Innovative Current Sensor ICs For Industrial, Consumer and Computer Applications (IC&C) Innovative Current Sensor ICs Allegro MicroSystems, LLC has developed a line of fully integrated Hall-effect current sensor ICs and Hall-effect linear ICs that provide highly accurate, low noise output voltage signals that are proportional to an applied AC or DC current. These current sensor ICs are in high volume production in a wide variety of industrial, consumer, and computer applications, including motor controllers, inverters, compressors, handheld radios, and server power supplies. Allegro’s proprietary fully integrated Hall-effect current sensor ICs employ advanced IC and packaging techniques for sensing current from 5 A to 200 A. For currents up to 1000 A and beyond, an Allegro current sensor linear IC can be used with a magnetic concentrator to create a current sensing module. Allegro current sensor ICs allow design engineers to use Hall-effect-based current sensor ICs in new applications where increased energy efficiency or new operating features are required. Wherever current sensing is needed, an Allegro sensor IC can provide a solution. Current Sensor Packaging Technology Overview Allegro has a long history of packaging innovation for current sensor IC solutions. For measuring less than 50 A currents, Allegro employs its patented flip chip current sensor assembly technology for its integrated current sensor ICs. This packaging technique provides several major benefits to any circuit designer: increased sensitivity, high galvanic isolation, low primary resistance, and enables the use of standard, surface mount packages. By flipping the die inside the package, the Hall-effect sensor IC is placed as close as possible to the current conductor, thereby increasing the magnetic field that it sees. Second, the IC is electrically isolated from the primary conductor, providing galvanic isolation up to 3600 VRMS for 60 seconds. This enables high side current monitoring without the need for additional components to provide the isolation barrier necessary to interface the current measurement circuit with other low voltage circuits. Third, the primary conductor design is independent of the IC itself, so that its shape can be optimized for low resistance, <=1 m, reducing power losses in the system. Finally, these parts are all manufactured in surface mount packages with JEDEC standard foot prints, simplifying assembly for high volume applications. The complete assembly is calibrated at the factory, eliminating the need for the customer to program the part. These parts are UL recognized and provide superior galvanic isolation, with a dielectric withstand voltage of 4800 VRMS for 60 s, basic isolation of 700 VRMS and a reinforced isolation rating of 450 VRMS. Lastly, the ultra low resistance (typical = 100 µ) helps minimize power losses in high current applications. Allegro also offers Hall-effect current sensor ICs in SIP packages for integration with a magnetic concentrator to create custom current sensing assemblies. Allegro has recently developed an ultra-thin 1 mm thick KT package to enable magnetic concentrators with very small air gaps and therefore very high gain. For 50 A to 200 A current ranges, Allegro has created its proprietary CB package. The CB package integrates a copper primary conductor and a linear Hall-effect current sensor IC in a single thru-hole package. This provides an extremely robust solution that can handle up to 200 A continuously and pulses up to 1200 A. Signal Leads (8X ) Solder (8X) Die Hall Elemen t Primary Curren t Path Primary Curren t Path Figure 1: Flip chip current sensor IC assembly - Top view QFN SOIC-8 QSOP-24 SOIC-16 Figure 2: Current sensor IC package options www.allegromicro.com KT CB Digital Temperature Compensation Overview Allegro’s patented digital temperature compensation circuitry greatly improves both sensitivity and quiescent voltage output (QVO) error performance over a wide operating temperature range. The sensitivity and QVO of each part is measured at final test at both room temperature and hot (85°C ~ 150°C depending on the part), and the necessary compensation coefficients required to insure a flat response over the full operating temperature range are stored in EEPROM memory for both sensitivity and QVO. Allegro achieves ±1% typical total error performance from 25°C ~ 150°C with the use of this new technology. And by performing this calibration at final test, Allegro removes the need to do any temperature calibration of the parts once they are mounted on your PCB, making it easier to design into any application. compromising the response time of the output signal. See the plots below for typical sensitivity, QVO and total error performance for the ACS723LLCTR-20AB-T product, one of the most recent current sensor ICs from Allegro that incorporates this new digital temperature compensation technology. Hall Element Output Signal EEPROM Memory It is important to note that the temperature