| 摘要 |
A square wave power inverter (99) includes a transformer (21) having a primary winding (23) and a secondary winding (25), first and second input voltage sources (71, 73), and a pair of power switching transistors (51, 53) connected series between the first and second voltage sources for selectively connecting the first and second input voltage sources to the primary winding of the transformer. A pair of output terminals (33) is connected to the secondary winding of the transformer for receiving a load. An inverter control (81) is connected to the gates of the switching transistors for generating a gate drive signal. The inverter control generates a low impedance, substantially square wave, gate drive signal, producing a substantially square wave inverter output when a substantial load is connected to the output terminals, and a high impedance gate drive signal, producing a trapezoidal inverter output when a light load is connected to the output terminals. In particular, the inverter control is connected to the output terminals, and produces low impedance drive signal when the voltage at the output terminals is below a predetermined threshold, and high impedance drive signals when the voltage at the output terminals is above the predetermined threshold. Control includes a low impedance gate drive that is connected to the gates of the switching transistors when a substantial load is connected to the output terminals, and a higher impedance gate drive that is connected to the gates of the switching transistors when a light load is connected to the output terminals. |
