BL6503 Single Phase Energy Meter IC FEATURES DESCRIPTION High accuracy, less than 0.1% error over a dynamic range of 500 : 1 The BL6503 is a low cost, high accuracy, high stability, simple peripheral circuit electrical energy Exactly measure the real power in the positive meter IC. The meter based on the BL6503 is intended orientation and negative orientation, calculate the for using in single-phase, two-wire distribution energy in the same orientation systems. A PGA in the current channel allows using small value shunt and burden resistance The BL6503 adopts the oversample technology and digital signal processing technology. It can The low frequency outputs F1 and F2 can exactly measure the real power in the positive directly drive electromechanical counters and two orientation and negative orientation and calculate the phase stepper motors and the high frequency output energy in the same orientation. Moreover, BL6503 CF, supplies instantaneous real power, is intended for supplies the negative orientation indication on Pin20 calibration and communications (REVP). Therefore, the meter using the BL6503 has The logic outputs REVP can be used to indicate a great capability to avoid fault condition. potential orientation The BL6503 supplies average real power Low static power (typical value of 15mW). information on the low frequency outputs F1 (Pin23) The technology of SLiM (Smart–Low–current– and F2 (Pin24). These logic outputs may be used to Management ) is used. directly drive an electromechanical counter and On-Chip power supply detector two-phase stepper motors. The CF (Pin22) logic On-Chip anti-creep protection output gives instantaneous real power information. On-Chip voltage reference of 2.42V ± 8% This output is intended to be used for calibration (typical temperature coefficient of 30ppm/℃)，with purposes or interface to an MCU. external overdrive capability The BL6503 adopts the technology of SLiM and Single 5V supply decreases greatly the static power. This technology Credible work, working time is more than twenty also decreases the request for power supply. years BL6503 thinks over the stability of reading error in the process of calibration.. An internal no-load Interrelated patents are pending threshold ensures that the BL6503 does not exhibit any creep when there is no load. BLOCK DIAGRAM DVDD 1 24 F1 AC/DC 2 23 F2 AVDD 3 22 CF VREF power detector voltage reference NC 4 21 DGND V1P 5 20 REVP V1P V1N 6 19 NC V1N V2N 7 V2P RESET BL6503 18 CLKOUT 8 17 CLKIN 9 16 G0 VREF 10 15 G1 AGND 11 14 S0 SCF 12 13 S1 AVDD V2P V2N current sampling voltage sampling analog to digital analog to digital BL6503 high pass filter digital multiplication high pass filter digital to frequency and output low pass filter REVP CF F1 F2 logical control G0 G1 AC/DC RESET SCF S0 S1 DIP/SSOP 24 http://www.belling.com.cn -1Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC PIN DESCRIPTIONS Pin Symbol DESCRIPTIONS Digital Power Supply (+5V). Provides the supply voltage for the digital circuitry. It should be maintained at 5 V±5% for specified operation. 1 DVDD 2 AC/ DC High-Pass Filter Select. This logic input is used to enable the high pass filter in the current channel. Logic high on this pin enables the HPF. 3 AVDD Analog Power Supply (+5V). Provides the supply voltage for the analog circuitry. It should be maintained at 5 V±5% for specified operation. 4 NC 5,6 V1P,V1N Inputs for Current Channel. These inputs are fully differential voltage inputs with a maximum signal level of ±660 mV 7,8 V2N,V2P Negative and Positive Inputs for Voltage Channel. These inputs provide a fully differential input pair. The maximum differential input voltage is ±660 mV for specified operation. 9 RESET Reset Pin. Logic low on this pin will hold the ADCs and digital circuitry in a reset condition and clear internal registers. 10 VREF On-Chip Voltage Reference. The on-chip reference has a nominal value of 2.5V ± 8% and a typical temperature coefficient of 30ppm/℃. An external reference source may also be connected at this pin. 11 AGND Analog Ground Reference. Provides the ground reference for the analog circuitry. 12 SCF Calibration Frequency Select. This logic input is used to select the frequency on the calibration output CF. 13,14 S1,S0 Output Frequency Select. These logic inputs are used to select one of four possible frequencies for the digital-to-frequency conversion. This offers the designer greater flexibility when designing the energy meter. 