Failure diagnosing circuit and method
First Claim
1. A circuit for facilitating failure diagnosis of switching elements constituting a bridge circuit for driving a motor, the bridge circuit being formed by connecting a first and a second switching element in series and connecting a third and a fourth switching element in series, connecting one motor input terminal between the first and the second switching elements and connecting a second motor input terminal between the third and the fourth switching elements, the circuit comprising:
- pull up and pull down terminals respectively connected to the input terminals of the motor via resistors;
monitor terminals respectively connected to the input terminals of the motor;
said pull up/down terminals selectively providing two states including a pull up state for providing voltage for facilitating failure diagnosis to the motor input terminals and a pull down state for providing ground potential to the motor input terminals;
means for switching the two states of the pull up/down terminals; and
means for opening and closing one of the switching elements at a time;
whereby a change in potential of the monitor terminals in correspondence with each combination of switching the states and opening and closing of the switching elements indicates open and short-circuit failures or lack thereof and thereby facilitates failure diagnosis of the switching elements without energizing the motor.
1 Assignment
0 Petitions
Accused Products
Abstract
To provide a failure diagnosing circuit capable of carrying out failure diagnosis of respective switching elements of a bridge circuit without rotating a motor. Pull up/down terminals and as well as monitor terminals are respectively connected to both input terminals of a motor. The pull up/down terminals selectively provide two states: a pull up state providing voltage 5 V for failure diagnosis to the motor input terminals via resistors and a pull down state providing ground potential to the motor input terminals via the resistors. A failure diagnosing circuit switches the two states of the pull up/down terminals, opens and closes any one element of switching elements and monitors a change in the potential of the monitor terminal corresponding to each of the combinations of switching the states and opening and closing of the switching elements by which failure diagnosis of the opened and closed switching element is carried out.
-
Citations
19 Claims
-
1. A circuit for facilitating failure diagnosis of switching elements constituting a bridge circuit for driving a motor, the bridge circuit being formed by connecting a first and a second switching element in series and connecting a third and a fourth switching element in series, connecting one motor input terminal between the first and the second switching elements and connecting a second motor input terminal between the third and the fourth switching elements, the circuit comprising:
-
pull up and pull down terminals respectively connected to the input terminals of the motor via resistors; monitor terminals respectively connected to the input terminals of the motor; said pull up/down terminals selectively providing two states including a pull up state for providing voltage for facilitating failure diagnosis to the motor input terminals and a pull down state for providing ground potential to the motor input terminals; means for switching the two states of the pull up/down terminals; and means for opening and closing one of the switching elements at a time; whereby a change in potential of the monitor terminals in correspondence with each combination of switching the states and opening and closing of the switching elements indicates open and short-circuit failures or lack thereof and thereby facilitates failure diagnosis of the switching elements without energizing the motor. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A circuit for facilitating failure diagnosis of switching elements constituting a bridge circuit for driving a motor, said bridge circuit being formed by connecting a first and a second switching element in series and connecting a third and a fourth switching element in series, connecting one motor input terminal between the first and the second switching elements and connecting a second motor input terminal between the third and the fourth switching elements, the circuit comprising:
-
pull up and pull down terminals respectively connected to the input terminals of the motor via resistors; monitor terminals respectively connected to the input terminals of the motor; a first switch connected between said pull up terminal and a first voltage source; a second switch connected between said pull up terminal and ground; a third switch connected between said pull down terminal and a second voltage source; a fourth switch connected between said pull down terminal and ground; and a control circuit having first and second input terminals and a pulse width modulation signal input, said control circuit having control outputs connected to said first, second, third and fourth switches and to the first, second, third and fourth switching elements; said control circuit selectively providing two states including a pull up state for providing voltage for failure diagnosis to the motor input terminals and a pull down state for providing ground potential to the motor input terminals; said control circuit switching the two states of said pull up/down terminals by opening and closing said first, second, third, and fourth switches; said control circuit opening and closing one of the switching elements at a time; wherein a change in potential of the monitor terminals in correspondence with each combination of switching the states and opening and closing of the switching elements indicates open and short-circuit failures in the switching elements or lack thereof and thereby facilitates failure diagnosis of the switching elements without energizing the motor. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method for facilitating failure diagnosis of switching elements constituting a bridge circuit for driving a motor, the bridge circuit being formed by connecting a first and a second switching element in series and connecting a third and a fourth switching element in series, connecting one motor input terminal between the first and the second switching elements and connecting a second motor input terminal between the third and the fourth switching elements, the failure diagnosing circuit comprising the steps of:
-
connecting pull up and pull down terminals to the input terminals of the motor via resistors; connecting monitor terminals to the input terminals of the motor; selectively providing two states including a pull up state for providing voltage for facilitating failure diagnosis to the motor input terminals and a pull down state for providing ground potential to the motor input terminals; switching the two states of the pull up/down terminals; and opening and closing one of the switching elements at a time; whereby a change in potential of the monitor terminals in correspondence with each combination of switching the states and opening and closing of the switching elements whereby the potential change indicates open and short-circuit failures or lack thereof and thereby facilitates failure diagnosis of the switching elements without energizing the motor. - View Dependent Claims (16, 17, 18, 19)
-
Specification