Patents Assigned to Holtek Semiconductor
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Patent number: 7940876Abstract: A universal series bus (USB) frequency synchronous apparatus using a start of frame (SOF) signal generated by a master device to mark a reference interval is disclosed. The frequency synchronizing apparatus includes a frequency divider, a counter unit with a default pulse number, an arithmetic unit, and an adjusting unit. The frequency divider divides a high frequency signal by a variable frequency factor to generate a lock frequency signal. The counter is used to detect a pulse number of the lock frequency signal at a reference interval and obtain a pulse difference between the default pulse number and the detected pulse number of the lock frequency signal.Type: GrantFiled: January 23, 2008Date of Patent: May 10, 2011Assignee: Holtek Semiconductor Inc.Inventors: Min-Kun Wang, Min-Hsiung Hu, Chuen-An Lin
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Patent number: 7936131Abstract: An AC power feedback control device for a vacuum fluorescent display is provided. In the AC power feedback control device, the Class-D drivers are driven by the PWM controller so as to generate a sine wave voltage. After being filtered by the LPFs, the sine wave voltage is ready for filaments. The output voltage outputted by the filaments is detected by simple feedback elements so as to control and modulate the duty cycle of the PWM controller.Type: GrantFiled: September 22, 2008Date of Patent: May 3, 2011Assignee: Holtek Semiconductor, Inc.Inventor: Chen-Kuang Yeh
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Publication number: 20110084866Abstract: The configuration of a successive approximation analog to digital converter (ADC) and a method thereof are provided in the present invention. The proposed configuration includes a comparator having an inverting input terminal, a non-inverting input terminal and an output terminal outputting a comparison result, a most significant bit ADC coupled to the non-inverting input terminal, and a least significant bit ADC coupled to the inverting input terminal.Type: ApplicationFiled: January 26, 2010Publication date: April 14, 2011Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: Pochin HSU
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Publication number: 20110074834Abstract: For improving the brightness decay of a display due to its aging, a non-volatile memory such as Flash can be used to store a brightness accumulation value of each point of the display, and each point can be compensated for its brightness accordingly. However, the non-volatile memory suffers from incorrect write-in data or temporary power disconnection, and thus the error will exist all the time to make the display non-even. Hence, the present invention uses a multiple data backups and CRC error detection, plus new/old data comparison to protect data the non-volatile memory from incorrect brightness compensation value so as to uniform the brightness of the display.Type: ApplicationFiled: December 16, 2009Publication date: March 31, 2011Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Tzong-Kwei Chen, Chun-Lin Shen, Yi-Chen Liu, Chen-Ting Kuan
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Publication number: 20110074806Abstract: For improving the drawback of brightness decay of a display due to aging, a memory can be used to store the usage time of each pixel of the display, then based upon the usage time the brightness decay of each pixel of the display can be compensated and accordingly the value for the compensation can be stored in a volatile memory and a non-volatile memory. However, the usage of the non-volatile memory is limited. Hence, the present invention discloses a new approach for storing the data so as to decrease write-in sequence per unit area for the non-volatile memory rather than increasing its storing capacity proportionally.Type: ApplicationFiled: December 16, 2009Publication date: March 31, 2011Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Tzong-Kwei Chen, Chun-Lin Shen, Yi-Chen Liu, Chen-Ting Kuan
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Publication number: 20110036827Abstract: The present invention provides a micro-control device, which comprises a RC oscillator for generating a reference clock, a plurality of analog switches coupled to the touch switches for controlling transmission of the transition signal and a plurality of counters for counting time, all of the counters stop counting when one of the counters overflows and content of all counters being read, wherein ON/OFF of the analog switches controlled by a software.Type: ApplicationFiled: August 20, 2010Publication date: February 17, 2011Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Wen-Liang Liu, Chin-Hung Yang
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Patent number: 7872509Abstract: The provided delay lock loop delaying an input signal includes a quadrature generator, a voltage controller and a delay cell. The input signal is inputted into the quadrature generator and the delay cell. A phase-changing signal from the quadrature generator and a delay signal respectively from the delay cell are inputted into the voltage controller at the same time so that a control voltage inputted into the delay cell to control a delay time of the delay signal is generated. Also, the provided phase angle generator generates an output signal in an arbitrary phase.Type: GrantFiled: July 16, 2009Date of Patent: January 18, 2011Assignee: Holtek Semiconductor Inc.Inventors: Chih-Wei Yang, Chien-Hsun Lee
