LOAD-TESTING CIRCUIT FOR USB PORTS
First Claim
1. A load-testing circuit to simulate maximum standard load currents for different types of USB ports, each type of USB port comprising a power terminal, the load-testing circuit comprising:
- a first resistor, a second resistor, and a third resistor;
a current selection module comprising a plurality of current branch circuits;
a first electronic switch comprising a first terminal electrically connected to the power terminal through the first resistor, a second terminal electrically connected to the power terminal, and a third terminal electrically connected to each current branch circuit; and
a second electronic switch comprising a first terminal electrically connected to each current branch circuit through the second resistor, a second terminal electrically connected to the first terminal of the first electronic switch through the third resistor, and a third terminal grounded;
wherein in response to one of the current branch circuit being activated, a voltage at the third terminal of the first electronic switch is supplied to the first terminal of the second electronic switch through the activated current branch circuit and the second resistor in that order to turn on the second electronic switch, and a current of the third terminal of the first electronic switch is approximately equal to a current of the activated current branch circuit.
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Accused Products
Abstract
A load-testing circuit is used for simulating maximum standard load currents for different types of USB ports. The load-testing circuit includes a first electronic switch, a second electronic switch, and a current selection module including a plurality of current branch circuits. When one of the current branch circuits is activated, a voltage at a third terminal of the first electronic switch is supplied to a first terminal of the second electronic switch through the activated current branch circuit to turn on the second electronic switch. A current of the third terminal of the first electronic switch is approximately equal to a current of the activated current branch circuit.
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Citations
16 Claims
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1. A load-testing circuit to simulate maximum standard load currents for different types of USB ports, each type of USB port comprising a power terminal, the load-testing circuit comprising:
a first resistor, a second resistor, and a third resistor; a current selection module comprising a plurality of current branch circuits; a first electronic switch comprising a first terminal electrically connected to the power terminal through the first resistor, a second terminal electrically connected to the power terminal, and a third terminal electrically connected to each current branch circuit; and a second electronic switch comprising a first terminal electrically connected to each current branch circuit through the second resistor, a second terminal electrically connected to the first terminal of the first electronic switch through the third resistor, and a third terminal grounded; wherein in response to one of the current branch circuit being activated, a voltage at the third terminal of the first electronic switch is supplied to the first terminal of the second electronic switch through the activated current branch circuit and the second resistor in that order to turn on the second electronic switch, and a current of the third terminal of the first electronic switch is approximately equal to a current of the activated current branch circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A load-testing circuit to simulate maximum standard load currents for different types of USB ports, each type of USB port comprising a power terminal, the load-testing circuit comprising:
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a first resistor, a second resistor, and a third resistor; a first electronic switch comprising a first terminal electrically connected to the power terminal through the first resistor, a second terminal electrically connected to the power terminal, and a third terminal; a second electronic switch comprising a first terminal, a second terminal electrically connected to the first terminal of the first electronic switch through the second resistor, and a third terminal grounded; a first current branch circuit comprising; a fourth resistor; a first switch comprising a first terminal and a second terminal electrically connected to the first terminal of the second electronic switch through the third resistor; and a first relay comprising a first coil comprising a first terminal electrically connected to the third terminal of the first electronic switch and a second terminal electrically connected to the first terminal of the first switch, and a second switch comprising a first terminal electrically connected to the third terminal of the first electronic switch and a second terminal grounded through the fourth resistor; and a second current branch circuit comprising; a fifth resistor; a first diode comprising an anode and a cathode electrically connected to the first terminal of the second electronic switch through the third resistor; a third switch comprising a first terminal and a second terminal electrically connected to the anode of the first diode; and a second relay comprising a second coil comprising a first terminal electrically connected to the third terminal of the first electronic switch and a second terminal electrically connected to the first terminal of the third switch, and a fourth switch comprising a first terminal electrically connected to the third terminal of the first electronic switch and a second terminal grounded through the fifth resistor; wherein in response to the first switch being turned on, the first current branch circuit is activated, a current passes through the first coil, the second switch is turned on, a voltage at the third terminal of the first electronic switch is supplied to the first terminal of the second electronic switch through the first coil, the first switch, and the third resistor in that order to turn on the second electronic switch, a voltage of the fourth resistor is approximately equal to a sum of a voltage at the first terminal of the second electronic switch and a voltage of the third resistor, and a current of the third terminal of the first electronic switch is approximately equal to a current of the fourth resistor; and wherein in response to the third switch being turned on, the second current branch circuit is activated, the first diode is turned on, a current passes through the second coil, the fourth switch is turned on, a voltage at the third terminal of the first electronic switch is supplied to the first terminal of the second electronic switch through the second coil, the third switch, the first diode, and the third resistor in that order to turn on the second electronic switch, a voltage of the fifth resistor is approximately equal to a sum of the voltage at the first terminal of the second electronic switch, the voltage of the third resistor, and a voltage of the first diode, and the current of the third terminal of the first electronic switch is approximately equal to a current of the fifth resistor. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification