ADI公司的AD8452是单一的硅芯片平台,集成了精密模拟前端控制器和开关电源(SMPS)脉宽调制器(PWM)驱动器,以实现大规模电池测试和化成生产.精密仪器放大器以优于 ±0.1% 的精度测量电池充电/放电电流和测量电池电压.具有供出色的性能,功能和总体可靠性,简化了设计,工作温度范围为−40℃至+85℃,主要用在电池化成和测试,具有回收功能的高效电池测试系统和电池调节(充电和放电)系统.本文介绍了AD8452主要特性,功能框图和应用电路,以及评估板AD8452-EVALZ主要特性,测试建立图,电路图和材料清单与PCB设计图.
The AD8452 combines a precision analog front-end controllerand switch mode power supply (SMPS), pulse-width modulator(PWM) driver into a single silicon platform for high volumebattery testing and formation manufacturing. A precisioninstrumentation amplifier (in-amp) measures the battery charge/discharge current to better than ±0.1% accuracy, while an equallyaccurate difference amplifier measures the battery voltage.
Internal laser trimmed resistor networks establish the in-ampand difference amplifier gains (66 V/V and 0.4 V/V, respectively),and stabilize the AD8452 performance across the ratedoperating temperature range.
Desired battery cycling current and voltage levels are establishedby applying precise control voltages to the ISET and VSETinputs. Actual charge and discharge current levels are sensed(usually by a high power, highly accurate shunt resistor) whosevalue is carefully selected according to system parameters.
Switching between constant current (CC) and constant voltage(CV) loop integration is instantaneous, automatic, and completelytransparent to the observer. A logic high at the MODE inputselects the charge or discharge mode (high for charge, low fordischarge).
The AD8452 simplifies designs by providing excellentperformance, functionality, and overall reliability in a spacesaving 48-lead, 7 mm×7 mm× 1.4 mm LQFP package rated for operation at temperatures from −40℃ to +85℃.
CC and CV battery test and formation modes withtransparent and automatic switchover, for systems of20 Ah or less
Precise measurement of voltage and currentIndependent feedback control blocks
Highly accurate, factory trimmed instrumentation anddifferential amplifiers
In-amp for current sense gain: 66 V/V
Difference amplifier for voltage sense gain: 0.4 V/V
Stable over temperature: offset voltage drift <0.6 μV/℃(maximum)
Gain drift: <3 ppm/℃ (maximum)
Current sense CMRR: 120 dB minimum
Popular SMPS control for charge/discharge
High PWM linearity with internal ramp voltage
50 kHz to 300 kHz user controlled switching frequency
Synchronization output or input with adjustable phase shift
Programmable soft start
Battery formation and testing
High efficiency battery test systems with recycle capability
Battery conditioning (charging and discharging) systems
The AD8452-EVALZ is a platform for the AD8452, designed for investigation of the AD8452 analog and pulse-width modulation (PWM) features and performance without the added complications of a driver and/or switch mode power supply (SMPS) design. For convenience, a precision 5 V reference IC and four trim pots are built in to the evaluation board, for driving the battery current and voltage ISET and VSET inputs. All device pins are accessible with test loops or probe landings. At the same time, the AD8452-EVALZ has the flexibility to interface and drive a typical half bridge inductor input SMPS with output levels in the 1 A to 15 A range. SMPS and associated components are specified and sourced by the user. The AD8452 is intended for use as the core controller for commercial battery test and formation systems. Its advanced miniaturization and extraordinarily high level of analog precision meet the challenge of mass production of high energy density storage lithium ion packs for transportation and energy storage in homes.
Pin accessible, standalone AD8452
Simplified operation: connect a power supply and scope and start looking at waveforms
On-board precision 5 V reference included for accurate gain measurements
Four optional control loops available but not necessary for operation; may be bypassed as desired
Safe: only low power circuitry is present; no accidental power discharges