Transformerless ultrasonic transducer activation with only one external energy store
Disclosed is a driver stage for activating a first ultrasonic transducer and a method for the operation thereof. The driver stage comprises a first charge pump or power source and a first capacitor. The driver stage also comprises first means for charging the first capacitor with electrical energy from the charge pump and second means for connecting the first capacitor and ultrasonic transducer to different polarities. The first means do not charge the first capacitor with energy from the charge pump or power source when the first capacitor is connected to the ultrasonic transducer by the second means.
1. A driver stage for activating a first ultrasonic transducer (TD 1 ), comprising:
a first charge pump (CP 1 );
a first switch (SW 1 ) that has at least a first connection and a second connection;
a second switch (SW 2 ) that has at least a first connection and a second connection;
a third switch (SW 3 ) that has at least a first connection and a second connection;
a fourth switch (SW 4 ) that has at least a first connection and a second connection;
a fifth switch (SW 5 ) that has at least a first connection and a second connection;
a first capacitor (C 1 ) that has a positive connection (C 1 P) for the first capacitor (C 1 ) and a negative connection (C 1 N) for the first capacitor;
a first signal connection (DRV 1 );
a first node (K 1 );
a second node (K 2 );
a third node (K 3 ); and
a first ground (GND 1 );
wherein the first charge pump (CP 1 ) is connected to the first connection on the second switch (SW 2 );
wherein the second connection on the second switch (SW 2 ) is connected at the first node (K 1 ) to the first connection on the first switch (SW 1 ), the positive connection (C 1 P) on the first capacitor (C 1 ), and the first connection on the fifth switch (SW 5 );
wherein the second connection on the first switch (SW 1 ) is connected to the first ground (GND 1 );
wherein the second connection on the fifth switch (SW 5 ) is connected at the second node (K 2 ) to the first signal connection (DRV 1 ) and the first connection on the third switch (SW 3 );
wherein the second connection on the third switch (SW 3 ) is connected at the third node (K 3 ) to the first connection on the fourth switch (SW 4 ) and the negative connection (C 1 N) for the first capacitor (C 1 );
wherein the second connection on the fourth switch (SW 4 ) is connected to the first ground (GND 1 );
wherein the first signal connection (DRV 1 ) is connected to a signal connection (STD 1 ) on the first ultrasonic transducer (TD 1 ); and
wherein a ground connection (MTD 1 ) for the first ultrasonic transducer (TD 1 ) is connected to the first ground (GND 1 ).
2. A method for activating a first ultrasonic transducer (TD 1 ) to transmit ultrasonic signals through a driver stage, comprising:
a first phase for charging a first capacitor (C 1 ) with an output voltage of a first charge pump (CP 1 ) by connecting a positive connection (C 1 P) on the first capacitance (C 1 ) to an output on the first charge pump (CP 1 ) by closing a second switch (SW 2 ) and by connecting a negative output (C 1 N) on the first capacitor (C 1 ) to a first ground (GND 1 ) by closing a fourth switch (SW 4 ), while a first switch (SW 1 ), a third switch (SW 3 ), and a fifth switch (SW 5 ) are open;
a second phase for applying a negative voltage from the first capacitor (C 1 ) to a signal connection (STD 1 ) for the first ultrasonic transducer (TD 1 ) by connecting the negative connection (C 1 N) on the first capacitor (C 1 ) to the signal connection (STD 1 ) on the first ultrasonic transducer (TD 1 ) by closing the third switch (SW 3 ) and by connecting the positive connection (C 1 P) on the first capacitor (C 1 ) to the first ground (GND 1 ) by closing the first switch (SW 1 ), while the second switch (SW 2 ), the fourth switch (SW 4 ), and the fifth switch (SW 5 ) are open; and
a third phase for applying a positive voltage from the first capacitor (C 1 ) to the signal connection (STD 1 ) on the first ultrasonic transducer (TD 1 ) by connecting the positive connection (C 1 P) on the first capacitor (C 1 ) to the signal connection (STD 1 ) on the first ultrasonic transducer (TD 1 ) by closing the fifth switch (SW 5 ) and by connecting the negative connection (C 1 N) on the first capacitor (C 1 ) to the first ground (GND 1 ) by closing the fourth switch (SW 4 ) while the first switch (SW 1 ), the second switch (SW 2 ) and the third switch (SW 3 ) are open;
wherein the first phase is only carried out once at a start of the transmission; and
wherein the second phase and the third phase are carried out alternatingly over a course of the transmission.