參數(shù)資料
型號(hào)： LM13700
廠商： National Semiconductor Corporation
元件分類： 運(yùn)動(dòng)控制電子
英文描述： Dual Operational Transconductance Amplifiers with Linearizing Diodes and Buffers
中文描述： 雙路運(yùn)算跨導(dǎo)放大器的線性化二極管和緩沖器
文件頁(yè)數(shù)： 18/24頁(yè)
文件大?。?/td> 633K
代理商： LM13700
Additional Applications
(Continued)
Figure 23shows a Tachometer or Frequency-to-Voltage con-
verter. Whenever A1 is toggled by a positive-going input, an
amount of charge equal to (V
–V
) C
is sourced into C
and
R
. This once per cycle charge is then balanced by the cur-
rent of V
/R
. The maximum F
is limited by the amount of
time required to charge C
from V
to V
with a current of I
B
,
where V
and V
represent the maximum low and maximum
high output voltage swing of the LM13700. D1 is added to
provide a discharge path for C
t
when A1 switches low.
The Peak Detector of Figure 24 uses A2 to turn on A1 when-
ever V
becomes more positive than V
O
. A1 then charges
storage capacitor C to hold V
equal to V
PK. Pulling the
output of A2 low through D1 serves to turn off A1 so that V
O
remains constant.
The Ramp-and-Hold of Figure 26sources I
into capacitor C
whenever the input to A1 is brought high, giving a ramp-rate
of about 1V/ms for the component values shown.
The true-RMS converter of Figure 27 is essentially an auto-
matic gain control amplifier which adjusts its gain such that
the AC power at the output of amplifier A1 is constant. The
output power of amplifier A1 is monitored by squaring ampli-
fier A2 and the average compared to a reference voltage
with amplifier A3. The output of A3 provides bias current to
the diodes of A1 to attenuate the input signal. Because the
output power of A1 is held constant, the RMS value is con-
stant and the attenuation is directly proportional to the RMS
value of the input voltage. The attenuation is also propor-
tional to the diode bias current. Amplifier A4 adjusts the ratio
of currents through the diodes to be equal and therefore the
voltage at the output of A4 is proportional to the RMS value
of the input voltage. The calibration potentiometer is set such
that V
O
reads directly in RMS volts.
DS007981-30
FIGURE 23. Tachometer
DS007981-31
FIGURE 24. Peak Detector and Hold Circuit
www.national.com
18
相關(guān)PDF資料
PDF描述
LM13700AN Dual Operational Transconductance Amplifiers with Linearizing Diodes and Buffers
LM13700M Dual Operational Transconductance Amplifiers with Linearizing Diodes and Buffers
LM13700N Dual Operational Transconductance Amplifiers with Linearizing Diodes and Buffers
LM1391 LM1391 Phase-Locked Loop
LM1391N LM1391 Phase-Locked Loop
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM13700A 制造商:未知廠家 制造商全稱:未知廠家 功能描述:
LM13700AN 制造商:Rochester Electronics LLC 功能描述:- Bulk
LM13700AN/A+ 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Transconductance Operational Amplifier
LM13700AN/B+ 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Transconductance Operational Amplifier
LM13700M 功能描述:運(yùn)算放大器 - 運(yùn)放 RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
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