Aimtron Technology Corp.

Li-Cheng Chen

Chi-Yang Chen

Rong-Chin Lee

Tien-Tzu Chen

Fang-Te Su

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.

Switching voltage regulator with an improved range of input voltage

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.

Dimming control circuit for light-emitting diodes

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.

Motor control circuit for supplying a controllable driving voltage

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.

Motor control circuit for supplying a controllable driving current

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.

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Kao-Hsiung, Taiwan

Li-Cheng Chen