Himax Technologies, Inc.

Wei-Kai Tseng

Chin-Tien Chang

Ming-Huang Lee

Ying-Chuan Liu

A voltage generator for providing a plurality of output voltages having different levels includes: a reference block and a plurality of digital-to-analog conversion blocks. The reference block is employed for providing a plurality of reference voltages according to a supply voltage. The plurality of digital-to-analog conversion blocks is coupled to the reference block, and each of the digital-to-analog conversion blocks receives the reference voltages and generates a digital-to-analog output voltage according to a digital code, wherein digital-to-analog output voltages generated by the digital-to-analog conversion blocks have different levels, respectively. In addition, a range of the digital-to-analog output voltage generated by a first digital-to-analog conversion block of the digital-to-analog conversion blocks is different from that of the digital-to-analog output voltage generated by a second digital-to-analog conversion block.

Voltage generator

A programmable gamma circuit for gamma correction is disclosed. The programmable gamma circuit includes a string digital-to-analog converter, a first operational amplifier, and an output resistor string. The string digital-to-analog converter selects an analog voltage from a plurality of candidate voltages according to a digital reference code. An output terminal of the first operational amplifier outputs a first output voltage. A positive input terminal of the first operational amplifier is electrically connected to the string digital-to-analog converter for receiving the analog voltage. The output resistor string is divided into a first resistor part and a second resistor part by a connection terminal which is electrically connected to a negative input terminal of the first operational amplifier, and a resistance of the first resistor part is a multiple of a resistance of the second resistor part.

Programmable gamma circuit for gamma correction

The present invention provides an over temperature protection circuit. The over temperature protection circuit includes a reference circuit and a hysteretic comparator. The reference circuit is used for generating a reference voltage and a changeable voltage. The changeable voltage is varied by temperature. The hysteretic comparator compares the reference voltage with the changeable voltage to output a power down signal.

Over temperature protection circuit

A structure of an output stage, and the structure includes a first electrode, a second electrode, a third electrode, a plurality of first auxiliary electrodes, a plurality of second auxiliary electrodes, a plurality of third auxiliary electrodes, a plurality of fourth auxiliary electrodes, a first switching unit, and a second switching unit. Wherein, a plurality of first currents flow through the turned-on first switching unit, and a first flowing direction of the first currents in the turned-on first switching unit is from the first electrode to the second electrode. A plurality of second currents flow through the turned-on second switching unit, and a second flowing direction of the second currents in the turned-on second switching unit is from the second electrode to the third electrode.

Structure of output stage

An adaptive protection circuit module for an operational amplifier including an over temperature protection circuit and an over current protection circuit is provided. The over temperature protection circuit provides a temperature protection function to power down the operational amplifier when an operating temperature of the operational amplifier increases higher than a first threshold temperature. The over current protection circuit provides a current protection function to limit an output current of the operational amplifier and adjusts the first threshold temperature to a second threshold temperature when the over current protection circuit is enabled. The second threshold temperature is lower than the first threshold temperature. After the first threshold temperature is adjusted to the second threshold temperature, the over temperature protection circuit powers down the operational amplifier when the operating temperature increases higher than the second threshold temperature. Furthermore, an adaptive protection method for the foregoing operational amplifier is also provided.

Adaptive protection circuit module for operational amplifier and adaptive protection method thereof

A reference circuit for an oscillator module is provided. The reference circuit includes a reference voltage generation unit and a reference current generation unit. The reference voltage generation unit includes an electric element having a voltage proportional to absolute temperature (PTAT voltage) and provides a reference voltage based on the PTAT voltage. The reference current generation unit is coupled to the reference voltage generation unit and provides a reference current to the oscillator circuit to serve as an input current based on the PTAT voltage. The oscillator circuit generates a clock signal based on the reference voltage and the input current. The reference voltage and the input current are proportional to absolute temperature and have the same change trend relative to absolute temperature, such that the clock signal is a temperature insensitive signal. An oscillator module including an oscillator circuit and the foregoing reference circuit is also provided.

Oscillator module and reference circuit thereof

An operational circuit includes: a first stage having a first input terminal for receiving an input signal and a second input terminal for receiving an output signal of the operational circuit, for outputting a first control signal at a first output terminal and a second control signal at a second output terminal according to the input signal and the output signal; and a second stage coupled to the first stage, for generating the output signal according to a first driving current controlled by the first control signal and a second driving current controlled by the second control signal; and a protection circuit coupled between the first stage and the second stage, for adjusting the first driving current from a first predetermined threshold current toward a second predetermined threshold current when the first driving current reaches the first predetermined threshold current.

Operational circuit and related control method

A structure of an output stage includes a first electrode, a second electrode, a third electrode, multiple first auxiliary electrodes connected to the first electrode, multiple second auxiliary electrodes and multiple third auxiliary electrodes both connected to the second electrode, multiple fourth auxiliary electrodes connected to the third electrode, multiple first transistors and multiple second transistors. The widths of each the first auxiliary electrode and each the fourth auxiliary electrode are inversely proportional to the distance thereof respectively from the first electrode and the third electrode. The width of each of the second auxiliary electrodes and the third auxiliary electrodes is inversely proportional to the distance thereof from the second electrode. The first and second auxiliary electrodes are electrically connected to each other respectively through the turned-on first transistors. The third and fourth auxiliary electrodes are electrically connected to each other respectively through the turned-on second transistors.

A start circuit adapted to start a reference circuit including a plurality of bias nodes is provided. The start circuit includes a current source, a current mirror, a load device, and a control device. The current source determines whether or not to generate an internal current according to a plurality of bias voltages on a part of the bias nodes. The current mirror duplicates the internal current to produce a mirrored current. The load device adjusts a control voltage according to the mirrored current. The control device determines whether or not to generate a start voltage according to the control voltage, and transmits the start voltage to one of the part of the bias nodes, so as to break the reference circuit away from a zero-current state.

Bandgap circuit and start circuit thereof

A source driver includes at least a channel, and the channel includes an N-type digital-to-analog converter (NDAC) and an operational amplifier. The NDAC is utilized for receiving input data and selecting one of a plurality of gamma voltages to generate output data according to the input data. The operational amplifier is coupled to the NDAC, and is utilized for amplifying at least the output data to generate an amplified output data. In addition, the channel does not include any P-type digital-to-analog converter.

Source driver not including any P-type digital-to-analog converter

An operational circuit includes: a first stage having a first input terminal for receiving an input signal and a second input terminal for receiving an output signal of the operational circuit, for outputting a first control signal at a first output terminal and a second control signal at a second output terminal according to the input signal and the output signal; a second stage coupled to the first stage, for generating the output signal according to a first driving current controlled by the first control signal and a second driving current controlled by the second control signal; and a protection circuit coupled between the first stage and the second stage, for detecting the first driving current to selectively adjust the first control signal.

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Tainan, Taiwan

Wei-Kai Tseng