Patent ID: 11936229
Assignee: TEXAS INSTRUMENTS INCORPORATED
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 18:
19. A device, comprising:
a USB connector having a D+ data pin and a D− data pin;
a first switch coupled between the D+ data pin and a resistor coupled to a voltage source;
a second switch coupled between the D− data pin and a resistor coupled to the voltage source;
a third switch coupled between the D+ data pin and a current sink configured to sink a current;
a first circuit having a first circuit input and a first circuit output, wherein the first circuit input is coupled to the D+ data pin, the first circuit is configured to provide at the first circuit output a true value responsive to a voltage on the D+ data pin being equal to or greater than 0.25-0.4V, and provide at the first circuit output a false value otherwise;
a second circuit having a second circuit input and a second circuit output, wherein the second circuit input is coupled to the D+ data pin, the second circuit is configured to provide at the second circuit output a true value responsive to a voltage on the D+ data pin being equal to or greater than 0.8-2.0V, and provide at the second circuit output a false value otherwise;
a third circuit having a third circuit input and a third circuit output, wherein the third circuit input is coupled to the D− data pin, the third circuit is configured to provide at the third circuit output a true value responsive to a voltage on the D− data pin being equal to or greater than 2.25-2.39V, and provide at the third circuit output a false value otherwise; and
a control circuit having first, second and third control circuit inputs and first, second and third control circuit outputs, wherein the first control circuit input is coupled to the first circuit output, the second control circuit input is coupled to the second circuit output, the third control circuit input is coupled to the third circuit output, the first control circuit output is configured to actuate the first switch, the second control circuit output is configured to actuate the second switch, and the third control circuit output is configured to actuate the third switch, the control circuit configured to:
close the first switch and the second switch;
determine a first condition, wherein the first condition has a true value if the third circuit output is false for a period longer than 500 microseconds (μs), and the first condition having a false value otherwise;
open the first switch and the second switch and close the third switch for a period of at least 20 μs, responsive to determining that the first condition is true;
determine a second condition, wherein the second condition has a true value if the first circuit output is true and the second circuit output is false, and the second condition has a false value otherwise;
wait for a third condition to be false responsive to the second condition being false, wherein the third condition has a true value if the second circuit output is true, and

the third condition having a false value otherwise; and
close the first switch and the second switch responsive to the third condition being false.