EV High Voltage Drivetrain Test
Dynamic Power Supply
Dynamic power supplies are required for many of the most critical tests in the automotive world. For example, a key aspect of an EV drivetrain is the inverter. A test-bench to develop and validate an inverter requires a battery emulator with dynamic power supply, the unit under test, and a load and power meter to measure the output. The battery emulator—a high voltage and current DC supply—must be capable of simulating dynamic transient conditions such as engine starting profile, battery voltage drop-out, and reset behavior during voltage drop (per ISO 16750-2).
Interactive Signal Chains
The AD7606C-18 is an 18-bit, simultaneous sampling, analog-to-digital data acquisition system (DAS) with eight channels. Each channel contains analog input clamp protection, a programmable gain amplifier (PGA), a low-pass filter (LPF), and an 18-bit successive approximation register (SAR) analog-to-digital converter (ADC). The AD7606C-18 also contains a flexible digital filter, a low drift, 2.5 V precision reference, a reference buffer to drive the ADC, and flexible parallel and serial interfaces.
The AD7606C-18 operates from a single 5 V supply and accommodates the following input ranges when sampling at throughput rates of 1 MSPS for all channels:
- Bipolar single-ended: ±12.5 V, ±10 V, ±6.25 V, ±5 V, and ±2.5 V
- Unipolar single-ended: 0 V to 12.5 V, 0 V to 10 V, and 0 V to 5 V
- Bipolar differential: ±20 V, ±12.5 V, ±10 V, and ±5 V
The input clamp protection tolerates voltages up to ±21 V. The single supply operation, on-chip filtering, and high input impedance eliminate the need for external driver op amps, which require bipolar supplies. For applications with lower throughput rates, the AD7606C-18 flexible digital filter can be used to improve noise performance.
In hardware mode, the AD7606C-18 is fully compatible with the AD7608 and AD7609. In software mode, the following advanced features are available:
- Analog input range selectable per channel with added ranges available
- High bandwidth mode (220 kHz) selectable per channel
- Additional oversampling options with an oversampling ratio up to 256
- System gain, system offset, and system phase calibration, per channel
- Analog input open circuit detector
- Diagnostic multiplexer
- Monitoring functions (serial peripheral interface (SPI) invalid read and write, cyclic redundancy check (CRC), busy stuck monitor, and reset detection)
Note that throughout the data sheet, multifunction pins, such as the RD/SCLK pin, are referred to either by the entire pin name or by a single function of the pin, for example, the SCLK pin, when only that function is relevant.
- Power line monitoring
- Protective relays
- Multiphase motor control
- Instrumentation and control systems
- Data acquisition systems
- Building Utilities
- Building Safety and Security Solutions
Precision High Voltage
The ADN4620/ADN4621 are dual-channel, signal isolated, low voltage differential signaling (LVDS) buffers that operate at up to 2.5 Gbps with very low jitter. The devices integrate Analog Devices, Inc., iCoupler® technology, enhanced for high speed operation to provide drop-in galvanic isolation of LVDS signal chains. AC coupling and/or level shifting to the LVDS receivers and from the LVDS drivers allows isolation of other high speed signals, such as current mode logic (CML).
The ADN4620/ADN4621 include a refresh mechanism to monitor the input and output states and ensure that they remain the same in the absence of data transitions (for example, at power-on). For lower power consumption and high speed operation with low jitter, the isolator circuits rely on 1.8 V supplies, while 3.3 V supplies are used for LVDS receivers to support the full common-mode range with an input voltage range (input common mode plus differential input voltage) of 0 V to 2.4 V per Table 2 in the data sheet.
The devices are fully specified over a wide industrial temperature range and are available in a compact SSOP package with 5.3 mm creepage (for reinforced insulation at ac mains voltages) or a wide SOIC_IC package with 15.1 mm creepage (for high working insulation voltages up to 1500 V peak, reinforced).
- Analog front-end isolation
- Data plane isolation
- Isolated high speed clock and data links
- Multigigabit serialization/deserialization (SERDES)
- PCB-to-PCB optical replacement (for example, short reach fiber)
Protected by U.S. Patents 7,075,329; 9,941,565; and 10,205,442. Other patents are pending.