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Publication number: 20110006705Abstract: The present invention discloses a control apparatus, which not only accepts multiple dimming control signals, but also combines the signals in analog manner. By means of this, an inevitable analog to digital converter in a conventional voltage multiple dimming control apparatus can be saved without hurting the performance of generation of pulse width modulation signals. Compared with the conventional arts, the present invention further exhibits reduction in view of chip size and power consumption.Type: ApplicationFiled: August 13, 2009Publication date: January 13, 2011Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Wen-kuen Vincent Liu, Yi-Tai Chang
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Patent number: 7863879Abstract: An AC signal producer comprises a controlling unit, a Class-D switch circuit, and a low-pass filter. The control unit receives a DC signal and produces a PWM control signal via checking reference tables. The Class-D switch circuit receives the PWM control signal and outputs a square-wave signal. The low-pass filter converts the square-wave signal into the AC signal. Thereby, disadvantages associated with the utilization of an oscillator and a transformer to convert the DC signal to an AC signal could be solved.Type: GrantFiled: January 14, 2008Date of Patent: January 4, 2011Assignee: Holtek Semiconductor Inc.Inventor: Yi-Chen Lin
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Patent number: 7859812Abstract: A power IC with an over-current protection receives an input voltage and converts the input voltage into an output voltage to a load. The present invention controls a power transistor to provide an output current to the load, and uses the output control unit to control the power transistor. Furthermore, the over-current protection circuit has a constant current limit threshold and a fold-back current limit threshold for controlling the power transistor. When the output current is larger than the constant current limit threshold, the output current is clamped to a constant current value to descend the output voltage to a rated value. When the output current is larger than the fold-back current limit threshold, the output current is limited to a low current value to descend the output voltage to zero. Thereby, the inner circuit of the power IC and the load are protected.Type: GrantFiled: April 24, 2008Date of Patent: December 28, 2010Assignee: Holtek Semiconductor Inc.Inventors: Chia-Min Chen, Ming-Hong Jian
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Patent number: 7816957Abstract: The invention mainly relates to a power on reset signal generating circuit and method thereof wherein said reset signal remains as a constant being independent of rising or descending power or repeated switching. The power on reset signal circuit can be implemented by a conventional RC power on reset circuit together with a coupled N-type transistor switch to charge or discharge the capacitor inside the conventional RC power on reset circuit.Type: GrantFiled: October 14, 2008Date of Patent: October 19, 2010Assignee: Holtek Semiconductor Inc.Inventor: Yu-Ren Chen
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Publication number: 20100245132Abstract: A compensation method devoid of operating voltage calibration, establishing fundamental linearity calibration table and inputting, and detecting the actual operating voltage is disclosed. The compensation method comprises the steps of: a) turning off a switch in a touch sensor system; b) initializing the touch sensor system and measuring a reference frequency outputted from a oscillator in the touch sensor system; c) turning on the switch and measuring a first frequency outputted from the oscillator; and d) deducting the first frequency from the reference frequency so as to obtain a frequency difference; and e) comparing the difference with a predetermined value, and judging based upon the difference if the touch sensor system is touched by a foreign object.Type: ApplicationFiled: April 23, 2009Publication date: September 30, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: TING-YUAN LU, WEN-LIANG LIU, CHENG-MU WU
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Publication number: 20100250180Abstract: A compensation method devoid of operating voltage calibration, establishing fundamental linearity calibration table and inputting, and detecting the actual operating voltage is disclosed. The compensation method comprises the steps of: a) turning off a switch in a touch sensor system; b) initializing the touch sensor system and measuring a reference frequency outputted from a oscillator in the touch sensor system; c) turning on the switch and measuring a first frequency outputted from the oscillator; and d) deducting the first frequency from the reference frequency so as to obtain a frequency difference; and e) comparing the difference with a predetermined value, and judging based upon the difference if the touch sensor system is touched by a foreign object.Type: ApplicationFiled: December 31, 2009Publication date: September 30, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: TING-YUAN LU, WEN-LIANG LIU, CHENG-MU WU
