Richtek Technology Corporation

Vxis Technology Corp.

Hsien-Chih She

Chi-Jen Yang

Chun-Jen Yu

Tsung-Wei Huang

Shui-Mu Lin

Wei-Jen Huang

Yuan-Hao Huang

Hsuan-Kai Wang

Chun-Cheng Huang

Teng-Cheng Chen

Shang-Yi Lin

Jen-Shi Wu

Ssu-Wei Huang

An amplifier circuit having low parasitic pole effect includes a preamplifier, an output transistor and a buffer circuit. The buffer circuit generates a driving signal to control the output transistor according to a preamplification signal generated by the preamplifier. The buffer circuit includes: a buffer input transistor generating the driving signal, wherein an input impedance at its control end is less than that of the output transistor; a low output impedance circuit having an output impedance which is less than an inverting output impedance of the buffer input transistor; an amplification transistor generating an amplification signal at its inverting output; and an amplification stage circuit amplifying the amplification signal by an amplification ratio, so that an equivalent output impedance at a non-inverting output of the buffer input transistor is less than or equal to a product of the reciprocal of an intrinsic output impedance thereof and an amplification ratio.

Amplifier circuit having low parasitic pole effect and buffer circuit thereof

A state detection circuit for detecting whether a state of an input node is floating, grounded, or electrically connected to an external voltage includes: a unidirectional device circuit and a determination circuit. The unidirectional device circuit electrically conducts a test node to a detection node unidirectionally. The detection node is coupled to the input node. The test node, the unidirectional device circuit, the detection node and the input node form a current path. The determination circuit determines a state of the input node according to a voltage level of the detection node. Within a detection stage, the state detection circuit provides a test voltage at the test node. A voltage of the detection node is determined by the input node, the test voltage, and a characteristic of the unidirectional device circuit.

State detection circuit for detecting tri-state and state detection method thereof

A charging circuit for providing a charging current to a battery includes a power delivery unit and a capacitive power conversion circuit. The power delivery unit converts an input power to a DC output voltage and current, and regulates the DC output current to a predetermined output current level. The capacitive power conversion circuit includes a conversion switch circuit including plural conversion switches coupled to one or more capacitors, and a conversion control circuit which operates the plural conversion switches in plural conversion periods to connect the one or more capacitors between a pair of nodes selected from plural voltage division nodes, the DC output voltage, and a ground node periodically, so that the level of the charging current is scaled-up of the predetermined output current level.

Charging circuit and capacitive power conversion circuit and charging control method thereof

A clamping system for clamping a video signal, wherein the clamping system uses a charge-pump unit in company with a digital clamping controller to clamp the potential of the video signal, prior to the video signal being input to a programmable gain amplifier and an A/D converter, so as to reach a desired level. The charge-pump unit provides two charge-pump circuits, wherein one charge-pump circuit supplies a strong burst to boost the potential of the video signal while the video signal is below a threshold value. Otherwise, the other charge-pump circuit supplies a weak burst to fine tune the potential of the video signal when the video signal has reached the threshold value.

Clamping system for clamping a video signal by using a charge-pump circuit

Growing community of inventors

Hsinchu, Taiwan

Hsien-Chih She