Patent ID: 8810105

Claim:
An apparatus ( 1 , 4 ) for reducing energy consumption in monitoring means of a plurality of piezoelectric components, the apparatus ( 1 , 4 ) comprising: a plurality of piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ) that are piezoelectric sensors; monitoring means ( 122 , 124 , 126 ; 62 , 64 ) for monitoring the status of the piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ), said monitoring means ( 122 , 124 , 126 ; 62 , 64 ) having two states that are active and inactive; and wherein: the piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ) are connected in parallel to each other and to a current detecting circuit ( 132 ; 68 ) that comprises: i) a switch ( 54 ) and ii) a resistor ( 52 ) that is connected in parallel to said switch ( 54 ), and iii) a controller ( 58 ) having two states that are active and inactive, the controller ( 58 ) configured to: open the switch ( 54 ), in response to the controller ( 58 ) being in the inactive state when no signal from any of the piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ) exceeding a threshold (V TRIGREF ) is present, thus disconnecting a bypass of an additional resistor ( 52 ) between the plurality of piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ) and the monitoring means ( 122 , 124 , 126 ; 62 , 64 ); and close the switch ( 54 ), in response to the controller ( 58 ) being in the active state, the closing of the switch ( 54 ) triggering a state change in the monitoring means ( 122 , 124 , 126 ; 62 ) from their inactive state to their active state when a signal from any of the piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ) exceeding a threshold (V TRIGREF ) is present, thus bypassing the additional resistor ( 52 ) between the plurality of piezoelectric components ( 102 , 104 , 106 ; 72 , 74 , 76 ) and the monitoring means ( 122 , 124 , 126 ; 62 , 64 ).