Niko Semiconductor Co., Ltd.

Mediatek Corporation

Shamrock Micro Devices Corp.

Chun-Ming Lin

Yao-Chi Wang

Ta-Ching Hsu

Keng-Meng Chang

Sen-You Liu

Yun-Kang Chu

Hsin-Yu Pan

Jian-He Li

Yanjie Mo

Ker Cheng Liu

A fast start-up crystal oscillator (XO) and a fast start-up method thereof are provided. The fast start-up XO may include a XO core circuit, a frequency synthesizer, and a fast start-up interfacing circuit, wherein the frequency synthesizer may include a voltage control oscillator (VCO) and a divider. The XO core circuit generates a XO signal having a XO frequency. The VCO generates a VCO clock having a VCO frequency, and the divider generates a divided clock having a divided frequency, wherein the VCO frequency is divided by a divisor of the divider to obtain the divided frequency. The fast start-up interfacing circuit transmits the divided clock to the XO core circuit, and then generates a reference clock having the XO frequency according to the XO signal. More particularly, the VCO frequency is calibrated according to the reference clock, in order to make the divided frequency approach the XO frequency.

Fast start-up crystal oscillator and fast start-up method thereof

Disclosed are a voltage waveform detector, a power controller and a control method used therein, adaptive for a switched-mode power supply having a power switch and an inductive device. A disclosed power controller has a voltage waveform detector and a constant-current control unit. The voltage waveform detector estimates a discharge time of the inductive device when the power switch is turned off. In the voltage waveform detector, a differential capacitor is coupled between an input node of a comparator and a feedback node, at which the feedback voltage corresponds to a reflection voltage of the inductive device. The constant-current control unit integrates a current-detection signal over the discharge time to control a maximum output current of the switched-mode power supply.

Voltage waveform detector, power controller and control method for switched-mode power supplies with primary-side control

A pulse width modulation regulator IC is provided for controlling a duty cycle of at least one switch to convert one input voltage signal into an output voltage. An input pin is provided for receiving an input signal different from the input voltage signal. The input signal has a lasting time substantially the same as the time that input voltage signal situated at a high level, but the waveforms of the two signals are different. The input signal is converted into a square wave signal by a conversion unit, and a PWM signal is generated by a PWM controller according to the square wave signal to control the duty cycle of the switch. Therefore, the input pin can be saved by adjusting an internal or external circuit of the IC for the usage of the different kinds of input signals without increasing the number of input pins of the IC.

Pulse width modulation regulator IC and circuit thereof

A synchronous rectifier control device comprises a status detecting unit, an analog circuit, a first counter, a second counter and a signal process unit. The status detecting unit receives at least one reference signal and a detecting signal to generate a first synchronous control signal. The analog circuit generates a delay signal in accordance with the first synchronous control signal. The first counter receives a clock signal and generates a first counter signal in accordance with the first synchronous control signal, the clock signal, and the delay signal. The second counter receives the clock signal and generates a second counter signal in accordance with the first synchronous control signal, the clock signal, and the first counter signal. The signal process unit generates a second synchronous control signal in accordance with the first synchronous control signal and the second signal.

Synchronous rectifier control device and a forward synchronous rectifier circuit

Disclosed are a synchronous rectifier control device and a forward synchronous rectifier circuit. The synchronous rectifier control device is coupled with the secondary side of the forward synchronous rectifier circuit, comprising a condition detecting unit, a reference time circuit and a synchronous signal generator. The condition detecting unit receives at least one reference signal and a detecting signal in response to the condition of the secondary side of the forward synchronous rectifier circuit, and accordingly generates a first synchronous control signal. The reference time circuit is coupled with the condition detecting unit, and generates a reference time signal in response to the first synchronous control signal. The synchronous signal generator generates a second synchronous control signal in response to the first synchronous control signal and the reference time signal.

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Hsinchu, Taiwan

Chun-Ming Lin