초록 ▼

A high power grounded-drain source follower RF amplifier circuit employs a high voltage MOSFET. The RF signal at the input is applied with respect to ground via an isolation transformer whose secondary feeds the signal between gate and source. The output is taken from the source with respect to drai

A high power grounded-drain source follower RF amplifier circuit employs a high voltage MOSFET. The RF signal at the input is applied with respect to ground via an isolation transformer whose secondary feeds the signal between gate and source. The output is taken from the source with respect to drain, which is grounded. A 13.56 MHz 3 KW power amplifier topology with isolated RF input drive for each MOSFET die uses a pair of kilowatt power transistors or KPTs, in which there are multiple large area MOSFET dies, with the drain regions of the dies being formed over a major portion of the die lower surface. The drain regions are in direct electrical and thermal contact with the conductive copper flange. The source and gate regions are formed on the dies away from the flat lower surface. One or more pairs of multi-chip KPTs can be configured to design stable 2.5 KW, 5 KW and 10 KW RF plasma generators at 13.56 MHz. The generators employ a low pass/high pass filter arrangement (diplexer) at the output for low harmonic distortion and dissipative harmonic termination. The terminated high pass filter reduces the gate-to-source differential RF voltage and protects the MOSFETS from damage.

대표청구항 ▼

[ We claim:] [1.] A high power push-pull RF amplifier for amplifying RF power in a given frequency band, comprising an RF input terminal, an RF output terminal, a DC power source, first and second kilowatt power transistor devices, each said kilowatt power transistor device including a thermally and

[ We claim:] [1.] A high power push-pull RF amplifier for amplifying RF power in a given frequency band, comprising an RF input terminal, an RF output terminal, a DC power source, first and second kilowatt power transistor devices, each said kilowatt power transistor device including a thermally and electrically conductive flange, a multi-chip array formed of a plurality of semiconductor dies, each said die having a flat lower surface with a drain formed over a majority of said lower surface, a source and a gate formed respectively on portions of the die away from said flat lower surface, and means for seating the drains of the dies in direct thermal and electrical contact with said flange so that said flange serves as drain terminal and as heat sink for said dies; first splitter means coupled to said RF input terminal for splitting an RF input drive signal into a forward phase portion and a reverse phase portion; second splitter means for splitting said forward phase portion of the drive signal into a plurality of isolated signals for supplying to the gates of said first kilowatt power transistor device; third splitter means for splitting said reverse phase portion into a plurality of isolated signals for supplying to the gates of said second kilowatt power transistor device; for each of said semiconductor die of said first kilowatt power transistor device a respective gate-source input circuit which is RF coupled to an associated output of said second splitter means and which is floating with respect to the flange of said first kilowatt power transistor device; for each said semiconductor die of said second kilowatt power transistor device a respective gate-source input circuit which is RF coupled to an associated output of said third splitter means but is floating with respect to the flange of said second kilowatt power transistor device; combiner means having inputs coupled to the sources of said first and second kilowatt power transistor devices for combining amplified RF outputs therefrom to supply an amplified RF signal to said RF output terminal; a supply of DC source voltage; and filter means connecting the sources of said kilowatt power transistor devices to said supply of DC voltage, said filter means including choke means for blocking said amplified RF signal from said supply of DC voltage, and means for bypassing RF energy as may be picked up from the DC power supply or other circuitry.