Battery Formation & Test

The AD8452 combines a precision analog front-end controller and switch mode power supply (SMPS), pulse-width modulator (PWM) driver into a single silicon platform for high volume battery testing and formation manufacturing. A precision instrumentation amplifier (in-amp) measures the battery charge/discharge current, while an equally accurate difference amplifier measures the battery voltage. Internal laser trimmed resistor networks establish the in-amp and difference amplifier gains (66 V/V and 0.4 V/V, respectively), and stabilize the AD8452 performance across the rated operating temperature range.

Desired battery cycling current and voltage levels are established by applying precise control voltages to the ISET and VSET inputs. Actual charge and discharge current levels are sensed (usually by a high power, highly accurate shunt resistor) whose value is carefully selected according to system parameters. Switching between constant current (CC) and constant voltage (CV) loop integration is instantaneous, automatic, and completely transparent to the observer. A logic high at the MODE input selects the charge or discharge mode (high for charge, low for discharge).

The AD8452 simplifies designs by providing excellent performance, functionality, and overall reliability in a space saving 48-lead, 7 mm × 7 mm × 1.4 mm LQFP package rated for operation at temperatures from −40°C to +85°C.

Applications

• Battery formation and testing
• High efficiency battery test systems with recycle capability
• Battery conditioning (charging and discharging) systems

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.

APPLICATIONS

• 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.

APPLICATIONS

• 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.

APPLICATIONS

• 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

The ADP1974 is a constant frequency, voltage mode, synchronous, pulse-width modulation (PWM) controller for bidirectional dc-to- dc applications. The ADP1974 is designed for use in battery testing, formation, and conditioning applications with an external, high voltage field effect transistor (FET) half bridge driver, and an external control device such as the AD8450/AD8451. The device operates as a buck converter in battery charge mode and as a boost converter in discharge mode to recycle energy to the input bus.

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.

Applications

• 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/AD5687R members of the nanoDAC+™ family are low power, dual, 16-/12-bit buffered voltage output digital-to-analog converters (DACs). The devices include 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 devices operate from a single 2.7 V to 5.5 V supply, are guaranteed monotonic by design, and exhibit less than 0.1% FSR gain error and 1.5 mV offset error performance. Both devices are available in a 3 mm × 3 mm LFCSP and a TSSOP package.

The AD5689R/AD5687R also incorporate a power-on reset circuit and a RSTSEL pin that ensure that the DAC outputs power up to zero scale or midscale and remain there until a valid write takes place. Each 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/AD5687R use a versatile serial peripheral interface (SPI) that operates at clock rates up to 50 MHz. Both devices contain a V_LOGIC pin that is intended for 1.8 V/3 V/5 V logic.

Product Highlights

1. High Relative Accuracy (INL).
   AD5689R (16-bit): ±2 LSB maximum
   AD5687R (12-bit): ±1 LSB maximum
2. Low Drift 2.5 V On-Chip Reference.
   2 ppm/°C typical temperature coefficient
   5 ppm/°C maximum temperature coefficient 
3. Two Package Options.
   3 mm × 3 mm, 16-lead LFCSP
   16-lead TSSOP

Applications

• Optical transceivers
• Base station power amplifiers
• Process control (PLC I/O cards)
• Industrial automation
• Data acquisition systems

The LTC4368 protects applications from power supply voltages that may be too high, too low, or even negative and from overcurrent faults in both forward and reverse directions. The LTC4368 controls the gate voltage of a pair of external N-channel MOSFETs to ensure that the load is connected to the input supply only when there are no voltage or current faults.

Two comparator inputs allow configuration of the overvoltage (OV) and undervoltage (UV) set points using an external resistive divider. A current sense resistor sets the forward and reverse circuit breaker current thresholds. After a forward current fault, the LTC4368 will either latchoff power, or retry after a user adjustable delay. After a reverse current fault, the LTC4368 waits for the output to fall 100mV below the input to reconnect power to the load.

The LTC4368 has a 32ms turn-on delay that debounces live supply input connections and blocks 50Hz and 60Hz AC power. UV/OV faults also trigger the 32ms recovery delay before the external MOSFETs are turned back on.

APPLICATIONS

• Reverse Battery Protection
• Portable Instrumentation
• Automotive and Industrial Surge Protection
• Energy Storage Systems

The ADuM7223 is a 4A isolated, half-bridge gate driver that employ Analog Devices, Inc.’s iCoupler^® technology to provide independent and isolated high-side and low-side outputs. Combining high speed CMOS and monolithic transformer technology, these isolation components provide outstanding performance characteristics superior to alternatives such as the combination of pulse transformers and non-isolated gate drivers. By integrating the isolator and driver in a single package, propagation delay is a maximum of only 60 ns and the propagation skew from channel to channel is a maximum of only 7ns.The ADuM7223 provides two independent isolation channels. 

The ADuM7223 operates with an input supply ranging from 3.0 V to 5.5 V, providing compatibility with lower voltage systems. The outputs operate in a wide range from 4.5V to 18V with three output voltage versions available. The 5 x 5 mm, LGA package provides 2500 V_{DC PEAK} operating voltage from input to output and from output to output.

In comparison to gate drivers employing high voltage level translation methodologies, these gate drivers offer the benefit of true, galvanic isolation between the input and each output. As a result, these gate drivers provide reliable control over the switching characteristics of IGBT/MOSFET configurations over a wide range of positive or negative switching voltages.

Applications

• Switching power supplies
• Isolated IGBT/MOSFET gate drives
• Industrial inverters

The LTC4446 is a high frequency high voltage gate driver that drives two N-channel MOSFETs in a DC/DC converter with supply voltages up to 100V. The powerful driver capability reduces switching losses in MOSFETs with high gate capacitance. The LTC4446’s pull-up for the top gate driver has a peak output current of 2.5A and its pull-down has an output impedance of 1.2Ω. The pull-up for the bottom gate driver has a peak output current of 3A and the pull-down has an output impedance of 0.55Ω.

The LTC4446 is configured for two supply-independent inputs. The high side input logic signal is internally level-shifted to the bootstrapped supply, which may function at up to 114V above ground.

The LTC4446 contains undervoltage lockout circuits that disable the external MOSFETs when activated.

The LTC4446 is available in the thermally enhanced 8-lead MSOP package.

The LTC4446 does not have adaptive shoot-through protection. For similar drivers with adaptive shoot-through protection, please refer to the chart below.

Applications

• Distributed Power Architectures
• Automotive Power Supplies
• High Density Power Modules
• Telecommunication Systems

Low voltage offset, low offset drift, low gain drift, high gain accuracy, and high CMRR make this part an excellent choice in applications that demand the best dc performance possible, such as bridge signal conditioning.

Programmable gain affords the user design flexibility. A single resistor sets the gain from 1 to 1000. The AD8221 operates on both single and dual supplies and is well suited for applications where ±10 V input voltages are encountered.

The AD8221 is available in a low cost 8-lead SOIC and 8-lead MSOP, both of which offer the industry’s best performance. The MSOP requires half the board space of the SOIC, making it ideal for multichannel or space-constrained applications.

Performance is specified over the entire industrial temperature range of −40°C to +85°C for all grades. Furthermore, the AD8221 is operational from −40°C to +125°C*.

Applications

• Weigh scales
• Industrial process controls
• Bridge amplifiers
• Precision data acquisition systems
• Medical instrumentation
• Strain gages
• Transducer interfaces