Apple Inc.

Salvatore Reddiconto

Dong Yang

Gregory B Arndt

Robert M Proie

Aspects of the subject technology relate to a circuit for reducing random-telegraph noise in bandgap circuits. The circuit includes a number of diodes coupled in parallel at their respective first nodes to a ground potential. A number of switches are coupled to respective second nodes of the diodes. The circuit further includes a first resistor and a resistor voltage divider. The first node of the first resistor is coupled to a first node of a current source, and the first node of the resistor voltage divider is coupled to the first node of the current source. The switches are used to implement cyclic switching of the diodes in response to a train of pulses. An output voltage of the circuit is derived between a mid-node of the resistor voltage divider and a second node of the first resistor.

Cyclic switching design to reduce RTN in bandgap circuits

According to some embodiments, a bi-directional converter is configured to operate in a boost mode or a buck mode. The bi-directional converter includes a hysteresis control unit that includes a comparator that can be configured to determine whether the reference voltage has a positive slope or a negative slope in conjunction with the bi-directional converter operating in boost mode or buck mode. In addition, the comparator is configured to compare a fractional load voltage to a reference voltage so that the output load voltage corresponds to the waveform shape of the reference voltage.

Integrated bi-directional driver with modulated signals

A host electronic device may be coupled to an accessory electronic device. The host device and the accessory device may be connected via power supply lines and user data lines. If the host and accessory devices are improperly connected or if the accessory device is exposed to an incorrect voltage environment, the internal circuitry on the accessory device can be damaged. The accessory device may therefore include a reverse voltage protection circuit that can help prevent a large amount of current from inadvertently flowing into the accessory device. The protection circuit may include a low-side-enabled reverse current protection switch coupled between the external and internal ground terminals and also a single low-drop switch coupled to each of the user data lines. The low-drop switch will be activated whenever the voltage at the external ground terminal exceeds the voltage at the data line to help deactivate low-side-enabled reverse current protection switch.

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San Jose, CA, United States of America

Salvatore Reddiconto