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[原创] Maxim MAX40056带PWM抑制双向电流检测放大器解决方案

关键词:汽车电子 马达控制 PWM MAX40056

时间:2019-07-18 10:56:08       来源:中电网

Maxim公司的MAX40056是带PWM抑制双向电流检测放大器(CSA),输入共模范围从-0.1V到65V,负电感跳变电压保护到-5V.因此,CSA非常适合于电感负载的相电流检测如马达和螺线管,这些设备的PWM用来控制驱动电压和电流.MAX40056采用改进技术有助抑制共模模式输入PWM边沿,其转换速率高达或超过±500V/μs,共模抑制比(CMRR)典型值为60dB (50V,±500V/μs,输入)和140dB DC.-3dB带宽为300kHz,多个增益可选择:10V/V, 20V/V和50V/V,内部双向失调为1%基准电压,典型输入失调电压为5μV,轨到轨输出,单电源工作电压+2.7V到+5.5V,工作温度-40℃到+125℃,主要用在PWM H桥马达电流检测,螺线管电流检测,电感负载电流检测,电池组监视器汽车电子.本文介绍了MAX40056主要优势和特性,简化框图,内部ESD箝位架构图,多种应用电路以及评估板MAX40056 EVK主要特性,电路图,材料清单和PCB设计图.

The MAX40056 is a bidirectional current-sense amplifierwith an input common-mode range that extends from-0.1V to +65V together with protection against negative inductive kickback voltages to -5V. This CSA is well-suitedfor phase current monitoring of inductive loads, such asmotors and solenoids, where pulse width modulation isused to control the drive voltage and current. TheMAX40056 uses an improved technique to help reject common-mode input PWM edges with slew rates up toand beyond ±500V/μs. Common mode rejection ratio(CMRR) is typically 60dB (50V, ±500V/μs input) and140dB DC, typical.

The MAX40056 has an internal +1.5V reference for usewith a nominal +3.3V power supply. The reference can alsobe used to drive an adjoining differential ADC. The referenceis used to offset the output to indicate the directionof the input sensed current. The REF pin can source currentinto external loads and helps to avoid the performancecompromises resulting from routing reference voltagesacross noisy PCBs. Alternatively, for higher supplyvoltages and higher full-scale output swings, the internalreference can be overridden by a higher voltage, externalreference.The internal or external reference can be used to definethe trip threshold for the integrated overcurrent comparator.

This can provide immediate indication of an overcurrentfault condition.The MAX40056 operates over the full -40℃ to +125°Ctemperature range and runs from a supply voltage of+2.7V to +5.5V. It is offered in a 2.02mm x 1.4mm 8-pinwafer-level package (WLP) and 8-pin μMAX packages.

MAX40056主要优势和特性:

● Fast, 500ns PWM Edge Recovery from500V/μs PWM Edges
● 60dB AC CMRR Rejection at 50V, ±500V/μs PWMEdges
● 140dB DC CMRR Rejection
● -0.1V to +65V Input Voltage Range
● -5V to +70V Protective Immunity
● 300kHz, -3dB Bandwidth
● Multiple Gain Options; 10V/V, 20V/V, 50V/V
● Internal, 1% Reference for Bidirectional Offset
● 5μV (Typ) Input Offset Voltage
● Rail-to-Rail Output
● 2.02mm x 1.4mm WLP-8 and 8-pin μMAX
● -40℃ to +125℃ Temperature Range

MAX40056应用:

● PWM H-Bridge Motor In-line/In-phase/Winding Current Sensing
● Solenoid Current Sensing
● Current Monitoring of Inductive Loads
● Battery Stack Monitors
● Automotive

图1.MAX40056简化框图

图2.MAX40056内部ESD箝位架构图

图3.MAX40056马达控制的在线电流检测电路图

图4.MAX40056三相伺服马达的电流检测电路图

评估板MAX40056 EVK

The MAX40056 evaluation kit (EV kit) is a fully assembled electrical demonstration kit that provides a proven design to evaluate the MAX40056F/MAX40056T/MAX40056U high-precision, high-voltage, bidirectional current sense amplifier for PWM applications, such as servo motor con­trol and solenoid drive. The MAX40056F/MAX40056T/ MAX40056U are ideal for 48V, or less BLDC, induction motor applications (such as robotics), pick-and-place machines, 3D prints, or other servo motor control systems.
This EV kit demonstrates the MAX40056FAUA+ in an 8-pin μMAX package, with Gain = 50V/V. For other available pin-compatible options (MAX40056TAUA+, Gain = 20V/V, MAX40056HAUA+, Gain = 10V/V), contact the factory.

评估板MAX40056 EVK主要特性:

Precision Real-Time Current-Monitoring with Fault Detection
Internal Available1.5V Reference
-0.3V to +65V Input Common Mode Range
-40°C to +125°C Temperature Range
Evaluates 8-μMAX MAX40056FAUA+ Device
Proven PCB Layout
Fully Assembled and Tested

图5.评估板MAX40056 EVK外形图

图6.评估板MAX40056 EVK电路图
评估板MAX40056 EVK材料清单:


图7.评估板MAX40056 EVK PCB装配图(顶层)

图8.评估板MAX40056 EVK PCB布局图:左:顶层丝印;右:底层布局

图9.评估板MAX40056 EVK PCB布局图:左:顶层;右:底层丝印
详情请见:
https://datasheets.maximintegrated.com/en/ds/MAX40056F-MAX40056U.pdf
https://datasheets.maximintegrated.com/en/ds/MAX40056EVKIT.pdf
MAX40056F-MAX40056U.pdf
MAX40056EVKIT.pdf

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