15,16 G1,G0 Gain Select. These logic inputs are used to select one of four possible gains for current channel. The possible gains are 1, 2, 8, and 16. 17 CLKIN Clock In. An external clock can be provided at this logic input. Alternatively, a crystal can be connected across this pin and pin18 (CLKOUT) to provide a clock source 18 CLKOUT Clock Out. A crystal can be connected across this pin and pin17 (CLKIN) as described above to provide a clock source. 19 NC Reserved. Reserved. Negative Indication. Logic high indicates negative power, i.e., when the phase angle 20 REVP between the voltage and current signals is greater that 90°. This output is not latched and will be reset when positive power is once again detected. 21 DGND Digital Ground Reference. Provides the ground reference for the digital circuitry. 22 CF Calibration Frequency. The CF logic output gives instantaneous real power information. This output is intended to use for calibration purposes. 23,24 F1,F2 Low-Frequency. F1 and F2 supply average real power information. The logic outputs can be used to directly drive electromechanical counters and 2-phase stepper motors. http://www.belling.com.cn -2Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC ABSOLUTE MAXIMUM RATINGS ( T = 25 ℃ ) Symbol Value Unit Analog Power Voltage AVDD AVDD -0.3~+7(max) V Digital power Voltage DVDD DVDD -0.3~+7(max) V -0.3~+0.3 V Parameter DVDD to AVDD Analog Input Voltage of Channel 2 to AGND V (V) VSS+0.5≤V(v)≤VDD-0.5 V Analog Input Voltage of Channel 1 to AGND V (I) VSS+0.5≤V(i)≤VDD-0.5 V Operating Temperature Range Topr -40~+85 ℃ Storage Temperature Range Tstr -55~+150 ℃ 400 mW Power Dissipation（DIP24） Electronic Characteristic Parameter (T=25℃, AVDD=5V, DVDD= 5V, CLKIN=3.58MHz Parameter Symbol Test Condition ) Measure Pin Min Value Typical Value Max Value Unit 1 Analog Power Current IAVDD Pin1 2 3 mA 2 Digital Power Current IDVDD Pin3 1 2 mA 3 Logic Input Pins G0, G1, SCF,S0,S1, ACDC, /RESET Pin2, 9,12, 13,14, 15,16 Input High Voltage VIH Input Low Voltage VIL Input Capacitance CIN AVDD=5V DVDD=5V 4 Logic Output Pins F1, F2 VOH1 IH=10mA Output Low Voltage VOL1 IL=10mA V 10 pF V 0.5 10 V mA Pin22, 20,19 Output High Voltage VOH2 IH=10mA Output Low Voltage VOL2 IL=10mA 6 On-chip Reference Vref AVDD=5V 7 Analog Input Pins V1P, V1N V2N, V2P 4 Pin10 2.3 V 2.6 0.5 V 2.8 V ±1 V Pin 5,6, 7,8 VAIN DC Input Impedance 330 Input Capacitance http://www.belling.com.cn 1 4.4 IO1 5 Logic Output Pins CF, REVP, Maximum Input Voltage V Pin23, 24 Output High Voltage Output Current 2 Kohm 10 -3Total 12 Pages pF 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC 8 Accuracy Measurement Error on Channel 1 and 2 Gain=1 ENL1 Pin22 0.1 0.4 % Gain=2 ENL2 Pin22 0.1 0.4 % Pin22 0.1 0.4 % Pin22 0.1 0.4 % Channel 1 Lead 37° (PF=0.8Capacitive) Pin22 0.1 0.3 % Channel 1 Lags (PF=0.5Inductive) Pin22 0.1 0.3 % Gain=8 ENL8 Gain=16 ENL16 Phase Error Channels Both Channels with Full-Scale Signal ±660mV Over a Dynamic Range500 to 1 between 9 Start Current ISTART Ib=5A C=3200, Pin5 cosϕ=1 Voltage Channel 0.2%I b A Inputs ±110mV Gain of Current Channel 16 10 Positive and Negative Real Power Error (%) ENP Vv=±110mV,V(I)= 2mV, cosϕ=1 Vv=±110mV,V(I)= 2mV, cosϕ=-1 Pin22 0.4 % 11 Gain Error Gain error External 2.5V Reference,Gain=1, V1=V2=500mV DC Pin22 ±10 % 1 % 4.1 V 12 Gain Error Match 13Power Supply Monitor Voltage Vdown Power Supply vary from 3.5V to 5V,and Current Channel with Full-Scale Signal Pin22 0.2 Pin22 3.9 4 TERMINOLOGY 1) Measurement Error The error associated with the energy measurement made by the BL6503 is defined by the following formula: Pencentage Error = Energy Re gistered by the BL6501 − True Energy × 100% True Energy http://www.belling.com.cn -4Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC 2) Nonlinear Error The Nonlinear Error is defined by the following formula: eNL%＝[(Error at X-Error at Ib) / (1+Error at Ib )]*100% When V(v)= ±110mV, cosϕ=1, over the arrange of 5%Ib to 800%Ib, the nonlinear error should be less than 0.1%. 3) Positive and Negative Real Power Error When the positive real power and the negative real power is equal, and V(v) =±110mV, the test current is Ib, then the positive and negative real power error can be achieved by the following formula: eNP%=|[(eN%-eP%)/(1+eP%)]*100%| Where: eP% is the Positive Real Power Error, eN% is the Negative Real Power Error. 