TTL integrated circuit with independent switched output - has two separate emitter supply rails and limiter to prevent interference when several output stages switch over

摘要

The integrated circuit has several independently switched output stages each comprosing a transistor with a collector output. The emitter supply voltage (VEE) is supplied via two internal rails (S1,S2) leading to separate external connection points (P1,P2). The emitters of all output transistors (T1-Tn) are connected to the first rail (S1). The second rail is used for supplying the emitter voltage for the remaining transistors in the circuit. A limiter limits the voltage drop (UL) at the lead inductance (L1) to the first rail caused by the change in current produced as a result of one or more output transistors (T1-Tn) switching.