INA240A1DR

Current Sense Amplifiers ti.com/currentsense 2019 Current Sense Amplifiers Introduction What are Current Sense Amplifiers? Current sense amplifiers, also called current shunt monitors, are specialized differential amplifiers with a precisely matched resistive gain network with the following characteristics: • Designed to monitor the current flow by measuring the voltage drop across a sense element, typically a shunt resistor • Tend to be easier to use, more precise and less prone to noise • Support currents from 10s of µA to 100s of A • Natively support common-mode voltages from -16 to +80 V and with additional circuitry up to 100s of volts System benefits addressed by using current sense amplifiers: • Real-time overcurrent protection • Current and power monitoring for system optimization • Current measurement for closed-loop feedback Analog Output + _ Integrates the full analog signal processing and provides a voltage or current output. Digital Output Key Parameters Common Mode Range: This specification defines the DC voltage range at the input of an amplifier with respect to ground. Current sense amplifiers are typically designed to support common-mode voltages well beyond the chip supply voltage. For example, the INA240 is capable of supporting a common-mode voltages between -4 V to +80 V while running on a supply as low as 2.7 V. Offset Voltage: This is a differential DC error at the input of the amplifier. Historically, to reduce the impact of amplifiers with high offsets, larger value shunt resistors were used to increase the measured voltage drop. Today, TI is able to offer current sense amplifiers with offsets as low as 10µV, enabling higher precision measurements at low currents and allowing the use of smaller value shunt resistors for improved system efficiency. Gain: Current sense amplifiers come with various gain options that have robust performance over temperature and process variations by integrating a precisely matched resistive gain network. The gain options for fixed gain amplifiers vary from 0.125 V/V to 1000 V/V with gain errors as low as 0.01%. Temperature Stability: Current sense amplifiers integrate the amplifier along with all the gain-setting resistors which enables small and unified temperature drift. This allows for robust current measurements across the whole specified temperature range. The achieved temperature stability is one of the key advantages current sense amplifiers have over discrete implementations. Integrates the full signal conditioning path and utilizes a standard 2-wire digital interface. Comparator Output _ _ + + Provides a simple ALERT signal when the load current exceeds a threshold. Integrated Shunt + _ Offers a low-drift, precision integrated sense element. 2 | Current Sense Amplifiers Guide 2019 Texas Instruments Current Sense Amplifiers Key Design Considerations High-Side Measurements Current sensing techniques connect the current sense element between the supply bus and the load. System Advantages: • Able to detect load short to ground • Current is monitored directly from the source • High immunity to ground disturbance System Challenges: • High bus voltage limits the availability of high input common-mode voltage devices +5V Bus Voltage INA240 +5V + RS – ADS114 I2C LOAD Advantages Over Discrete Current Sense Circuit: • Integrated gain resistors provide excellent matching to enable a higher performing and more stable platform • Reduction in board space requirements • High dynamic changes in the common-mode voltage are difficult to achieve with standard op amps • Unique input architecture allows for the common-mode voltage to greatly exceed the device supply voltage Low-Side Measurements Current sensing techniques connect the current sense element between the load and ground. System Advantages: • Simple to implement and low-cost solution • Wide range of available options System Challenges: • Difficult to detect load short to ground • System ground disturbance by the shunt resistor Advantages Over Discrete Current Sense Circuit: • Integrated gain resistors provide excellent matching to enable a higher performing and more stable platform • Reduction in board space requirements • True differential measurement across the shunt resistor • Lower VOFFSET saves system power by enabling the use of smaller value shunt resistors to achieve the same error level