Datasheet

TL05x, TL05xA
ENHANCED-JFET LOW-OFFSET
OPERATIONAL AMPLIFIERS
SLOS178A – FEBRUARY 1997 - REVISED FEBRUARY 2003
41
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
phase meter
The phase meter in Figure 84 produces an output voltage of 10 mV per degree of phase delay between the two
input signals V
A
and V
B
. The reference signal V
A
must be the same frequency as V
B
. The TLC3702 comparators
(U1) convert these two input sine waves into ±5-V square waves. Then, R1 and R4 provide level shifting prior
to the SN74HC109 dual J-K flip flops.
Flip-flop U2B is connected as a toggle flip-flop and generates a square wave at one-half the frequency of V
B
.
Flip-flop U2A also produces a square wave at one-half the input frequency. The pulse duration of U2A varies
from zero to one-half the period, where zero corresponds to zero phase delay between V
A
and V
B
and one-half
the period corresponds to V
B
lagging V
A
by 360 degrees.
The output pulse from U2A causes the TLC4066 (U3) switch to charge the TL05x (U4) integrator capacitors C1
and C2. As the phase delay approaches 360 degrees, the output of U4A approximates a square wave, and U2A
has an output of almost 2.5 V. U4B acts as a noninverting amplifier with a gain of 1.44 in order to scale the
0- to 2.5-V integrator output to a 0- to 3.6-V output range.
R8 and R10 provide output gain and zero-level calibration. This circuit operates over a 100-Hz to 10-kHz
frequency range.
+
–
+
–
+5 V
R2
100 kΩ
R1
100 kΩ
U1A
V
A
S
1J
C1
U2A
1K
R
NC
U2B
2K
R3
V
B
U1B
R6
10 kΩ
R7
10 kΩ
+5 V
S
2J
C1
R
NC
100 kΩ
R4
100 kΩ
U3
R5
C1
10 kΩ
0.016 µF
C2
0.016 µF
U4A
U4B V
O
R9
20 kΩ
R8
Gain
50 kΩ
+5 V
R10
10 kΩ
Zero
–5 V
NOTE A: U1 = TLC3702; V
CC±
= ±5 V
U2 = SN74HC109
U3 = TLC4066
U4, U5 = TL05x; V
CC±
= ±5 V
Figure 84. Phase Meter