Abstract: A motor driver having a startup adjusting mechanism is provided. A steady-state detector circuit detects data for driving a motor to stably rotate to output a steady-state detected signal. A startup waveform pattern circuit selects one of a plurality of startup waveform patterns to output a startup waveform pattern signal according to the steady-state detected signal. A startup waveform generator circuit outputs a startup waveform signal according to the startup waveform pattern signal. A motor controlling circuit controls a motor driving circuit to start up the motor according to the startup waveform signal.

Abstract: A micro electro-mechanical film speaker device is provided. A signal input terminal of a signal amplifier circuit is connected to an external input circuit. A second output terminal of the signal amplifier circuit is connected to a negative terminal of a micro electro-mechanical film speaker. A first terminal of a first high-pass filter is connected to a first output terminal of the signal amplifier circuit. A second terminal of the first high-pass filter is connected to a positive terminal of the micro electro-mechanical film speaker. A first terminal of a second high-pass filter is connected to a feedback terminal of the signal amplifier circuit. A second terminal of the second high-pass filter is connected to the positive terminal of the micro electro-mechanical film speaker.

Abstract: A light sensor having a voltage reversing mechanism is provided. A photoelectric component converts a first light signal into a first photocurrent. A capacitor is charged to a first voltage by the first photocurrent. A counter counts a first coarse count value according to the first voltage. The photoelectric component converts a second light signal into a second photocurrent. The capacitor is charged from a reversed first voltage to a second voltage by the second photocurrent. The counter counts a second coarse count value according to the second voltage. The counter counts a fine count value according to the second coarse count value. One of the first light signal and the second light signal is emitted by both of an ambient light source and a light-emitting component and then reflected by a tested object, and the other one of them is emitted by only the ambient light source.

Abstract: A motor controlling circuit is provided. A first terminal of a first high-side transistor and a first terminal of a second high-side transistor are coupled to a common voltage. A first terminal of a first low-side transistor is connected to a second terminal of the first high-side transistor. A first node between the first terminal of the first low-side transistor and the second terminal of the first high-side transistor is connected to a first terminal of a motor. A first terminal of a second low-side transistor is connected to a second terminal of the second high-side transistor. A second node between the first terminal of the second low-side transistor and the second terminal of the second high-side transistor is connected to a second terminal of the motor. The driver circuit regulates at least one of the transistors such that no current flows to the common voltage.

Abstract: A power converter having a smooth transition control mechanism is provided. An oscillator circuit outputs a clock signal. A control circuit receives the clock signal from the oscillator circuit and outputs a control signal based on the clock signal. A driver circuit outputs a high-side conduction signal and a low-side conduction signal according to the control signal. A high-side switch is turned on or off according to the high-side conduction signal from the driver circuit. A low-side switch is turned on or off according to the low-side conduction signal from the driver circuit. The oscillator circuit receives the high-side conduction signal from the driver circuit. The oscillator circuit, according to the high-side conduction signal, determines whether or not the clock signal outputted to the control circuit needs to be adjusted.

Abstract: An automatic control system for a phase angle of a motor is provided. A current detector circuit detects a current signal of the motor to output a current detected signal. A control circuit outputs a control signal according to the current detected signal indicating a time point at which the current signal reaches a zero value. A driver circuit outputs a driving signal according to the control signal. An output circuit operates to output a motor rotation adjusting signal to the motor to adjust a rotational state of the motor according to the driving signal.

Abstract: A power converter having a mechanism of dynamically controlling a minimum off time is provided. A high-side overcurrent protecting circuit determines whether or not a current flows from a high-side switch through a node between a second terminal of the high-side switch and a first terminal of a low-side switch toward an inductor, and determines whether or not the current is larger than a threshold to output a high-side overcurrent detected signal and a high-side overcurrent protecting signal. An off time adjusting circuit outputs a minimum off time signal to a driver circuit according to the high-side overcurrent protecting signal. The driver circuit determines that an overcurrent event occurs when the high-side switch is turned on according to the high-side overcurrent detected signal, and accordingly the driver circuit at least continually turns on the low-side switch during a longer minimum off time of the minimum off time signal.

Abstract: A sensor is provided. A first terminal of a first current source and a first terminal of a first transistor are connected to a cathode of the photodiode. A control terminal of a second transistor is connected to an output terminal of a first operational amplifier. A first terminal of the second transistor is connected to a second terminal of the first transistor through a first current mirror circuit. A second terminal of the second transistor is connected to a second current source, a second input terminal of a second operational amplifier and a first terminal of a third transistor. A first input terminal of the second operational amplifier is connected to the first terminal of the first transistor. A control terminal of the third transistor is connected to an output terminal of the second operational amplifier.

Abstract: A motor current protecting circuit is provided. A voltage calculating circuit determines whether or not each of low-side switches is fully turned on and then determines whether or not a voltage difference between a first terminal and a second terminal of each of the low-side switches being fully turned on is larger than or equal to a zero value. The voltage calculating circuit adds up the voltage differences each of which is larger than or equal to the zero value to output a voltage signal. A control circuit controls a driver circuit to switch the low-side switches and high-side switches according to the voltage signal.

Abstract: A closed-loop inductor current emulating circuit is provided. An emulation controller circuit generates an emulating signal according to a current flowing through a first terminal of a low-side switch of a power converter. When the emulation controller circuit outputs the emulating signal to a charging and discharging circuit, the charging and discharging circuit outputs a charging and discharging signal to a first terminal of a capacitor according to the emulating signal. When the emulation controller circuit outputs the emulating signal to a control terminal of the capacitor to adjust a capacitance of the capacitor, the charging and discharging circuit outputs a charging and discharging signal to the first terminal of the capacitor according to one or both of an input voltage and an output voltage of the power converter.

