Details of Operation: Precision V-T

Details of Operation: Precision V-To-F Converter (Figure 16)
In this circuit, integration is performed by using a conventional operational amplifier and feedback capacitor, CF.
When the integrator's output crosses the nominal threshold level at pin 6 of the LM231/331, the timing cycle is
initiated.
The average current fed into the op-amp's summing point (pin 2) is i × (1.1 RtCt) × f which is perfectly balanced
with −VIN/RIN. In this circuit, the voltage offset of the LM231/331 input comparator does not affect the offset or
accuracy of the V-to-F converter as it does in the stand-alone V-to-F converter; nor does the LM231/331 bias
current or offset current. Instead, the offset voltage and offset current of the operational amplifier are the only
limits on how small the signal can be accurately converted. Since op-amps with voltage offset well below 1 mV
and offset currents well below 2 nA are available at low cost, this circuit is recommended for best accuracy for
small signals. This circuit also responds immediately to any change of input signal (which a stand-alone circuit
does not) so that the output frequency will be an accurate representation of VIN, as quickly as 2 output pulses'
spacing can be measured.
In the precision mode, excellent linearity is obtained because the current source (pin 1) is always at ground
potential and that voltage does not vary with VIN or fOUT. (In the stand-alone V-to-F converter, a major cause of
non-linearity is the output impedance at pin 1 which causes i to change as a function of VIN).
The circuit of Figure 17 operates in the same way as Figure 16, but with the necessary changes for high speed
operation.
*Use stable components with low temperature coefficients. See APPLICATIONS INFORMATION

Kết quả (Anh) 1:

Details of Operation: Precision V-To-F Converter (Figure 16)In this circuit, the integration is performed by using a conventional operational amplifier and feedback capacitor, CF.When the integrator's output crosses the nominal threshold level at pin 6 of the LM231/331, the timing cycle isinitiated.The average current fed into the op-amp's summing point (pin 2) is i × (RtCt 1.1) × f which is perfectly balancedwith − VIN/RIN. In this circuit, the voltage offset of the LM231/331 input comparator does not affect the offset oraccuracy of the V-to-F converter as it does in the stand-alone V-to-F converter; nor does the LM231/331 biascurrent or current offset. Instead, the offset voltage and offset current of the operational amplifier are the onlylimits on how small the signal can be accurately converted. Since the op-amps with offset voltage well below 1 mVand offset currents well below 2 nA are available at low cost, this circuit is recommended for best accuracy forsmall signals. This circuit also responds immediately to any change of input signal (which a stand-alone circuitdoes not) so that the output frequency will be an accurate representation of VIN, as quickly as 2 output pulses 'spacing can be measured.In the precision mode, excellent linearity is obtained because the current source (pin 1) is always at groundpotential and that voltage does not vary with VIN or fOUT. (In the stand-alone V-to-F converter, a major cause ofnon-linearity is the output impedance at pin 1 which causes i to change as a function of VIN).The circuit of Figure 17 operates in the same way as Figure 16, but with the necessary changes for high speedoperation.* Use stable components with low temperature coefficients. See The APPLICATIONS INFORMATION

Kết quả (Anh) 2:

Details of Operation: Precision V-To-F Converter (Figure 16)
In this circuit, integration is Performed by using a conventional operational amplifier and feedback capacitor, CF
When the integrator's output crosses the nominal threshold level at pin 6 of the LM231 / 331, the timing cycle is
initiated.
The average current fed Into the op-amp's summing point (pin 2) is i × (1.1 RtCt) × f mà perfectly-balanced
with -VIN / RIN. In this circuit, the voltage offset of the LM231 / 331 does not hưởng the comparator input offset or
accuracy of the V-to-F converter as it does in the stand-alone V-to-F converter; nor does the LM231 / 331 bias
current or offset current. Thay, the offset voltage and offset current of the operational amplifier are the only
limits on how small the signal can be accurately converted. Since op-amps with well below 1 mV offset voltage
and offset currents well below 2 nA are available at low cost, this circuit is recommended for best accuracy for
small signals. This circuit ngay am also responds to any change of input signal (mà a stand-alone circuit
does not) than rằng Will Be an accurate output frequency Representation of VIN, as Quickly as 2 output pulses'
spacing can be measured.
In the precision mode , excellent linearity is thu được vì current source (pin 1) is always at ground
potencial and mà does not vary with voltage VIN or Fout. (In the stand-alone V-to-F converter, a major cause, of
non-linearity is the output impedance at pin 1 mà Causes i to change as a function of VIN).
The circuit of Figure 17 operates in the same way as Figure 16, but with the changes cần for high speed
operation.
* Use with low temperature coefficients stable components. See APPLICATIONS INFORMATION