Dual-Phase Power-On Reset Module
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Disclosed is a circuit which generates a positive reset pulse and a negative reset pulse when power is initially applied to the circuit. Referring to Fig. 1, a standard transistor-transistor logic module 10 is modified by adding two resistor-capacitor circuits to inputs thereof. The values of the resistors and capacitors in circuits R1C1 and R2C2, having time constants t1 and t2, respectively, are chosen such that t2 equals 100t1 . Referring to Figs. 1 and 2, at time t0, a positive voltage signal is applied simultaneously to circuits R1C1 and R2C2. Capacitors C1 and C2 are charged through resistors R1 and R2, respectively, to a threshold voltage level. Capacitor C1, which attains the threshold voltage level at time t1 as shown in Fig.