Bidirectional motor stall protection circuit
First Claim
Patent Images
1. A stall protection circuit for use with a motor comprising:
- a switch for controlling powering of the motor, the switch being operable to first, second, and third states, the first state powering the motor with current flowing in a forward direction, the second state powering the motor with current flowing in a reverse direction, and the third state preventing powering of the motor;
a single current sensor configured to sense current flowing in both of the forward and reverse directions;
a stall detection circuit configured to compare current sensed by the single current sensor to a current threshold and to output a first signal if the current is less than the threshold and to output a second signal if the current is greater than the threshold;
a first switch connected on one side of the motor and a second switch connected to an other side of the motor, each switch being controllable to an open or closed position; and
a latching circuit configured to receive the first and second signals and for connecting or disconnecting the motor from the powering associated with the first or second state depending on whether the first or second signal is received, the latching circuit connecting the motor by closing both switches when the first signal is received and disconnecting the motor by opening at least one of the switches when the second signal is received.
9 Assignments
0 Petitions
Accused Products
Abstract
A stall protection circuit is provided for bidirectional motor operation that is controlled by a half bridge switch that has forward, reverse and off positions. A method of protecting a motor is also disclosed. A Hall effect current sensor may be provided in a stall current protection circuit that engages a latching circuit. The latching circuit is operative to interrupt current flowing to the motor by disabling MOSFETs on opposite sides of the motor. Alternatively, FET voltage from drain to source may be used to measure the current supplied to the motor that is used to engage the latching circuit.
-
Citations
20 Claims
-
1. A stall protection circuit for use with a motor comprising:
-
a switch for controlling powering of the motor, the switch being operable to first, second, and third states, the first state powering the motor with current flowing in a forward direction, the second state powering the motor with current flowing in a reverse direction, and the third state preventing powering of the motor; a single current sensor configured to sense current flowing in both of the forward and reverse directions; a stall detection circuit configured to compare current sensed by the single current sensor to a current threshold and to output a first signal if the current is less than the threshold and to output a second signal if the current is greater than the threshold; a first switch connected on one side of the motor and a second switch connected to an other side of the motor, each switch being controllable to an open or closed position; and a latching circuit configured to receive the first and second signals and for connecting or disconnecting the motor from the powering associated with the first or second state depending on whether the first or second signal is received, the latching circuit connecting the motor by closing both switches when the first signal is received and disconnecting the motor by opening at least one of the switches when the second signal is received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A stall protection circuit for use with a motor comprising:
-
a switch for controlling powering of the motor, the switch being operable to first, second, and third states, the first state powering the motor with current flowing in a forward direction, the second state powering the motor with current flowing in a reverse direction, and the third state preventing powering of the motor; a first switch connected on one side of the motor and a second switch connected to an other side of the motor, each switch being controllable to an open or closed position; a stall detection circuit configured to simultaneously compare a voltage drop across each of the switches to a threshold and to output a first signal if the voltage drop is less than the threshold and to output a second signal if the voltage drop is greater than the threshold; and a latching circuit configured to receive the first and second signals and for connecting or disconnecting the motor from the powering associated with the first or second state depending on whether the first or second signal is received, the latching circuit connecting the motor by closing both switches when the first signal is received and disconnecting the motor by opening at least one of the switches when the second signal is received. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
-
18. A seating system comprising:
-
a switch for controlling movement of a motor used to position the seat between stops included on opposite ends of a seat rail, the switch being operable to first, second, and third states, the first state moving the seat forwardly with current flowing through the motor in a forward direction, the second state moving the seat rearwardly with current flowing through the motor in a reverse direction, and the third state preventing movement of the seat by preventing current flow through the motor, wherein the current flowing in the forward directions has a forward polarity opposite to a reverse polarity of the current flowing in the reverse direction; a stall detection circuit configured to disconnect power to the motor when the seat abuts one of the stops, the stall detection circuit has a first comparator configured to compare current flowing with the forward polarity to a current threshold and a second comparator configured to compare current flowing with the reverse polarity to the current threshold and to output a signal if the current associated with either one of the forward and reverse polarities is greater than the threshold; and a latching circuit configured to disconnect power to the motor upon receipt of the signal. - View Dependent Claims (19, 20)
-
Specification