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The present invention discloses a resonant wireless power transmitter circuit, which has an input impedance. The resonant wireless power transmitter circuit includes: a driver circuit coupled with a power supply, which includes at least a power switch; a switching resonant control circuit coupled with the driver circuit, such that the driver operates at a pre-determined or a variable resonant frequency; an adjustable impedance matching circuit coupled with the driver circuit, which includes at least a varactor; a transmitter circuit coupled with the impedance matching circuit and the driver circuit, which includes at least a transmitter coil; and an impedance control circuit coupled with the adjustable impedance matching circuit and the driver circuit, which provides an impedance control signal to control the reactance of the varactor, such that the input impedance of the resonant wireless power transmitter circuit is matched at the pre-determined or the variable resonant frequency.


A MEMS device includes: a fixed structure, a movable structure, and a compensation circuit. The fixed structure includes a fixed electrode and a fixed compensation electrode. The movable structure includes a movable electrode and a movable compensation electrode. The movable electrode and the fixed electrode form a sensing capacitor, and the movable compensation electrode and the fixed compensation electrode form a compensation capacitor. The compensation circuit compensates a sensing signal generated by the sensing capacitor with a compensation signal generated by the compensation capacitor. The sensing capacitor and the compensation capacitor do not form a differential capacitor pair. A proportion of the sensing area of the compensation capacitor to the sensing area of the sensing capacitor is lower than 1.


A lateral double diffused metal oxide semiconductor device, includes: a P-type substrate, an epitaxial layer, a P-type high voltage well, a P-type body region, an N-type well, an isolation oxide region, a drift oxide region, a gate, an N-type contact region, a P-type contact region, a top source, a bottom source, and an N-type drain. The P-type body region is between and connects the P-type high voltage well and the surface of the epitaxial layer. The P-type body region includes a peak concentration region, which is beneath and indirect contact the surface of the epitaxial layer, wherein the peak concentration region has a highest P-type impurity concentration in the P-type body region. The P-type impurity concentration of the P-type body region is higher than a predetermined threshold to suppress a parasitic bipolar transistor such that it does not turn ON.


Patent
Richtek Technology Corporation | Date: 2016-09-09

The present invention discloses a vertical semiconductor device and a manufacturing method thereof. The vertical semiconductor device includes: a substrate having a first surface and a second surface, the substrate including a conductive array formed by multiple conductive plugs through the substrate; a semiconductor layer formed on the first surface, the semiconductor layer having a third surface and a fourth surface, wherein the fourth surface faces the first surface; a first electrode formed on the third surface; and a second electrode formed on the second surface for electrically connecting to the conductive array.


Patent
Richtek Technology Corporation | Date: 2016-02-10

A resonant wireless power receiver circuit includes an adjustable impedance matching circuit and a receiver circuit, the impedance matching circuit and the receiver circuit in combination receive a wireless power and generate a resonant output. A rectifier is coupled to the combination of the adjustable impedance matching circuit and the receiver circuit to rectify the resonant output to generate a rectified output. The impedance of the adjustable impedance matching circuit is controlled by a feedback control circuit such that the load impedance of rectified output is regulated at a pre-determined impedance value, or the voltage of the rectified output is regulated at a pre-determined voltage value


Patent
Richtek Technology Corporation | Date: 2016-09-16

A feedback signal stabilized by a capacitor and related to an output voltage of a power converter is used to acquire the output power information of the power converter, and a control circuit uses a second clock not related to the switching frequency of the power converter to count a duration time of the feedback signal being higher than a threshold. When the duration time is higher than a preset time, an abnormal output power of the power converter is distinguished and the power converter will be turned off. The feedback signal will not vary severely even if the output terminal of the power converter is interfered, and the counted duration time will not be influenced when the switching frequency is changing caused by a load changing.


Patent
Richtek Technology Corporation | Date: 2016-09-16

A frequency jittering control circuit for a PFM power supply includes a pulse frequency modulator to generate a frequency jittering control signal to switch a power switch to generate an output voltage. The frequency jittering control circuit jitters an input signal or an on-time or off-time of the pulse frequency modulator to jitter the switching frequency of the power switch to thereby improve EMI issue.


The present invention discloses a lateral double diffused metal oxide semiconductor (LDMOS) device and a manufacturing method thereof. The LDMOS device includes: drift region, an isolation oxide region, a first oxide region, a second oxide region, a gate, a body region, a source, and a drain. The isolation oxide region, the first oxide region, and the second oxide region have an isolation thickness, a first thickness, and a second thickness respectively, wherein the second thickness is less than the first thickness. The present invention can reduce a conduction resistance without decreasing a breakdown voltage of the LDMOS device by the first oxidation region and the second oxidation region.


Patent
Richtek Technology Corporation | Date: 2016-05-12

The present invention provides a power converter, and a control circuit and a standby power saving method thereof. The power converter provides an output voltage from an output terminal through an enable switch circuit to a power receiver. A detection signal shows whether a voltage at a signal transmission pin of the power converter is in a predetermined range, if not, the enable switch circuit is turned OFF. The power converter adjusts a feedback signal according to the detection signal or according to the detection signal and the output voltage, so as to adjust the output voltage to be lower than a normal operation level in a normal operation mode, to save power in a standby mode.


Patent
Richtek Technology Corporation | Date: 2016-05-16

A driver circuit of a LED luminance device includes: a signal pin; a determining circuit for determining the magnitude of an input signal; an indication signal generating circuit for outputting an indication signal to the signal pin according to the determining result of the determining circuit; an alignment signal generating circuit for generating an alignment signal when triggered by a predetermined edge of a signal at the signal pin; an indication signal detecting circuit for detecting the signal at the signal pin to generate a detection signal; and a control signal generating circuit for generating multiple control signals according to the detection signal to respectively control multiple switching elements in parallel connection with multiple LED devices when triggered by the alignment signal.

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