| 摘要 |
<p>The present invention, generally speaking, provides an improved base drive arrangement for scan and/for EHT output stages in a television or video display monitor. In accordance with one aspect of the invention, by adding just a few components to an existing main base drive circuit, two power transistors may be driven, e.g., a scan output transistor and an EHT output transistor. The two power transistors are switched at the same time, allowing pulse width modulators of the scan and EHT circuits to operate on a common time base. Switching of two power transistors at the same time would usually require a quite complicated design to offset the different storage times of the two devices, thereby achieving high performance but at a considerable cost premium. The base drive circuit of the invention achieve substantial synchronization of the two transistors at minimal cost. In accordance with another aspect of the invention, a base drive circuit uses a low DC supply voltage and a resistive element in series with the main current path in order to produce a more constant maximum base current over frequency.</p> |
