Abstract: A wireless battery charging system includes a trickle power device (e.g., FET) that generates a trickle charging current for charging a battery and a trickle charging regulator that controls the trickle power device. A fast charging device generates a fast charging current for charging the battery, where the fast charging current is greater than the trickle charging current. A fast charging regulator controls the fast charging device. A digital control module generates a trickle charging codeword to control the trickle charging regulator and a fast charging codeword to control the fast charging regulator. Each charging regulator has a programmable current mirror that generates a mirrored current signal based on a codeword from the digital control module. The digital control module instructs the charging regulators to control the power devices to operate in a trickle charging mode, a fast charging mode, and transitions between those modes.

Abstract: In a wireless charging system having a power transmitter (TX) and a power receiver (RX), the RX has a rectifier that rectifies an AC power signal received wirelessly from the TX into a rectified DC power signal. The RX also has regulation modules that monitor the DC power signal at various different voltage regions having one or more different high-voltage regions and one or more different low-voltage regions. Each regulation module affects operations of the wireless charging system in a different way. The regulation modules protect the RX from both over-voltage and under-voltage conditions.

Abstract: Aspects of the present disclosure are directed to circuitry to control a gate voltage. As may be implemented in accordance with one or more embodiments, a voltage level is controlled for a field effect transistor (FET) having a floating gate and a target operating voltage above which the FET would be overcharged and around which the FET has a nominal operating range. Pulse circuitry is configured to apply energy to the floating gate in pulses, in operation the applied energy being pulsed low relative to the gate's target operating voltage, and then being changed by adjusting successive pulses until the gate reaches the target operating voltage. A feedback circuit samples a voltage level of, and enables the pulse circuitry to apply pulsed energy to, the floating gate for directing operation of the FET based on the target operating voltage in the nominal operating range.

Abstract: A wireless battery charging system includes a trickle power device (e.g., FET) that generates a trickle charging current for charging a battery and a trickle charging regulator that controls the trickle power device. A fast charging device generates a fast charging current for charging the battery, where the fast charging current is greater than the trickle charging current. A fast charging regulator controls the fast charging device. A digital control module generates a trickle charging codeword to control the trickle charging regulator and a fast charging codeword to control the fast charging regulator. Each charging regulator has a programmable current mirror that generates a mirrored current signal based on a codeword from the digital control module. The digital control module instructs the charging regulators to control the power devices to operate in a trickle charging mode, a fast charging mode, and transitions between those modes.

Abstract: In a wireless charging system having a power transmitter (TX) and a power receiver (RX), the RX has a rectifier that rectifies an AC power signal received wirelessly from the TX into a rectified DC power signal. The RX also has regulation modules that monitor the DC power signal at various different voltage regions having one or more different high-voltage regions and one or more different low-voltage regions. Each regulation module affects operations of the wireless charging system in a different way. The regulation modules protect the RX from both over-voltage and under-voltage conditions.

Abstract: Systems of clock generation for integrated radio frequency receiver. In an integrated radio frequency receiver, a mixer is often used to down convert the incoming radio frequency signal. The down converted signal is then digitized and digital signal processing circuitry is used for efficient and flexible implementation of various functions to receive the underlying audio and/or data information. The mixer requires clock generation circuitry to provide a proper local oscillator signal for a selected channel. On the other hand, the digital signal processing circuitry requires its separate digital clock for proper operations. The clock generation system utilizes single local oscillator generation circuitry to provide the local oscillator signals required by the mixer and the digital clock signals required by the digital signal processing circuitry.

Abstract: A low noise VCO circuit for an LC VCO circuit comprising MOS varactors is disclosed. The LC VCO circuit usually comprises an LC tuning circuit coupled with a pair of cross-coupled transistors used as a negative impedance element. A pair of varactors is used to provide fine tuning by applying a control voltage to the varactor. Since the varactor is also coupled to the pair of cross-coupled transistor, the process variation and temperature change may affect the bias voltage coupled to the pair of varactors. Therefore, a bias circuit usually is used to alleviate the impact of process variation and temperature change associated with the pair of transistor. Nevertheless, the bias voltage typically is implemented by providing a current flowing through a resistor, wherein the current is generated by a current source. The noise associated with the current source will affect the performance of the VCO circuit. A low noise VCO circuit is disclosed which utilizes a low noise bias circuit.

Abstract: Voltage controlled oscillator (VCO) has been widely used in radio frequency communication systems. In a typical VCO implementation, a pair of directly cross-coupled MOS transistors is used as a switching device and an LC resonant circuit is used to tune the desired frequency. The direct cross coupling of the MOS transistor pair will result in limited output voltage swing since a large swing may cause the MOS transistors into a linear region to increase phase noise. The VCO system to increase the output voltage swing according to one embodiment of the present invention includes DC-blocking capacitors to avoid direct cross coupling of the MOS pair. The VCO further includes circuit to provide bias for the gate voltage of the MOS pair. A method for increasing the output voltage swing is disclosed for a VCO system having LC resonant circuit. The method includes providing DC-blocked cross coupling from the drains of the cross-coupled transistor pair to the gates of the cross-coupled transistor pair.

Abstract: Systems of clock generation for integrated radio frequency receiver. In an integrated radio frequency receiver, a mixer is often used to down convert the incoming radio frequency signal. The down converted signal is then digitized and digital signal processing circuitry is used for efficient and flexible implementation of various functions to receive the underlying audio and/or data information. The mixer requires clock generation circuitry to provide a proper local oscillator signal for a selected channel. On the other hand, the digital signal processing circuitry requires its separate digital clock for proper operations. The clock generation system utilizes single local oscillator generation circuitry to provide the local oscillator signals required by the mixer and the digital clock signals required by the digital signal processing circuitry.