| 摘要 |
<p>A power supply typology in which the pulse width modulated invertor switches (25-31) serve two functions; conversion of the a.c. input (10) to a d.c. rail voltage in addition to inversion of the d.c. rail voltage to a regulated a.c. output (32, 34). An a.c. input ground terminal (41) is connected to a node (43) between two of the invertor switches (25, 27) and this node (43) is also connected to the a.c. output (32, 34) to provide a common ground (41) between the a.c. input (10) and the a.c. output (32, 34). A silicon control rectifier switch (38) and one of the invertor switches (27) connected to the ground node (43) connect the back-up battery (28) to the a.c. source (10) during positive half cycles of the a.c. input (10) in order to maintain a charge on the back-up battery (28).</p> |
