Circuit for driving the motor of a temperature blend door
AssigneeSGS-Thomson Microelectronics S.A.
InventorDavid Frank Swanson
Life of this patent
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Abstract
A circuit for driving a motor used to control the HVAC blend door in an automobile is disclosed. The circuit includes an amplifier circuit, an motor, and a three state driver circuit. The driver circut includes three NPN bipolar transistors and two PNP bipolar transistors configured such that the output of the three state driver circuit is turned off if the input is at a intermediate voltage. The output of the three state driver circuit is at a high voltage if the input is at a low voltage. Conversely, the output of the three state driver circuit is at low voltage when the input is at a high voltage.
Claims19
A circuit for driving a motor used to control an HVAC blend door comprising:
- a motor having a first input, a second input, and a shaft connected to the HVAC blend door and a potentiometer having an output;
- an amplifier stage having a first input for receiving a control voltage, having a second input connected to the output of the potentiometer, having a third input connected to a reference voltage and having an output connected to the first in put of the motor;
- and
- a three state driver circuit having an input connected to the output of the amplifier stage and having an output connected to the second input of the motor, the output of the three state driver circuit being turned off when the output of the amplifier stage is at a steady state voltage, the amplitude of the voltage at the output of the three state driver circuit, when the three state driver circuit is mined on, being different from the amplitude of the voltage at the output of the amplifier stage.
A three state driver circuit for driving one side of a motor, the three state driver circuit comprising:
- an input connected to an output of an amplifier stage;
- an output connected to a second input of the motor, the output of the three state driver circuit being turned off when the output of the amplifier stage is at a steady state voltage;
- a first transistor having an emitter, having a base, and having a collector;
- a second transistor having an emitter connected to the emitter of the first transistor and forming the input of the three state driver circuit, having a base connected to the base of the first transistor and to a voltage reference, and having a collector;
- a third transistor having an emitter connected to ground, having a base connected to the collector of the second transistor, and having a collector;
- a fourth transistor having an emitter connected to a voltage source Vcc, having a base connected to the collector of the first transistor, and having a collector;
- and
- a fifth transistor having an emitter connected to the collector of the third transistor and forming the output of the three state driver circuit, having a base connected to the collector of the fourth transistor, and having a collector connected to the voltage source.
An automobile having a temperature control system wherein the temperature control system includes a circuit for driving a motor used to control an HVAC blend door comprising:
- a motor having a first input, a second input, and a shaft connected to the HVAC blend door and a potentiometer having an output;
- an amplifier stage having a first input for receiving a control voltage, having a second input connected to the output of the potentiometer, having a third input connected to a reference voltage and having an output connected to the first input of the motor;
- and
- a three state driver circuit having an input connected to the output of the amplifier stage and having an output connected to the second input of the motor, the output of the three state driver circuit being turned off when the output of the amplifier stage is at a steady state voltage, the amplitude of the voltage at the output of the three state driver circuit, when the three state driver circuit is mined on, being different from the amplitude of the voltage at the output of the amplifier stage.
A circuit for driving a motor comprising:
- a potentiometer coupled to the shaft of the motor, the potentiometer having an output;
- an amplifier stage having a first input for receiving a control voltage, having a second input coupled to the output of the potentiometer, having a third input coupled to a reference voltage and having an output coupled to the first input of the motor;
- and
- a three state driver circuit having an input coupled to the output of the amplifier stage and having an output coupled to the second input of the motor, the output of the three state driver circuit being turned off when the output of the amplifier stage is at a steady state voltage, the amplitude of the voltage at the output of the three state driver circuit, when the three state driver circuit is mined on, being different from the amplitude of the voltage at the output of the amplifier stage.
Dependencies are inferred from the claim text.