AUTOMOTIVE CURRENT TRANSDUCER DHAB S/25

Transcription

1 AUTOMOTIE CURRENT TRANSDUCER Introduction The DHAB family is best suited for DC, AC, or pulsed currents measurement in high power and low voltage automotive applications. Its contains galvanic isolation between the primary circuit (high power) and the secondary circuit (electronic circuit). The DHAB family gives you a choice of having different current measuring ranges in the same housing (from ± 20 up to ± 600 A). Features Open Loop transducer using the Hall effect sensor Low voltage application Unipolar + 5 DC power supply Primary current measuring range up to ± 25 A for range 1 and ± 200 A for range 2 Maximum rms primary admissible limited by the busbar, the magnetic core or the ASIC temperature T < C Operating temperature range: - 40 C < T < C Output voltage: fully ratiometric (in sensitivity and offset) 2 measuring ranges to have a better accuracy. Principle of DHAB Family The open loop transducers use an Hall effect integrated circuit. The magnetic flux density B, contributing to the rise of the Hall voltage, is generated by the primary current to be measured. The current to be measured is supplied by a current source i.e. battery or generator (Fig. 1). Within the linear region of the hysteresis cycle, B is proportional to: B ( ) = constant (a) x The Hall voltage is thus expressed by: H = (R H /d) x I x constant (a) x Except for, all terms of this equation are constant. Therefore: H = constant (b) x The measurement signal H amplified to supply the user output voltage or current. Advantages Good accuracy for high and low current range Good linearity Low thermal offset drift Low thermal sensitivity drift Hermetic package. + c - c 0 Automotive applications Battery Pack Monitoring Hybrid ehicles E and Utility ehicles.principle of HAH1DR Famil Primary current Fig. 1: Principle of the open loop transducer Isolated output voltage Page 1/5

2 Dimensions DHAB S/45 Bill of materials System architecture (example) Plastic case Magnetic core Pins Mass >PA66-GF25< : FeNi alloy : FeSi alloy Brass tin plated 69.5 g IP Primary current LEM - DHAB sensor nf 10 nf C Typical application Schematic interface CLOAD 47 nf RLOAD R + 5 C R 10 nf CLOAD RLOAD C R L > 10 kw optional resistor for signal line diagnosis C L < 100 nf EMC protection RC Low pass filter EMC protection (optional) Page 2/5

3 Absolute maximum ratings Supply voltage Operating characteristics C Over voltage 14 1 min Reverse voltage T A Output voltage (Analog) 8.5 Output over voltage (Analog) OUT 14 1 T A Continuous output current I OUT ma Output short-circuit duration T c min 2 Ambient storage temperature T S C Note: 1) The output voltage OUT is fully ratiometric (concerning O, sensitivity and clamping) and is dependent on the supply voltage C relative to the following formula: C 1 5 IP = OUT with G in ( / A) 2 G C 8.5 Supply voltage C Output current (Analog) I OUT ma Current consumption I C ma Power up inrush current C < 3.5 Load resistance R L ΚΩ 10 Capacitive loading C L nf Ambient operating temperature T A C High accuracy Reduced accuracy Primary current channel 1 A Calibration current I CAL -25 T A Offset voltage 1) O C Sensitivity 1) G m/a C Resolution m C Output clamping voltage min 1) C SZ Output clamping voltage max 1) C Output internal resistance R OUT Ω 1 10 Frequency bandwidth BW Hz -3 db Power up time ms Setting time after over load ms 25 Primary current channel 2 A Calibration current I CAL -200 T A Offset voltage 1) O C Sensitivity 1) G m/a C Resolution m C Output clamping voltage min 1) C SZ Output clamping voltage max 1) C Output internal resistance R OUT Ω 1 10 Frequency bandwidth BW Hz -3 db Power up time ms Setting time after over load ms 25 Page 3/5

4 ACCURACY Electrical offset current I OE channel 1 ma ± T A Magnetic offset current I OM channel 1 ma ± T A ± T A Global offset current I O channel 1 ma C < T < 65 C C < T < 125 C ± T A Sensitivity error ε G % C < T < 65 C C < T < 125 C Linearity error ε L % off full range Electrical offset current I OE channel 1 A ± T A Magnetic offset current I OM channel 1 A ± T A ± T A Global offset current I O channel 1 A C < T < 65 C C < T < 125 C ± T A Sensitivity error ε G % C < T < 65 C C < T < 125 C Linearity error ε L % off full range Note: In case of short circuit of any DHAB output to + batt, a current is reinjected in the power supply. If the output voltage is not protected against this current, this voltage may increase or decrease, which must be taken into account for the second channel. Page 4/5

5 PERFORMANCES PARAMETERS DEFINITIONS Output noise voltage: The output voltage noise is the result of the noise floor of the Hall elements and the linear I C amplifier gain. Magnetic offset: The magnetic offset is the consequence of an over-current on the primary side. It s defined after an excursion of max. Linearity: The maximum positive or negative discrepancy with a reference straight line OUT = f ( ). Unit: linearity (%) expressed with full scale of max. Linearity is measured on cycle +, O, -, O, + without magnetic offset (average values used) Sensitivity: The Transducer s sensitivity G is the slope of the straight line = f ( ), it must establish the relation: ( ) = C /5 (G x + 2.5) (*) (*) For all symetrics transducers. Offset with temperature: The error of the offset in the operating temperature is the variation of the offset in the temperature considered with the initial offset at 25 C. The offset variation I OT is a maximum variation the offset in the temperature range: I OT = I OE max - I OE min The Offset drift TCI OEA is the I OT value divided by the temperature range. Reference straight line OUT Non linearity example Max linearity error Linearity variation in I N % Sensitivity with temperature: The error of the sensitivity in the operating temperature is the relative variation of sensitivity with the temperature considered with the initial offset at 25 C. The sensitivity variation G T is the maximum variation (in ppm or %) of the sensitivity in the temperature range: G T = (Sensitivity max - Sensitivity min) / Sensitivity at 25 C. The sensitivity drift TCG A is the G T value divided by the temperature range. Response time (delay time) t r : The time between the primary current signal and the output signal reach at 90 % of its final value Offset = 0 A: Is the output voltage when the primary current is null. The ideal value of O is C /2 at C. So, the difference of O - C /2 is called the total offset voltage error. This offset error can be attributed to the electrical offset (due to the resolution of the ASIC quiescent voltage trimming), the magnetic offset, the thermal drift and the thermal hysteresis. I [A] I T Environmental test specifications Name Standard 90 % I S Thermal shocks GM &5.5.5 (IEC Part 2-14) T - 40 C to 125 C / 300 cycles not connected. t r Power temperature GM &5.5.6 (IEC Part 2-14 Nb T C/595 cycles, supply voltage Temperature humidity cycle test GM & (IEC ) T C/10 cycles, supply voltage Mechanical tests GM &6.6.2 (IEC ) t [µs] Typical: Theorical value or usual accuracy recorded during the production. ibration test Drop test GM &6.10 (IEC ) EMC Test GM & (IEC ) Acceleration 30m/s2, 25 C, frequency 20 to 1000 Hz/8h each axis Drop 1m, 2 falls/part, 1 part/axis, 3 axes, criteria: relative sensitivity error 3% Rms voltage for AC isolation test Bulk current injection immunity Electrostatic discharge immunity test ISO Criteria B 2 K, Criteria B Page 5/5