Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS5656216 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an output impedance control circuit according to the prior art, and FIG. 2 is a circuit diagram showing an embodiment of the output impedance control circuit according to the present invention. ′Ｚｓ１． Zs2: Impedance element, VRt: Variable resistor, R1, Load: R1-R3: Resistance, El: Positive power supply, A1: Amplifier, R2: Negative power supply. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an output impedance control circuit that can be made negative to the output impedance of an amplifier. Conventionally, various output impedance control circuits capable of achieving zero output impedance by canceling out the impedance component of the speaker cord for connecting the speaker to the auio amplifier temple have been announced, as shown in FIG. 1 Also shown is a representative example. This circuit detects the output signal current of the amplifier A1o with a resistor Rs connected between the load R1, ··· and the ground 2 and the detection current is inverted and amplified with the amplifier All to make a voltage negative return of the amplifier Al ·. In the configuration to be applied to the ring loop, the current return amount by the detection current is continuously changed from negative to 0 to positive by adjustment of the variable resistor VR,. The output impedance of the amplifier A16 may be changed continuously from positive to zero. However, in this circuit, an inverting amplifier is required for current return, and the circuit is also complicated, which is disadvantageous in terms of cost and production. SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art, and its object is to provide an output kinobeadance control circuit purple of an amplifier having a simple circuit configuration without requiring an active element for current return. An embodiment of the present invention will be described below with reference to FIG. In the figure, A1 is an amplifier and has a voltage negative feedback loop by resistors Rv and Rs, and a load Bt is connected to the output of the amplifier AI via an impedance Zzk such as a speaker cord etc. There is. A first impedance element zsl is connected between the load RL and the ground, rvoEl is 07-05-2019 1 a positive power supply for the amplifier, E2 is a negative power supply for the amplifier, and the positive poles of E 負 -N and B2 are mutually connected. It is connected, and this connection point is grounded to a 1-piece,-ヱ 6 ground via a second impedance element. Furthermore, the two fixed ends of the variable resistor VRI are connected n between the other ends of each of the two I-1-impedance elements not on the common ground side of the two, while the slider end is the reverse phase of the amplifier AI. The input 4jK is connected. The output impedance control circuit of the present invention is constituted by the above Zst + Zsz + VR +. In the figure, rl + rfi represents the resistance value divided by the slider of the variable resistor VR1 as Q, respectively, and each reference symbol also represents the element power of each element. Further, in the figure, Va represents an input terminal and an input voltage, and Vo represents an output voltage. In such a configuration, in the case of R1 >> r ++ rz >> Zst + z12, the following relationship is established between the valley element width and the voltage of the valley. Zstv 8 VO + z 2 + Fatty IV OV 8 ′ ′ ′ ′ K; = R 2 ·· − 2 Vo + on, □ ′ V. ZstR4r ++ ra2a + R / a ,,, 1) If I arrange IC and obtain the transfer function of the circuit, RIRs + & Rs + & & (Zs + R4) 7-bile □ medical cord-ml-11 (Z * + Rt1) "i, (rs + r *)- (2 + Therefore, the output impedance of the amplifier Zo is expressed by equation (2) シ, zO: ((r ++ r * R R * + R 鵞) rt & Z ml-rs Ba Zm z & (rx + r *) = (r ++ rt) (Rt " One stop force ... (8) R + (ri + r *). Here, the right side of this M (3) equation is rewritten to 1, 2, and n * J! Force-proof Zo-one "Force wood 124 is 1 □ Force for □-(3) -mm (R1 R2) ZB1 and, regarding the second term of the right-hand side of this formula, & (Zs ++ Zs + 1) If K− (r1 + r2 is L & + &) Zst ′ ′, rt / (r ++ rx) in this formula is 1. IIJ Continuous change from 0 to 1Q due to the adjustment of the slider of the removable resistance 潴 VR + f 7). Therefore, in the equation (4), 1.0 and the value of K is 0 ≦? (5) Since the right side of the equation (5) is larger than 1 ',:! , 5 ζ □ ツ シ ノ 値 4 例 え ば value, for example, 2 v If it is said that adjusting the VR1 to change the value of K in the range of 0 ≦ 2 in the range of ≦ 2 Then, according to the relationship between the equation (4) and the equation (3), the value of Zo in the case of O changes continuously in the range of 1 匪 匪 2 2 ≦ J Jt 16) 1 It is better than V. In other words, it is possible to adjust the value of Rt * fhlt appropriately by setting the value of Oυ 臥 1 and the value of output in-vidance Zo to be continuous 0 to negative and negative vcf by port 11m device VRIK. It will be. Slightly adjust the variable resistor so that the unnecessary impedance component Zs of the speaker code etc. which enters the series vc output circuit with the load RLs without fail when amplifying 6ArVC load R1, all connections become Zo = -Z * If it is possible to offset isometrically in the above case G mentioned above, the output impedance control circuit according to the present invention may set the output impedance of the amplifier using it positive to 0 to negative. Since the variable control can be continuously performed, it is possible to cancel out the unnecessary speaker cord etc., → 6 components, and therefore it is possible to ideally apply the output signal of the amplifier to the load. It is said that the current positive feedback (Q7t active element is unnecessary and the circuit configuration is extremely simple and the VC configuration is extremely advantageous in cost and production) while having the 07-05-2019 2 same function as the conventional similar circuit. Features Those having. 07-05-2019 3

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