4) Gain Error The gain error of the BL6503 is defined as the difference between the measured output frequency (minus the offset) and the ideal output frequency. It is measured with a gain of 1 in channel V1. The difference is expressed as a percentage of the ideal frequency. The ideal frequency is obtained from the BL6503 transfer function. 5) Gain Error Match The gain error match is defined as the gain error (minus the offset) obtained when switching between a gain of 1 and a gain of 2, 8, or 16. It is expressed as a percentage of the output frequency obtained under a gain of 1. This gives the gain error observed when the gain selection is changed from 1 to 2, 8 or 16. 6) Power Supply Monitor BL6503 has the on-chip Power Supply monitoring The BL6503 will remain in a reset condition until the supply voltage on AVDD reaches 4 V. If the supply falls below 4 V, the BL6503 will also be reset and no pulses will be issued on F1, F2 and CF. TIMING CHARACTERISTIC (AVDD=DVDD=5V, AGND=DGND=0V, On-Chip Reference, CLKIN=3.58MHz, Temperature range: -40~+85°C) http://www.belling.com.cn -5Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC Parameter t1 Value 275ms t2 Comments F1 and F2 pulse-width (Logic Low). When the power is low, the t1 is equal to 275ms; when the power is high, and the output period exceeds 550ms, t1 equals to half of the output period. F1 or F2 output pulse period. t3 ½ t2 Time between F1 falling edge and F2 falling edge. t4 90ms CF pulse-width (Logic high). When the power is low, the t4 is equal to 90ms; when the power is high, and the output period exceeds 180ms, t4 equals to half of the output period. t5 CF Pulse Period. See Transfer Function section. t6 CLKIN/4 Minimum Time Between F1 and F2. Notes: 1) CF is not synchronous to F1 or F2 frequency outputs. 2) Sample tested during initial release and after any redesign or process changes that may affect this parameter. THEORY OF OPERATION Principle of Energy Measure In energy measure, the power information varying with time is calculated by a direct multiplication of the voltage signal and the current signal. Assume that the current signal and the voltage signal are cosine functions; Umax, Imax are the peak values of the voltage signal and the current signal; ωis the angle frequency of the input signals; the phase difference between the current signal and the voltage signal is expressed asφ. Then the power is given as follows: p (t ) = U max cos( wt ) × I max cos( wt + ϕ ) If φ=0: p (t ) = U max I max [1 + cos(2 wt )] 2 If φ≠0: p (t ) = U max cos(ωt ) × I max cos(ωt + Φ ) = U max cos(ωt ) × [I max cos(ωt ) cos(Φ ) + I max sin(ωt ) sin(Φ )] U max I max [1 + cos(2ωt )] cos(Φ ) + U max I max cos(ωt ) sin(ωt ) sin(Φ ) 2 U I U I = max max [1 + cos(2ωt )] cos(Φ ) + max max sin( 2ωt ) sin(Φ) 2 2 U I U I = max max cos(Φ) + max max [cos(2ωt ) cos(Φ ) + sin( 2ωt ) sin(Φ)] 2 2 U I U I = max max cos(Φ) + max max cos(2ωt + Φ) 2 2 = P(t) is called as the instantaneous power signal. The ideal p(t) consists of the dc component and ac http://www.belling.com.cn -612/31/2004 Total 12 Pages Wrote by 1452 BL6503 Single Phase Energy Meter IC component whose frequency is 2ω. The dc component is called as the average active power, that is: P= U max I max cos(ϕ ) 2 The average active power is related to the cosine value of the phase difference between the voltage signal and the current signal. This cosine value is called as Power Factor (PF) of the two channel signals. Figure1. The Effect of phase When the signal phase difference between the voltage and current channels is more than 90°, the average active power is negative. It indicates the user is using the electrical energy reversely. Operation Process In BL6503, the two ADCs digitize the voltage signals from the current and voltage transducers. These ADCs are 16-bit second order sigma-delta with an oversampling rate of 900 kHz. This analog input structure greatly simplifies transducer interfacing by providing a wide dynamic range for direct connection to the transducer and also simplifying the antialiasing filter design. A programmable gain stage in the current channel further facilitates easy transducer interfacing. A high pass filter in the current channel removes any dc component from the current