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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: 2016-12-22

A control circuit includes: a comparing circuit, having a first input terminal and second input terminal, configured to operably generate a comparison signal according signals received by the first and second input terminals, wherein the first input terminal is utilized for coupling with a reference signal and the second input terminal is utilized for coupling with a feedback signal; a periodic signal generating circuit configured to operably generate a periodic signal and apply the periodic signal to the first input terminal or the second input terminal of the comparing circuit; and a control signal generating circuit for controlling an on time of a power switch according to the comparison signal. The periodic signal generating circuit clamps a limit of the periodic signal to a predetermined value, but does not configure the slope of the periodic signal to be zero when there is no current passing through the inductor.


The present invention discloses an event detection method for waking up a portable electronic device and an action sensor using same. The event detection method includes the steps of: under a normal operation mode, sensing action events by the action sensor with a first data sensing frequency, wherein the action sensor operates by a normal current to detect the action events; entering into a sleep mode; under the sleep mode, detecting a wake-up event by the action sensor with a second data sensing frequency, wherein the action sensor operates by a weak current to detect the wake-up event, wherein the weak current is smaller than the normal current, and the second data sensing frequency is not higher than the first data sensing frequency; and returning to the normal operation mode when the wake-up event is detected.


Patent
Richtek Technology Corporation | Date: 2016-06-24

A high-side device includes: a substrate, an epitaxial layer, a high voltage well, a body region, a gate, a source, a drain, and a buried region. A channel junction is formed between the body region and the high voltage well. The buried region is formed in the substrate and the epitaxial layer, and in a vertical direction, a part of the buried region is located in the substrate and another part of the buried region is located in the epitaxial layer. In the channel direction, an inner side boundary of the buried region is between the drain and the channel junction. An impurity concentration of a second conductive type of the buried region is sufficient to prevent the high voltage well between the channel junction and the drain from being completely depleted when the high-side power device operates in a conductive operation. A corresponding manufacturing method is also disclosed.


Patent
Richtek Technology Corporation | Date: 2015-11-03

A MEMS device includes: a substrate; a proof mass suspended over the substrate, the proof mass including at least one proof mass body and a proof mass frame connected to and accommodating the proof mass body, the proof mass frame including at least one self-test frame; and at least one self-test electrode inside the self-test frame, and connected to the substrate; wherein when a voltage difference is applied between the self-test electrode and the self-test frame, the proof mass is driven to have an in-plane movement, and wherein the self-test electrode and the self-test frame do not form a sensing capacitor in between.


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: 2016-09-16

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.

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