Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Current driver
Reexamination Certificate
1999-04-13
2001-03-20
Wells, Kenneth B. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Current driver
C327S170000, C327S376000
Reexamination Certificate
active
06204700
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to predriver circuits operable to control the operation of power drive circuits, and more specifically to such predriver circuits used in high voltage applications such as, for example, in controlling the operation of DC motors.
BACKGROUND OF THE INVENTION
Systems for controlling speed, torque and/or position of DC motors are known and have been widely used in a variety of applications including automotive control systems. Generally, such DC motors fall into two broad categories; namely brushed DC motors and brushless DC motors. While brushless DC motors typically offer desirable performance features and certain advantages over brushed DC motors in an automotive environment, such features and advantages may often be offset by the complexity of motor control and motor drive circuits required to accurately control motor operation. For example, controlled stoppage, accurate motor shaft positioning, motor reversal and consistent control of motor output torque are all difficult to achieve with brushless DC motors.
Dedicated systems for controlling and driving brushless DC motors are known. In such systems, a motor control circuit is typically operable to detect motor shaft position as well as motor drive current, and a motor drive circuit is, in turn, responsive to motor control signals supplied by the motor control circuitry to drive the DC motor in a desired manner. In known DC motor drive circuits, the motor driving function is often partitioned into a two-stage drive operation; namely a pre-driver circuit and a power drive circuit. The pre-driver circuit typically serves as an interface between a motor control logic circuit and a power drive device such as a discrete power transistor, wherein the pre-driver circuit is operable to convert the logic level motor control signals to one or more signals suitable for driving the power drive device.
While known pre-driver circuits have been widely used in various DC brushless motor control systems, such pre-driver circuits suffer from several drawbacks, particularly when used in automotive applications. For example, known pre-driver circuits in automotive applications are often strictly analog circuits that suffer from slow response time and high power dissipation. Conversely, while known digital pre-driver circuits may provide for fast and accurate motor control, such systems are typically incapable of supplying such control in a high voltage automotive environment, and are consequently not often used. In either case, electromagnetic interference (EMI) requirements are difficult to satisfy in a high voltage environment, and known pre-driver circuits often suffer from deleterious effects resulting from EMI. What is therefore needed is an improved pre-driver circuit for a motor control system that is both power efficient and capable of high speed operation in a high voltage automotive environment. Ideally, such an improved pre-driver circuit should also be compatible with imposed EMI requirements.
SUMMARY OF THE INVENTION
The present invention addresses the foregoing shortcomings in known motor drive circuits. In accordance with one aspect of the present invention, a predriver circuit for controlling a power drive circuit comprises a turn on drive circuit having a first analog input adapted to receive a first analog signal and an analog output adapted for connection to an input of a power drive circuit, wherein the turn on drive circuit is responsive to one of an active and an inactive state of a first digital signal to supply an amplified representation of the first analog signal to the analog output. The turn on drive circuit is further responsive to the other of an active and an inactive state of the first digital control signal to disable supply of the amplified representation of the first analog signal to the analog output. Also included is a turn off drive circuit having a second analog input adapted to receive a second analog signal and an analog output defined by the analog output of the turn on drive circuit, wherein the turn off drive circuit is responsive to the other of an active and inactive state of the first digital control signal to draw an amplified representation of the second analog signal from the analog output. The turn off drive circuit is further responsive to the one of an active and an inactive state of the first digital control signal to disable draw of the amplified representation of the second analog signal from the analog output.
In accordance with another aspect of the present invention, a predriver circuit for controlling a power drive circuit comprises a first analog signal amplifier defining an input adapted to receive a first analog signal and a second analog signal amplifier coupled to the first analog signal amplifier and defining an output adapted for connection to an input of a power drive circuit, wherein the first and second analog amplifiers are responsive to a first state of a predriver control signal to supply an amplified representation of the first analog signal to the output. A sense circuit is included and is responsive to detection of the amplified representation of the first analog signal to disable operation of the first analog signal amplifier and a first portion of the second analog amplifier to thereby reduce electrical power consumed thereby. Also included is a control circuit responsive to disablement of the first analog signal amplifier to maintain a second portion of the second analog amplifier operable to thereby maintain the output near a predefined signal level for a duration of the first state of the predriver control signal. A turn off drive circuit is further included and is responsive to a second state of the predriver control signal to draw a second analog signal from the output.
In accordance with a further aspect of the present invention, a predriver circuit for controlling a power drive circuit comprises a turn on drive circuit responsive to a first state of a predriver control signal to supply a first analog signal to a predriver circuit output thereof, wherein the predriver circuit output is adapted for connection to an input of a power drive circuit, a first analog signal amplifier defining an input adapted to receive a second analog signal, a second analog signal amplifier having an input coupled to the first analog signal amplifier and defining a second amplifier output, a third analog signal amplifier coupled to the second amplifier output and defining an output connected to the predriver circuit output, wherein the first, second and third amplifiers are responsive to a second opposite state of the predriver control signal to draw an amplified representation of the second analog signal from the predriver circuit output, a sense circuit responsive to detection of the amplified representation of the second analog signal drawn from the predriver circuit output to disable operation of the first and second analog signal amplifiers and a first portion of the third analog signal amplifier to thereby reduce electrical power consumed thereby, and a control circuit responsive to disablement of the first and second analog signal amplifiers and the first portion of the third analog signal amplifier to maintain a second portion of the third analog signal amplifier operable to thereby maintain the predriver circuit output near a predefined signal level for a duration of the second state of the predriver control signal.
In accordance with yet another aspect of the present invention, a predriver circuit for controlling a power drive circuit comprises a turn on drive circuit having a first analog input adapted to receive a first analog signal and an analog output adapted for connection to an input of a power drive circuit, wherein the turn on drive circuit is responsive to one of an active and an inactive state of a first digital signal to supply an amplified representation of the first analog signal to the analog output and to produce a digital turn off circuit disable signal. Also included is a turn off drive circuit havin
Delphi Technologies Inc.
Funke Jimmy L.
Wells Kenneth B.
LandOfFree
Predriver circuit for controlling a power drive circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Predriver circuit for controlling a power drive circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Predriver circuit for controlling a power drive circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2442017