fs7755 Fortune Semiconductor Corporation, fs7755 Datasheet
fs7755
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fs7755 Summary of contents
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... FS7755-DS-10_EN REV. 1.0 Datasheet FS7755 Energy Metering IC with Impulse Output SEP 2009 ...
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... This manual contains new product information. Fortune Semiconductor Corporation reserves the rights to modify the product specification without further notice. No liability is assumed by Fortune Semiconductor Corporation as a result of the use of this product. No rights under any patent accompany the sale of the product. Rev. 1.0 FS7755 2/22 ...
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... The FS7755 is a high accuracy electrical energy measurement IC. The part specifications surpass the accuracy requirements as quoted in the IEC1036 standard. The only analog circuitry used in the FS7755 is in the ADCs and reference circuit. All other signal processing (e.g., DSP) is carried out in the digital domain. This approach provides superior stability and accuracy over extremes in environmental conditions and over time ...
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... Pin Description Pin Name Digital Power Supply. This pin provides the supply voltage for the digital circuitry in the FS7755. The supply voltage should be maintained at 5V ± 5% for specified operation This pin should be decoupled with a 10μF capacitor in parallel with a ceramic 100nF capacitor ...
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... Reset Pin for the FS7755. A logic low on this pin will hold the ADCs and digital circuitry 9 RESET in a reset condition. Bringing this pin logic low will clear the FS7755 internal registers. This pin provides access to the on-chip voltage reference. The on-chip reference has a nominal value of 2.5V ± ...
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... Vref in/out 8. Typical Application Circuit Rev. 1.0 DV DGN igit al Signal Pr ocessor Power Supply P ower Supply Monitor System CLKIN CLKOU Fig2 Functional Block Diagram Fig3 Application Circuit FS7755 RESET REVP SCF 6/22 ...
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... V1P, V1N, V2N, and V2P to AGND kΩ min CLKIN = 3.579545MHz 14 kHz typ CLKIN/256, CLKIN = 3.579545MHz mV max Gain = 1, See Terminology and Performance Graphs ±7 % Ideal typ External 2.5 V Reference, Gain = 470mV % Ideal typ External 2.5 V Reference FS7755 + min max , V2 = 100mV , @50Hz rms ...
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... SOURCE 0.5 V max I = 10mA SINK min I = 5mA SOURCE 0.5 V max I = 5mA SINK For Specified Performance V min 5V – max min 5V – max max Typically 2mA 2.5 mA max Typically 1.5mA FS7755 = 8/22 ...
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... F1 and F2 Pulse width (Logic Low) sec Output Pulse Period. See Transfer Function section. sec Time between F1 Falling Edge and F2 Falling Edge Pulse Width (Logic High). sec CF Pulse Period. See Transfer Function section. sec Minimum Time between F1 and F2 Pulse FS7755 to T min max 9/22 ...
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... Gain Error The gain error of the FS7755 is defined as the difference between the measured output frequency (minus the offset) and the ideal output frequency measured with a gain Channel V1. The difference is expressed as a percentage of the ideal frequency. The ideal frequency is obtained from the FS7755 transfer function (see Transfer Function section) ...
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... Sig nal i(t), v(t) Time The low frequency output of the FS7755 is generated by accumulating 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 ...
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... Using Equations (1) and (2), the real power P can be expressed in terms of its fundamental real power (P ) and harmonic real power ( Where ×I cosφ φ =α -β Rev. 1.0 Instantaneous Instantaneous Real Power Signal Power Signal V× V(t) I(t) Instantaneous Instantaneous Power Signal Real Power Signal I( V( (3) FS7755 12/22 ...
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... Analog Inputs 4.1 Channel V1 (Current Channel) The voltage output from the current transducer is connected to the FS7755 here. Channel fully differential voltage input. V1P is the positive input with respect to V1N. The maximum peak differential signal on Channel 1 should be less than ±470mV (330mV rms for a pure sinusoidal signal) for specified operation ...
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... Channel V2 (Voltage Channel) The output of the line voltage transducer is connected to the FS7755 at this analog input. Channel fully differential voltage input. The maximum peak differential signal on Channel 2 is ± 660mV. V2 +660mV VCM -660mV Fig8 Fig8 illustrates the maximum signal levels that can be connected to the FS7755 Channel 2. ...
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... Power Supply Monitor The FS7755 contains an on-chip power supply monitor. The Analog Supply (AV monitored by the FS7755. If the supply is less than 4V ± 5%, the FS7755 will be reset. 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. ...
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... Interfacing the FS7755 to a Micro- Controller for Energy Measurement The easiest way to interface the FS7755 to a micro-Controller is to use the CF high frequency output with the output frequency scaling set to 2048×F1, F2. This is done by setting SCF = 0 and (see Table Ⅳ). With full-scale AC signals on the analog inputs, the output frequency on CF will be approximately 5 ...
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... Frequency Outputs F1 and F2 The FS7755 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, e ...
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... Table Ⅲ shows a complete listing of all maximum output frequencies Table Rev. 1.0 − (Hz) XTAL/CLKIN 1-4 0 1.7 3.579545MHz/2 1 3.4 3.579545MHz/2 0 6.8 3.579545MHz/2 1 13.6 3.579545MHz/2 F Frequency Selection 1-4 Volts 2 Volts 2 S0 Max Frequency for AC Inputs (Hz) 0 0.34 1 0.68 0 1.36 1 2.72 Maximum Output Frequency on F1 and F2 Ⅲ FS7755 18/22 ...
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... F2 = 21. 3.4 64×F1 43. 3.4 32×F1 21. 6.8 32×F1 43. 6.8 16×F1 21. 13.6 16×F1 43. 13.6 2048×F1 5570 Maximum Output Frequency (A) F1 and F2 (Hz) Max 12.5 0.076 25 0.153 40 0.244 60 0.367 80 0.489 120 0.733 F1 and F2 Frequency at 100imp/kWhr FS7755 ) with a Max 19/22 ...
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... Table Ⅴ). Looking at Table Ⅵ, the closest frequency to 0.153Hz in column four is 0.17Hz. Therefore, F2 (3.4Hz—see Table II) is selected for this design. Rev. 1.0 Frequency on F1 and F2 (Hz) 1-4 (Ch1 and Ch2 Half Scale AC Inputs) 0.085 0.17 0.34 0.68 1–4 FS7755 (maximum load) Max ). For example meter with a 20/22 ...
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... The FS7755 also includes a “no load threshold” and “startup current” feature that will eliminate any creep effects in the meter. The FS7755 is designed to issue a minimum output frequency on all modes except when SCF = 0 and The no load detection threshold is disabled on this output mode to accommodate specialized application of the FS7755 ...
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... TYP FS7755 Nom Max —— 0.079 —— —— 0.069 0.073 —— 0.015 —— 0.01 0.323 0.345 0.307 0.323 0.209 0.220 ...