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Patent number: 7800392Abstract: The present invention discloses a detection control circuit for preventing a leakage current, which comprises a register unit comprising a clock signal input terminal for receiving a clock signal; a reset signal input terminal, for receiving a reset signal; a signal generating terminal, for generating a logic signal; and a logic gate, coupled to said register unit, comprising a first signal input terminal for receiving said logic signal; a second signal input terminal for receiving a control signal; and a signal output terminal, for outputting an output signal according to said logic signal and said control signal; wherein said control signal controls said logic gate so as to keep said output signal to be in a fixed state which detects a leakage current in an integrated circuit due to the process flaw.Type: GrantFiled: November 4, 2008Date of Patent: September 21, 2010Assignee: Holtek Semiconductor Inc.Inventors: Jia-Hsuan Wu, Chuen-An Lin
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Patent number: 7800025Abstract: The present invention provides a micro-control unit a RC oscillator for generating a reference clock, a plurality of touch switches for generating a transition signal indicating one of the touch switches being touched by human beings, a plurality of analog switches coupled to the touch switches for controlling transmission of the transition signal and a plurality of counters for counting time, all of the counters stop counting when one of the counters overflows and content of all counters being read, wherein ON/OFF of the analog switches controlled by a software.Type: GrantFiled: June 4, 2007Date of Patent: September 21, 2010Assignee: Holtek Semiconductor Inc.Inventors: Wen-Liang Liu, Chin-Hung Yang
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Patent number: 7777555Abstract: A temperature compensating circuit including a reference circuit, a transistor and a first circuit is provided. The reference circuit has a reference current and a resistance circuit, wherein the resistance circuit includes a first terminal receiving the reference current, a second terminal and a negative-temperature-coefficient resistor. The transistor has a drain, a source and a path disposed between the drain and the source, wherein the path of the transistor is connected in series with the resistance circuit, a gate of the transistor is electrically connected to the drain of the transistor and the second terminal of the resistance circuit, and the drain of the transistor produces a bias-voltage signal.Type: GrantFiled: January 27, 2009Date of Patent: August 17, 2010Assignee: Holtek Semiconductor Inc.Inventors: Chun-Yao Liao, Guan-Xing Huang, J-Ian Wu
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Patent number: 7764200Abstract: The present invention discloses a capacitive button device, comprising: a signal input unit, a first amplifier, a first switching unit, a second amplifier, a second switching unit, an analog-to-digital converting unit, a third switching unit, a data output unit, a data storage unit and a digital-to-analog converting unit. Thereby, the present invention overcomes the problem due to poor resolution of conventional capacitive buttons and can be used with touch panels. Moreover, the digital-to-analog converting unit is downsized with improved resolution and reduced cost in design and fabrication.Type: GrantFiled: May 20, 2008Date of Patent: July 27, 2010Assignee: Holtek Semiconductor Inc.Inventor: Yi-Chan Lin
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Patent number: 7728750Abstract: A display panel driver including a binary-weighted current-type D/A converter and a source follower with current mirror is provided. The binary-weighted current-type D/A converter receives n input signals and sends a D/A output voltage signal based on 2n?1 times a reference current. The source follower with current mirror receives the D/A output voltage signal and sends 2n?1 times the reference current to the output of the source follower with current mirror, so as to output a output voltage and drive the display panel.Type: GrantFiled: September 3, 2008Date of Patent: June 1, 2010Assignee: Holtek Semiconductor, Inc.Inventors: Yuh-Diahn Wang, Yan-Kai Huang
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Publication number: 20100128503Abstract: Disclosed is a Power Factor Correction Controller, which comprises a boost converter, a current sensing unit, an arithmetic unit, and a switch driving unit. The current sensing unit can sense or derive the current that pass through the energy delivery device, which is normally implemented by a diode or a switch. The current sensing unit can also sense the inductor current, or the switch current. With the current sensing unit, the arithmetic unit can calculate the optimum switch on-time or when to turn off the switch, without direct-sensing of the load. The disclosed method reduces the system cost by removing the needs to sense the load condition as in the prior arts. The disclosed method also improves the system response by sensing the delivered current at energy delivery side, rather than the receiver side as in the prior arts.Type: ApplicationFiled: March 20, 2009Publication date: May 27, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Vincent Liu, Yi-Meng Lan, Ming-Hung Chien
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Patent number: 7714673Abstract: The present invention relates to a control method for the operation modes of an oscillator and the apparatus thereof, for which the method and the apparatus can be applied to the electronic circuits with multi-operation modes of the oscillator so as to correctly choose the desirable oscillator operation mode. Furthermore, an oscillator checking circuit sets up the oscillation mode automatically and judges if the oscillator operates properly. Hence, there is no need for the user to set up the oscillator operation mode manually.Type: GrantFiled: July 18, 2008Date of Patent: May 11, 2010Assignee: Holtek Semiconductor Inc.Inventors: Jia-Hsuan Wu, Cheng-Mu Wu