Bi-mode circuit for driving an output load
US5528192A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 12, 1993 |
| Grant date | Jun 18, 1996 |
| Priority date | — |
| Expiry date | Nov 12, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/0136
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A bi-mode circuit for driving an output load selectively couples the output load to a supply voltage source or to a low discharge voltage source such as ground using switches which are controlled by an input buffer in response to an input signal. A high input signal closes a first switch to provide a biasing current to first and second current amplifiers to turn on a first output transistor which couples the output load to the low reference voltage to discharge the output load. Conversely, a low input signal closes a second switch to provide the biasing current to a third current amplifier to turn on a second output transistor which couples the output load to the supply voltage source. When the input signal becomes high, rapid pulldown of a capacitive output load is achieved using a high internal pre-drive current provided by the first and second current amplifiers, in a first mode of operation. As the output voltage decreases, turnoff of the first output transistor is prevented by switching to a second mode when the output voltage drops below a threshold value as determined by a comparator. The comparator effectively closes a third switch and thereby a loop which bypasses the firs…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.