ADE7758
Data Sheet
VAP
GAIN[6:5]
×1, ×2, ×4
PHASE
CALIBRATION
Φ
PHCAL[6:0]
TO ACTIVE AND
REACTIVE ENERGY
CALCULATION
VA
VN
+
PGA
ADC
LPF1
f 3dB = 260Hz
TO VOLTAGE RMS
CALCULATION AND
WAVEFORM SAMPLING
LPF OUTPUT
50Hz
WORD RANGE
0x2797
VA
0V
ANALOG INPUT
RANGE
0.5V
GAIN
0x2852
0x0
0xD7AE
0x0
0xD869
60Hz
LPF OUTPUT
WORD RANGE
0x2748
0x0
0xD8B8
Figure 49. ADC and Signal Processing in Voltage Channel
VOLTAGE CHANNEL ADC
Figure 49 shows the ADC and signal processing chain for the
input VA in the voltage channel. The VB and VC channels have
similar processing chains.
For active and reactive energy measurements, the output of the
ADC passes to the multipliers directly and is not filtered. This
solution avoids the much larger multibit multiplier and does not
affect the accuracy of the measurement. An HPF is not
implemented on the voltage channel to remove the dc offset
because the HPF on the current channel alone should be
sufficient to eliminate error due to ADC offsets in the power
0
–20
–40
–60
(60Hz; –13 ° )
(60Hz; –0.2dB)
0
–10
–20
–30
calculation. However, ADC offset in the voltage channels
–80
10
100
–40
1k
produces large errors in the voltage rms calculation and affects
the accuracy of the apparent energy calculation.
Voltage Channel Sampling
The waveform samples on the voltage channels can also be
routed to the WFORM register. However, before passing to the
WFORM register, the ADC outputs pass through a single-pole,
low-pass filter (LPF1) with a cutoff frequency at 260 Hz.
Figure 50 shows the magnitude and phase response of LPF1.
This filter attenuates the signal slightly. For example, if the line
frequency is 60 Hz, the signal at the output of LPF1 is
attenuated by 3.575%. The waveform samples are 16-bit, twos
complement data ranging between 0x2748 (+10,056d) and
0xD8B8 (?10,056d). The data is sign extended to 24-bit in the
WFORM register.
FREQUENCY (Hz)
Figure 50. Magnitude and Phase Response of LPF1
Note that LPF1 does not affect the active and reactive energy
calculation because it is only used in the waveform sampling
signal path. However, waveform samples are used for the
voltage rms calculation and the subsequent apparent energy
accumulation.
The WAVSEL[2:0] bits in the WAVMODE register should be set
to 001 (binary) to start the voltage waveform sampling. The
PHSEL[1:0] bits control the phase from which the samples are
routed. In waveform sampling mode, one of four output sample
rates can be chosen by changing Bit 5 and Bit 6 of the WAVMODE
register (see Table 20). The available output sample rates are
26.0 kSPS, 13.5 kSPS, 6.5 kSPS, or 3.3 kSPS. By setting the WFSM
1 + ?
? 60 Hz ?
? 260 Hz ?
H ( f ) =
? ?
1
?
2
= 0 . 974 = ? 0 . 225 dB
(3)
bit in the interrupt mask register to Logic 1, the interrupt request
output IRQ goes active low when a sample is available. The 24-
bit waveform samples are transferred from the ADE7758 one byte
(8 bits) at a time, with the most significant byte shifted out first.
The sign of the register is extended in the upper 8 bits. The
timing is the same as for the current channels, as seen in Figure 40.
Rev. E | Page 22 of 72
相关PDF资料
ADE7761AARSZ-RL IC ENERGY METERING 1PHASE 20SSOP
ADE7761BARSZ-RL IC ENERGY METERING 1PHASE 20SSOP
ADE7768ARZ-RL IC ENERGY METERING 1PHASE 16SOIC
ADE7769ARZ-RL IC ENERGY METERING 1PHASE 16SOIC
ADM8843ACPZ-REEL7 IC LED DRVR WHITE BCKLGT 16LFCSP
ADP1653ACPZ-R7 IC LED DRVR PHOTO FLASH 16-LFCSP
ADP1712-EVALZ BOARD EVALUATION ADP1712
ADP1720-EVALZ BOARD EVAL FOR ADP1720-ADJ
相关代理商/技术参数
ADE7759 制造商:AD 制造商全称:Analog Devices 功能描述:Active Energy Metering IC with di/dt Sensor Interface
ADE7759ARS 功能描述:IC ENERGY METERING 1PHASE 20SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 能量测量 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:*
ADE7759ARSRL 功能描述:IC ENERGY METERING 1PHASE 20SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 能量测量 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:*
ADE7759ARSZ 功能描述:IC ENERGY METERING 1PHASE 20SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 能量测量 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:*
ADE7759ARSZRL 功能描述:IC ENERGY METERING 1PHASE 20SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 能量测量 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:*
ADE7760 制造商:AD 制造商全称:Analog Devices 功能描述:Energy Metering IC with On-Chip Fault Detection
ADE7760ARS 制造商:Analog Devices 功能描述:Energy Measurement 20-Pin SSOP 制造商:Analog Devices 功能描述:ENERGY METER IC W/ ONCHIP FAULT & OSCIL. - Rail/Tube
ADE7760ARSRL 制造商:Analog Devices 功能描述:Energy Measurement 20-Pin SSOP T/R 制造商:Analog Devices 功能描述:ENERGY METER IC W/ONCHIP FAULT & OSCIL. - Tape and Reel