Verity Instruments, Inc.

David Buice

Mike Whelan

Cesar Alfaro

The power supply may be operated during a given cycle sequentially to produce high and low frequency drive signals for operating an ultrasonic transducer for sequentially producing an ultrasonic output at the two frequencies to carry out bonding operations at two different bond sites respectively.

Dual frequency power supply and transducer

The power supply includes a voltage controlled oscillator, two potentiometers and a by-pass circuit coupled to the output of the voltage controlled oscillator. The two potentiometers form two channels, channel 1 and channel 2, one of which will be selected during the bonding cycle to be coupled to a power amplifier. The output of the power amplifier is adapted to be coupled to an ultrasonic transducer for operating the transducer. Selectable channel 1 and channel 2 reference voltage devices are provided. The voltage and current applied to the amplifier are converted to power. During a bonding cycle, a comparator compares the power applied to the transducer with that of a selected reference voltage and varies the output of the potentiometer of the selected channel to maintain the output of the power amplifier constant during bonding. Also provided is a switching arrangement for coupling the by-pass circuit to the power amplifier at the initial part of a bonding cycle and for coupling the potentiometers the selected channel 1 or channel 2 to the power amplifier such that a maximum burst of energy is applied to the transducer initially during the bonding cycle and then the desired voltage level from the selected channel 1 or channel 2 is applied to the transducer.

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Dallas, TX, United States of America

David Buice