Protection element and method for protecting a circuit
First Claim
1. A protection element for protecting a battery pack having a first battery terminal and a second battery terminal from a faulty condition in a load having a first load terminal and a second load terminal, comprising a first switch, wherein the first switch includes:
- a first transistor having a control electrode, a first current conducting electrode for coupling to the first battery terminal, and a second current conducting electrode for coupling to the first load terminal;
a second transistor having a control electrode, a first current conducting electrode coupled to the first current conducting electrode of the first transistor, and a second current conducting electrode coupled to the control electrode of the first transistor;
a first resistor having a first electrode for coupling to the second battery terminal and to the second load terminal, and a second electrode coupled to the control electrode of the first transistor;
a second resistor having a first electrode coupled to the second current conducting electrode of the first transistor and a second electrode coupled to the first current conducting electrode of the second transistor; and
a third resistor having a first electrode coupled to the first electrode of the second resistor and a second electrode coupled to the control electrode of the second transistor.
7 Assignments
0 Petitions
Accused Products
Abstract
A protection element (10) protects a battery pack (36) from potential faulty conditions in a load (38). The protection element (10) includes a switch (12), a control FET (14), and three resistors (16, 18, and 22). Under normal operating conditions, the switch (12) is conductive and the control FET (14) is non-conductive. If a short circuit is detected, the controller (14) becomes conductive and turns off the switch (12). The switch (12) remains non-conductive until the load (38) is disconnected from the protection element (10). The protection element (10) further includes a temperature sensor (24) that turns off the switch (12) at high temperatures and a current limiting element (28) that imposes an upper limit on the current flowing through the protection element (10). Control signals can be applied to the gate electrodes of the switch (12) and the control FET (14) to modulate the current in the protection element (10).
73 Citations
30 Claims
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1. A protection element for protecting a battery pack having a first battery terminal and a second battery terminal from a faulty condition in a load having a first load terminal and a second load terminal, comprising a first switch, wherein the first switch includes:
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a first transistor having a control electrode, a first current conducting electrode for coupling to the first battery terminal, and a second current conducting electrode for coupling to the first load terminal; a second transistor having a control electrode, a first current conducting electrode coupled to the first current conducting electrode of the first transistor, and a second current conducting electrode coupled to the control electrode of the first transistor; a first resistor having a first electrode for coupling to the second battery terminal and to the second load terminal, and a second electrode coupled to the control electrode of the first transistor; a second resistor having a first electrode coupled to the second current conducting electrode of the first transistor and a second electrode coupled to the first current conducting electrode of the second transistor; and a third resistor having a first electrode coupled to the first electrode of the second resistor and a second electrode coupled to the control electrode of the second transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A protection switch having a first terminal, a second terminal, and a common terminal, comprising a first switching element having a first current conducting terminal coupled to the first terminal, a second current conducting terminal coupled to the second terminal, and a control terminal coupled to the common terminal, wherein the first switching element includes:
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a first transistor of a first type having a control electrode, a first current conducting electrode, and a second current conducting electrode, wherein the first current conducting electrode serves as the first current conducting terminal of the first switching element and the second current conducting electrode serves as the second current conducting terminal of the first switching element; a second transistor of a second type having a control electrode, a first current conducting electrode, and a second current conducting electrode, wherein the first current conducting electrode is coupled to the control terminal of the first switching element and the second current conducting electrode is coupled to the control electrode of the first transistor; a first resistor having a first electrode and a second electrode, wherein the first electrode is coupled to the first current conducting electrode of the first transistor and the second electrode is coupled to the control electrode of the first transistor; a second resistor having a first electrode and a second electrode, wherein the first electrode is coupled to the second current conducting electrode of the first transistor and the second electrode is coupled to the control electrode of the second transistor; and a third resistor having a first electrode and a second electrode, wherein the first electrode is coupled to the first current conducting electrode of the first transistor and the second electrode is coupled to the second current conducting electrode of the first transistor. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for protecting a circuit, comprising the steps of:
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providing the circuit comprising a first circuit block and a second circuit block, wherein the first circuit block has a first terminal and a second terminal, and the second circuit block has a first terminal and a second terminal; coupling the first terminal of the first circuit block to the first terminal of the second circuit block; providing a first switch having a first current conducting electrode coupled to the second terminal of the first circuit block and a second current conducting electrode coupled to the second terminal of the second circuit block; placing the first switch in a conductive state; passing a current from the first terminal of the first circuit block to the second terminal of the first circuit block via the second circuit block and the first switch; directly sensing a voltage across the first terminal and the second terminal of the second circuit block; and placing the first switch in a non-conductive state to terminate the current in response to the voltage being less than a predetermined voltage value. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification