CN101063706A - Multichannel precision secondary batteries testing system - Google Patents

本发明公开了一种多通道精密二次电池测试系统。包括由与单片机电路连接的看门狗电路和串口通信电路构成的单片机控制电路，DAC控制电路，充放电切换电路，电压和电流测量电路和过压过流保护电路。由单片机控制电路发送控制命令，由DAC控制电路传送至充放电切换电路，电压电流测量电路对二次电池上的电压和电流信号放大，通过电压和电流采集电路读取二次电池上的电压和电流信号，再输出送回单片机控制电路，由单片机控制电路的输出送到上位机，由上位机进行数据处理和绘制充放电特性曲线。本发明可大大提高测量的精确度和准确度，大大降低温漂系数，即使在工作时间较长，温度变化大时，也能保证测试的精确度和准确度，大大减小了测量误差。The invention discloses a multi-channel precision secondary battery testing system. It includes a single-chip control circuit composed of a watchdog circuit connected with the single-chip circuit and a serial port communication circuit, a DAC control circuit, a charging and discharging switching circuit, a voltage and current measuring circuit and an overvoltage and overcurrent protection circuit. The control command is sent by the single-chip control circuit, which is transmitted to the charge-discharge switching circuit by the DAC control circuit. The voltage and current measurement circuit amplifies the voltage and current signals on the secondary battery, and reads the voltage and current on the secondary battery through the voltage and current acquisition circuit. The current signal is sent back to the single-chip microcomputer control circuit, and the output of the single-chip microcomputer control circuit is sent to the upper computer, and the upper computer performs data processing and draws the charge-discharge characteristic curve. The invention can greatly improve the precision and accuracy of measurement, greatly reduce the temperature drift coefficient, even when the working time is long and the temperature changes greatly, the accuracy and accuracy of the test can be guaranteed, and the measurement error is greatly reduced.

多通道精密二次电池测试系统Multi-channel precision secondary battery test system

                          技术领域Technical field

本发明涉及一种电池测试电路，特别是适用于锂离子、镍氢、镍镉等二次电池的测试系统。The invention relates to a battery test circuit, in particular to a test system suitable for secondary batteries such as lithium ion, nickel hydrogen, nickel cadmium and the like.

                          背景技术 Background technique

在测试二次电池的充放电特性时，必须测量二次电池充放电时的电压和电流信号，由于二次电池在充放电时，其电压和电流信号的变化速度相对较慢，因此对这两个信号进行监视需要准确、高精度模数转换器(ADC)，但是，在当前的二次电池测试仪中，通常是采用16位以下的ADC。如中国专利CN200520060665.8所公开的一种数字式蓄电池检测仪，包括蓄电池、电源电路，外壳、夹子，其特征在于：还有微处理电路、脉冲发生电路、交流采样放大电路、A/D转换电路、显示电路、操作键盘，微处理电路控制脉冲发生电路产生流信号，送到蓄电池上，交流采样放大电路对蓄电池上微弱的交流信号采样放大，通过A/D转换电路读取蓄电池上的交流电压值，A/D转换电路的输出送回微处理电路，微处理电路的输出送到显示电路。这种数字式蓄电池检测仪当电流信号要转换为电压信号时，其放大倍数是确定值，则测量误差就相当大。现有其它检测仪还存在温漂系数较大，在工作时间较长，温度变化大时，测试的精度和准确度比较低，误差较大。When testing the charging and discharging characteristics of the secondary battery, it is necessary to measure the voltage and current signals when the secondary battery is charging and discharging. Since the voltage and current signals change relatively slowly when the secondary battery is charging and discharging, the two An accurate, high-precision analog-to-digital converter (ADC) is required for monitoring each signal. However, in current secondary battery testers, ADCs below 16 bits are usually used. As disclosed in Chinese patent CN200520060665.8, a digital battery tester includes a battery, a power supply circuit, a casing, and a clip, and is characterized in that it also has a microprocessing circuit, a pulse generating circuit, an AC sampling amplifier circuit, and an A/D conversion Circuit, display circuit, operation keyboard, micro-processing circuit controls the pulse generation circuit to generate a stream signal, which is sent to the battery, the AC sampling amplifier circuit samples and amplifies the weak AC signal on the battery, and reads the AC signal on the battery through the A/D conversion circuit The output of the A/D conversion circuit is sent back to the micro-processing circuit, and the output of the micro-processing circuit is sent to the display circuit. When the current signal of this digital battery tester is to be converted into a voltage signal, its magnification is a certain value, and the measurement error is quite large. Other existing detectors also have a relatively large temperature drift coefficient, and when the working time is long and the temperature changes greatly, the test precision and accuracy are relatively low, and the error is relatively large.

                          发明内容Contents of Invention

本发明的目的在于克服上述电池测试仪的不足之处，提供一种可大大提高测量的精确度和准确度，大大降低温漂系数的多通道、高精度、智能化的二次电池测试系统。The purpose of the present invention is to overcome the shortcomings of the above-mentioned battery tester, and provide a multi-channel, high-precision, intelligent secondary battery test system that can greatly improve the accuracy and accuracy of measurement and greatly reduce the temperature drift coefficient.

本发明的技术方案是：包括由与单片机电路连接的看门狗电路和串口通信电路构成的单片机控制电路，DAC控制电路，充放电切换电路，电压和电流测量电路和过压过流保护电路，其特征在于，所述DAC控制电路包括D/A转换电路、基准电压电源电路、移位逻辑控制电路以及带有若干个测试通道的采样保持电路，每一个采样保持电路分别与充放电电路相连接；所述电压和电流采集电路包括A/D转换电路以及分别与A/D转换电路连接的两个缓冲电路，所述单片机控制电路中的单片机电路分别与D/A转换电路和A/D转换电路相连接；所述充放电切换电路与电压、电流测量电路和过压过流保护电路连接，所述充放电切换电路、电压、电流测量电路和过压过流保护电路均与待测电池相相连，所述电压、电流测量电路与A/D转换电路相连接，所述基准电压源电路与D/A转换电路和A/D转换电路连接。The technical scheme of the present invention is: comprise the single-chip microcomputer control circuit that is made of the watchdog circuit that is connected with single-chip microcomputer circuit and serial port communication circuit, DAC control circuit, charging and discharging switching circuit, voltage and current measuring circuit and overvoltage and overcurrent protection circuit, It is characterized in that the DAC control circuit includes a D/A conversion circuit, a reference voltage power supply circuit, a shift logic control circuit, and a sample-and-hold circuit with several test channels, and each sample-and-hold circuit is connected to the charging and discharging circuit respectively Described voltage and current acquisition circuit comprise A/D conversion circuit and two buffer circuits that are connected with A/D conversion circuit respectively, the single-chip microcomputer circuit in the described single-chip microcomputer control circuit is connected with D/A conversion circuit and A/D conversion respectively The charging and discharging switching circuit is connected with the voltage and current measuring circuit and the overvoltage and overcurrent protection circuit, and the charging and discharging switching circuit, the voltage and current measuring circuit and the overvoltage and overcurrent protection circuit are all connected with the battery to be tested. The voltage and current measurement circuits are connected to the A/D conversion circuit, and the reference voltage source circuit is connected to the D/A conversion circuit and the A/D conversion circuit.

所述D/A转换电路包括D/A转换芯片U6以及运算放大器U8，D/A转换芯片U6选用16位转换器；D/A转换芯片U6的DIN、SCLK和CS管脚分别与单片机芯片U1的P11、P16和P14相连接，D/A转换芯片U6的1脚与运算放大器U8的3脚相连接。Described D/A conversion circuit comprises D/A conversion chip U6 and operational amplifier U8, and D/A conversion chip U6 selects 16 converters for use; The P11, P16 and P14 of the D/A conversion chip U6 are connected to each other, and the 1 pin of the D/A conversion chip U6 is connected to the 3 pin of the operational amplifier U8.

