Datasheet

ManualsBrandsANALOG DEVICES ManualsPMICsPMIC - power monitoring Three-phase SOIC 24 Surface-mount

Polyphase Energy Metering IC

with Pulse Output

ADE7752/ADE7752A

FEATURES

High accuracy, supports 50 Hz/60 Hz IEC62053-2x

Less than 0.1% error over a dynamic range of 500 to 1

Compatible with 3-phase/3-wire delta and 3-phase/4-wire

Wye configurations

The ADE7752 supplies average real power on frequency

outputs F1 an

d F2

High frequency output CF is intended for calibration and

supplies instantaneous real power

Logic output REVP indicates a potential miswiring or

nega

tive power for each phase

Direct drive for electromechanical counters and 2-phase

epper motors (F1 and F2)

Proprietary ADCs and DSP provide high accuracy over large

ariations in environmental conditions and time

On-chip power supply monitoring

On-chip creep protection (no load threshold)

On-chip reference 2.4 V ±8% (20 ppm/°C typical) with

external overdrive capability

Single 5 V supply, low power

60 mW t

ypical: ADE7752

30 mW typical: ADE7752A

Low cost CMOS process

GENERAL DESCRIPTION

The ADE7752 is a high accuracy polyphase electrical energy

measurement IC. The ADE7752A is a pin-to-pin compatible

low power version of ADE7752. The functions of ADE7752 and

ADE7752A are the same. Both products are referred to in the

text of this data sheet as ADE7752.

The part specifications surpass the accuracy requirements as

uoted in the IEC62053-2x standard. The only analog circuitry

used in the ADE7752 is in the analog-to-digital converters (ADCs)

and reference circuit. All other signal processing (such as multi-

plication, filtering, and summation) is carried out in the digital

domain. This approach provides superior stability and accuracy

over extremes in environmental conditions and over time.

The ADE7752 supplies average real power information on the

w frequency outputs, F1 and F2. These logic outputs may be

used to directly drive an electromechanical counter or to

interface with an MCU. The CF logic output gives instanta-

neous real power information. This output is intended to be

used for calibration purposes.

The ADE7752 includes a power supply monitoring circuit on

the V

pin. The ADE7752 remains inactive until the supply

voltage on V

reaches 4 V. If the supply falls below 4 V, no

pulses are issued on F1, F2, and CF. Internal phase matching

circuitry ensures that the voltage and current channels are

phase matched. An internal no load threshold ensures the part

does not exhibit any creep when there is no load. The ADE7752

is available in a 24-lead SOIC package.

FUNCTIONAL BLOCK DIAGRAM

LPF

HPF

CLKOUT

CLKIN

DGND

CFS1 F1F2S0SCFREVP

DIGITAL-TO-FREQUENCY CONVERTER

2.4V REF

REF

IN/OUT

AGND

IBP

IBN

VBP

ICP

ICN

VCP

IAP

IAN

VA P

ADC

ADE7752/

ADE7752A

POWER

SUPPLY

MONITOR

ADC

PHASE

CORRECTION

PHASE

CORRECTION

PHASE

CORRECTION

11 12 4 18 21 22 23 24 1

HPF

LPF

ABS

02676-A-001

Figure 1. 24-Lead Standard Small Outline Package [SOIC]

Rev. C

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice.

No license is granted by implication or otherwise under any patent or patent rights of Analog

Devices. Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700 www.analog.com

Summary of content (24 pages)