The ADuM4146 is a single-channel gate driver specifically optimized for driving silicon carbide (SiC), metal-oxide semiconductor field effect transistors (MOSFETs). Analog Devices, Inc., iCoupler® technology provides isolation between the input signal and the output gate drive.
The ADuM4146 includes a Miller clamp to provide robust SiC turn off with a single-rail supply when the gate voltage drops to less than 2 V. Operation with unipolar or bipolar secondary supplies is possible with or without the Miller clamp operation.
The Analog Devices chip scale transformers also provide isolated communication of control information between the high voltage and low voltage domains of the chip. Information on the status of the chip can be read back from dedicated outputs. Control of resetting the device after a fault on the secondary side is performed on the primary side of the device.
Integrated onto the ADuM4146 is a desaturation detection circuit that provides protection against high voltage short-circuit SiC operation. The desaturation protection contains noise reducing features, such as a 300 ns masking time after a switching event to mask voltage spikes due to initial turn on (see Figure 17 in the data sheet). An optional internal 500 μA current source allows low device count, and the internal blanking switch allows the addition of an external current source if more noise immunity is needed.
The secondary undervoltage lockout (UVLO) is set to 14.5 V (typical) for Grade A and is set to 11.5 V (typical) for Grade B and Grade C with common SiC and insulated gate bipolar transistor (IGBT) levels taken into consideration.
- SiC/MOSFET/IGBT gate drivers
- Photovoltaic (PV) inverters
- Motor drives
- Power supplies
ADI in 5G
Isolated Gate Drive & Sense
Designing and optimizing power solutions for data processing, networking, portable, wearable, and other computing applications require precision, wide band, high dynamic range measurement of voltages and currents. Systems may contain one, tens, or hundreds of central processing units (CPUs), graphical processing units (GPUs), network interfaces, storage hardware, and a myriad of support circuitry.
In response to changing system demands, these circuits can transition from drawing microamps of current in an idle state to hundreds of amps under full load in a matter of microseconds. In addition, automatic test equipment (ATE) test solutions and power analyzers typically use multiple channels to precisely capture the current, voltage, or power profile; and measure harmonics over a wider bandwidth.
Low voltage supply rails have stringent noise requirements and must be characterized under varying load conditions, temperatures, and account for bypass capacitor degradation over time.
The circuit shown in Figure 1 provides a complete, wide-range current measurement system suitable for these challenging applications. Accuracy, bandwidth, and drift performance are at the same level with benchtop and rack-mount test equipment suitable for use in a production test environment. At the same time, the solution is small enough to be incorporated into these applications that need to be continuously monitored. A 15 MSPS sample rate greatly relaxes the antialiasing filter requirements and maximizes bandwidth when digitizing fast transients and small signal levels. Additional oversampling can be applied to trade off between noise and bandwidth to suit the specific measurement being performed.
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Precision Wide Bandwidth
Testing and evaluating power systems in industrial and communications settings often requires multiple voltage and current measurements. Individual supplies may be referenced to different grounds, have either positive or negative polarity, or may be floating with no defined relationship to other power domains. Such scenarios necessitate either individual floating multimeters, or multichannel meters with per-channel isolation, which are physically cumbersome and expensive.
The circuit shown in Figure 1 is a complete, isolated current and voltage measurement system for industrial, telecommunications, instrumentation, and automated test equipment (ATE) applications. The system is galvanically isolated and will tolerate up to +/-250 V between the host controller and measurement grounds. The isolation design includes both digital data and power domain signals; no additional power source is required from the circuit being measured.
The current input range is +/-10 A and the voltage input range is selectable from 16 V to 80 V, with several ranges between these values. Both voltage and current inputs feature 16-bit resolution with adjustable output data rate and signal bandwidth, including modes that reject both 50 Hz and 60 Hz line noise.
The circuit is compatible with Arduino form-factor platform boards, and supports logic voltages from 1.8 V to 5 V. When paired with the open-source firmware example, application software can easily communicate with the reference design over the Linux Industrial Input/Output (IIO) framework using the libiio library, which includes bindings for C, C#, MATLAB, Python, and LabVIEW.
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Avoiding the Hidden Costs of Isolation Design—How to Manage Project Risk with Next-Generation Solutions