compensation is done in parallel with the analog signal path, so there is no reduction in the overall system bandwidth as a result of this new temperature compensation circuitry. When compared to previous generations of products, this circuitry results in much more accurate and stable output signal performance without Mixed Signal Circuitry for Interpolation Digital Thermometer Figure 3: Typical signal chain for current sensor IC with digital temperature compensation Total Error (%) ACS723LLCTR-20AB-T Total Error vs. Temperature 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -50 0 50 100 150 200 Temperature (°C) QVO Error (mV) ACS723LLCTR-20AB-T QVO Error vs. Temperature 10.0 8.0 6.0 4.0 2.0 0.0 -2.0 -4.0 -6.0 -8.0 -10.0 -50 0 50 100 150 200 Temperature (°C) Sensitivity Error (%) ACS723LLCTR-20AB-T Sensitivity Error vs. Temperature 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -50 Average +3 Sigma -3 Sigma 0 50 100 150 200 Temperature (°C) Figure 4: Typical performance characteristics for a current sensor IC with digital temperature compensation www.allegromicro.com Innovative Current Sensor ICs Current Sensing in Motor Control Applications Allegro’s current sensor ICs can be used in several locations in a typical motor drive application due to their galvanic isolation and good dV/dt performance. They can be used to measure the DC+ bus, position 1 in the diagram below, phase currents, shown in position 2, or on the low side, position 3. Due to their high galvanic isolation, Allegro's current sensor ICs are well suited to measuring the phase currents in a motor directly. This simplifies the control (no need to recreate the phase currents from indirect measurements) and reduces the bandwidth requirements on the current sensor, leading to a lower noise solution. The low resistance primary conductor, <= 1mOhm, translates into low power losses. And the surface mount packages make assembly cheaper and more reliable. Parts like the ACS710, ACS711, and ACS716 also include integrated fault outputs that can be used to detect short circuits or other over current conditions. Figure 5: Typical current sensing locations in motor controller applications Available Features Key Devices • High bandwidth, low noise analog outputs – up to 120 kHz • ACS710 – 5 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation • High galvanic isolation – up to 3 kV dielectric withstand strength • ACS716 – 3.3 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation • Low resistance on the primary conductor – 0.65 m ~ 1 m • ACS722 – 3.3 V, 80 kHz current sensor IC w/ digital temperature compensation • Dedicated fault pin available on selected devices • ACS723 – 5 V, 80 kHz current sensor IC w/ digital temperature compensation • High dV/dt immunity due to integrated shield in flip chip devices • ACS726 – differential output current sensor IC w/ digital temperature compen sation • ACS711 – price competitive current sensor IC for low side sensing www.allegromicro.com Current Sensing in Solar Microinverters In any microinverter for use with solar panels, there are multiple stages where current sensing is needed for efficient control. The DC/DC converter stage requires current sensor ICs that can accurately sense the current flowing in the DC bus, withstand high dV/dt events, and provide the necessary functional isolation to survive operation at 400 Vdc or greater. With increasing demands on the accuracy of reporting power fed back onto the grid, there are increased requirements on the measurement accuracy at the output of the inverter as well. Photovoltaic Single Panel Array Supply Side Current Sensor 3 Current Sensor 2 Current Sensor 1 VPV IPV Load Side Current Sensor 6 VS IS kW Current Sensor 5 Scaling Scaling Gating Signals IShort_Circuit DC-to-DC and MPPT Control Power Meter Current Sensor 4 High Efficiency DC-to-AC Inverter DC-to-DC Converter Utility Power Grid Gating Signals Scaling Inverter Control Microcontroller Control Panel Loads Residential Commercial Figure 6: Typical current sensing locations in a solar inverter Available Features Key Devices • High bandwidth, low noise analog outputs – up to 120 kHz • ACS710 – 5 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation • High galvanic isolation – up to 3 kV dielectric withstand strength • ACS716 – 3.3 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation • Low resistance on the primary conductor – 0.65 m ~ 1 m • ACS722 – 3.3 V, 80 kHz current sensor IC w/ digital temperature compensation • Dedicated fault pin available on selected devices • ACS723 – 5 V, 80 kHz current sensor IC w/ digital temperature compensation • High dV/dt immunity due to integrated shield in flip chip devices • ACS726 – differential output current sensor IC w/ digital temperature compen sation www.allegromicro.com Innovative Current Sensor ICs Current Sensing in Power Amplifiers Whether you are designing a base station or a handheld radio, being able to properly control the power amplifier in your radio is key