PAGE 1
Polyphase Energy Metering IC with Pulse Output ADE7752/ADE7752A FEATURES High accuracy, supports 50 Hz/60 Hz IEC62053-2x Less than 0.
PAGE 2
ADE7752/ADE7752A TABLE OF CONTENTS Specifications..................................................................................... 3 Voltage Channels Connection .................................................. 15 Timing Characteristics..................................................................... 4 Meter Connections..................................................................... 15 Absolute Maximum Ratings............................................................
PAGE 3
ADE7752/ADE7752A SPECIFICATIONS VDD = 5 V ± 5%, AGND = DGND = 0 V, on-chip reference, CLKIN = 10 MHz, TMIN to TMAX = –40°C to +85°C, unless otherwise noted. Table 1. Parameter ACCURACY 1, 2 Measurement Error on Current Channel Min ADE7752 Typ Max 0.1 Phase Error Between Channels PF = 0.8 Capacitive PF = 0.5 Inductive AC Power Supply Rejection Output Frequency Variation (CF) ±0.1 ±0.
PAGE 4
ADE7752/ADE7752A TIMING CHARACTERISTICS VDD = 5 V ± 5%, AGND = DGND = 0 V, on-chip reference, CLKIN = 10 MHz, TMIN to TMAX = –40°C to +85°C, unless otherwise noted 1, 2 . Table 2. Parameter t1 3 t2 t3 t43, 4 t5 5 t6 Conditions F1 and F2 Pulse Width (Logic High). Output Pulse Period. See the Transfer Function section. Time between F1 Falling Edge and F2 Falling Edge. CF Pulse Width (Logic High). CF Pulse Period. See the Transfer Function and the Frequency Outputs sections.
PAGE 5
ADE7752/ADE7752A ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 3.
PAGE 6
ADE7752/ADE7752A PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 1 24 F1 DGND 2 23 F2 VDD 3 22 S1 21 S0 20 CLKOUT CF REVP 4 IAP 5 ADE7752/ ADE7752A CLKIN TOP VIEW IBP 7 (Not to Scale) 18 SCF 19 IBN 8 17 ABS ICP 9 16 VAP ICN 10 15 VBP AGND 11 14 VCP REFIN/OUT 12 13 VN 02676-A-003 IAN 6 Figure 3. Pin Configuration Table 4. Pin Function Descriptions Pin No.
PAGE 7
ADE7752/ADE7752A Pin No. 19 Mnemonic CLKIN 20 CLKOUT 21, 22 S0, S1 24, 23 F1, F2 Description Master Clock for ADCs and Digital Signal Processing. An external clock can be provided at this logic input. Alternatively, a parallel resonant AT crystal can be connected across CLKIN and CLKOUT to provide a clock source for the ADE7752. The clock frequency for specified operation is 10 MHz. Ceramic load capacitors between 22 pF and 33 pF should be used with the gate oscillator circuit.
PAGE 8
ADE7752/ADE7752A TYPICAL PERFORMANCE CHARACTERISTICS 0.5 1.0 WYE CONNECTION ON-CHIP REFERENCE 0.4 0.2 PHASE A + B + C PHASE A 0.1 PHASE B 0 –0.1 –0.2 0.4 0.2 0 –0.2 +25°C PF = 1 –40°C PF = 1 –0.4 10 1 CURRENT CHANNEL (% of Full Scale) –0.8 –1.0 0.1 100 Figure 4. Error as a Percent of Reading with Internal Reference (Wye Connection) 0.5 WYE CONNECTION ON-CHIP REFERENCE 0.4 +85°C PF = +0.5 0.3 0.4 +25°C PF = –0.5 0.2 0 –0.2 –0.4 +25°C PF = +1 –40°C PF = +0.5 –0.8 1 10 0 –0.1 –0.
PAGE 9
ADE7752/ADE7752A 0.5 WYE CONNECTION ON-CHIP REFERENCE 0.4 18 0.3 15 0.2 12 0.1 0 9 PF = 0.5 –0.1 6 –0.2 –0.3 3 02676-A-010 –0.4 –0.5 45 50 55 60 02676-A-012 ERROR (% of Reading) PF = 1 N: 88 MEAN: 4.48045 SD: 3.23101 MIN: –2.47468 MAX: 12.9385 RANGE: 15.4132 0 –20 65 –15 –10 0.5 WYE CONNECTION EXTERNAL REFERENCE 5V 0.1 0 5.25V –0.1 –0.2 15 20 4.75V 0.2 5V 0.1 0 –0.1 5.25V –0.2 –0.3 –0.3 –0.4 –0.5 0.1 10 10 1 CURRENT CHANNEL (% of Full Scale) 02676-A-013 0.
