Motor control circuit for mirror device
First Claim
1. A control circuit that is used in a mirror device, where the position of a mirror attached to a vehicle is changed in a predetermined direction by the driving force of a motor, and controls electrical power supplied to the motor, the control circuit comprising:
- a drive current controlling transistor where, when a first terminal is connected to a power source, a second terminal is connected to the motor and a voltage equal to or greater than a predetermined value is applied to a third terminal that is different from both the first and second terminals, a current flows from the first terminal to the second terminal and application of the voltage is released, whereby the current is blocked; and
a switching transistor where a fourth terminal is connected between the power source and the third terminal, a fifth terminal is grounded, and which includes a sixth terminal connected to the motor at an opposite side from the second terminal, and a voltage equal to or greater than a specific value corresponding to a lock current flowing through the motor is applied to the sixth terminal, whereby the fourth terminal and the fifth terminal are switched to a conductive state and the voltage applied to the third terminal is made less than the predetermined value.
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Accused Products
Abstract
The present invention provides a mirror device motor control circuit that can reliably stop a mirror at predetermined positions with a simple configuration. In the control circuit of the invention, part of a lock current flowing to the motor flows to a base terminal of a transistor. Thus, as long as a voltage corresponding to the lock current is equal to or greater than a specific value, this voltage is applied to the base terminal of the transistor, whereby between a collector terminal and an emitter terminal becomes conductive, and the current flowing to a gate of a MOSFET is grounded via the collector terminal and the emitter terminal of the transistor. For this reason, when the lock current flows, conduction between a drain terminal and a base terminal of the MOSFET is released and a drive current of the motor is cut off.
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Citations
11 Claims
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1. A control circuit that is used in a mirror device, where the position of a mirror attached to a vehicle is changed in a predetermined direction by the driving force of a motor, and controls electrical power supplied to the motor, the control circuit comprising:
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a drive current controlling transistor where, when a first terminal is connected to a power source, a second terminal is connected to the motor and a voltage equal to or greater than a predetermined value is applied to a third terminal that is different from both the first and second terminals, a current flows from the first terminal to the second terminal and application of the voltage is released, whereby the current is blocked; and
a switching transistor where a fourth terminal is connected between the power source and the third terminal, a fifth terminal is grounded, and which includes a sixth terminal connected to the motor at an opposite side from the second terminal, and a voltage equal to or greater than a specific value corresponding to a lock current flowing through the motor is applied to the sixth terminal, whereby the fourth terminal and the fifth terminal are switched to a conductive state and the voltage applied to the third terminal is made less than the predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification