Magnetic sensor and an integrated circuit

Abstract

The present teaching relates to a method/apparatus for a magnetic sensor. The apparatus of the magnetic sensor resides in a housing and includes an input port and an output port, both extending from the housing. The apparatus also includes an electrical circuit which comprises a magnetic field detecting circuit, configured to detect an external magnetic field and output a magnetic induction signal that is indicative of information related to the external magnetic field, an output control circuit coupled between the magnetic field detecting circuit and the output port, and a state control circuit coupled with the output control circuit and configured to determine whether a predetermined condition is satisfied and signal the same to the output control circuit. When the predetermined condition is satisfied, the state control circuit is at least responsive to the magnetic induction signal to enable the output control circuit to control the magnetic sensor to operate in at least one of a first state and a second state. In the first state, a load current flows in a first direction from the output port to outside of the magnetic sensor. In the second state, a load current flows in a second direction opposite of the first direction from outside of the magnetic sensor into the magnetic sensor via the output port. When the predetermined condition is not satisfied, the state control circuit enables the output control circuit to control the magnetic sensor to operate in a third state.

We claim: 
     
         1 . A magnetic sensor, comprising:
 a housing;   an input port and an output port, both extending from the housing; and   an electrical circuit comprising:
 a magnetic field detecting circuit, configured to detect an external magnetic field and output a magnetic induction signal that is indicative of information related to the external magnetic field; 
 an output control circuit coupled between the magnetic field detecting circuit and the output port; and 
 a state control circuit coupled with the output control circuit and configured to enable the output control circuit to control the magnetic sensor to alternately operate in a first state and a second state when a predetermined condition is satisfied, the predetermined condition comprising a voltage of the magnetic sensor reaching a predetermined voltage for a predetermined period; 
   wherein in the first state by allowing a load current flow in a first direction when the magnetic induction signal indicates that the external magnetic field has a first magnetic polarity of the external AC power supply has a first polarity; and   in the second state by allowing the load current to flow in a second direction opposite that of the first direction when the magnetic induction signal indicates that the external magnetic field has a second magnetic polarity opposite the first magnetic polarity and the external AC power supply has a second polarity.   
     
     
         2 . The magnetic sensor of  claim 1 , wherein the magnetic field detecting circuit comprises:
 a magnetic sensing element configured to detect the external magnetic field and output an analog electric signal that corresponds to the external magnetic field;   a signal processing element configured to amplify the analog electric signal, remove interference therefrom, and generate a processed analog electric signal; and   an analog-digital conversion element configured to convert the processed analog electric signal to the magnetic induction signal, which corresponds to a switching digital signal.   
     
     
         3 . The magnetic sensor of  claim 1 , wherein the output control circuit comprises:
 a first switch coupled with the output port to form a first current path for the load current to flow in the first direction; and   a second switch coupled with the output port to form a second current path for the load current to flow in the second direction, wherein   the first switch and the second switch respond respectively to the magnetic induction signal to selectively turn on the first current path and second current path, respectively.   
     
     
         4 . The magnetic sensor of  claim 1 , wherein when the predetermined condition is not satisfied, the state control circuit enables the output control circuit to control the magnetic sensor to operate in a third state, and in the third state, there is no or a negligible amount of load current flowing through the output port. 
     
     
         5 . The magnetic sensor of  claim 1 , wherein the input port is coupled with an external alternating current (AC) power supply and an operating frequency of the magnetic sensor is positively proportional to a frequency of the external AC power supply. 
     
     
         6 . The magnetic sensor of  claim 5 , further comprising:
 a rectifier coupled with the input port and configured to convert the external AC power supply to a direct current (DC) power supply provided to the magnetic field detecting circuit.   
     
     
         7 . The magnetic sensor of  claim 1 , wherein the state control circuit comprises:
 a voltage detecting circuit configured to detect a specific voltage and, when the specific voltage equals to or is greater than a predetermined voltage threshold, output a triggering signal.   
     
     
         8 . The magnetic sensor of  claim 7 , wherein the state control circuit further comprises:
 a delay circuit configured to time, upon receiving the triggering signal, a length of time during which the specific voltage equals to or is greater than the predetermined voltage threshold; and   a logic circuit configured to be responsive to the magnetic induction signal, when the length of time exceeds a predetermined length of time, to enable the output control circuit to control the magnetic sensor to operate in at least one of the first state and the second state.   
     
     
         9 . An integrated circuit comprising:
 a magnetic sensor, the magnetic sensor comprising:
 a housing; 
 an input port and an output port, both extending from the housing; and 
 an electrical circuit comprising:
 a magnetic field detecting circuit, configured to detect an external magnetic field and output a magnetic induction signal that is indicative of information related to the external magnetic field; 
 an output control circuit coupled between the magnetic field detecting circuit and the output port; and 
 a state control circuit coupled with the output control circuit and configured to enable the output control circuit to control the magnetic sensor to alternately operate in a first state and a second state when a predetermined condition is satisfied, the predetermined condition comprising a voltage of the magnetic sensor reaching a predetermined voltage for a predetermined period; 
 
   wherein in the first state by allowing a load current flow in a first direction when the magnetic induction signal indicates that the external magnetic field has a first magnetic polarity of the external AC power supply has a first polarity; and   in the second state by allowing the load current to flow in a second direction opposite that of the first direction when the magnetic induction signal indicates that the external magnetic field has a second magnetic polarity opposite the first magnetic polarity and the external AC power supply has a second polarity.   
     
     
         10 . A motor assembly, comprising:
 a motor configured to operate based on an alternating current (AC) power supply;   a magnetic sensor configured to detect a magnetic field generated by the motor and to operate in an operating state determined based on the detected magnetic field, wherein the magnetic sensor comprising:
 a housing; 
 an input port and an output port, both extending from the housing; and 
 an electrical circuit comprising:
 a magnetic field detecting circuit, configured to detect an external magnetic field and output a magnetic induction signal that is indicative of information related to the external magnetic field, 
 an output control circuit coupled between the magnetic field detecting circuit and the output port, and 
 a state control circuit coupled with the output control circuit and configured to enable the output control circuit to control the magnetic sensor to alternately operate in a first state and a second state when a predetermined condition is satisfied, the predetermined condition comprising a voltage of the magnetic sensor reaching a predetermined voltage for a predetermined period, wherein:
 in the first state by allowing a load current flow in a first direction when the magnetic induction signal indicates that the external magnetic field has a first magnetic polarity of the external AC power supply has a first polarity, and 
 in the second state by allowing the load current to flow in a second direction opposite that of the first direction when the magnetic induction signal indicates that the external magnetic field has a second magnetic polarity opposite the first magnetic polarity and the external AC power supply has a second polarity; and 
 
 
   a bi-directional AC switch serially coupled with the motor and configured to control the motor based on the operating state of the magnetic sensor.   
     
     
         11 . The motor assembly of  claim 10 , wherein the motor further comprises:
 a stator, a permanent magnet rotor, wherein the bi-directional AC switch is configured to control a conductive state of the stator in response to the first state and the second state, respectively, such that the stator operates in a manner consistent with a magnetic position of the permanent magnet rotor relative to the stator to drive the permanent magnet rotor in order to rotate in a pre-determined direction.   
     
     
         12 . The motor assembly of  claim 11 , wherein the stator comprises a stator core and a single phase winding wound on the stator core.