Abstract: A wireless power-reception system has a bridge rectifier with two high-side and two low-side transistors, linked to input-nodes and sense-resistors. During a first phase, a control circuit activates certain transistors for rectification, producing an output voltage, while modulating a gate voltage of a non-activated low-side transistor to dissipate excess power and regulate the output voltage. During a first given number of occurrences of the first phase, the control circuit determines the current through the low-side transistor having its gate voltage modulated based upon a voltage across a first sense resistor coupled between that low-side transistor and ground. During a second given number of occurrences of the first phase, the control circuit determines the current delivered to the load based upon a voltage across the first sense resistor and a voltage across a second sense resistor coupled between the other low-side transistor and ground.

Abstract: An over-voltage protection circuit and methods of operation are provided. In one embodiment, a method includes monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof. The method further includes determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.

Abstract: Disclosed herein is a wireless power reception system that utilizes a switched capacitor DC-DC voltage converter to charge a load. Current sensing circuits described herein enable the measurement of the input current to the switched capacitor DC-DC voltage converter while being relatively insensitive to temperature variation. Voltage/current sensing circuits described herein enable the selective measurement of load voltage, high side load current, and low side load current. One of the current sensing circuits may be used together with one of the voltage/current sensing circuits in a single device, or the current sensing circuits and voltage/current sensing circuits may be used separately in different devices.

Abstract: In a DC-DC converter, a layout is designed to enable utilization the conductive trace connecting the converter output node to an output bump at which the load is attached as a sense resistor. The layout forces the output current down into lower metallization levels of an interconnect layer reaching the converter output node before the output current flows up into this conductive trace and out through the output bump. The conductive trace includes resistive pillars connected in parallel or series between the lower metallization levels and a top metallization layer of the conductive trace, with these resistive pillars being substantially greater in resistance than the lower metallization levels and the top metallization layer of the conductive trace.

Abstract: An over-voltage protection circuit and methods of operation are provided. In one embodiment, a method includes monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof. The method further includes determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.

Abstract: A method of wirelessly transmitting power includes: causing a power transmission circuit to transmit, to a master power reception circuit, a portion of power it is capable of transmitting; adjusting operation of a slave power reception unit until a first rectified voltage produced by the master power reception circuit and a second rectified voltage produced by the slave power reception unit are equal; causing the power transmission circuit to transmit additional power to the slave power reception unit, resulting in the first and second rectified voltages being unequal; and adjusting operation of the slave power reception unit until the first and second rectified voltages are again equal. A dummy load is connected to the slave power reception unit prior to causing the power transmission circuit to transmit the additional power, and is disconnected once the first and second rectified voltages are equal.

Abstract: A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

Abstract: A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

Abstract: A circuit includes a tank capacitor coupled between first and second nodes, and a sense resistor having a first terminal coupled to the first node and a second terminal coupled to a regulator input. A switching circuit has first and second inputs coupled to the first and second terminals of the sense resistor. A gain stage has first and second inputs capacitively coupled to first and second outputs of the switching circuit. An analog-to-digital converter receives the output of the gain stage, and receives first and second differential voltages. A reference voltage generator has a temperature independent current source coupled to source current to a reference resistor, the first differential reference voltage being formed across the reference resistor. The reference resistor and sense resistor are located sufficiently close to one another on a single common substrate such that they remain at substantially a same temperature.

Abstract: A receiver circuit includes a rectifier operable in full-, half-synchronous and asynchronous modes. A measurement circuit, with method, provides for real-time power measurement within the rectifier. The measurements are made based on the average output current from the rectifier delivered to the load and measurements sampled over time of the instantaneous voltage at each input/output node of the rectifier. Equivalent resistance in the rectifier is determined from the measurements and power dissipation calculated from the determined equivalent resistance and the average output current. The instantaneous voltages are synchronously captured through high-voltage AC coupling in order to detect the voltage drop across each element of the rectifier. The sensed voltages are amplified in the low voltage domain and converted by a high-speed analog-to-digital converter in order to produce data useful in computing equivalent resistance values.

Abstract: Disclosed herein is a bridge rectifier and associated control circuitry collectively forming a “regtifier”, capable of both rectifying an input time varying voltage as well as regulating the rectified output voltage produced. To accomplish this, the gate voltages of transistors of the bridge rectifier that are on during a given phase may be modulated via analog control (to increase the on-resistance of those transistors) or via pulse width modulation (to turn off those transistors prior to the end of the phase). Alternatively or additionally, the transistors of the bridge rectifier that would otherwise be off during a given phase may be turned on to help dissipate excess power and thereby regulate the output voltage. A traditional voltage regulator, such as a low-dropout amplifier, is not used in this design.

Abstract: A bridge rectifier is controlled by control circuitry to act a “regtifier” which both regulates and rectifies without the use of a traditional voltage regulator. To accomplish this, the gate voltages of transistors of the bridge that are on during a given phase may be modulated to dissipate excess power. Gate voltages of transistors of the bridge that are off during the given phase may alternatively or additionally be modulated to dissipate excess power. The regtifier may act as two half-bridges that each power a different voltage converter, with those voltage converters powering a battery. The voltage converters may be switched capacitor voltage converters that switch synchronously with switching of the two half-bridges as they perform rectification.

