Novatek Microelectronics Corp.

Hsiang-Yi Chiu

Zhen-Guo Ding

Chih-Yuan Hsieh

Lan-Shan Cheng

Tuo-Kuang Chen

Yao-Cheng Lin

Chiun-He Lin

A voltage-to-current converter includes a first transistor having a drain coupled to a first node, a second transistor having a drain coupled to the first node, an operational amplifier having a first input terminal configured to receive a reference voltage and a second input terminal coupled to a source of the first transistor or a source of the second transistor, a control circuit having an input terminal coupled to an output terminal of the operational amplifier, a first output terminal coupled to a gate of the first transistor, and a second output terminal coupled to a gate of the second transistor, a first resistor coupled between the source of the first transistor and a ground, and a second resistor coupled between the source of the second transistor and the ground. An output current of the voltage-to-current converter is generated from the first node.

Voltage to current converter of improved size and accuracy

A level shifter includes a pre-level shifter and a selector. The selector is coupled to the pre-level shifter. The pre-level shifter shifts an input digital voltage to a first digital voltage and a second digital voltage. The levels of the first digital voltage and the second digital voltage transition sequentially in time when the level of the input digital voltage transitions from one logic to the other. The selector selects and outputs the first digital voltage whose level transitions earlier in time compared to the transition of the level of the second digital voltage.

Level shifter

An overcurrent detector for multiple level shifter circuits includes an overcurrent detecting circuit that senses currents acquired through level shifter circuits, and that outputs an indication signal indicating occurrence of overcurrent when one of the currents sensed thereby is greater than a predefined current level.

Overcurrent detector for a multi-channel level shifter module

A driving circuit, for providing a driving current to a light emitting diode, includes a PWM demodulator, a current source and a local clock generator. The PWM demodulator is configured to sample a PWM input signal in reference with a local clock signal and generate a brightness code according to a duty ratio of the PWM input signal. The current source is coupled with the PWM demodulator and the light emitting diode. The current source is configured to generate the driving current with a current amplitude according to the brightness code. The local clock generator is configured to generate the local clock signal according to a global clock signal during a first cycle period of successive cycle periods of the PWM input signal. The local clock generator suspends oscillation of the local clock signal during a second cycle period of the successive cycle periods of the PWM input signal.

Control method and driving circuit for light emitting diode

The invention provides a light-emitting diode (LED) driver and a driving method thereof. The LED driver includes a brightness code calculation circuit, a driving current generation circuit and a control circuit. The brightness code calculation circuit is configured to to receive a pulse width modulation (PWM) signal and perform a calculation operation comprising calculating a duty cycle of the PWM signal with respect to a period of the PWM signal and generating a brightness code according to the duty cycle of the PWM signal. The driving current generation circuit is configured to generate a driving current according to the brightness code. The control circuit is configured to detect a plurality of brightness codes generated by the brightness code calculation circuit repeatedly performing the calculation operation and determine whether or not to adjust an execution frequency of the calculation operation of the brightness code calculation circuit according to the brightness codes.

Light emitting diode driver and driving method thereof

A level shifter is disclosed. The level shifter comprises a pulse generating circuit, configured to receive an input signal, and generate a plurality of first-level pulses having a pulse width shorter than a pulse width of the input signal, wherein the input signal swings over a first voltage domain; a pulse transforming circuit, coupled to the pulse generating circuit, configured to generate a plurality of second-level pulses corresponding to the plurality of first-level pulses; and a latching circuit, coupled to the pulse transforming circuit, configured to generate an output signal by latching a status of the output signal in response to the plurality of second-level pulses, wherein the output signal swings over a second voltage domain.

Level shifter with low power consumption

An amplifier circuit includes an input stage, having a positive input end and a negative a negative input end, for generating a pair of differential signals according to a first input voltage received from the positive input end and a second input voltage received from a negative input end; an output stage, coupled to the input stage for generating an output voltage at an output end according to the pair of differential signals; a feedback stage, coupled between the output end and the negative input end; and a clamping unit, coupled between the positive input end and the negative input end for adjusting the second input voltage when the first input voltage is varied so as to clamp a voltage difference between the first input voltage and second input voltage.

Amplifier circuit of high response speed and related clamping method

A voltage generating circuit including a pre-driving unit and a voltage generating unit is provided. The pre-driving unit receives an oscillation signal and enhances a driving capability of the oscillation signal to generate a pre-driving signal. The voltage generating unit receives an input signal and the pre-driving signal, and generates an output signal according to the input signal and the pre-driving signal. The voltage generating unit generates a voltage signal according to the pre-driving signal. One of the pre-driving unit and the voltage generating unit adjusts a slew rate or a ringing component of the voltage signal by using the pre-driving signal. A pre-driving signal generating module for driving a voltage generating circuit is also provided.

Voltage generating circuit and pre-driving signal generating module

A charge pump device is disclosed. The charge pump device includes a driving stage, for generating a driving signal corresponding to a driving capability; a charge pump circuit, for generating an output voltage according to the driving signal; a comparing circuit, comprising a first comparator for comparing the output voltage and a first reference voltage to generate a first comparing result; an overload detection circuit, for generating a detection result according to at least one of the first comparing result and the output voltage; and a driving capability control circuit, coupled between the overload detection circuit and the driving stage for controlling the driving capability corresponding to the driving signal according to the detection result.

Charge pump device and driving capability adjustment method thereof

A charge pump device includes a charge pump circuit, for generating an output voltage according to a driving signal, a comparing circuit, for generating a comparison result according to the output voltage and a reference voltage, a detecting circuit, for detecting a frequency range of a ripple of the output voltage according to the comparison result and generating a detection result, and a driving stage, for generating the driving signal according to the comparison result, and adjusting a driving capability corresponding to the driving signal according to the detection result.

Charge pump device

A power factor correction device includes a rectifier for converting an AC input voltage into a DC input voltage, an output module for generating and outputting a DC output voltage, an intermediate inductor coupled between the rectifier and the output module, a power switch for controlling an inductor current of the intermediate inductor and generating a source voltage, a reset module for generating a reset instruction according to the DC input voltage, the DC output voltage and the source voltage, an SR flip-flop for outputting a latch result according to a set instruction and the reset instruction, and a set module for generating the set instruction in response to variation of the intermediate inductor or variation of the latch result.

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Taipei, Taiwan

Hsiang-Yi Chiu