Solenoid driving circuit for automatic transmission
First Claim
1. A solenoid driving circuit for an automatic transmission for a vehicle, comprising:
- a solenoid disposed in a hydraulic controller of the automatic transmission for a vehicle, said hydraulic controller controlling hydraulic pressure supplied thereto;
solenoid driving means for driving said solenoid with an actuating current;
setting means for setting a value for said actuating current;
a resistance element electrically connected in series with said solenoid;
a Darlington-connected transistor circuit electrically connected between the resistance element and a power ground;
first detecting means for detecting a voltage of a connecting point between the solenoid and the resistance element, said first detecting means being connected to a signal ground;
second detecting means for detecting a voltage of a connecting point between the resistance element and the Darlington-connected transistor circuit, said second detecting means being connected to the signal ground;
monitoring current determining means for receiving the detected voltages of the first and second detecting means and for calculating a monitoring current as a function of a voltage difference between opposite ends of the resistance element;
controlling means for effecting feedback control of the actuating current by comparing the calculated monitoring current with the set value and generating an error signal on the basis of said comparing, said actuating current being corrected to said set value responsive to said error signal, said controlling mens being connected to a signal ground; and
wherein said controlling means includes abnormality determining means for determining if the calculated monitoring current is abnormal and for turning off said Darlington-connected transistor circuit when the monitoring current value is determined to be abnormal.
1 Assignment
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Accused Products
Abstract
A solenoid driving circuit for an automatic transmission in which a potential difference compensating device, such as a Darlington-connected transistor circuit, switching transistor, and/or diode, is connected between a resistance element and a power ground, and a controlling device monitors voltage values at opposite sides of the resistor element so as to detect a current value flowing across a solenoid. The controlling device determines whether the detected value of the current flowing across the solenoid is abnormal, and the controlling device shuts off the current of a solenoid driving device when it is abnormal. The potential difference compensating device is provided with a switching device, and the controlling device turns off the switching device when the monitoring current value is abnormal. This circuit prevents an excessive current from flowing to the solenoid and an excessive discharge from the potential difference compensating device to the power ground owing to a short circuit with the supply line of a battery.
23 Citations
4 Claims
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1. A solenoid driving circuit for an automatic transmission for a vehicle, comprising:
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a solenoid disposed in a hydraulic controller of the automatic transmission for a vehicle, said hydraulic controller controlling hydraulic pressure supplied thereto; solenoid driving means for driving said solenoid with an actuating current; setting means for setting a value for said actuating current; a resistance element electrically connected in series with said solenoid; a Darlington-connected transistor circuit electrically connected between the resistance element and a power ground; first detecting means for detecting a voltage of a connecting point between the solenoid and the resistance element, said first detecting means being connected to a signal ground; second detecting means for detecting a voltage of a connecting point between the resistance element and the Darlington-connected transistor circuit, said second detecting means being connected to the signal ground; monitoring current determining means for receiving the detected voltages of the first and second detecting means and for calculating a monitoring current as a function of a voltage difference between opposite ends of the resistance element; controlling means for effecting feedback control of the actuating current by comparing the calculated monitoring current with the set value and generating an error signal on the basis of said comparing, said actuating current being corrected to said set value responsive to said error signal, said controlling mens being connected to a signal ground; and wherein said controlling means includes abnormality determining means for determining if the calculated monitoring current is abnormal and for turning off said Darlington-connected transistor circuit when the monitoring current value is determined to be abnormal. - View Dependent Claims (2)
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3. A solenoid driving circuit for an automatic transmission for a vehicle, comprising:
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a solenoid disposed in a hydraulic controller of the automatic transmission for a vehicle, said hydraulic controller controlling hydraulic pressure supplied thereto; solenoid driving means for driving said solenoid with an actuating current; setting means for setting a value for said actuating current; a resistance element electrically connected in series with said solenoid; a switching transistor in series with a diode electrically connected between the resistance element and a power ground; first detecting means for detecting a voltage of a connecting point between the solenoid and the resistance element, said first detecting means being connected to a signal ground; second detecting means for detecting a voltage of a connecting point between the resistance element and the switching transistor, said second detecting means being connected to the signal ground; monitoring current determining means for receiving the detected voltages of the first and second detecting means and for calculating a monitoring current as a function of a voltage difference between opposite ends of the resistance element; controlling means for effecting feedback control of the actuating current by comparing the calculated monitoring current with the set value and generating an error signal on the basis of said comparing, said actuating current being corrected to said set value responsive to said error signal, said controlling means being connected to a signal ground; and wherein said controlling means includes abnormality determining means for determining if the calculated monitoring current is abnormal and for turning off said switching transistor when the monitoring current value is determined to be abnormal. - View Dependent Claims (4)
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Specification