JPS6251301A - Ac signal bypass circuit - Google Patents

Abstract

PURPOSE:To reduce remarkably a leading time of an electronic circuit after power on by connecting the 1st capacitor between a bypass terminal and ground of an electronic circuit, connecting further one terminal of the 2nd capacitor with a prescribed capacity to the power supply and the other terminal to the bypass terminal of the electronic circuit. CONSTITUTION:A capacitor 5 having a prescribed capacity in relation to a capacitor 4 connected between the bypass terminal 3 and earth of the electronic circuit 2 is connected between the bypass terminal 3 and a power terminal 1. A voltage Vp at the bypass terminal 3 after (t) sec when the power to the power terminal 1 is turned on stepwise at t=0 is expressed in equation I, where Vcc is a power voltage of the power terminal 1 and C1 is a capacitance of the capacitor 5. Thus, in satisfying the condition of equation II in equation I, the relation of Vp=Es is obtained and the Vp rises quickly independently of the time (t).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an alternating current signal innovation circuit for an electronic circuit;
In particular, it concerns an AC signal bypass circuit with a fast power supply start-up.

[Conventional technology]

Various AC bypass circuits are used in electronic circuits, but the AC signal bypass circuits discussed here basically cut off the WI current voltage ta and have a sufficiently low impedance for AC signals. is a prerequisite, and capacitors are usually widely used.

Conventionally, this type of AC signal bypass circuit is
The circuit shown in the figure is common and widely used. In FIG. 4, a capacitor 4 is connected between the bypass terminal 3 of the electronic circuit 2 and the ground, and the capacitor 4 has a sufficiently low impedance for the AC signal to be handled.

By the way, as a method for reducing the power consumption of electronic circuits, a so-called power-down method has been used in the past, in which power is supplied to the circuits when they are not in use. Therefore, the fourth
Even in the case shown in the figure, is there a method for power down that completely reduces power consumption? It is desirable to measure.

[Problem that the invention seeks to solve]

However, in the conventional AC signal bypass circuit, it takes time to fully charge the capacitor 4 after the power is turned on, which has an effect on the rise time of the entire circuit, which often causes problems. Let me explain this problem. In Fig. 4, the steady state stone flow voltage 'tE81 at the bypass terminal 3
Assuming that the DC impedance t when looking at the bypass terminal 3 and the electronic circuit 2 is RaCfc, and the reactance of the electronic circuit 2 is ignored compared to the reactance of the bypass capacitor 4), as shown in Figure 5. etc. How many times can it be expressed in terms of 〆路? From this figure 5, all power supplies 1 = 0
When the bypass terminal 3 is turned on stepwise at 7'c, the voltage vp of the bypass terminal 3 is given by the following equation.

-''- Vp=Eli (1g ''') @@116
(1) C2 is the capacitance of the capacitor 4. Therefore, from equation (i) above, the time constant becomes τ=RsC*,
When these Rs and Cs are large, the time constant becomes large, which affects the 9 hours from when the power supply starts up.

The present invention has been devised in view of the above-mentioned drawbacks, and is
The start-up time and noise caused by turning on the power from FF (FF) can be greatly shortened, and a complete AC signal bypass circuit can be provided.

[Friendly means of solving problems]

The AC signal bypass circuit of the present invention includes an electronic circuit, a first capacitor connected between the bypass terminal of the electronic circuit, and ground, and a second capacitor connected between the bypass terminal and a power source. A product featuring a capacitor connected to it.

[For production]

In the present invention, a first capacitor is connected between the bypass terminal of the electronic circuit and the ground, and a second capacitor having a predetermined capacity is further connected between the bypass terminal of the electronic circuit and the ground. By connecting one end of the electronic circuit to the power source and the other end to the bypass terminal of the top-stop distribution electronic circuit, it is possible to significantly shorten the startup time of the electronic circuit after the power is turned on.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing an AC signal bypass circuit according to an embodiment of the present invention.The difference between FIG. 1 and the conventional circuit shown in FIG. This is achieved by connecting a capacitor 5 having a predetermined capacity with respect to the connected capacitor 4 between the bypass terminal 3 and the power supply terminal 1.

Here, FIG. 2 is represented by the eleventh equivalent circuit, and the electronic circuit 20 equivalent model is the same as that used in FIG. Note that in the drawings, the same reference numerals indicate the same things.

However, according to the configuration of the above embodiment, in FIG.
Now, the voltage Vp of the bypass terminal 3 after t seconds is given by the following equation when the power supply of the source terminal 1 is turned on in a stepwise manner with all t=o.

÷ (2) However, Vcc is the power supply voltage of the power supply terminal 1, and C1 is the capacitance of the capacitor 5. Therefore, in the above equation (2), 6. □ - (1 □ 7, =.8 5ee - (4) 1
2′! ″″・″f'4 t KfilQaK-j'-1
4-"<vp7>"It can be seen that the angle is 151°.
l1°
1170ゞfi(!1M′”f ′<, 1.DOli!
0itJ: Calculated using specific parameters based on the 1-turn characteristic and the 1-rise 9 characteristic of the AC signal bypass circuit according to the present invention. Here, the parameters are Vcc = 2KB, Rs = 10Ω, 02 = 10μp, -0□Y, A. 1o□,
a. , =ll, J', 'C1=lOμF, C1
The three types of =9μF are shown below. 3rd drawing C1=1
The rise characteristic I at 1μF overshoots,
It can be seen that the rising 9 characteristic (2) when +=9 μF undershoots, and the rising 9 characteristic (2) when CI''j10 μF rises instantaneously.

Furthermore, it can be seen that even if the condition of the above equation (3) is not completely satisfied, it is significantly improved compared to the rise 9 characteristic (2) of the conventional AC signal bypass circuit.

〔Effect of the invention〕

As explained above, according to the present invention, by simply adding one capacitor to the conventional circuit, the startup time after power-on can be reduced.
The effect is significant in that it can improve the time all-sky width.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an AC signal bypass circuit according to an embodiment of the present invention, FIG. 2 is a schematic diagram of the AC signal bypass circuit of FIG. FIG. 4 is a circuit diagram showing a conventional AC signal bypass circuit, and FIG. 5 is a schematic diagram similar to FIG. 4. 1...-'N:N: Child terminal...electronic circuit, 3...
...Bypass terminal, 4...Capacitor, 5...Fist capacitor.

Claims (2)

[Claims] (1) In an AC signal bypass circuit in which a first capacitor is connected between an electronic circuit and a bypass terminal of the electronic circuit and ground, a second capacitor is connected between the bypass terminal and the power supply. Characteristic AC signal bypass circuit. (2) When the voltage of the power supply is Vcc and the DC voltage of the bypass terminal is Es, the ratio of the capacitance C_2 of the first capacitor and the capacitance C_1 of the second capacitor is C_2/C_1=(Vcc/Es-1). Claim 1 characterized in that
The AC signal bypass circuit described in .