所述A/D转换电路包括A/D转换芯片U61，A/D转换芯片U61选用24位Δ-∑ADC LTC2498型转换器，A/D转换芯片U61的CHO接电压和电流测量电路中的运算放大器U46的输出端CH1CM，CH1接运算放大器U45的输出端CH1VM；A/D转换芯片U61的1、2、3、4、5、6、7、30、31、32、32脚接地，A/D转换芯片U61的SDO脚接单片机芯片U1的P10，电源VCC+5V通过电阻R61接入SDO脚，SDO脚和Fo脚之间接20pF电容，Fo脚接地，A/D转换芯片U61的SCLK、CS、SDI脚接单片机芯片U1的P16、P17、P11脚。Described A/D conversion circuit comprises A/D conversion chip U61, and A/D conversion chip U61 selects 24 Δ-∑ADC LTC2498 type converters for use, and the CHO of A/D conversion chip U61 is connected to the operation in the voltage and current measurement circuit The output terminal CH1CM of the amplifier U46, CH1 is connected to the output terminal CH1VM of the operational amplifier U45; 1, 2, 3, 4, 5, 6, 7, 30, 31, 32, 32 pins of the A/D conversion chip U61 are grounded, A/D The SDO pin of the D conversion chip U61 is connected to the P10 of the single-chip microcomputer chip U1, the power supply VCC+5V is connected to the SDO pin through the resistor R61, a 20pF capacitor is connected between the SDO pin and the Fo pin, the Fo pin is grounded, and the SCLK and CS of the A/D conversion chip U61 , The SDI pin is connected to the P16, P17, and P11 pins of the single-chip microcomputer chip U1.

所述基准电压源电路包括基准电压电源芯片U7，基准电压源芯片U7选用低温度漂移、低噪声基准电压源MAX6033型，基准电压源芯片U7的输入端IN与电源VCC5连接，并通过104电容接地，5、6管脚相连接，2管脚接地，在5、6管脚与模拟地之间接入去耦电容0.1uF和10uF。The reference voltage source circuit includes a reference voltage power supply chip U7, the reference voltage source chip U7 selects a low temperature drift, low noise reference voltage source MAX6033 type, the input terminal IN of the reference voltage source chip U7 is connected to the power supply VCC5, and grounded through a 104 capacitor , Pins 5 and 6 are connected, pin 2 is grounded, and decoupling capacitors 0.1uF and 10uF are connected between pins 5 and 6 and the analog ground.

所述电压和电流测量电路包括运算放大器U45和运算放大器U46，运算放大器U45和运算放大器U46都是选用低漂移运算放大器LTC1012型，运算放大器U45通过电阻R110和电阻R112接入到待测电池两端，运算放大器U46的3脚通过电阻R132接到采样电阻R103，采样电阻R103接地。The voltage and current measurement circuit includes an operational amplifier U45 and an operational amplifier U46. Both the operational amplifier U45 and the operational amplifier U46 are of the low-drift operational amplifier LTC1012 type. The operational amplifier U45 is connected to both ends of the battery to be tested through a resistor R110 and a resistor R112. , the pin 3 of the operational amplifier U46 is connected to the sampling resistor R103 through the resistor R132, and the sampling resistor R103 is grounded.

本发明的单片机控制电路，过压过流保护电路，移位逻辑控制电路均与已有技术相同。The single-chip microcomputer control circuit, overvoltage and overcurrent protection circuit and shift logic control circuit of the present invention are all the same as those of the prior art.

工作时由单片机控制电路发送控制命令，由DAC控制电路传送至充放电切换电路，控制二次电池在恒流放电、恒流充电、恒压充电或静置四种工作状态，电压电流测量电路对二次电池上的电压和电流信号放大，通过电压和电流采集电路读取二次电池上的电压和电流信号，电压和电流采集电路的输出送回单片机控制电路，单片机控制电路的输出送到上位机，由上位机进行数据处理和绘制充放电特性曲线。When working, the control command is sent by the single-chip control circuit, which is transmitted to the charge-discharge switching circuit by the DAC control circuit, to control the secondary battery in four working states of constant current discharge, constant current charge, constant voltage charge or static, and the voltage and current measurement circuit. The voltage and current signals on the secondary battery are amplified, and the voltage and current signals on the secondary battery are read through the voltage and current acquisition circuit. The output of the voltage and current acquisition circuit is sent back to the single-chip control circuit, and the output of the single-chip control circuit is sent to the host computer, the upper computer performs data processing and draws the charge and discharge characteristic curve.

本发明具有以下优点：可大大提高测量的精确度和准确度，大大降低温漂系数，即使在工作时间较长，温度变化大时，也能保证测试的精度和准确度，大大减小了测量误差。The present invention has the following advantages: the precision and accuracy of measurement can be greatly improved, and the temperature drift coefficient can be greatly reduced. error.

                          附图说明Description of drawings

图1为本发明结构方框图；Fig. 1 is a structural block diagram of the present invention;

图2为DAC控制电路图；Figure 2 is a DAC control circuit diagram;

图3为电压和电流采集电路图；Fig. 3 is a voltage and current acquisition circuit diagram;

图4为充放电电路、电压和电流测量电路图；Fig. 4 is a charge and discharge circuit, voltage and current measurement circuit diagram;

图5为本发明单片机工作流程图。Fig. 5 is the working flowchart of the single-chip microcomputer of the present invention.

                         具体实施方式 Detailed ways

以下结合附图及实施例对本发明作进一步说明。The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

参照附图1：Referring to attached drawing 1:

本实施例包括单片机控制电路，DAC控制电路，充放电电路，电压、电流测量电路和过压过流保护电路以及电压、电流采集电路。其中单片机控制电路包括与单片机电路1-2连接的看门狗电路1-1和串口通信电路1-3。DAC控制电路包括顺次连接的D/A转换电路2-1，基准电压源电路2-2，移位逻辑控制电路2-3以及8个测试通道的采样保持电路(2-4-1、------2-4-8)。其中D/A转换电路中的D/A转换器选用16位MAX541；基准电压源选用超高精度、串联型电压基准MAX6033，它具有7ppm/℃的低温漂系数和低压差(200mV，最大值)特性。所述充放电电路3-1、电压和电流测量电路和过压过流保护电路5-1均与待测电池相连，所述电压和电流测量电路和过压过流保护电路5-1都反馈到充放电电路3-1，形成闭环控制系统；所述电压和电流采集电路包括A/D转换电路6-1和二个缓冲电路6-2和6-3，二个缓冲电路的电路结构相同，并均与A/D转换电路6-1相连接。A/D转换电路中的A/D转换器选用16通道Δ-∑ADC(24位)LTC2498。单片机电路1-2分别与D/A转换电路2-1和A/D转换电路6-1相连接；采样保持电路2-4-1、------2-4-8分别与充放电电路3-1、3-2----3-8相连接；每个电压和电流测量电路均与A/D转换电路6-1相连接。This embodiment includes a single-chip microcomputer control circuit, a DAC control circuit, a charge and discharge circuit, a voltage and current measurement circuit, an overvoltage and overcurrent protection circuit, and a voltage and current acquisition circuit. Wherein the single-chip microcomputer control circuit includes a watchdog circuit 1-1 and a serial port communication circuit 1-3 connected with the single-chip microcomputer circuit 1-2. The DAC control circuit comprises a D/A conversion circuit 2-1 connected in sequence, a reference voltage source circuit 2-2, a shift logic control circuit 2-3 and sample-and-hold circuits (2-4-1,- -----2-4-8). Among them, the D/A converter in the D/A conversion circuit uses 16-bit MAX541; the reference voltage source uses ultra-high-precision, series-type voltage reference MAX6033, which has a low-temperature drift coefficient of 7ppm/℃ and low dropout (200mV, maximum) characteristic. The charge and discharge circuit 3-1, the voltage and current measurement circuit and the overvoltage and overcurrent protection circuit 5-1 are all connected to the battery to be tested, and the voltage and current measurement circuit and the overvoltage and overcurrent protection circuit 5-1 all feed back To the charging and discharging circuit 3-1, a closed-loop control system is formed; the voltage and current acquisition circuit includes an A/D conversion circuit 6-1 and two buffer circuits 6-2 and 6-3, and the circuit structures of the two buffer circuits are identical , and are connected to the A/D conversion circuit 6-1. The A/D converter in the A/D conversion circuit selects 16-channel Δ-Σ ADC (24 bits) LTC2498. Single-chip microcomputer circuit 1-2 is connected with D/A conversion circuit 2-1 and A/D conversion circuit 6-1 respectively; The discharge circuits 3-1, 3-2----3-8 are connected; each voltage and current measurement circuit is connected with the A/D conversion circuit 6-1.

本实施例单片机电路1-2与已有技术相同，电池测试系统的仪器编号以及8个测试通道的校准系数存储放在看门狗电路中。单片机控制电路主要负责从上位机传送的测试参数(包括恒流放电、恒流充电、恒压充电、静置等工测试参数)、数据处理并发送测试指令。上电工作时，初始化串口以及初始化各个通道状态，并监听串口有无数据，如果有数据则处理串口数据，否则控制各个通道的工作状态。The single-chip microcomputer circuit 1-2 of this embodiment is the same as the prior art, and the instrument number of the battery test system and the calibration coefficients of the 8 test channels are stored in the watchdog circuit. The single-chip microcomputer control circuit is mainly responsible for the test parameters (including constant current discharge, constant current charge, constant voltage charge, static and other test parameters) transmitted from the host computer, data processing and sending test instructions. When power on, initialize the serial port and initialize the status of each channel, and monitor whether there is data in the serial port, if there is data, process the serial port data, otherwise control the working status of each channel.

参照附图2：Referring to attached picture 2:

本实施例D/A转换电路2-1包括D/A转换芯片U6以及缓冲器U8，D/A转换芯片U6采用MAX541型，D/A转换芯片U6是低功耗、串行输入、电压输出，用单+5V电源工作的串行16位数模转换器，D/A转换芯片U6的DIN、SCLK和CS管脚分别与单片机芯片U1的P11、P16和P14相连接，D/A转换芯片U6的1脚与缓冲器U8的3脚相连接，运算放大器U8用于增加D/A的驱动能力。The D/A conversion circuit 2-1 of this embodiment includes a D/A conversion chip U6 and a buffer U8, the D/A conversion chip U6 adopts the MAX541 type, and the D/A conversion chip U6 is a low power consumption, serial input, voltage output , a serial 16-bit digital-to-analog converter working with a single +5V power supply, the DIN, SCLK and CS pins of the D/A conversion chip U6 are respectively connected to the P11, P16 and P14 of the single-chip microcomputer chip U1, and the D/A conversion chip Pin 1 of U6 is connected to pin 3 of the buffer U8, and the operational amplifier U8 is used to increase the driving capability of the D/A.

本实施例基准电压源电路2-2包括基准电压源芯片U7，基准电压源芯片U7采用精密基准电压源MAX6033型，基准电压源芯片U7用于产生高精度的+2.5V电压源。基准电压源芯片U7的输入端IN与电源VCC5连接，并通过104电容接地，5、6管脚相连接，2管脚接地，为了消除高频或低频干扰，在5、6管脚与模拟地之间接入去耦电容0.1uF和10uF。工作时，基准电压源芯片U7为D/A转换芯片U6提供高精度的+2.5V电压；D/A转换芯片U6的CS为片选端，用于启动D/A转换，SCLK为串行时钟，用于控制D/A转芯片U6的串行输入，DIN为串行数据输入，用于输入D/A转换芯片U6的输入控制值。The reference voltage source circuit 2-2 in this embodiment includes a reference voltage source chip U7. The reference voltage source chip U7 adopts a precision reference voltage source MAX6033 type, and the reference voltage source chip U7 is used to generate a high-precision +2.5V voltage source. The input terminal IN of the reference voltage source chip U7 is connected to the power supply VCC5, and grounded through a 104 capacitor, 5 and 6 pins are connected, and 2 pins are grounded. Connect decoupling capacitors 0.1uF and 10uF between them. When working, the reference voltage source chip U7 provides a high-precision +2.5V voltage for the D/A conversion chip U6; the CS of the D/A conversion chip U6 is the chip select terminal, which is used to start the D/A conversion, and SCLK is the serial clock , used to control the serial input of the D/A conversion chip U6, DIN is the serial data input, used to input the input control value of the D/A conversion chip U6.

参照附图3：Referring to attached drawing 3:

本实施例A/D转换电路6-1包括A/D转换芯片U61，A/D转换芯片U61采用LTC2498型。LTC2498是24位Δ-∑ADC，可对16个单端通道、8个差分通道或两者的组合进行测量。本实施例提供了8个测试通道的电池测试系统，每个通道都需要测量电池电压和充放电电流，所以使用A/D转换芯片U61的16个单端通道作为测量16个信号输入通道，不需要外接多路开关。A/D转换芯片U61的CHO接电压和电流测量电路中的运算放大器U46的输出端CH1CM，CH1接运算放大器U45的输出端CH1VM，其他通道与A/D转换芯片U61的连接结构相同。A/D转换芯片U61的1、2、3、4、5、6、7、30、31、32、32脚接地，单片机芯片U1的P10脚接A/D转换芯片U61的SDO脚，电源VCC+5V通过电阻R61接入SDO脚，SDO脚和Fo脚之间接20pF电容，Fo脚接地，单片机芯片U1的P16、P17、P11脚分别接A/D转换芯片U61的SCLK、CS、SDI脚；The A/D conversion circuit 6-1 of this embodiment includes an A/D conversion chip U61, and the A/D conversion chip U61 adopts the LTC2498 type. The LTC2498 is a 24-bit delta-sigma ADC that can measure 16 single-ended channels, 8 differential channels, or a combination of both. This embodiment provides a battery test system with 8 test channels, and each channel needs to measure battery voltage and charge and discharge current, so 16 single-ended channels of the A/D conversion chip U61 are used as 16 signal input channels for measurement. An external multi-way switch is required. The CHO of the A/D conversion chip U61 is connected to the output terminal CH1CM of the operational amplifier U46 in the voltage and current measurement circuit, CH1 is connected to the output terminal CH1VM of the operational amplifier U45, and the connection structure of other channels is the same as that of the A/D conversion chip U61. Pins 1, 2, 3, 4, 5, 6, 7, 30, 31, 32, and 32 of the A/D conversion chip U61 are grounded, pin P10 of the single-chip microcomputer chip U1 is connected to the SDO pin of the A/D conversion chip U61, and the power supply is VCC +5V is connected to the SDO pin through the resistor R61, a 20pF capacitor is connected between the SDO pin and the Fo pin, the Fo pin is grounded, and the P16, P17, and P11 pins of the single-chip microcomputer chip U1 are respectively connected to the SCLK, CS, and SDI pins of the A/D conversion chip U61;

A/D转换芯片U61的MUXOUTN脚通过缓冲电路U62接入ADCINN，MUXOUTP通过缓冲电路U63接入ADCINP，REF+接基准电压源芯片U7的+2.5V输出端。A/D转换芯片U61的SCLK为系统时钟，用于控制A/D转换芯片U61的采样率及内部工作时序，采样率可高达7.5Hz或15Hz。SCLK为串行时钟，用于控制A/D转换芯片U61的串行输出。单片机芯片U1可以通过控制SCLK来实现对A/D转换芯片U61的数据读取。The MUXOUTN pin of the A/D conversion chip U61 is connected to ADCINN through the buffer circuit U62, MUXOUTP is connected to ADCINP through the buffer circuit U63, and REF+ is connected to the +2.5V output terminal of the reference voltage source chip U7. The SCLK of the A/D conversion chip U61 is a system clock, which is used to control the sampling rate and internal working sequence of the A/D conversion chip U61, and the sampling rate can be as high as 7.5Hz or 15Hz. SCLK is a serial clock used to control the serial output of the A/D conversion chip U61. The single-chip microcomputer chip U1 can realize data reading from the A/D conversion chip U61 by controlling SCLK.

