发明授权
- 专利标题: State-dependent discharge path circuit
- 专利标题(中): 状态依赖放电路径电路
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申请号: US804906申请日: 1991-12-06
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公开(公告)号: US5184034A公开(公告)日: 1993-02-02
- 发明人: James R. Ohannes , Stephen W. Clukey , Ernest D. Haacke , Roy L. Yarbrough
- 申请人: James R. Ohannes , Stephen W. Clukey , Ernest D. Haacke , Roy L. Yarbrough
- 申请人地址: CA Santa Clara
- 专利权人: National Semiconductor Corporation
- 当前专利权人: National Semiconductor Corporation
- 当前专利权人地址: CA Santa Clara
- 主分类号: H03K19/0175
- IPC分类号: H03K19/0175 ; H03K19/003 ; H03K19/08 ; H03K19/082 ; H03K19/088 ; H03K19/0944
摘要:
A circuit for use in connection with tristate output buffers in order to provide concurrently for fast discharge of the output pulldown transistor base and at the same time for building in protection against reverse breakdown in the pulldown transistor. The innovation consists of providing a two discharge paths to ground for the base of the output pullup transistor. A low-capacitance path is activated only while the output buffer is in its active mode. In the preferred embodiment of the invention, this low discharge path consists of two CMOS transistors in series, one of which is controlled by the enable signal input E of the buffer circuit and the other by the data signal input V.sub.IN of the buffer circuit. The other path to ground is available whenever the data signal input V.sub.IN is low, regardless of whether the buffer is in its active or inactive mode. This other path provides discharge protection for the base of the pullup transistor for the buffer in its inactive mode, and has incorporated into it reverse breakdown protection in the form of voltage drop devices such as forward-biased diodes.
公开/授权文献
- US5984076A Drive assembly for reciprocating slat conveyor 公开/授权日:1999-11-16
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