Active Current Switch Driver
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
A technique is described using a lateral PNP device to act as an active load across a fixed resistor in bipolar driver and array circuits for semiconductor applications. The new arrangement lowers the resistor's effective impedance and voltage drop with a resultant increase in the circuit's up-level and an improvement in its noise margin. The use of the PNP transistor with a push-pull driver is shown in Fig. 1. When all inputs are low in the push-pull driver, the NPN transistor TR is turned on by the Ics of the current source. The new PNP transistor Q1 will then be turned on to provide most of the base current which is required by the driving transistor Q5 .