to balancing power output vs. performance. Drain bias current is a key parameter to monitor in many output stages, and Allegro offers several current sensor ICs that are well suited to this task. VDD Ip+ VIOUT Available Features Control Logic • Space saving, surface mount packages – QFN and SOIC-8 • Integrated low resistance primary conductor for low power loss – 0.6 m~1.2 m • 3.3 V or 5 V single supply operation Ip- Power Amp Audio In • Resistor-like transfer function for easy integration Key Devices • ACS711 – 100 kHz current sensor IC in QFN or SOIC package Figure 7: Typical current sensing location in a power amplifier • ACS712 – 80 kHz current sensor IC in SOIC package Current Sensing in Servers Allegro offers several current sensing solutions for use in server power management. The integrated current conductor in these ICs reduces I2R losses in the power path. Some ICs include I2C communications interfaces and dedicated fault output pins for easy system integration. Available Features Key Devices • Low resistance primary conductor for low power losses – 0.1 m ~ 0.5 m • ACS764 – 0.5 m current sensor IC w/ I2C interface • Allegro’s latest digital temperature compensation circuitry • ACS770 – 0.1 m current sensor IC for up to 200 A 2 • I C interface for easy system integration • Dedicated fault output for fast response to overcurrent events www.allegromicro.com 0 to 50 A Integrated Current Sensor ICs Part Number Type Measurement Isolation Supply Bandwidth Temperature Packages Range (A) Voltage (VRMS) Voltage (kHz) Ranges ACS709 Bidirectional ±12 to 75 2100 3.3 ~ 5 120 L QSOP-24 ACS710 Bidirectional ±12 to 75 3000 3.3 ~ 5 120 K SOIC-16 High bandwidth, low noise current sensor IC in a high isolation package with a customer programmable fault output ACS711 Bidirectional ±12.5 to 32 <100 VDC 3.3 ~ 5 100 E, K QFN-12 SOIC-8 Economic, high bandwidth current sensor IC offered in space saving QFN and SOIC-8 packages ACS712 Bidirectional ±5 to 30 2100 5 80 E SOIC-8 Low noise, shielded current sensor IC with fast response times ACS713 Unidirectional 0~20, 0~30 2100 5 80 E SOIC-8 Low noise, shielded current sensor IC with fast response times ACS714 Bidirectional ±5 to 50 2100 5 80 E, L SOIC-8 Automotive-grade, low noise, shielded current sensor IC with fast response times ACS715 Unidirectional 0~20, 0~30 2100 5 80 E, L SOIC-8 Automotive-grade, low noise, shielded current sensor IC with fast response times ACS716 Bidirectional ±12 to 75 3000 3.3 120 K SOIC-16 High bandwidth, low noise current sensor IC that operates off a single 3.3 V supply in a high isolation package ACS722 Bidirectional & Unidirectional ±5 to 40 2400 3.3 80 L SOIC-8 Next generation temperature compensation circuitry in an improved SOIC-8 package with lower resistance and higher isolation ACS723 Bidirectional & Unidirectional 0~10 to 0~40 2400 5 80 L SOIC-8 Next generation temperature compensation circuitry in an improved SOIC-8 package with lower resistance and higher isolation ACS726 Bidirectional ±20, ±40 2100 3.3 120 L QSOP-24 Includes an on-chip back-end amplifier to scale the output to fully utilize the dynamic range of your ADC, no matter what the size of the input signal is ACS764 Unidirectional 0~16, 0~32 <100 VDC 3.3 2 X QSOP-24 Unidirectional current sensor IC with I2C interface and fault output Features High bandwidth, low noise current sensor IC in a thermally enhanced package 50 to 200 A Integrated Current Sensor ICs Part Number Type Measurement Isolation Supply Bandwidth Temperature Packages Range (A) Voltage (VRMS) Voltage (kHz) Ranges ACS758 Bidirectional & Unidirectional ±50 to 200 4800 5 120 E, K & L CB Thermally enhanced, high bandwidth current sensor IC for monitoring currents from 50 to 200 A ACS759 Bidirectional & Unidirectional ±50 to 200 4800 3.3 120 E, K & L CB Thermally enhanced, high bandwidth current sensor IC for monitoring currents from 50 to 200 A ACS770 Bidirectional & Unidirectional ±50 to 200 4800 5 120 E, K & L CB Next generation temperature compensation for improved accuracy Features SIP Package 0 to >1000 A Current Sensor ICs Part Number Supply Voltage Quiescent Output (V) Typical Output Temperature Packages Sensitivity (mV/G) Bandwidth (kHz) Ranges A1363 4.5 to 5.5 Typ 50% VCC 0.6~14, customer programmable 120 L KT, LU Next generation temperature compensation, TC factory programmed to 0%/°C A1366 4.5 to 5.5 Typ 50% VCC 1, 2, 5, & 10, factory programmed 120 L KT, LU Next generation temperature compensation, TC factory programmed to 0%/°C Temperature range codes: S = -20°C to 85°C, E = -40°C to 85°C, K = -40°C to 125°C, L = -40°C to 150°C, X = -20°C to 125°C www.allegromicro.com Features North America: +1-508-853-5000 [email protected] Europe: +33-450-51-23-59 [email protected] China: +86-21-54500188 [email protected] Japan: +81-03-3986-6166 [email protected] Korea: +82-70-8852-8250 [email protected] Taiwan: +886-2-27577231 [email protected] 115 Northeast Cutoff, Worcester, MA USA 01606 PN 103708 | Issue 2 | 11.2014 www.allegromicro.com