signal. This eliminates any inaccuracies in the real power calculation due to offsets in the voltage or current signals. The real power calculation is derived from the instantaneous power signal. The instantaneous power signal is generated by a direct multiplication of the current and voltage signals. In order to extract the real power component (i.e., the dc component), the instantaneous power signal is low-pass filtered. Figure 2 illustrates the instantaneous real power signal and shows how the real power information can be extracted by low-pass filtering the instantaneous power signal. This scheme correctly calculates real power for nonsinusoidal current and voltage waveforms at all power factors. All signal processing is carried out in the digital domain for superior stability over temperature and time. http://www.belling.com.cn -7Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC I V current sampling voltage sampling analog to digital high pass filter analog to digital digital multiplication high pass filter CF low pass filter F1 F2 instantaneous real power signal instantaneous power signal p(t) V*I digital to frequency integral p(t)=i(t)*v(t) v(t)=V*cos(wt) i(t)=I*cos(wt) V*I 2 p(t)= V*I 2 V*I 2 [1+cos(2wt)] t t Figure 2. Signal Processing Block Diagram The low frequency output of the BL6503 is generated by accumulatingm this real power information. This low frequency inherently means a long accumulation time between output pulses. The output frequency is therefore proportional to the average real power. This average real power information can, in turn, be accumulated (e.g., by a counter) to generate real energy information. Because of its high output frequency and hence shorter integration time, the CF output is proportional to the instantaneous real power. This is useful for system calibration purposes that would take place under steady load conditions. VOLTAGE CHANNEL INPUT The output of the line voltage transducer is connected to the BL6503 at this analog input. As Figure4 shows that channel V2 is a fully differential voltage input. The maximum peak differential signal on Channel 2 is ±660mV. Figure4 illustrates the maximum signal levels that can be connected to the BL6503 Voltage Channel. V1 +660mV Maximun input differential voltage ± 660mV V2P + V1 V2N V2 - V2 -660mV Maximun input common-mode voltage ± 100mV AGND Figure 4. Voltage Channels Voltage Channel must be driven from a common-mode voltage, i.e., the differential voltage signal on the input must be referenced to a common mode (usually AGND). The analog inputs of the BL6503 can be driven with common-mode voltages of up to 100 mV with respect to AGND. However, best results are achieved using a common mode equal to AGND. Figure5 shows two typical connections for Channel V2. The first option uses a PT (potential transformer) to provide complete isolation from the mains voltage. In the second option, the BL6503 is biased around the neutral wire and a resistor divider is used to provide a voltage signal that is proportional to the line voltage. Adjusting the ratio of Ra and Rb is also a convenient way http://www.belling.com.cn -8Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC of carrying out a gain calibration on the meter. RF CT V2P CF ± 660mV RF AGND V2N + - CF AGND Phase Neutral AGND CF Ra Rb AGND Rv AGND ± 660mV V2P Phase Neutral RF AGND V2N Ra >> RF Rb+Rv=RF Figure 5. + - CF AGND AGND Typical Connections for Voltage Channels CURRENT CHANNEL INPUT The voltage outputs from the current transducers are connected to the BL6503 here. The maximum differential voltage on Current Channel 2 is ±660mV. The maximum common-mode voltage is ±100mV. Power Supply Monitor The BL6503 contains an on-chip power supply monitor. If the supply is less than 4V±5% then the BL6503 will go in an inactive state, i.e. no energy will be accumulated when the supply voltage is below 4V. This is useful to ensure correct device operation at power up and during 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. The trigger level is nominally set at 4V, and the tolerance on this trigger level is about ±5%. The power supply and decoupling for the part should be such that the ripple at VDD does not exceed 5V±5% as specified for normal operation. SLiM technology http://www.belling.com.cn -9Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC The BL6503 adopts