CS5463 datasheet(17/46 Pages) CIRRUS

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CS5463

DS678F3

for unsigned registers is a normalized value between 0

and 1. A register value of

represents the maximum possible value.

At each instantaneous measurement, the CRDY bit will

be set in the Status Register, and the INT pin will be-

come active if the CRDY bit is unmasked in the Mask

. At the end of each computation cycle, the

DRDY bit will be set in the Status Register, and the INT

pin will become active if the DRDY bit is unmasked in

the Mask Register. When these bits are asserted, they

must be cleared before they can be asserted again.

If the Cycle Count Register (N) is set to 1, all output cal-

culations are instantaneous, and DRDY, like CRDY, will

indicate when instantaneous measurements are fin-

ished. Some calculations are inhibited when the cycle

count is less than 2.

Epsilon (

) is the ratio of the input line frequency (f

i) to

the sample frequency (fs) of the ADC.

where fs = MCLK / (K*1024). With MCLK = 4.096 MHz

and clock divider K = 1, fs = 4000 Hz. For the two

most-common line frequencies, 50 Hz and 60 Hz

and

respectively. Epsilon is used to set the frequency of the

internal sine/cosine reference for the fundamental ac-

tive and reactive measurements, and the gain of the 90°

phase shift (IIR) filter for the average reactive power.

5.5 Energy Pulse Output

The CS5463 provides three output pins for energy reg-

istration. By default, E1 registers active energy, E3 reg-

isters reactive energy, and E2 indicates the sign of both

active and reactive energy. (See Figure 2. Timing Dia-

gram for E1, E2, and E3

on page13.) The E1 pulse out-

put is designed to register the Active Energy. The E2 pin

can be set to register Apparent Energy. Table 2 defines

the pulse output mode, which is controlled by bit

E2MODE in the Operational Mode Register.

The E3 pin can be set to register Reactive Energy (de-

fault), PFMON, Voltage Channel Sign, or Apparent En-

ergy. Table 3 defines the pulse output format, which is

controlled by bits E3MODE[1:0] in the Operational

Mode Register.

The pulse output frequency of E1, E2, and E3 is directly

proportional to the power calculated from the input sig-

nals. The value contained in the PulseRateE Register is

the ratio of the frequency of energy-output pulses to the

number of samples, at full scale, which defines the av-

erage frequency for the output pulses. The pulse width,

tpw in Figure 2, is programmable through the Pulse-

Width register, and is approximately equal to:

If MCLK = 4.096 MHz, K = 1, and PulseWidth = 1, then

tpw  0.25 ms.

5.5.1 Active Energy

The E1 pin produces active-low pulses with an output

frequency proportional to the active power. The E2 pin

is the energy direction indicator. Positive energy is rep-

resented by E1 pin falling while the E2 is high. Negative

energy is represented by the E1 pin falling while the E2

is low. The E1 and E2 switching characteristics are

specified in Figure 2. Timing Diagram for E1, E2, and E3

on page13.

Figure 5 illustrates the pulse output format with positive

active energy and negative reactive energy.

–



------------------------

0.99999988

 f

i fs



 50 Hz 4000 Hz



0.0125

 60 Hz 4000 Hz



0.015

E2MODE

E2 Output Mode

Sign of Energy

Apparent Energy

Table 2. E2 Pin Configuration

E3MODE1

E3MODE0

E3 OutPut Mode

Reactive Energy

PFMON

Voltage Channel Sign

Apparent Energy

Table 3. E3 Pin Configuration

sec

 PulseWidth

( MCLK/K ) / 1024

------------------------------------------------





Figure 5. Active and Reactive energy pulse outputs

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