USB PORT DETECTING CIRCUIT

• US 20120153993A1
• Filed: 06/27/2011
• Published: 06/21/2012
• Est. Priority Date: 12/15/2010
• Status: Active Grant

• Current Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Inventors: XIE, LING-YU, XIE, XING-PING
• Granted Patent: US 8,443,130 B2
• Time in Patent Office: Days
• US Class Current: 327/77
• CPC Class Codes: G01R 19/165 Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision

Abstract

A Universal Series Bus USB port detection and testing circuit, configured to detect the voltage output of a USB port of an electronic device, includes a voltage comparing circuit and an indicating circuit. The indicating circuit is connected to an output terminal of the voltage comparing circuit. The voltage comparing circuit compares the voltage output from the USB port against a reference voltage and output a signal whereby the indicating circuit indicates whether the voltage is within, or above, or below, the standard range.

Claims

1. A Universal Series Bus (USB) port detecting circuit for detecting whether a voltage of a USB port of an electronic device is within a standard range, the USB port detecting circuit comprising:

a voltage comparing circuit, adapted to compare the voltage of the USB port with a reference voltage and output voltage signals according to a comparing result; and

an indicating circuit, connected to the voltage comparing circuit, adapted to receive the voltage signals and indicate whether the voltage of the USB port is within the standard range.

2. The USB port detecting circuit of claim 1, further comprising a voltage dividing circuit connected to the voltage comparing circuit, the voltage dividing circuit is adapted to divide the voltage of the USB port before sending a divided voltage to the voltage comparing circuit.

3. The USB port detecting circuit of claim 2, wherein the voltage dividing circuit comprises a first resistor, a second resistor, and a third resistor connected in series.

4. The USB port detecting circuit of claim 3, wherein the voltage comparing circuit comprises a voltage comparing chip, the voltage comparing chip comprises a first comparator and a second comparator;

a negative input terminal of the first comparator is connected to a first node to which the first resistor and the second resistor are connected, an output terminal of the first comparator is connected to the indicating circuit; and

a positive input terminal of the second comparator is connected to a second node to which the second resistor and the third resistor are connected, an output terminal of the second comparator is connected to the indicating circuit.

5. The USB port detecting circuit of claim 4, wherein a positive input terminal of the first comparator is coupled to the reference voltage, and a negative input terminal of the second comparator is connected to the positive input terminal of the first comparator.

6. The USB port detecting circuit of claim 5, wherein the indicating circuit comprises a first light emitting diode (LED), a second LED, a third LED, and a fourth LED, an anode of the first LED is connected to a positive terminal of the USB port, a cathode of the first LED is connected to the output terminal of the second comparator;

an anode of the second LED is connected to the output terminal of the second comparator, a cathode of the second LED is connected to an anode of the fourth LED;

an anode of the third LED is connected to the output terminal of the first comparator, a cathode of the third LED is connected to the anode of the fourth LED; and

a cathode of the fourth LED is connected to a negative terminal of the USB port.

7. The USB port detecting circuit of claim 6, wherein the indicating circuit further comprises a first diode and a second diode, the first diode is connected to and located between the cathode of the first LED and the output terminal of the second comparator, and the second diode is connected to and located between the cathode of the first LED and the output terminal of the first comparator.

8. The USB port detecting circuit of claim 3, wherein a resistance of the first resistor is substantially equal to the resistance of the third resistor, and a resistance of the second resistor is less than the resistance of the first resistor or the third resistor.

9. The USB port detecting circuit of claim 8, wherein the resistance of the second resistor is three twenty-eighths of the resistance of the first resistor or the third resistor.

10. The USB detecting circuit of claim 1, further comprising a variable electric load connected to the USB port.

11. A Universal Series Bus (USB) port detecting circuit for detecting a USB port having a first terminal and a second terminal, the USB port detecting circuit comprising:

a voltage dividing circuit adapted to divide a voltage between the first terminal and the second terminal and output at least one divided voltage;

a voltage comparing circuit, connected to the voltage dividing circuit, adapted to compare the at least one divided voltage with a reference voltage and output voltage signals according to a comparing result; and

an indicating circuit, connected to the voltage comparing circuit, adapted to receive the voltage signals and indicate whether the voltage between the first terminal and the second terminal is within a predetermined range.

12. The USB port detecting circuit of claim 11, wherein the voltage dividing circuit comprises a first resistor, a second resistor, and a third resistor connected in series.

13. The USB port detecting circuit of claim 12, wherein the voltage comparing circuit comprises a voltage comparing chip, the voltage comparing chip comprises a first comparator and a second comparator;

a negative input terminal of the first comparator is connected to a first node to which the first resistor and the second resistor are connected, an output terminal of the first comparator is connected to the indicating circuit; and

a positive input terminal of the second comparator is connected to a second node to which the second resistor and the third resistor are connected, an output terminal of the second comparator is connected to the indicating circuit.

14. The USB port detecting circuit of claim 13, wherein a positive input terminal of the first comparator is coupled to the reference voltage, and a negative input terminal of the second comparator is connected to the positive input terminal of the first comparator.

15. The USB port detecting circuit of claim 14, wherein the indicating circuit comprises a first light emitting diode (LED), a second LED, a third LED, and a fourth LED, an anode of the first LED is connected to the first terminal, a cathode of the first LED is connected to the output terminal of the second comparator;

an anode of the second LED is connected to the output terminal of the second comparator, a cathode of the second LED is connected to an anode of the fourth LED;

an anode of the third LED is connected to the output terminal of the first comparator, a cathode of the third LED is connected to the anode of the fourth LED; and

a cathode of the fourth LED is connected to the second terminal.

16. The USB port detecting circuit of claim 15, wherein the indicating circuit further comprises a first diode and a second diode, the first diode is connected to and located between the cathode of the first LED and the output terminal of the second comparator, and the second diode is connected to and located between the cathode of the first LED and the output terminal of the first comparator.

17. The USB port detecting circuit of claim 12, wherein a resistance of the first resistor is substantially equal to the resistance of the third resistor, and a resistance of the second resistor is less than the resistance of the first resistor or the third resistor.

18. The USB port detecting circuit of claim 17, wherein the resistance of the second resistor is three twenty-eighths of the resistance of the first resistor or the third resistor.

19. The USB detecting circuit of claim 11, further comprising a variable electric load connected to the first terminal and the second terminal.