Abstract: A receiver is energized by wireless power from a coil antenna. A matching network tunes the receiver to a resonant frequency and a bridge and capacitor generate an output voltage. The output voltage is divided and compared to a reference voltage. An asynchronous digital controller increases a digital count when the compare result is true, but decreases the digital count when the compare result is false. A current-steering Digital-to-Analog Converter (DAC) shunts a current from the output that is a function of the digital count. The asynchronous digital controller, comparator, and DAC do not use a system clock, so the digital feedback to the shunt current operates when the target output voltage is reached, preventing over-voltage when waiting for the system clock to begin pulsing. The digital count is compared to a digital threshold to recover transmitted Amplitude-Shifted-Keyed (ASK) data.

Abstract: A receiver is energized by wireless power from a coil antenna. A matching network tunes the receiver to a resonant frequency and a bridge and capacitor generate an output voltage. The output voltage is divided and compared to a reference voltage. An asynchronous digital controller increases a digital count when the compare result is true, but decreases the digital count when the compare result is false. A current-steering Digital-to-Analog Converter (DAC) shunts a current from the output that is a function of the digital count. The asynchronous digital controller, comparator, and DAC do not use a system clock, so the digital feedback to the shunt current operates when the target output voltage is reached, preventing over-voltage when waiting for the system clock to begin pulsing. The digital count is compared to a digital threshold to recover transmitted Amplitude-Shifted-Keyed (ASK) data.

Abstract: A Programmable-Gain Amplifier (PGA) has programming steps that are linear when expressed in Decibels (linear-in-dB). A Recursive Current Division (RCD) resistor network generates currents that are selected by programmable switches to connect to a summing node input of an amplifier. A feedback resistor is connected across the summing node and the amplifier output. The resistor network has only three resistance values regardless of the number of currents selectable as programming steps. The value of a third resistor is set equal to the equivalent resistance of a second resistor in parallel with a series connection of a first resistor and the third resistors. Each final cell in the resistor network is equivalent to the third resistor, allowing recursive division of adjacent currents. The ratio of adjacent currents remains constant for all cells. Recursive Current Division (RCD) produces linear-in-dB programming steps. Floating switches are avoided since switches connect to ground.

Abstract: A Programmable-Gain Amplifier (PGA) has programming steps that are linear when expressed in Decibels (linear-in-dB). A Recursive Current Division (RCD) resistor network generates currents that are selected by programmable switches to connect to a summing node input of an amplifier. A feedback resistor is connected across the summing node and the amplifier output. The resistor network has only three resistance values regardless of the number of currents selectable as programming steps. The value of a third resistor is set equal to the equivalent resistance of a second resistor in parallel with a series connection of a first resistor and the third resistors. Each final cell in the resistor network is equivalent to the third resistor, allowing recursive division of adjacent currents. The ratio of adjacent currents remains constant for all cells. Recursive Current Division (RCD) produces linear-in-dB programming steps. Floating switches are avoided since switches connect to ground.