Bus Voltage LOAD INA181 +5V RS + – ADS114 I2C Total Error • For light loads with small current values that result in small differential voltage signals at the input, the total error will be dominated by the amplifier’s offset voltage. Low input offsets are critical to achieving accurate measurements at the low end of the dynamic range. • For heavy loads with large current values that result in large differential voltage signals at the input, the total error will be dominated by the amplifier’s gain error. Texas Instruments Current Sense Amplifiers Guide 2019 | 3 Current Sense Amplifiers Reference Designs Current sensing reference designs. See more designs online at ti.com/referencedesigns. Design Number Description Bi-Directional eFuse Automotive Precision eFuse Current Shunt Reverse Polarity Protection & Switch Battery / LOAD Battery / LOAD + INA300 INA300 + TIDA-00795 One of the keys to preventing damage in automotive electronic systems is the ability to detect and react to potentially damaging conditions as rapidly as possible. This INA300-Q1 eFuse reference design is focused on providing high accuracy and fast response over-current protection at current levels as high as 30 A and scalable to > 100 A. Transient Supressiion Transient Supressiion Bus Supply 400 V VSENSE RSHUNT + - VSENSE + R1 10 Ω 10K Ω - VSENSE + R1 10 Ω Three-phase Current Measurements for Motor TIDA-00753 4 | Current Sense Amplifiers Guide 2019 Device Supply VS (2.7 to 5.5 V) VBus RZ Load Maximizing motor control requires accurate current measurement. This reference design featuring the INA199 demonstrates a method for enhancing the signal chain on the output of a current transformer. In addition, this circuit offers significant power savings by lowering the burden resistor value. 4.75K Ω 600 V P-FET OPA333 - TIDA-00528 This reference design demonstrates a simple, nonisolated technique using a precision op amp and a high voltage P-FET to extend the common-mode voltage of a current sense amplifier up to 400 V. With minor component changes, this design can be optimized for any voltage ranging from 40 to 400 V. I = VSENSE / R1 5.1 V Zener 36 V Transorb 300K Ω 40 V to 400 V Unidirectional Current/ Voltage/Power Monitoring INA226 IN- IN+ RSHUNT C SCL SDA SCL MicroController/ USBDIG SDA GND INA199 + C OUT – C INTDKCT 0–300 A N=3000 VS IN+ REF 0.1 E, 1W 15ppm, 2515 Texas Instruments Current Sense Amplifiers Reference Designs Current sensing reference designs. See more designs online at ti.com/referencedesigns. Design Number Description DC-DC 48 V to 5 V 5V Option to provide 3.3 V to Launchpad™ 3.3 V LDO 3.3 V 3.3 V LM5018 LP38691 VREF 3.3 V IC IA /PWM enable /PCB OT alert DC input LMG5200 LMG5200 PCB overtemperature DC input 12 V to 60 V GaN Driver 6 PWM_AH PWM_AL PWM_BH PWM_BL PWM_CH PWM_CL INA240 GaN Driver 4 INA240 GaN Driver VA,VB, VC, VDC INA240 LaunchPad™ interface connector TIDA-00913 This design realizes a 48 V/10A 3-phase GaN inverter with precision in-line shunt-based phase current sensing for accurate control of precision drives such as servo drives. One of the largest challenges with in-line shunt-based phase current sensing is the high common-mode voltage transients during PWM switching. The INA240 current sense amplifier overcomes this problem using enhanced PWM rejection. REF3333 IB Buffer for PWM w/ OE 48 V 3-Phase Inverter with Shunt-based In-line Motor Phase Current Sensing LMG5200 Phase A Phase B Phase C TMP302 Motor terminal VA VB VC AC Motor EMI filter (optional) 10-V to 20-V DC TIDA-00440 This design provides a reference solution to measure insulation resistance up to 100MΩ. It has an on-board isolated 500 V DC power supply and an isolated signal conditioning circuit to measure the leakage current. This design is useful to find leakage due to insulation breakdown in transformer and motor windings. R LIMIT LDO 5V_VCC2 LDO (Fly-BuckTM) MUX TS5A23157 INA225 To MCU V SENSE 150-V to 800-V DC Flyback (DC/DC) UCC28711 500-V DC R CAL LM5160 V SENSE Digital Isolator ISO 7640 R ISO R ISO = Insulation resistance R CAL = Calibration resistance Texas Instruments Low-voltage DC/DC AMC1200 Leakage Current Measurement Reference Design for Determining Insulation Resistance 5V_VCC1 Basic isolation Current Sense Amplifiers Guide 2019 | 5 Analog Output Current Sense Amplifiers Featured Products AEC-Q100 Available Bi–Directional Low–Side For more