Abstract: RF transistor amplifier circuits are provided that comprise a circuit board and an RF transistor amplifier die. The RF transistor amplifier die is flip-chip mounted on an upper surface of the circuit board so that a gate terminal, a drain terminal and a source terminal of the die face the upper surface of the circuit board. These RF transistor amplifier circuits further include a heatsink mounted on an upper surface of the RF transistor amplifier die and a plurality of surface mount circuit elements mounted on the upper surface of the circuit board so that a footprint of the heatsink vertically overlaps each of the plurality of surface mount circuit elements.

Abstract: A control system for a PWM inverter may reduce a DC component of an output of the inverter. An output voltage signal may be attenuated with a low-pass filter to produce a signal with a high DC content. A duty cycle of an output of the low pass filter may be determined with a zero-crossing detector. A calculation may be performed to determine a magnitude of a DC offsetting voltage that may offset the DC component of the inverter output. The inverter may be commanded to produce a DC offsetting voltage with an opposite polarity from the DC component of the inverter output. The opposite polarity DC offsetting voltage may effectively cancel the DC component of the inverter output. A monitoring system may employ an alternate system for determining the level of the DC component, thus providing a desirable redundancy to the system.

Abstract: A control system for a PWM inverter may reduce a DC component of an output of the inverter. An output voltage signal may be attenuated with a low-pass filter to produce a signal with a high DC content. A duty cycle of an output of the low pass filter may be determined with a zero-crossing detector. A calculation may be performed to determine a magnitude of a DC offsetting voltage that may offset the DC component of the inverter output. The inverter may be commanded to produce a DC offsetting voltage with an opposite polarity from the DC component of the inverter output. The opposite polarity DC offsetting voltage may effectively cancel the DC component of the inverter output. A monitoring system may employ an alternate system for determining the level of the DC component, thus providing a desirable redundancy to the system.