
TL05x, TL05xA, TL05xY
ENHANCED-JFET LOW-OFFSET
OPERATIONAL AMPLIFIERS
SLOS178 – FEBRUARY 1997
56
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 half the frequency of V
B
.
Flip-flop U2A also produces a square wave at half the input frequency. The pulse duration of U2A varies from
zero to half the period, where zero corresponds to zero phase delay between V
A
and V
B
and 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.
+
–
+
U4B
–
+ 5 V
R2
100 k
R1
100 k
U1A
VA
S
1J
C1
U2A
1K
R
NC
U2B
2K
R
R3
VB
U1B
R6
10 k
R7
10 k
+ 5 V
S
2J
C1
NC
100 k
R4
100 k
U3
R5
C1
10 k
0.016
μ
F
C2
0.016
μ
F
U4A
VO
R9
20 k
R8
50 k
Gain
+ 5 V
R10
10 k
Zero
– 5 V
NOTE A: U1 = TLC3702; VCC
±
=
±
5 V
U2 = SN74HC109
U3 = TLC4066
U4, U5 = TL05x; VCC
±
=
±
5 V
Figure 84. Phase Meter