Fault detection circuit for a driver circuit
First Claim
1. A fault detection circuit for a driver circuit for a drive source, the driver circuit including an electric motor and a FET that are connected in series between a power source and ground and the FET being configured to be selectively turned on and off for controlling the electric motor when the electric motor is in operation, said fault detection circuit comprising:
- a test voltage supply circuit adapted to feed a test voltage to a node between the electric motor and the FET, the test voltage supply circuit being different from a power source circuit;
a test voltage detection circuit adapted to detect a voltage of the node; and
a controller adapted to evaluate the voltage at the node before a power-up of the drive circuit when the test voltage is applied and when the test voltage is not applied.
2 Assignments
0 Petitions
Accused Products
Abstract
Various component parts of a driver circuit for drive sources such as electric motors and clutches, such as relays and FETs as well as the drive sources can be tested by selectively energizing the relays and evaluating the voltage levels of the selected points by using the first and second test voltage detection circuits. This testing process is typically executed before the power up of the drive circuit. The test current is so small that the drive sources would not be inadvertently activated and various components would not be damaged even when there is any faulty component in the driver circuit. When any faulty component is detected in the testing process, the driver circuit may be prevented from being powered up so that any undesired operation of the drive sources or permanent damage to various components owing to such a faulty component may be avoided.
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Citations
16 Claims
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1. A fault detection circuit for a driver circuit for a drive source, the driver circuit including an electric motor and a FET that are connected in series between a power source and ground and the FET being configured to be selectively turned on and off for controlling the electric motor when the electric motor is in operation, said fault detection circuit comprising:
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a test voltage supply circuit adapted to feed a test voltage to a node between the electric motor and the FET, the test voltage supply circuit being different from a power source circuit; a test voltage detection circuit adapted to detect a voltage of the node; and a controller adapted to evaluate the voltage at the node before a power-up of the drive circuit when the test voltage is applied and when the test voltage is not applied. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fault detection circuit for a driver circuit for an electric motor and an electromagnetic clutch, the driver circuit including first and second serial connections between a power source and ground, the first serial connection including an electric motor, a first switching device and a pair of second switching devices connected on either end of the electric motor to allow the electric motor to receive a drive voltage of either polarity, the second serial connection including an electromagnetic clutch and a first switching device;
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the fault detection circuit, comprising; a test voltage supply circuit adapted to feed a test voltage to a test voltage node between the electric motor and the first switching device in the first serial connection and another test voltage node between the electromagnetic clutch and the first switching device in the second serial connection, the test voltage supply circuit including a current limiting element; a first test voltage detection circuit adapted to detect a voltage of the test voltage node of the first serial connection; a second test voltage detection circuit adapted to detect a voltage of the test voltage node of the second serial connection; and a controller adapted to evaluate the voltage at the test voltage nodes of the first and second serial connections before a power-up of the drive circuit; wherein the test voltage supply circuit is different from the power source circuit. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A fault detection circuit for a driver circuit for a drive source, the driver circuit including an electromagnetic clutch and a FET that are connected in series between a power source and ground and the FET being configured to be selectively turned on and off for controlling the electromagnetic clutch when the electromagnetic clutch is in operation, said fault detection circuit comprising:
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a test voltage supply circuit adapted to feed a test voltage to a node between the electromagnetic clutch and the FET, the test voltage supply circuit being different from a power source circuit; a test voltage detection circuit adapted to detect a voltage of the node; and a controller adapted to evaluate the voltage at the node before a power-up of the drive circuit when the test voltage is applied and when the test voltage is not applied. - View Dependent Claims (15, 16)
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Specification