the technology of SLiM (Smart Low current Management) to decrease the static power greatly. The static power of BL6503 is about 12mW. It is half of the previous product BL0955 (about 25mW ).This technology also decreases the request for power supply design. BL65XX series products used 0.35um CMOS process. The reliability and consistency are advanced. OPERATION MODE Transfer Function The BL6503 calculates the product of two voltage signals (on Channel 1 and Channel 2) 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 low pulses. The pulse rate at these outputs is relatively low. It means that the frequency at these outputs is generated from real power information accumulated over a relatively long period of time. The result is an output frequency that is proportional to the average real power. The average of the real power signal is implicit to the digital-to-frequency conversion. The output frequency or pulse rate is related to the input voltage signals by the following equation. (use 3.58MHz oscillator) Freq = 8.34 × V (v) × V (i ) × gain × FZ 2 VREF Freq——Output frequency on F1 and F2 (Hz) V(v)——Differential rms voltage signal on Channel 1 (volts) V(i)——Differential rms voltage signal on Channel 2 (volts) Gain——1, 2, 8 or 16, depending on the PGA gain selection, using logic inputs G0 and G1 Vref——The reference voltage (2.42 V±8%) (volts) Fz——One of four possible frequencies selected by using the logic inputs S0 and S1. S1 S0 Fz(Hz) XTAL/CLKIN 0 0 1.7 CLKIN/2^21 0 1 3.4 CLKIN/2^20 1 0 6.8 CLKIN/2^19 1 1 13.6 CLKIN/2^18 Frequency Output CF The pulse output CF (Calibration Frequency) is intended for use during calibration. The output pulse rate on CF can be up to 128 times the pulse rate on F1 and F2. The following Table shows how the two frequencies are related, depending on the states of the logic inputs S0, S1 and SCF. Mode SCF S1 S0 CF/F1 (or F2) 1 1 0 0 128 2 0 0 0 64 3 1 0 1 64 4 0 0 1 32 http://www.belling.com.cn - 10 Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC 5 1 1 0 32 6 0 1 0 16 7 1 1 1 16 8 0 1 1 2048 Because of its relatively high pulse rate, the frequency at this logic output is proportional to the instantaneous real power. As is the case with F1 and F2, the frequency is derived from the output of the low-pass filter after multiplication. However, because the output frequency is high, this real power information is accumulated over a much shorter time. Hence less averaging is carried out in the digital-to-frequency conversion. With much less averaging of the real power signal, the CF output is much more responsive to power fluctuations. GAIN SELECTION By select the digital input G0 and G1 voltage (5V or 0V), we can adjust the gain of current channel. We can see that while increasing the gain, the input dynamic range is decreasing. G1 G0 Gain Maximum Differential Signal 0 0 1 ±660mV 0 1 2 ±330mV 1 0 8 ±82mV 1 1 16 ±41mV ANALOG INPUT RANGE The maximum peak differential signal on Voltage Channel is ± 660 mV, and the common-mode voltage is up to 100 mV with respect to AGND. The analog inputs V1A, V1B, and V1N have the same maximum signal level restrictions as V2P and V2N. However, The Current Channel has a programmable gain amplifier (PGA) with user-selectable gains of 1, 2, 8, or 16. These gains facilitate easy transducer interfacing. The maximum differential voltage is ±660 mV and the maximum common-mode signal is ±100 mV. The corresponding Max Frequency of CF/F1/F2 is shown in the following table. SCF S1 S0 Fz Max Frequency of F1, F2 (Hz) DC CF Max Frequency (Hz) AC DC AC 1 0 0 1.7 0.72 0.36 128×F1,F2=92.16 128×F1,F2=46.08 0 0 0 1.7 0.72 0.36 64×F1,F2=46.08 64×F1,F2=23.04 1 0 1 3.4 1.44 0.72 64×F1,F2=92.16 64×F1,F2=46.08 0 0 1 3.4 1.44 0.72 32×F1,F2=46.08 32×F1,F2=23.04 1 1 0 6.8 2.88 1.44 32×F1,F2=92.16 32×F1,F2=46.08 0 1 0 6.8 2.88 1.44 16×F1,F2=46.08 16×F1,F2=23.04 1 1 1 13.6 5.76 2.88 16×F1,F2=92.16 16×F1,F2=46.08 0 1 1 13.6 5.76 2.88 2048×F1,F2=11.8K 2048×F1,F2=5.9K http://www.belling.com.cn - 11 Total 12 Pages 12/31/2004 Wrote by 1452 BL6503 Single Phase Energy Meter IC Application Notice：Sample tested during initial release and after any redesign or process changes that may affect parameter. Specification subject to change without notice. Please ask for the newest product specification at any moment. http://www.belling.com.cn - 12 Total 12 Pages 12/31/2004 Wrote by 1452