Patent ID: 9355285
Filing Date: 2016-05-31
CPC Classification: G06F,G06K,G06Q

Claim Text:
1. A computer-implemented method for waking up a card reader connected to an audio jack of a mobile device using a wake up circuit disposed within the card reader, the method comprising: receiving, at an audio plug of the card reader, a microphone bias signal from the audio output jack of the mobile device; transitioning the card reader to an awake mode in response to a rising edge of the microphone bias signal; transitioning the card reader to a sleep mode using a microprocessor while the microphone bias signal is still present; receiving, at the audio plug of the card reader, an audio input signal from the audio output jack of the mobile device; conditioning the audio input signal to produce a conditioned audio input signal having an amplitude between an amplitude of the microphone bias signal and ground; conditioning the microphone bias signal to produce a conditioned microphone bias signal having substantially half the amplitude of the microphone bias signal; comparing the conditioned audio input signal and the conditioned microphone bias signal to output a third signal using a comparator, the comparator configured to output the third signal having an amplitude substantially the same as the microphone bias signal when the voltage of the conditioned audio input signal is greater than the voltage of the conditioned microphone bias signal; converting the third signal to a fourth signal using an envelope detector, the third signal being a square wave and the fourth signal being a substantially DC voltage signal; and providing the fourth signal to an enable pin of a voltage regulator that is connected to the output of the envelope detector.