Patents Assigned to Holtek Semiconductor
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Publication number: 20100090664Abstract: The present invention mainly relates to a voltage regulator, comprising: a P typed power MOS; a feedback circuit; a differential amplifier; a protecting circuit having a N-typed transistor current mirror; and an active foldback current limiting circuit rather than using a resistor. When the P typed power MOS is under short circuit current situation, the current at the output side of the current mirror is increased in order to limit the current flown through the power MOS. Meanwhile, the same purpose can also be served by increasing the current at the input side of the DC current mirror.Type: ApplicationFiled: November 24, 2008Publication date: April 15, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: MING-HONG JIAN
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Publication number: 20100090665Abstract: The present invention mainly relates to a current limiting circuit, also known as over-current protection circuit, and a power regulator using the same. The purpose for the circuit is to protect the power device and the loading circuit for the power regulator. The conventional current limiting circuit takes advantage of a resistor and a MOS to convert the detected over current into a voltage and then turn on a P-typed MOS to clamp the gate voltage of a power transistor so as to achieve the goal of current limiting. However, the process variation for the resistor and said MOS and their temperature variation lead to a significant error to the limiting current. The present invention, therefore, takes advantage of the current comparison to enhance the accuracy for the current limiting circuit.Type: ApplicationFiled: December 5, 2008Publication date: April 15, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: MING-HONG JIAN
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Publication number: 20100085072Abstract: 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: ApplicationFiled: November 4, 2008Publication date: April 8, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: JIA-HSUAN WU, Chuen-An Lin
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Publication number: 20100066342Abstract: A control circuit for a single chip IC controlled by an external power is provided. The control circuit includes a regulating circuit, an MCU and a trigger circuit. The regulating circuit is controlled by the external power and includes a regulator to be enabled to generate an internal power for an internal circuit of the single chip IC. The MCU is controlled by the internal power and generates a switch signal to disable the regulator when the internal circuit of the single chip IC is standby. The trigger circuit is controlled by the external power and generates a trigger signal to enable the regulator based on an external signal.Type: ApplicationFiled: November 7, 2008Publication date: March 18, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: Chun-Yao Liao
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Publication number: 20100066434Abstract: 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: ApplicationFiled: January 27, 2009Publication date: March 18, 2010Applicant: Holtek Semiconductor Inc.Inventors: Chun-Yao Liao, Guan-Xing Huang, J-Ian Wu
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Publication number: 20100066679Abstract: The invention mainly relates to a mouse with a capacitive tact switch incorporated thereto. When the user touches the mouse, the capacitive tact switch in the mouse will sense the proximity and inform the host control circuit immediately. Contrarily, when the user's hand is leaving the mouse, the capacitive tact switch will inform the host control circuit to shut down completely the most power consuming parts such as RF module, CMOS sensor thereby the goal of power saving can be achieved.Type: ApplicationFiled: October 14, 2008Publication date: March 18, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: CHIEN-CHOU PAN
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Publication number: 20100060330Abstract: 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: ApplicationFiled: October 14, 2008Publication date: March 11, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: YU-REN CHEN
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Publication number: 20100054387Abstract: The present invention discloses a synchronizing device for real-time USB audio data transmission, comprising: a first adder unit, a start-of-frame countdown unit, a phase-locked loop circuit, a frequency divider, a second adder unit, a third adder unit, a fourth adder unit, a frame calibrating register unit, a calibrating mapping unit and a calibrating pulse generating unit. A start-of-frame token sent by the USB host is used as a 1-ms reference cycle so that a high-frequency clock passes through the frequency divider to issue a first clock. The first clock signal has a constant clock number in a USB start-of-frame. The absolute time is automatically adjusted according to the duration of a previous start-of-frame. Therefore, asynchronicity of data transmission between the USB host and external devices can be overcome.Type: ApplicationFiled: November 14, 2008Publication date: March 4, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: MIN-SHING WU, CHUEN-AN LIN
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Patent number: 7671669Abstract: A device and a method for reducing input noise providing at least a microcontroller. The microcontroller comprises: at least a noise reduction device, at least an analog switch and at least a signal output unit. The noise reduction device connected to the ground or a voltage is turned on to charge or discharge a stray capacitor existing on a turned off analog switch so that the amount of charge stored in the stray capacitor is zero or a specific value. Thereby, the noise in a touch switch is reduced and the cost of layout on the PCB is saved.Type: GrantFiled: March 3, 2008Date of Patent: March 2, 2010Assignee: Holtek Semiconductor Inc.Inventors: Wen-Liang Liu, Chin-Hung Yang
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Patent number: 7669025Abstract: The present invention provides an apparatus for security of accessing data, comprising a storage device including an address transform detector, a first lock bit register and a data comparator, the address transform detector providing a predetermined correction signal, data outputted from the storage device could be correctly identified when a memory address signal matches the predetermined correction signal and a latch signal is provided to the first lock bit register; and a micro-control unit for receiving data outputted from the storage device, the outputted data being stored in a second lock bit register and encoded by a serial encoding unit, a locking signal being feedback to the storage device; wherein a data encoded signal outputted from the first lock bit register and the locking signal are provided to a data comparator for comparison and determining whether output correct data to an encoding control unit according to the comparison.Type: GrantFiled: June 4, 2007Date of Patent: February 23, 2010Assignee: Holtek Semiconductor Inc.Inventor: Chun-Yao Liao
