Battery Formation & Test
The AD8450 is a precision analog front end for testing and monitoring battery cells. Referring to figure one, a precision programmable gain instrumentation amplifier (PGIA) measures the battery’s charge/discharge current and a programmable gain difference amplifier (PGDA) measures the battery’s voltage. Internal laser trimmed resistor networks set the gains for the PGIA and the PGDA, optimizing the AD8450’s performance over the rated temperature range. PGIA gains are 26×, 66×, 133×, and 200×. PGDA gains are 0.2×, 0.27×,0.4×, and 0.8×.
Voltages at the ISET and VSET inputs set the desired constant voltage (CV) and constant current (CC) values. CC to CV switching is automatic and transparent to the system.
A TTL level logic input, MODE, selects between charge and discharge modes (high for charge, low for discharge). An analog output, VCTRL, interfaces directly with ADI’s ADP1972 & ADP1974 PWM controllers.
The AD8450 includes resistor programmable overvoltage and overcurrent detection and current sharing circuitry. Current sharing is used to balance charge among multiple batteries. The AD8450 simplifies designs by providing excellent accuracy, performance over temperature, flexibility with functionality, and overall reliability in a space-saving package. The AD8450 is available in an 80 lead 14 mm ×14 mm × 1 mm LQFP package and is rated at −40 °C to +85 °C operating temperature.
- Battery cell testing & formation
- Battery module testing
The AD8451 is a precision analog front end and controller for testing and monitoring battery cells. A precision fixed gain instrumentation amplifier (IA) measures the battery charge/discharge current, and a fixed gain difference amplifier (DA) measures the battery voltage. Internal laser trimmed resistor networks set the gains for the IA and the DA, optimizing the performance of the AD8451 over the rated temperature range. The IA gain is 26 and the DA gain is 0.8.
Voltages at the ISET and VSET inputs set the desired constant current (CC) and constant voltage (CV) values. CC to CV switching is automatic and transparent to the system.
A TTL logic level input, MODE, selects the charge or discharge mode (high for charge, low for discharge). An analog output, VCTRL, interfaces directly with the Analog Devices, Inc., ADP1972 PWM controller.
The AD8451 simplifies designs by providing excellent accuracy, performance over temperature, flexibility with functionality, and overall reliability in a space-saving package. The AD8451 is available in an 80-lead, 14 mm × 14 mm × 1 mm LQFP package and is rated for an operating temperature of −40°C to +85°C.
- Battery cell formation and testing
- Battery module testing
The ADP1972 is a constant frequency, voltage mode, pulse width modulation (PWM) controller for buck or boost, dc-to-dc, asynchronous applications. The ADP1972 is designed for use in asynchronous battery testing applications with an external, high voltage field effect transistor (FET), half bridge driver, and an external control device, such as the AD8450.The asynchronous device operates as a buck converter in battery charge mode and operates as a boost converter in recycle mode to recycle energy to the input bus.
The ADP1972 high voltage, VIN supply pin can withstand a maximum operating voltage of 60 V and reduces the need for additional system supply voltages. The ADP1972 has integrated features such as precision enable, pin selective buck or boost mode operation, internal and external synchronization control with programmable phase shift, programmable maximum duty cycle, and programmable peak hiccup current limit.
Additional protection features include soft start to limit input inrush current during startup, input voltage undervoltage lockout (UVLO), and thermal shutdown (TSD). The ADP1972 also has a COMP pin to provide external control of the PWM operation and a FAULT pin that can be signaled to disable the DH and DL outputs if a fault condition occurs externally to the ADP1972.
The ADP1972 is available in a 16-lead TSSOP package.
- PWM battery test systems with recycle capability including hybrid vehicles, PCs, and camera batteries
- Compatible with AD8450 constant voltage (CV) and constant current (CC) monitors
Fast settling, highly accurate, low power, 8-/16-channel, multiplexed ADC for low bandwidth input signals with integrated input buffers.
Integrated precision, 2.5 V, low drift (3.5 ppm/°C), band gap reference and integrated oscillator.
Eight flexible setups with configurability for output data rate, digital filter mode, offset/gain error correction, reference selection, buffer enables and more. This per channel configurability extends to the output data rate used for each channel when using sinc5 + sinc1 filter.
Sinc5 + sinc1 filter maximizes channel scan rate, and sinc3 filter maximizes resolution and enhanced 50 Hz/60 Hz rejection, with four selectable options to maximize rejection.
Integrated diagnostic features, including CRC, register checksum, temperature sensor, crosspoint multiplexer, burnout currents, and GPIOs/GPOs.
- Process control: PLC/DCS modules
- Voltage, current, temperature, and pressure measurement
- Flow meters
- Medical and scientific multichannel instrumentation
- Seismic instrumentation
- Chemical analysis instrumentation: chromatography
The AD5689R nanoDAC+™ is a low power, dual, 16-bit buffered voltage output digital-to-analog converter (DAC). The device includes a 2.5 V, 2 ppm/°C internal reference (enabled by default) and a gain select pin giving a full-scale output of 2.5 V (gain = 1) or 5 V (gain = 2). The device operates from a single 2.7 V to 5.5 V supply, is guaranteed monotonic by design, and exhibits less than 0.1% FSR gain error and 1.5 mV offset error performance. The device is available in a 3 mm × 3 mm LFCSP and a TSSOP package.
The AD5689R also incorporates a power-on reset circuit and a RSTSEL pin that ensures that the DAC outputs power up to zero scale or midscale and remain there until a valid write takes place. The part contains a per channel power-down feature that reduces the current consumption of the device to 4 μA at 3 V while in power-down mode.
The AD5689R uses a versatile serial peripheral interface (SPI) that operates at clock rates up to 50 MHz. and contains a VLOGIC pin that is intended for 1.8 V/3 V/5 V logic.
- High Relative Accuracy (INL).
AD5689R (16-bit): ±2 LSB maximum
- Low Drift 2.5 V On-Chip Reference.
2 ppm/°C typical temperature coefficient
5 ppm/°C maximum temperature coefficient
- Two Package Options.
3 mm × 3 mm, 16-lead LFCSP
- Optical transceivers
- Base station power amplifiers
- Process control (PLC I/O cards)
- Industrial automation
- Data acquisition systems
- Ask the Applications Engineer—12: Grounding (Again)
- Demystifying Auto-Zero Amplifiers—Part 2
- Demystifying Auto-Zero Amplifiers—Part 1
- Ask the Applications Engineer—11: How Good Must a Voltage Reference Be?
- Finding the Needle in a Haystack: Measuring small differential voltages in the presence of large common-mode voltages