Cirrus Logic AN366 - Manual (Page 42)

AN366
42 AN366REV2
PHASE OFFSET
PC/Controller test for phase calibration range meet or fail meter. This example shows neg-
ative phase offset.
Figure 38. Negative Phase Offset
PHASE OFFSET
PC/Controller test for coarse phase calibration range.
When > 1 OWR, PC/Controller calculates Coarse Compensation
CPCC1 = 0
CPCC2 = 0
PC/Controller calculates Fine Compensation
FPCC1 = -(-0.55224327) / 0.008789 @ 50Hz = 62,
FPCC2 = -(-0.57051489) / 0.008789 @ 50Hz = 64,
CPCC1=0, FPCC1 = 62, CPCC2=0, FPCC2 = 64
SDI =
0x80 0x45 0x007C40 Write Phase Comp (page 0, register 69)
SDO = 0xFF 0xFF 0xFFFFFF
SDI = 0x80 0x05 0xFFFFFF Write Phase Comp (page 0, register 69)
SDO = 0xFF 0xFF 0x007C40
-8.99º <
PHASE OFFSET
< +8.99º ? (50Hz)
PHASE OFFSET
NEGATIVE?
-512 · 0.008789 <
PHASE OFFSET
< 0 (50Hz)
?
FINE
COMPENSATION
(FPCC) = -PHASE
OFFSET ÷
0.008789 (50Hz)
SET COARSE
COMPENSATION
(CPCC = 01)
1 OWR on I
PHASE OFFSET =
PHASE OFFSET +
4.5º (50Hz)
±10.79º @ 60Hz
0 to 512 · 0.010547 @ 60Hz
5.4º @ 60Hz
0.010547 @ 60Hz
FAIL
METER
2
YES
NO
YES
NO
3
YES Example Location
0º
Before Calibration V is delayed from I
Delay added to I
8.99º @ 50Hz
10.79º @ 60Hz
4.5º @ 50Hz
5.4º @ 60Hz
-4.5º @ 50Hz
-5.4º @ 60Hz
-8.99º @ 50Hz
-10.79º @ 60Hz