges of the two pulse wave signals occur simultaneously with either a peak or a valley of the two triangular wave signals, respectively.

Abstract: A motor control circuit includes a forward rotation control circuit, a reverse rotation control circuit, and a brake control circuit. The forward rotation control circuit allows a first current source to supply a first current signal to a motor drive circuit for operating a motor in a forward rotation mode. The reverse rotation control circuit allows a third current source to supply a third current signal to the motor drive circuit for operating the motor in a reverse rotation mode. The brake control circuit allows a second current source and a fourth current source to respectively supply a second current signal and a fourth current signal to the motor drive circuit for operating the motor in a brake mode. The motor control circuit reduces power dissipation in the brake mode since the second and fourth current signals may be smaller than the first and third current signals.

Abstract: A first oscillating signal presenting a peak, a valley, a rising portion gradually increasing from the valley to the peak, and a falling portion gradually decreasing from the peak to the valley is generated. A second oscillating signal presenting an instantly transiting edge, which occurs simultaneously with either the peak or the valley of the first oscillating signal, is generated. The first and the second oscillating signals are input to a first and a second power supply channels, respectively, for converting a DC voltage source into two separate DC output voltages. The first and the second oscillating signals cause at least one switching transition of the first power supply channel to occur separately in the time domain from at least one switching transition of the second power supply channel, thereby preventing transient spikes from superposing together.

Abstract: The present invention discloses a current sensing circuit and method of a high-speed driving stage, which comprises an input stage, a level converting unit, a feedback unit, a current mirror unit and a current shunting unit. The current sensing circuit is capable of linearly detecting the output current of the driving stage transistors, and directly condensing the detected current to an appropriate value using the geometric ratio of the transistors, so as to facilitate the subsequent signal processing circuit to use it for control purposes.