Abstract: A motor controller circuit having a rotational speed locking mechanism is provided. Each time when a motor commutates, a first signal generating circuit resets a first waveform signal and a second signal generating circuit resets a second waveform signal. An output signal generating circuit outputs a waveform output signal according to the first waveform signal and the second waveform signal. A motor controller circuit outputs an on-time signal according to the waveform output signal. A motor driving circuit outputs a driving signal to the motor to drive the motor to rotate according to the on-time signal.

Abstract: A power managing system and method are provided. When an under voltage lockout circuit determines that a common voltage of the power managing system is lower than a first lockout voltage, the under voltage lockout circuit outputs a first under voltage lockout signal for controlling one of a plurality of power converters that supplies a highest output voltage to rapidly reduce its output voltage to a zero value. Then, the under voltage lockout circuit outputs a second under voltage lockout signal for controlling another one of the power converters that supplies a lowest output voltage to gradually reduce its output voltage to the zero value.

Abstract: A motor driver having an automatic phase switching mechanism is provided. After a three-phase motor is started up, a back electromotive force detecting circuit starts detecting a back electromotive force signal of each of three phases of the three-phase motor. A driving waveform generating circuit extracts parts of a plurality of first wave segment patterns from a first wave segment pattern signal as a plurality of first wave segments of a first waveform signal according to the back electromotive force signal. A motor controlling circuit controls the motor driving circuit to drive the three-phase motor to rotate normally according to the first waveform signal.

Abstract: An overvoltage protecting system and method of a motor pre-driver are provided. An overvoltage protecting circuit compares a first reference voltage with a common voltage inputted to a single phase motor to output a first comparison signal. When a controller circuit determines that the common voltage is higher than the first reference voltage according to the first comparison signal, the controller circuit turns off a first high-side switch and a second high-side switch, and turns on the first low-side switch and the second low-side switch, during a phase time of a phase transition signal of the single phase motor. After the phase time ends, the controller circuit alternately turns on the first low-side switch and the second low-side switch according to a level of the phase transition signal.

Abstract: A multiphase power converter having a daisy chain control circuit and a method for controlling the same are provided. A main control circuit outputs an initial pulse width modulation signal having a plurality of initial pulses. One of a plurality of slave control circuits is connected to an output terminal of the main control circuit, and outputs a pulse width modulation signal according to the received initial pulse width modulation signal. Each of the rest of the plurality of slave control circuits outputs the next pulse width modulation signal to the next slave control circuit or the main control circuit according to the pulse width modulation signal received from the previous slave control circuit. The main control circuit automatically counts a quantity of the control circuits according to the received pulse width modulation signal and outputted initial pulse width modulation signal.

Abstract: A rotation locking system of a motor of a fan is provided. A closed-loop control circuit outputs an initial duty cycle signal according to a current rotational speed and a target rotational speed. A driver circuit outputs a driving signal to the motor to drive the motor to rotate according to the initial duty cycle signal. A lookup table arithmetic circuit looks up, from a lookup table, two reference duty cycles correspond to two reference rotational speeds that are respectively equal to the current rotational speed and the target rotational speed. The lookup table arithmetic circuit calculates a difference between the two reference duty cycles. A speed feedback control circuit compensates the initial duty cycle signal according to the difference to output a final duty cycle signal to the driver circuit. The driver circuit drives the motor to rotate according to the final duty cycle signal.

Abstract: A power saving system of a battery charger is provided. A control terminal of a first transistor receives a wake-up signal. A counter is connected to a first terminal of the first transistor. The counter determines whether or not a working period of the wake-up signal from the first transistor is larger than a time threshold to output a counting signal. When the counting signal indicates that the working period of the wake-up signal is not larger than the time threshold, the counter and electronic components of an electronic device are turned off, thereby saving power of a battery. When the counting signal indicates that the working period of the wake-up signal is larger than the time threshold, the electronic device is switched from a power saving mode to a normal operation mode. In the normal operation mode, the battery can supply power to the electronic device.

Abstract: A motor controller circuit having a stable speed controlling mechanism is provided. A duty cycle determining circuit determines duty cycles of the plurality of waveforms respectively of the first waveform signals within each of a plurality of time intervals to output a duty cycle instructing signal, according to a target working period corresponding to a target rotational speed. A signal generating circuit outputs the plurality of first waveform signals according to the duty cycle instructing signal, and outputs a second waveform signal. A motor control circuit outputs a plurality of on-time signals according to the plurality of first waveform signals and the second waveform signal. A motor driving circuit is controlled to operate and drive a motor to rotate according to the plurality of on-time signals.

Abstract: A light sensor having a control complexity reducing mechanism is provided. When light is emitted to a photodiode by both of an ambient light source and a light-emitting component, a first coarse count value is counted by a counter and then is sampled and held by a first sample and hold circuit. When light is emitted to the photodiode by only the ambient light source, a second coarse count value is counted by the counter and then is sampled and held by a second sample and hold circuit. After the coarse count values are held, the counter performs a fine counting operation on light intensity of the light emitted by both of the ambient light source and the light-emitting component to generate a first fine count value, and on light intensity of the light emitted by only the ambient light source to generate a second fine count value.

Abstract: A brake control system of a motor is provided. When a control circuit intends to brake the motor, the control circuit controls a driver circuit to turn off a first high-side switch and a second high-side switch, and to fully turn on the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off one of the first low-side switch and the second low-side switch, and to continually turn on the other one of the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off the other one of the first low-side switch and the second low-side switch, and to turn on the one of the first low-side switch and the second low-side switch, for a period of time.