CRD5490-Z Cirrus Logic, CRD5490-Z Datasheet - Page 33

• Manufacturer Part Number: CRD5490-Z
• Description: Power Management IC Development Tools CS5463 Pwr Meas/Mntr Reference Design
• Manufacturer: Cirrus Logic
• Type: Energy Meterr

Specifications of CRD5490-Z

• Rohs: yes
• Product: Reference Design Boards
• Tool Is For Evaluation Of: CS5490
• Input Voltage: 90 VAC to 260 VAC
• Output Current: 15 A

APPENDIX 3: NON-FULL SCALE GAIN CALIBRATION
When resources are limited, it may be necessary to provide non-full-scale amplitudes and perform built-in
calibration. To perform a non-full-scale calibration, the initial gain register conditions of the device must be identified
before calibration. Usually, initial gain register conditions are set to a default value of one, but this is not required.
Instead, the initial gain register conditions are set to accommodate the non-full-scale input calibration. Before
calibration is executed, the gain register can be set using the following equations:
Follow the steps below to perform a non-full-scale gain calibration:
1. Set the line voltage and load current V
2. Confirm that the reference meter shows V
3. Set V
4. Send the calibration command.
5. After calibration, the meter will be adjusted for a full-scale voltage of V
Reference Limits
The calibration line voltage (V
register values at a minimum of ½ of the maximum levels. Since the gain register can be set to a maximum value of
4, the input could be set to ¼ of the maximum levels. It is not recommended to set the input to ¼ of the maximum
levels due to variations in setup conditions. If the input is too low, the gain register will set the default value of one
after calibration.
DS988RD1
where:
suring the V
V
I
V
I
V
I
GAIN(pre)
MAX
REF
GAIN(pre)
MAX
REF
GAIN(pre)
REF
per Equation 1 and I
Value stored in voltage gain register (page 16, address 35) before calibration starts
Value stored in current gain register (page 16, address 33) before calibration starts
Maximum voltage of the meter defined by customer
Maximum current of the meter defined by customer
Voltage of the line just before calibration as measured with reference meter assumes
stable input
Load current just before calibration as measured with reference meter assumes stable
input
and I
REF
measurements.
REF
) or load current (I
GAIN(pre)
REF
V
REF
I
and I
GAIN pre
GAIN pre
per Equation 2.
and I


REF
REF


, respectively.
REF
=
=
) must not be set too low. It is recommended to keep the
V
-------------- -
I
----------- -
V
I
MAX
REF
of the input.
MAX
REF


2
2
22
22
MAX
and I
MAX
and will currently be mea-
CRD5490-Z
[Eq: 1]
[Eq: 2]
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