PAGE 10
ADE7752/ADE7752A TEST CIRCUIT VDD 100nF 3 1kΩ RB VDD 5 IAP 17 F2 23 ADE7752/ ADE7752A CF 33nF 1kΩ 6 IAN 7 IBP 8 IBN 9 ICP 10 ICN K7 ABS F1 24 TO FREQ. COUNTER 825Ω 1 22pF 33nF K8 CLKOUT 20 SAME AS IAP, IAN SAME AS IAP, IAN CLKIN 19 22pF S0 21 S1 22 SCF 18 1MΩ 220V 1kΩ 16 VAP SAME AS VAP 15 VBP SAME AS VAP 14 VCP 33nF PS2501-1 10MHz 1kΩ REFIN/OUT 12 100nF 10μF REVP 4 NOT CONNECTED VN AGND DGND 13 VDD 11 2 1kΩ 33nF Figure 14.
PAGE 11
ADE7752/ADE7752A TERMINOLOGY Measurement Error The error associated with the energy measurement made by the ADE7752 is defined by the following formula: ⎧ Energy Registered by ADE 7752–True Energy ⎫ Percentage Error = ⎨ ⎬ × 100% True Energy ⎩ ⎭ Error Between Channels The high-pass filter (HPF) in the current channel has a phase lead response. To offset this phase response and equalize the phase response between channels, a phase correction network is also placed in the current channel.
PAGE 12
ADE7752/ADE7752A THEORY OF OPERATION The six voltage signals from the current and voltage transducers are digitized with ADCs. These ADCs are 16-bit second-order ∑-Δ with an oversampling rate of 833 kHz. This analog input structure greatly simplifies transducer interface by providing a wide dynamic range for direct connection to the transducer and also by simplifying the antialiasing filter design. A high-pass filter in the current channel removes the dc component from the current signal.
PAGE 13
ADE7752/ADE7752A This is the correct real power calculation. INSTANTANEOUS POWER SIGNAL i (t ) = IO + 2 × ∑ Vn I × sin (nωt βn ) ∞ INSTANTANEOUS REAL POWER SIGNAL (2) n=0 where: V× I 2 i(t) is the instantaneous current. IO is the dc component. In is the rms value of current harmonic n. βn is the phase angle of the current harmonic.
PAGE 14
ADE7752/ADE7752A ANALOG INPUTS CURRENT CHANNELS VOLTAGE CHANNELS The voltage outputs from the current transducers are connected to the ADE7752 current channels, which are fully differential voltage inputs. IAP, IBP, and ICP are the positive inputs for IAN, IBN, and ICN, respectively. The output of the line voltage transducer is connected to the ADE7752 at this analog input. Voltage channels are a pseudodifferential voltage input. VAP, VBP, and VCP are the positive inputs with respect to VN.
PAGE 15
ADE7752/ADE7752A TYPICAL CONNECTION DIAGRAMS CURRENT CHANNEL CONNECTION METER CONNECTIONS Figure 19 shows a typical connection diagram for the current channel (IA). A current transformer (CT) is the current transducer selected for this example. Notice the common-mode voltage for the current channel is AGND and is derived by center tapping the burden resistor to AGND. This provides the complementary analog input signals for IAP and IAN.
PAGE 16
ADE7752/ADE7752A Figure 21 shows the connections of the analog inputs of the ADE7752 with the power lines in a 3-phase 3-wire delta service. Note that only two current inputs and two voltage inputs of the ADE7752 are used in this case. The real power calculated by the ADE7752 does not depend on the selected channels.
PAGE 17
