Tone-based wake up circuit for card reader
First Claim
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.
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Accused Products
Abstract
A card reader for a point-of-sale system that is configured to accept both magnetic strip-type and integrated circuit (IC) chip-type payment cards. The card reader is a component of a point-of-sale system including a portable computing device in communication with the card reader that is configured to present a first graphical user interface (GUI) when a magnetic stripe-type card is detected and a second GUI when an IC chip-type card is detected in the card reader. The card reader comprises a slot configured to receive the payment card, a magnetic reading device and an IC chip reading device. The card reader also includes a discriminator contact disposed within the slot that is configured to conduct across a surface of a metal pad of the IC chip-type card prior to the CI chip reading device making contact with the IC chip.
330 Citations
20 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A wake up circuit for a portable card reader comprising:
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a conditioning circuit comprising a capacitor coupled to an audio input, and two evenly valued resistors coupled to an input voltage (Vcc), whereby the capacitor is configured to block any DC component on the audio input and whereby the two evenly valued resistors are configured to bias the Vcc to a biased input voltage of about a value in the middle of a range of Vcc to ground; a comparator having a positive terminal and a negative terminal, the positive terminal of the comparator being coupled to the audio input, and the negative terminal being coupled to the biased input voltage, whereby the comparator is configured to output a signal whenever the voltage on the positive terminal is greater than the voltage on the negative terminal; an envelope detector connected to the output of the comparator, the output of the comparator being a square wave, the envelope detector configured to convert the square wave to a DC voltage signal; and an enable pin of a voltage regulator connected to the output of the envelope detector, the enable pin configured to receive the DC voltage signal, and to use the DC voltage signal to execute a preliminary instruction to turn the system on. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A portable card reader comprising:
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an audio plug configured to be inserted into an audio jack of a mobile device; a slot for receiving a payment card; a media reading device for reading information off the payment card; a wake up circuit comprising; a conditioning circuit comprising a capacitor coupled to an audio input of the audio jack of the mobile device, and two evenly valued resistors coupled to a microphone bias signal, whereby the capacitor is configured to block any DC component on the audio input and whereby the two evenly valued resistors are configured to bias the microphone bias signal to a biased input voltage; a comparator having a positive terminal and a negative terminal, the positive terminal of the comparator being coupled to the audio input, and the negative terminal being coupled to the biased input voltage, whereby the comparator is configured to output a signal whenever the voltage on the positive terminal is greater than the voltage on the negative terminal; and an envelope detector connected to the output of the comparator, the output of the comparator being a square wave, the envelope detector configured to convert the square wave to a DC voltage signal and provide the DC voltage signal to a voltage regulator connected to the output of the envelope detector. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification