Radio frequency generator and method for a cordless medical cauterization and cutting device
A circuit for generating a radio-frequency signal for a surgical device is disclosed. The circuit has a voltage regulator that supplies direct current (DC) voltage, a first MOSFET, a second MOSFET, and a MOSFET driver. The MOSFET driver receives the DC voltage supplied from the voltage regulator and has a local oscillator. The local oscillator switches the first MOSFET and the second MOSFET on and off at a frequency generated by the local oscillator. The circuit further includes a transformer connected to the first and second MOSFETs, having a center tap and a main voltage applied at the center tap, and providing an alternating current (AC) output.
1. A circuit for generating a radio-frequency signal for a surgical device, comprising:
a voltage regulator including a direct current (DC) voltage output;
a first MOSFET including a first terminal, a second terminal, and a third terminal;
a second MOSFET including a first terminal, a second terminal, and a third terminal, wherein the first terminal of the first MOSFET is coupled to the first terminal of the second MOSFET;
a MOSFET driver including:
an input coupled to the DC voltage output of the voltage regulator;
a first output;
a second output; and
a local oscillator directly coupled to the second terminal of the first MOSFET by way of the first output of the MOSFET driver and directly coupled to the second terminal of the second MOSFET by way of the second output of the MOSFET driver; and
a transformer including a first terminal, a second terminal, and a center tap, wherein the first terminal of the transformer is directly coupled to the third terminal of the first MOSFET, the second terminal of the transformer is directly coupled to the third terminal of the second MOSFET, and a main voltage is configured to be applied at the center tap.
2. The circuit according to claim 1 , further comprising an interlock terminal configured to control power through the voltage regulator.
3. The circuit according to claim 1 , wherein the DC voltage output of the voltage regulator is coupled to the local oscillator and to the MOSFET driver.
4. The circuit according to claim 1 , wherein the MOSFET driver is configured to self-oscillate.
5. The circuit according to claim 4 , wherein the MOSFET driver is a dual MOSFET driver.
6. The circuit according to claim 5 , wherein the MOSFET driver is configured to establish the frequency of the local oscillator.
7. The circuit according to claim 6 , further comprising a capacitor and a resistor connected to the local oscillator and having respective capacitance and resistance values that set a frequency of the local oscillator.
8. The circuit according to claim 7 , wherein the MOSFET driver has a resistance for a time delay port connected to the resistor.
9. The circuit according to claim 8 , wherein the MOSFET driver has an oscillator timing capacitor port connected to the capacitor.
10. The circuit according to claim 9 , wherein the frequency is set to 300 kHz.
11. The circuit according to claim 1 , wherein the first terminal of the transformer, in a first configuration, is coupled to ground by way of the third terminal of the first MOSFET.
12. The circuit according to claim 11 , wherein the second terminal of the transformer, in a second configuration, is coupled to ground by way of the third terminal of the second MOSFET.
13. The circuit according to claim 12 , wherein the output of the transformer is a product of a turns ratio of the transformer and the voltage supplied by the voltage regulator.
14. The circuit according to claim 13 , wherein:
the transformer has a secondary side; and
the output of the transformer is at the secondary side and comprises an output voltage.
15. The circuit according to claim 14 , wherein the output voltage on the secondary side of the transformer has a frequency of 300 kHz.