ADE7752/ADE7752A POWER SUPPLY MONITOR The ADE7752 contains an on-chip power supply monitor. The power supply (VDD) is continuously monitored by the ADE7752. If the supply is less than 4 V ± 5%, the outputs of the ADE7752 are inactive. This is useful to ensure correct device startup at power-up and power-down. The power supply monitor has built-in hysteresis and filtering. This gives a high degree of immunity to false triggering due to noisy supplies.
PAGE 18
ADE7752/ADE7752A DIGITAL-TO-FREQUENCY CONVERSION After multiplication, the digital output of the low-pass filter contains the real power information of each phase. Because this LPF is not an ideal brick wall filter implementation, however, the output signal also contains attenuated components at the line frequency and its harmonics (cos(hωt), where h = 1, 2, 3, and so on). power signal. The average value of a sinusoidal signal is zero.
PAGE 19
ADE7752/ADE7752A MODE SELECTION OF THE SUM OF THE THREE ACTIVE ENERGIES The ADE7752 can be configured to execute the arithmetic sum of the three active energies, Wh = WhϕA + WhϕB + WhϕC, or the sum of the absolute value of these energies, Wh = |WhϕA| + |WhϕB| + |WhϕC|. The selection between the two modes can be made by setting the ABS pin. Logic high and logic low applied on the ABS pin correspond to the arithmetic sum and the sum of absolute values, respectively.
PAGE 20
ADE7752/ADE7752A TRANSFER FUNCTION FREQUENCY OUTPUTS F1 AND F2 The ADE7752 calculates the product of six voltage signals (on current channel and voltage channel) and then low-pass filters this product to extract real power information. This real power information is then converted to a frequency. The frequency information is output on F1 and F2 in the form of active high pulses. The pulse rate at these outputs is relatively low, such as 29.
PAGE 21
ADE7752/ADE7752A As the voltage and current inputs respect Equations 5 and 6, the total real power (P) is P = (V A − VC ) (I AP − I AN ) + (V B − VC ) × (I BP − I BN ) ⎛ 4π ⎞ ⎞ ⎛ P = ⎜⎜ 2 × V A × cos(ω l t ) − 2 × VC × cos⎜ ω l t + ⎟⎟ 3 ⎠ ⎟⎠ ⎝ ⎝ × 2 × I A × cos(ω l t ) ⎛ 2π ⎞ 4π ⎞ ⎞ ⎛ ⎛ + ⎜⎜ 2 × V B × cos⎜ ω l t + ⎟ − v 2 × VC × cos⎜ ω l t + ⎟⎟ 3 ⎠ 3 ⎠ ⎟⎠ ⎝ ⎝ ⎝ 2π ⎞ ⎛ × 2 × I B × cos⎜ ω l t + ⎟ 3 ⎠ ⎝ For simplification, assume that ϕA = ϕB = ϕC = 0 and VA = VB = VC = V.
PAGE 22
ADE7752/ADE7752A SELECTING A FREQUENCY FOR AN ENERGY METER APPLICATION As shown in Table 5, the user can select one of seven frequencies. This frequency selection determines the maximum frequency on F1 and F2. These outputs are intended to be used to drive the energy register (electromechanical or other).
PAGE 23
ADE7752/ADE7752A NEGATIVE POWER INFORMATION The ADE7752 detects when the current and voltage channels of any of the three phase inputs have a phase difference greater than 90°: ϕA or ϕB or ϕC > 90°. This mechanism can detect wrong connection of the meter or generation of active energy. The REVP pin output goes active high when negative power is detected on any of the three phase inputs. If positive active energy is detected on all the three phases, REVP pin output is low.
PAGE 24
ADE7752/ADE7752A OUTLINE DIMENSIONS 15.60 (0.6142) 15.20 (0.5984) 24 13 7.60 (0.2992) 7.40 (0.2913) 1 12 2.65 (0.1043) 2.35 (0.0925) 10.65 (0.4193) 10.00 (0.3937) 0.75 (0.0295) × 45° 0.25 (0.0098) 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 1.27 (0.0500) BSC 0.10 0.51 (0.020) 0.31 (0.012) 8° SEATING 0.33 (0.0130) 0° PLANE 0.20 (0.0079) 1.27 (0.0500) 0.40 (0.