information see: ti.com/currentsense. Description INA190 Family 4 4 4 1.8 V, High-precision Current Sense Amplifier with Power Down -0.1 to 40 10 0.1 0.1 10 UQFN, 6 WCSP, 6 SC70 INA210 Family 4 4 4 High performance, Zero-Drift Current Sense Amplifier -0.3 to 26 35 0.1 0.02 10 UQFN, 6 SC70 4 4 4 High AC CMRR High Common Mode Current Sense Amplifier for Motor & Solenoid Control -4 to 80 25 0.05 0.05 Ultra-small, 5 V Current Sense Amplifier 1.8 to 5.5 100 0.06 0.01 4 Value line, Zero-Drift Current Sense Amplifier -0.3 to 26 150 0.1 0.03 4 350kHz Bandwidth, Unidirectional Current Sense Amplifier for Cost-sensitive Applications (Single, Dual, & Quad Options) -0.2 to 26 150 0.2 0.1 8 TSSOP, 8 SOIC 10 UQFN, 4 WSCP 10 UQFN, 6 SC70 5 SOT-23, 8 VSSOP, 14 TSSOP 6 SOT-23, 10 VSSOP, 20 TSSOP Part Number INA240 Family INA216 Family INA199 Family 4 4 Common Mode Voltage Range Input Offset ±µ V Max Input Offset Drift ±µ V/°C Typ Gain Error % Typ Package(s) INAx180 Family 4 INAx181 Family 4 4 4 350kHz Bandwidth, Bidirectional Current Sense Amplifier for Cost-sensitive Applications (Single, Dual, & Quad Options) -0.2 to 26 150 0.2 0.1 4 4 4 40 V Bidirectional, Precision Current Sense Amplifier -0.1 to 40 50 0.05 0.02 6 SC70 110 V High Voltage, High Bandwidth, Unidirectional Current Sense Amplifier 120 V High Voltage, High Bandwidth, High-side Current Sense Amplifier 350kHz Bandwidth, High-Precision, Bidirectional Current Sense Amplifier in SOT-563 Package -4 to 110 100 0.2 0.02 5 SOT-23 2.7 to 120 100 0.2 0.02 5 SC70 -0.2 to 26 55 0.2 0.05 6 SOT-563 Programmable-Gain, Zero-Drift, High Accuracy 0 to 36 150 0.2 0.05 8 MSOP High Common Mode, High-Speed Current Sense Amplifier 4.5 to 76 265 6 0.6 8 VSSOP High-Speed Current Sense Amplifier -2 to 42 900 2.6 0.25 6 SOT-23 High Accuracy, Zero-Drift Current Sense Amplifier with 0.1%, 15 PPM/°C 2mΩ Integrated Shunt High AC CMRR High Common Mode Current Sense Amplifier Solenoid Control with 0.1%, 15 PPM/°C 2mΩ Integrated Shunt Overcurrent Protection High-Speed, Precision Current Sense Amplifier with Integrated Comparator Overcurrent Protection High-Speed, Precision Current Sense Amplifier with Integrated Dual Comparators Overcurrent Protection High-Speed, Precision Current Sense Amplifier with Integrated Window Comparator Cost-efficient Current Sense Amplifier with Integrated Standalone Comparator 0 to 36 50mA 25µA/°C 0.3 16 TSSOP -4 to 80 12.5mA 25µA/°C 0.25 20 TSSOP 0 to 36 35 0.1 0.03 8 VSSOP 0 to 36 30 0.02 0.02 14 TSSOP 0 to 36 30 0.02 0.02 14 TSSOP -0.2 to 26 150 0.1 0.1 8 UQFN INA186 Family INA293 Family INA290 Family INA185 Family INA225 LMP8481 Family LMP8640 Family INA250 Family INA253 Family INA301 Family INA302 Family INA303 Family INA381 Family 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 Preview devices as of Q2 2019 Digital Output Power Monitors Measurement Parameter Values Description 4 4 I, V, P Ultra-High Accuracy, Current, Voltage, & Power INA260 4 4 I, V, P INA233 4 4 I, V, P, E Part Number INA226 AEC-Q100 Available Low–Side Bi–Directional Featured Products 4 INA229 4 4 4 I, V, P, E Ultra-High Accuracy, Current, Voltage, & Power Monitor with 0.1%, 15 PPM/°C 2mΩ Integrated Shunt High Accuracy, Current, Voltage, Power, & Energy Monitor with 1.8 V I2C/PMBus 85 V Current/Voltage/Power/Energy/Charge Monitoring Device with SPI Interface with Internal Temperature Sensor INA3221 4 4 4 I, V Triple-channel, Current & Voltage Monitor with Alert Common Mode Voltage Range Input Offset ±µ V Max Input Offset Drift ±µ V/°C Typ Gain Error % Typ 0 to 36 10 0.02 0.02 Package(s) 10 VSSOP 0 to 36 5mA 1µA/°C 0.02 16 TSSOP 0 to 36 10 0.02 0.02 10 VSSOP 0 to 85 10 0.01 0.02 10 VSSOP 16 VQFN 0 to 26 80 0.1 0.1 16 VQFN Preview devices as of Q2 2019 Texas Instruments Current Sense Amplifiers Guide 2019 | 6 TI Worldwide Technical Support Internet Asia TI Semiconductor Product Information Center Home Page support.ti.com TI E2E™ Community Home Page e2e.ti.com Product Information Centers Americas Mexico Phone +1(512) 434-1560 Phone 0800-670-7544 Internet/Email ti.com/lsds/ti/csc/support_Americas.page Europe, Middle East, and Africa Phone European Free Call 00800-ASK-TEXAS (00800 275 83927) International +49 (0) 8161 80 2121 Russian Support +7 (4) 95 98 10 701 Note: The European Free Call (Toll Free) number is not active in all c­ ountries. 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