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Patent number: 7663425Abstract: A fuse option circuit including a fuse, a control switch, a latch, and a logical operational controller is provided. The latch stores a selected level. The logical operational controller outputs a selected result signal and feedbacks a control signal to the control switch. The level of the control signal determines whether the control switch is on or off. Therefore, the required level is input to the latch and the working mode having an ultra low current is selected. Furthermore, when the fuse is in an untrimmed state, the level of the selected result signal could be selected by a reset pulse signal of the latch in order to test a product. Afterward, it is determined whether the fuse is trimmed or not. When the fuse is in a trimmed state, the level of the selected result signal is established by a rising edge of the reset pulse signal.Type: GrantFiled: November 24, 2008Date of Patent: February 16, 2010Assignee: Holtek Semiconductor Inc.Inventors: Yu-Ren Chen, Chun-Yao Liao
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Patent number: 7656737Abstract: A pumping circuit for multiple nonvolatile memories, comprising: a high voltage source; and a high voltage pass block with a gate controlled by a local booster to introduce the high voltage source into a plurality of nonvolatile memories for erase/write operation.Type: GrantFiled: April 28, 2008Date of Patent: February 2, 2010Assignee: Holtek Semiconductor Inc.Inventor: Chun-Yao Liao
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Publication number: 20100001798Abstract: The present invention relates to an trans-conductance amplifier, cooperating with a digital programmable current mirrors, can be applied to digital programmable current-mode integrated circuits, voltage control oscillators, adaptive frequency adjust mechanism, adaptive continuous analog filters via the corresponding trans-conductance adaptation controlled by the digital control signals. The present invention disclosed a digital programmable current mirror suitable for the second stage of the trans-conductance amplifier so as to reform the fixed gain trans-conductance amplifier to be digitally programmable.Type: ApplicationFiled: August 5, 2008Publication date: January 7, 2010Applicant: HOLTEK SEMICONDUCTOR INC.Inventor: HUNG-CHANG CHEN
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Patent number: 7642838Abstract: A voltage redoubling circuit, wherein said circuit relies on a voltage-detecting unit, an oscillating unit, an inversing unit, a first switching device, a second switching device, a third switching device, a fourth switching device, and a fifth switching device to pump a reference voltage to an output voltage. In such a way, a conducted memory cell can be quickly and accurately accessed via a circuit operated in a low voltage region by a single on-and-off signal rather than a number of pulse control signals.Type: GrantFiled: March 24, 2008Date of Patent: January 5, 2010Assignee: Holtek Semiconductor Inc.Inventor: Wen-Shyen Chao
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Publication number: 20090327593Abstract: The present invention provides a memory device and a method for accessing the memory device thereof. The memory device comprises an address encoding selector for selecting one of plurality of encoding circuits which encodes a first address into a second address, and a data decoding selector for selecting one of plurality of decoding circuits which decodes a first data corresponding to the second address into a second data and a non-volatile memory, coupled to address encoding selector and the data decoding selector, for storing the first data. The method for accessing the memory device comprises encoding a first address into a second address by an address encoding selector, and decoding a first data corresponding to the second address into a second data by a data decoding selector, wherein the first data being stored in the non-volatile memory.Type: ApplicationFiled: September 1, 2009Publication date: December 31, 2009Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Chuen-An Lin, Ching-Tsung Tung
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Publication number: 20090322434Abstract: 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: ApplicationFiled: July 18, 2008Publication date: December 31, 2009Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: JIA-HSUAN WU, CHENG-MU WU
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Patent number: 7639074Abstract: A linear programmable switch-capacitance gain amplifier (PGA) is described. The PGA divides the dB-gain curve into several parts by the concept of piece-wise linearity, and then simultaneously executes the dB-linear gain adjustment of MSB and the LSB at the same gain stage. Present invention achieves the PGA dB-linearity by setting up every capacitance of the sampling capacitor array and the holding capacitor array, then arranging the sampling capacitor array and the holding capacitor array by coordinating the switching of the capacitor switches.Type: GrantFiled: January 23, 2008Date of Patent: December 29, 2009Assignee: Holtek Semiconductor Inc.Inventor: Yi-Chen Chen
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Patent number: 7636014Abstract: The present invention relates to an trans-conductance amplifier, cooperating with a digital programmable current mirrors, can be applied to digital programmable current-mode integrated circuits, voltage control oscillators, adaptive frequency adjust mechanism, adaptive continuous analog filters via the corresponding trans-conductance adaptation controlled by the digital control signals. The present invention disclosed a digital programmable current mirror suitable for the second stage of the trans-conductance amplifier so as to reform the fixed gain trans-conductance amplifier to be digitally programmable.Type: GrantFiled: August 5, 2008Date of Patent: December 22, 2009Assignee: Holtek Semiconductor Inc.Inventor: Hung-Chang Chen
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Publication number: 20090303095Abstract: 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: ApplicationFiled: September 3, 2008Publication date: December 10, 2009Applicant: HOLTEK SEMICONDUCTOR INC.Inventors: Yuh-Diahn WANG, Yan-Kai HUANG
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Patent number: 7629758Abstract: A driving apparatus and a driving method for a single phase motor utilizes a driving transistor unit, and an auxiliary driving transistor unit to provide two driving currents with the same direction as the single phase coil. Next, a control unit is used to control the conducting and shutting down of the driving transistor unit and the auxiliary driving transistor unit according to the location of the rotating device of the single phase motor. Thereby, the driving current on the single phase coil recirculates to reduce the vibration and noise of the single phase motor, and prevent the problem of the single phase motor not turning on.Type: GrantFiled: March 8, 2007Date of Patent: December 8, 2009Assignee: Holtek Semiconductor Inc.Inventors: Ying-Chen Hsiao, Yi-Chen Chen, Yi-Chen Lin, Juh-Gua Shiau