1.1.4 The true RMS-to-DC conversion with ES636
If ES636 is used for true RMS-to-DC measurement, the test circuit is shown in Figure 1.
Make ADO and ADI pin short, and TEST5 pin keeps float. Connect OVSG pin to
AGND through a switch in ACV measurement mode.
OVSG
99.5
ACV
OR1
1K
10K
101K
1.111M
VR5
VR4
AGND
VR3
VR2
+Vs -Vs
TEST5
ACVL
7
4.7u
+
4
2
3
6
AGND
TL061
5
30K
N2
+Vs
14
13
12
11
10
9
1
2
3
4
5
6
7
1
N1
100K
ACVH
10K
-Vs
4.7u
+Vs
PWD
OP-
1.5K
-Vs
AGND
0.1u
AGND
10
1K
8
+Vs
500K
-Vs
OP+
AGND
27k
ADO
ADI
3.3u
5k
AGND
10K
AGND
100K
OPO
ADOHZ
Note: The filter capacitors for +Vs and -Vs
are recommended to near to the power
terminals of ES636 and external OPAMP.
AGND
Figure 1. The true RMS-to-DC conversion with ES636
v1.2
8
11/09/06
CYRUSTEK [ Cyrustek corporation ]
