CS196872B1 - Circuit for indication of the voltage drop or surpassing the signal duration time - Google Patents

Description

The object of the invention is a circuit that indicates a drop in the input voltage, or at least one of the multiple input voltages, below a set value, or exceeds a set signal duration, or at least one of a plurality of signals.

Circuits that indicate a voltage drop below the set value are known. Circuits indicating excess signal duration are also known. However, there is no known circuit that would simply combine both functions.

SUMMARY OF THE INVENTION The circuitry comprises at least one timing member consisting of a timing capacitor, a charging resistor, an input diode, and a diode wired such that one timing capacitor terminal is connected to a neutral terminal and its other terminal is connected to a power terminal terminal , an input diode with an input terminal and a separation diode with an emitter of the first transistor, wherein the emitter of the first transistor is further coupled via a diode and a limiting resistor to a reference voltage source, and the common diode and limiting resistor is connected via a zero terminal capacitor. The collector of the first transistor is coupled to the base of the second transistor having the opposite conductivity type to the first transistor, the base of the first transistor being coupled to the collector of the second transistor and simultaneously to the center of the resistive divider formed by two resistors connected between the supply and neutral terminal. The emitter of the second transistor is connected via a load to a zero terminal.

Such a circuit is simple and at the same time it is able to indicate a voltage drop below the set value and exceeding the set signal duration.

The attached drawing shows an exemplary embodiment of a circuit according to the invention. The timing capacitor 61 is connected to the neutral terminal 71 at one terminal, the other terminal is connected by a charging resistor 64 to the power terminal 72, the input diode 62 to the input terminal 6, and the diode 63 to the emitter of transistor 1. the limiting resistor 52 with the reference voltage source 54 and the common point of the diode 53 and the limiting resistor 52 is connected by a capacitor 51 with a neutral terminal 71. The collector of transistor 1 is connected to the base of transistor 2 and the base of transistor 1 is connected to the collector of transistor 2 a resistor divider consisting of resistors 41 and 42 connected between the supply and neutral terminals 72 and 71. The emitter of transistor 2 is connected by resistor 3 and neutral terminal 71 and at the same time is connected to output terminal 31. The supply terminal 72 is connected by resistor 81 to voltage input

196 872

196 872 terminal 8, a second input diode 91 with a voltage input terminal 9, and another diode 91a with a voltage input terminal 9a. If the current flowing through resistor 64 is negligible against the current flowing through divider 41, 42, the voltage U _B between the power terminal 72 and the neutral terminal 71 is the smallest value

U ₉ + Udsi

U _9a + Uneja

R41 + R42 ^Us R81 + R41 -I- R42, where U ₈ resp. U ₉ , U _9a are the voltages between terminal 8 and 8, respectively. 9, 9 _and a zero terminal 71, U _D9J , respectively. For _D9Ja , the voltage drop across the diode is 91, respectively. 91 _and in the forward direction and R41, respectively. R42, R81 is resistor size 41, resp. 42, 81. For voltage U _R42 at resistor 42:

Resistor values 41, 42, and 81 are selected such that when any of the voltage U ₈ , U ₉ , U _9a falls below a specified value, the voltage U _R42 drops below U _REF - U _D53 - U _BE1 . (The specified minimum values for U ₉ and U _9a must be the same J. This results in transistors 1 and 2 opening, and a voltage jump occurs at output 31.

Claims (2)

SUBJECT A circuit for indicating a voltage drop or exceeding a signal duration, comprising at least one timing member comprising a timing capacitor (61), a charging resistor (64), a diode stage (62), and a diode (63) connected so as to: that one terminal of the timing capacitor (61) is connected to the neutral terminal (71J) and the other terminal is connected by a charging resistor (64) to the power terminal (72), the input diode (62), the input terminal (6) and the diode (63) with the emitter of the first transistor (1), wherein the emitter of the first transistor (1) is further coupled via a diode (53) and a limiting resistor (52) to a reference voltage source (54) and a common point of the diode (53) and limiting resistor (52) connected to the neutral terminal (71) of the condenser On the input terminal 6, for the duration of the respective input signal, the voltage must be greater than Ur ₄₃ m + U _BE3 , where Ur ₄₂ m is the voltage generated at resistor 42 if all voltages U ₈ , U ₉ , U _{9a have} their maximum value If the corresponding input signal is not present, the voltage at input terminal 6 must be approximately zero. For the duration of the respective input signal, the timing capacitor 61 is charged via the charging resistor 64. If the signal lasts so long that the voltage at the timing capacitor 61 reaches U _R42 + U _BE1 + U _D63 , transistors 1 and 2 open and the timing capacitor 61 discharges through resistor 3, which is reflected as a voltage jump at output 31. If it is sufficient to indicate only one voltage drop below a specified value, this voltage can be applied directly to the power terminal 72. The resistor 81 of the diodes 91, 91a and the terminals 8, 9, 9a are then dropped. The circuit according to the invention can be advantageously used in particular in electronic systems comprising a stabilized power supply. In this case, the output voltage of the stabilizer can be used as a reference voltage and the input voltage for the stabilizer can be applied to the voltage input terminal, thus indicating its drop below the minimum value required for the proper functioning of the stabilizer. By monitoring the duration of some signals, you can check the correct operation of the system. The circuit according to the invention can also be realized with transistors of the opposite conductivity type and with diodes opposite to that shown in the drawing. BACKGROUND OF THE INVENTION by a transistor (51), the collector of the first transistor (1) is coupled to the base of the second transistor (2) having the opposite conductivity type than the transistor (1j), the emitter of the second transistor (2) ) and the base of the first transistor (1) is connected to the collector of the second transistor (2) and simultaneously to the center of the resistive divider formed by the resistors (41) and (42) connected between the power terminal (72J and the neutral terminal (71J). 2. A voltage drop or signal duration indication circuit as in claim 1, wherein the power terminal (72) is coupled by a resistor (81) to the voltage input terminal (8) and further coupled to at least one other voltage input terminal. (9j each through a second input diode (91).