Abstract: A wearable device includes a sensor, auxiliary electronics, a primary power supply configured to harvest radio frequency (RF) radiation received from an external reader and use the harvested RF radiation to power the sensor, and an auxiliary power supply configured to harvest energy other than that received from the external reader and use the harvested energy to supply power to the sensor and/or the auxiliary electronics. The external reader may supply less power in response to operation of the auxiliary power supply. Additionally or alternatively, in response to a determination that the auxiliary power supply is unable to supply power, the wearable device may disable all auxiliary electronics but for the sensor. In response to a determination that the primary power supply is unable to supply power but the auxiliary power supply is able to supply power, the wearable device may retain operating parameters in the memory storage unit using the auxiliary power supply.

Abstract: Amplifiers with improved isolation are disclosed. In an exemplary design, an apparatus (e.g., a wireless device, an integrated circuit, etc.) includes an amplifier having a gain transistor, first and second cascode transistors, and a shunt transistor. The gain transistor receives an input signal and provides an amplified signal. The first cascode transistor is coupled between the gain transistor and an intermediate node and receives the amplified signal. The second cascode transistor is coupled between the intermediate node and an output node and provides an output signal. The shunt transistor is coupled between the intermediate node and circuit ground. The first and second cascode transistors are enabled to provide the output signal. The shunt transistor is (i) disabled when the cascode transistors are enabled and (ii) enabled to short the intermediate node to circuit ground when the cascode transistors are disabled.

Abstract: An eye-mountable device can include a transparent material and a substrate at least partially embedded in the transparent material. The transparent material can have a concave surface and a convex surface, with the concave surface configured to removably mount the eye-mountable device on a corneal surface overlaying a pupil. A light source can be disposed on the substrate and configured to emit light through the concave surface and towards the corneal surface such that the emitted light is viewable through the pupil. The light source can be controlled by circuitry disposed on the substrate. The circuitry can be configured to modulate the light emitted by the light source to provide modulated light.

Abstract: Amplifiers with improved isolation are disclosed. In an exemplary design, an apparatus (e.g., a wireless device, an integrated circuit, etc.) includes an amplifier having a gain transistor, first and second cascode transistors, and a shunt transistor. The gain transistor receives an input signal and provides an amplified signal. The first cascode transistor is coupled between the gain transistor and an intermediate node and receives the amplified signal. The second cascode transistor is coupled between the intermediate node and an output node and provides an output signal. The shunt transistor is coupled between the intermediate node and circuit ground. The first and second cascode transistors are enabled to provide the output signal. The shunt transistor is (i) disabled when the cascode transistors are enabled and (ii) enabled to short the intermediate node to circuit ground when the cascode transistors are disabled.

Abstract: An eye-mountable device can include a transparent material and a substrate at least partially embedded in the transparent material. The transparent material can have a concave surface and a convex surface, with the concave surface configured to removably mount the eye-mountable device on a corneal surface overlaying a pupil. A light source can be disposed on the substrate and configured to emit light through the concave surface and towards the corneal surface such that the emitted light is viewable through the pupil. The light source can be controlled by circuitry disposed on the substrate. The circuitry can be configured to modulate the light emitted by the light source to provide modulated light.

Abstract: A wearable device includes a sensor, auxiliary electronics, a primary power supply configured to harvest radio frequency (RF) radiation received from an external reader and use the harvested RF radiation to power the sensor, and an auxiliary power supply configured to harvest energy other than that received from the external reader and use the harvested energy to supply power to the sensor and/or the auxiliary electronics. The external reader may supply less power in response to operation of the auxiliary power supply. Additionally or alternatively, in response to a determination that the auxiliary power supply is unable to supply power, the wearable device may disable all auxiliary electronics but for the sensor. In response to a determination that the primary power supply is unable to supply power but the auxiliary power supply is able to supply power, the wearable device may retain operating parameters in the memory storage unit using the auxiliary power supply.