Analog circuits today are typically biased from ±5 V to ±18 V. But the trend is toward lower voltages. For this reason, many components are designed to operate primarily in ±5-V systems. One example is the digitally controlled potentiometer (DCP). Can a low-voltage DCP be employed in a high-voltage circuit such as an amplifier? The answer is yes, if caution is paid to how and where the DCP is used.
This ±12-V inverting amplifier circuit is designed for a nominal gain of ten (Fig. 1). Use of a low-voltage, programmable DCP extends the programmable gain limits from 7.7 to 13.9. Xicor's 256-tap X9250/58 provides a gain resolution of 0.024 over this range. Therefore, it allows accurate gain setting without using expensive, precision resistors.
One feature of the inverting configuration is that the wiper is connected to 0 V or virtual ground. Consequently, any high common-mode voltages on the potentiometer terminals are removed. Another benefit is that the wiper resistance of the DCP is in series with the high input-resistance of the operational amplifier. So any error due to the wiper resistance is eliminated as well.
For the inverting amplifier, the gain is given by:
G = −(R2' + R2)/(R1' + R1)
A noninverting amplifier circuit can't be used since it lacks a virtual ground. The relative values of the potentiometer resistances R1' and R2' compared to R1 and R2 are established by the relative values of the maximum DCP and circuit voltages. For a 12-V circuit and a 5-V DCP, R1' and R2' must be less than five-sevenths of R1 and R2. Clamping-diodes D1 through D4 offer overvoltage protection to the DCP during power-up, power-down, and fault conditions.
i'm looking for 12w power amplifier circuits diagram.can u help me..
Anonymous -March 06, 2008
diagramas o esquemas de LNB
elmer carhuamaca aire -July 30, 2007
diagramas de LNB para poder realizarlo ademas digramas de decodificadores
elmer carhuamaca aire -July 30, 2007
circuit
channa -March 24, 2007 (Article Rating: )
o-40mv to 1-5v amplifire 0-40mv to 4-20ma
zoorba -November 09, 2006 (Article Rating: )
hai iwant small circuit i/p 28v 0/p 1-15v adjustable voltage regulator please send circuit diagram thank you
sreenu -June 16, 2006
iam study in engineering. so me required for more information so i will like you. you give the in formation about in emppeted system
maharaj -March 08, 2006
i love u fafa!
Anonymous -January 16, 2006 (Article Rating: )
i love u fafa!
Anonymous -January 16, 2006
There is no mention of what kind of applications for which this circuit is valid. Certainly the amplifier gain is not well defined for a given DCP tap setting as two different types of resistances with different tolerances and temperature coefficients are involved.
Anonymous -September 20, 2005 (Article Rating: )
I want to know can i use it as a power amplifier in the range of 500 KHZ to 1Mhz
Anonymous -June 22, 2005 (Article Rating: )
Hi Dear friend Please inform me more clear ,what type & power you need for your amplifier.
Best regards M.R.M.ZADEH
Anonymous -May 13, 2005
I want 12 voltage power amplifire circuit please help me
Shahid -May 12, 2005
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