Diode-transistor active pull up driver
US4417159A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 1981 |
| Grant date | Nov 22, 1983 |
| Priority date | — |
| Expiry date | Aug 18, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/01806
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A driver circuit for a capacitively loaded line employs the charge storage capacitance of a diode for raising the base of a driver transistor above the circuit power supply voltage level so as to pull up the line to within a transistor base-emitter voltage drop of the power supply voltage level. The driver is easily fabricated in integrated circuit form, as no capacitors, either on or off chip, are required. The driver circuit includes a driver transistor, the collector of which is connected to the power supply and the emitter of which is connected to the line. A switching transistor has an input voltage applied between its base and emitter. A diode is connected between the switching and driver transistors, the anode being connected to the base of the driver transistor, and the cathode being connected to the collector of the switching transistor. In response to a first input signal, the switching transistor turns on, forward biasing the diode and building up a voltage thereon as a result of the diode's charge storage capacitance. In response to a second input signal, the switching transistor turns off, raising the anode to the power supply voltage, and raising the cathode (and the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.