| 摘要 |
A switching bridge having at least one switching stage (10) for rapidly coupling and uncoupling at least one inductive load (18) across a source of power (V supply) for pulsing current therethrough in either of two directions, the at least one stage (10) comprising: first and second switch circuits (10a, 10b), each said switch circuit (10a, 10b) comprising, corresponding thereto, a power switch (Q1, Q2), the power switch (Q1, Q2) of each said switch circuit (10a, 10b) being coupled together to the other one in a series circuit path across said source of power (V supply), each power switch (Q1, Q2), when on, being adapted for serially coupling a different side of the source of power (V supply) to an output circuit (17) and, when off, being adapted for disabling the coupling, the load (18) being coupled tu between the output circuit (17) and the other side of the source of power (V supply) from the one coupled by one of the power switches (Q1, Q2) to the output circuit (17), a capacitor snubber (C1, R1, D1; C2, R2, D2) coupled across the power switch (Q1, Q2), in the corresponding switch circuit (10a, 10b), for limiting rate of change of voltage across such power switch (Q1, Q2), in at least one direction of voltage change; unidirectional circuit means (D3, D4) coupled to such output circuit (17) for directing decay current, flowing in the at least one load (18), in a loop back through the at least one load (18) upon turning the power switch (Q1, Q2), corresponding to the other said switch (10b, 10a), from on to off; and further unidirectional circuit means (D5, D6) located in the series circuit path for inhibiting the discharge of charge previously stored in the capacitor snubber (C1, R1, D1; C2, R2, D2) of the corresponding switch circuit (10a, 10b) until the power switch (Q1, Q2) of the corresponding switch circuit (10a, 10b) is turned on, each of the further unidirectional circuit means (D5, D6) also being adapted to be maintained in a back biased condition, due to the charge stored in the capacitor snubber (C1, R1, D1; C2, R2, D2), of the corresponding switch circuit (10a, 10b), to hereby substantially isolate the corresponding switch circuit (10a, 10b) from signal changes in the other of the switch circuits (10a, 10b). |
