Method and control circuit for driving an electric motor of a seatbelt retractor
First Claim
1. A method of controlling an electric motor that drives a belt spool of a seatbelt retractor in a vehicle using a micro-controller and a drive circuit that drives the electric motor, comprising the steps of:
- (a) providing a plurality of PWM control signal sources each of which has a trigger input and a control signal output, each control signal source, upon application of a trigger pulse to its trigger input, providing on its control signal output a control pulse of a duration different from durations of control pulses of all other control signal sources;
(b) providing a set of motor control programs permanently stored in the micro-controller;
(c) providing a program selection signal to said micro-controller from a sensor unit in the vehicle;
(d) applying trigger pulses to the trigger inputs of said control signal sources from said micro-controller; and
(e) selecting particular ones of said control signal sources for application of their signal outputs to said drive circuit in a control sequence defined by a selected control program.
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Accused Products
Abstract
An electric motor drives a belt spool of a seatbelt retractor in a vehicle using a micro-controller and a drive circuit that drives the electric motor. A plurality of PWM control signal sources are provided each of which has a trigger input and a control signal output. Each control signal source, upon application of a trigger pulse to its trigger input, provides on its control signal output a control pulse of a duration different from durations of control pulses of all other control signal sources. A set of motor control programs are permanently stored in the micro-controller. A program selection signal is sent to the micro-controller from a central sensor unit in the vehicle. Trigger pulses are sent by the micro-controller to the trigger inputs of the control signal sources. Particular ones of the control signal sources are selected for application of their signal outputs to the drive circuit in a control sequence defined by a selected control program.
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Citations
9 Claims
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1. A method of controlling an electric motor that drives a belt spool of a seatbelt retractor in a vehicle using a micro-controller and a drive circuit that drives the electric motor, comprising the steps of:
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(a) providing a plurality of PWM control signal sources each of which has a trigger input and a control signal output, each control signal source, upon application of a trigger pulse to its trigger input, providing on its control signal output a control pulse of a duration different from durations of control pulses of all other control signal sources;
(b) providing a set of motor control programs permanently stored in the micro-controller;
(c) providing a program selection signal to said micro-controller from a sensor unit in the vehicle;
(d) applying trigger pulses to the trigger inputs of said control signal sources from said micro-controller; and
(e) selecting particular ones of said control signal sources for application of their signal outputs to said drive circuit in a control sequence defined by a selected control program. - View Dependent Claims (2, 3, 4)
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5. A control circuit for driving an electric motor that drives a belt spool of a seat-belt retractor in a vehicle equipped with a central sensor unit, comprising
a drive circuit with a control input for driving the electric motor; -
a micro-controller with a sensor input connected to the central sensor unit and a trigger signal output, the micro-controller having a set of motor control programs permanently stored in a memory and the central sensor unit providing selection control signals to the micro-controller for selecting one out of the set of motor control programs at a time;
a plurality of PWM control signal sources each of which has a trigger input connected to the trigger signal output of the micro-controller and a control signal output, each control signal source, upon application of a trigger pulse to its trigger input, providing on its control signal output a control pulse of a duration different from durations of control pulses of all other control signal sources;
and a switching unit controlled by the micro-controller to selectively connect the control signal output of one of the PWM control signal sources with the control input of the drive circuit in accordance with a selected motor control program. - View Dependent Claims (6, 7, 8, 9)
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Specification