| abstract |
The invention is an improved phacoemulsification probe drive circuit for supplying electric power to an ultrasonic transducer. The drive circuit contains a power control loop (1412) and a frequency control loop (1413). The power control loop (1412) consists of a variable gain amplifier (1416) whose output is the input of a power amplifier (1417). After the power is amplified by the power amplifier, the power is delivered to a transformer (1436), which is then delivered to a transducer (1439). The voltage and current applied to the primary side of the transformer are sensed, and the result is compared with a power command generated from a pedal to generate a signal proportional to power (real or apparent). The result of the comparison is sent to a first controller which sends a correction signal to the variable gain amplifier based on the information. |