CS5467-IS View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS5467-IS

Four-channel Power / Energy IC

Cirrus Logic 

CS5467

P1OFF(P2 OFF)

V1ACOFF

(V2ACOFF)

I1ACOFF

(I2 ACOFF)

Figure 5. Low-rate Calculations

4.8 Power and Energy Results

The instantaneous voltage and current samples are

multiplied to obtain the instantaneous power (P1, P2)

(see Figure 3 and 4). The product is then averaged over

N conversions to compute active power (P1AVG,

P2AVG).

Apparent power (S1, S2) is the product of RMS voltage

and current as shown:

S = VRMS × IRMS

QWB = S2 – PA2 ctive

Quadrature power (Q1, Q2) are sample rate results ob-

tained by multiplying instantaneous current (I1, I2) by in-

stantaneous quadrature voltage (V1Q, V2Q) which are

created by phase shifting instantaneous voltage (V1,

V2) 90 degrees using first-order integrators. (See Fig-

ure 3 and 4). The gain of these integrators is inversely

related to line frequency, so their gain is corrected by

the Epsilon register, which is based on line frequency.

Power factor (PF1, PF2) is active power divided by ap-

parent power as shown below. The sign of the power

factor is determined by the active power.

PF

=

P-----A---c---t--i-v---e-

S

Wideband reactive power (Q1WB, Q2WB) is calculated

by doing a vector subtraction of active power from ap-

parent power.

Reactive power (Q1Avg, Q2AvG) is generated by inte-

grating the instantaneous quadrature power over N

samples.

Active power (P1AVG, P2AVG), apparent power (S1, S2),

and reactive power (Q1AVG, Q2AVG) of the two channels

are summed up and then divided by 2. The calculation

results are placed in EPULSE, SPULSE, and QPULSE reg-

isters which can be configured to drive energy pulse

outputs. (See Figure 6.)

P1AVG

P2AVG

+

÷2

EPULSE

OVF=

×+

EACCM

S1

OVF=

+

÷2

SPULSE

×+

SACCM

S2

Q1AVG

Q2AVG

+

÷2

QPULSE

OVF=

×+

QACCM

PulseRate

( E1, E2, E3 )

Figure 6. Two-channel Power Summation

16

DS714F1

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