Abstract: A bridge rectifier and associated control circuitry collectively form a “regtifier” which rectifies an input time varying voltage and regulates the rectified output voltage produced without the use of a traditional voltage regulator. To accomplish this, the gate voltages of transistors of the bridge rectifier that are on during a given phase may be modulated via analog control (to increase the on-resistance of those transistors) or via pulse width modulation (to turn off those transistors prior to the end of the phase). The transistors of the bridge rectifier that would otherwise be off during a given phase may be turned on to help dissipate excess power and thereby regulate the output voltage. This modulation is based upon both a voltage feedback signal and a current feedback signal.

Abstract: A touch screen controller includes an input stage configured to receive and condition a touch output from a touch matrix to produce a touch signal. An accumulation stage is configured to receive the touch signal and accumulate the touch signal to produce an accumulated output. The accumulated output is digitized by an analog to digital converter to produce a touch strength value. A given amount of charge is subtracted from or added to accumulated output during a next accumulation if the touch strength value is greater than an upper threshold or less than a lower threshold. This avoids saturation of components in the touch screen controller and therefore increases the signal to noise ratio.

Abstract: A circuit includes a tank capacitor coupled between first and second nodes, and a sense resistor having a first terminal coupled to the first node and a second terminal coupled to a regulator input. A switching circuit has first and second inputs coupled to the first and second terminals of the sense resistor. A gain stage has first and second inputs capacitively coupled to first and second outputs of the switching circuit. An analog-to-digital converter receives the output of the gain stage, and receives first and second differential voltages. A reference voltage generator has a temperature independent current source coupled to source current to a reference resistor, the first differential reference voltage being formed across the reference resistor. The reference resistor and sense resistor are located sufficiently close to one another on a single common substrate such that they remain at substantially a same temperature.

Abstract: A wireless-power-system includes a bridge-rectifier having first and second inputs coupled to first and second terminals of a coil, and an output coupled to a rectified voltage node. An excitation circuit is coupled to the first input. A protection circuit has a first connection node capacitively coupled to the first terminal. The protection circuit, in Q-factor measurement mode, clamps the first connection node when the first input is coupled to ground, and connects the first connection node to the rectified voltage node when the first input is coupled to a supply voltage. The protection circuit, in wireless power mode, is acting as one leg of the rectifier. A pass gate circuit is coupled between the first connection node and a sense node, and a sensing circuit is coupled to the sense node and measures a Q-factor of the wireless power system when the protection circuit is in Q-factor measurement mode.

Abstract: A wireless-power-system includes a bridge-rectifier having first and second inputs coupled to first and second terminals of a coil, and an output coupled to a rectified voltage node. An excitation circuit is coupled to the first input. A protection circuit has a first connection node capacitively coupled to the first terminal. The protection circuit, in Q-factor measurement mode, clamps the first connection node when the first input is coupled to ground, and connects the first connection node to the rectified voltage node when the first input is coupled to a supply voltage. The protection circuit, in wireless power mode, is acting as one leg of the rectifier. A pass gate circuit is coupled between the first connection node and a sense node, and a sensing circuit is coupled to the sense node and measures a Q-factor of the wireless power system when the protection circuit is in Q-factor measurement mode.

Abstract: A high-side switching transistor of a rectifier circuit is driven by a high-side driver circuit to supply current to an output node. The high-side driver circuit is powered between a capacitive bootstrap node and the output node. A boot charge circuit charges the bootstrap capacitor by supplying current to the bootstrap node. The boot charge circuit includes: a first current path that selectively supplies a first charging current to the bootstrap node when the rectifier circuit is operating in a switching mode; and a second current path that selectively supplies a second charging current to the bootstrap node when the rectifier circuit is operating in a reset mode.

Abstract: Disclosed herein is a bridge rectifier and associated control circuitry collectively forming a “regtifier”, capable of both rectifying an input time varying voltage as well as regulating the rectified output voltage produced. To accomplish this, the gate voltages of transistors of the bridge rectifier that are on during a given phase may be modulated via analog control (to increase the on-resistance of those transistors) or via pulse width modulation (to turn off those transistors prior to the end of the phase). Alternatively or additionally, the transistors of the bridge rectifier that would otherwise be off during a given phase may be turned on to help dissipate excess power and thereby regulate the output voltage. A traditional voltage regulator, such as a low-dropout amplifier, is not used in this design.

Abstract: A method of wirelessly transmitting power includes: causing a power transmission circuit to transmit, to a master power reception circuit, a portion of power it is capable of transmitting; adjusting operation of a slave power reception unit until a first rectified voltage produced by the master power reception circuit and a second rectified voltage produced by the slave power reception unit are equal; causing the power transmission circuit to transmit additional power to the slave power reception unit, resulting in the first and second rectified voltages being unequal; and adjusting operation of the slave power reception unit until the first and second rectified voltages are again equal. A dummy load is connected to the slave power reception unit prior to causing the power transmission circuit to transmit the additional power, and is disconnected once the first and second rectified voltages are equal.