参照附图4：Referring to attached drawing 4:

本实施例电压和电流测量电路中的充放电控制方式及电路与已有技术相同，不同的是运算放大器U44、运算放大器U45和运算放大器U46都是采用LTC1012型。运算放大器U45通过电阻R110和电阻R112接入到待测电池两端，用于测量电池两端电压。运算放大器U46的3脚通过电阻R132接到采样电阻R103，采样电阻R103接地，用于测量电池充放电的电流。The charging and discharging control mode and circuit in the voltage and current measuring circuit of this embodiment are the same as the prior art, the difference is that the operational amplifier U44, operational amplifier U45 and operational amplifier U46 all adopt the LTC1012 type. The operational amplifier U45 is connected to both ends of the battery to be tested through the resistors R110 and R112 to measure the voltage at both ends of the battery. Pin 3 of the operational amplifier U46 is connected to the sampling resistor R103 through the resistor R132, and the sampling resistor R103 is grounded for measuring the charging and discharging current of the battery.

本发明的过压过流保护电路与已有技术相同。The overvoltage and overcurrent protection circuit of the present invention is the same as the prior art.

本实施例移位逻辑控制电路与已有技术相同。工作时，可由单片机芯片U1向移位存储总线寄存器写入控制字，控制通道工作指示灯的打开或关闭，实现控制采样保持芯片的采样或保持状态；并对电压或电流测量值反馈控制，以及对充放电状态切换进行控制。The shift logic control circuit of this embodiment is the same as that of the prior art. When working, the single-chip microcomputer chip U1 can write the control word to the shift storage bus register, control the opening or closing of the channel work indicator light, and realize the control of the sampling or holding state of the sampling and holding chip; and feedback control of the voltage or current measurement value, and Control the switching of charging and discharging states.

本实施例由于A/D转换电路中的A/D转换器使用精准的24位Δ-∑ADC，能够产生最佳的效果，非常适合于测量电池充电等应用中的微细变化，本发明设置了多个电池测试通道，可选择LTC2498的16个单端通道作为信号输入通道，LTC2498包含一个高准确度的、具1/30℃分辨率和2℃绝对准确度的内部温度传感器使得冷结点补偿简单而且准确，通过温度传感器的读数，可记录温度梯度，以保证测试仪不致发生过热现象。在DAC转换电路中采用了16位D/A转换器，只有0.3mA的低供电电流和1LSB的低漂移误差，输出范围为0V至V_REF，可保证恒流充放电的恒流输出值和恒压充电的恒压输出值的高分辨率和高精度；为使LTC2498和MAX541获得高分辨率和高精度，本发明还提供了高精度的+2.5V基准电压源，只有7ppm/℃的低温漂系数和低压差。In this embodiment, because the A/D converter in the A/D conversion circuit uses an accurate 24-bit Δ-Σ ADC, it can produce the best results, and is very suitable for measuring subtle changes in applications such as battery charging. The present invention sets Multiple battery test channels, 16 single-ended channels of LTC2498 can be selected as signal input channels, LTC2498 contains a high-accuracy internal temperature sensor with 1/30°C resolution and 2°C absolute accuracy to make cold junction compensation Simple and accurate, the temperature gradient can be recorded through the readings of the temperature sensor to ensure that the tester will not overheat. In the DAC conversion circuit, a 16-bit D/A converter is used, with only a low supply current of 0.3mA and a low drift error of 1LSB, and the output range is from 0V to V _REF , which can ensure constant current output value and constant current charging and discharging. The high resolution and high precision of the constant voltage output value of voltage charging; in order to enable LTC2498 and MAX541 to obtain high resolution and high precision, the present invention also provides a high precision +2.5V reference voltage source, which has a low temperature drift of only 7ppm/°C coefficient and low dropout.

参照附图5：Referring to attached drawing 5:

本实施例单片机工作流程如下：The workflow of the single-chip microcomputer in this embodiment is as follows:

(1)上电1后，要对A/D、串口通信等进行初始化2，为测试做准备。(1) After power-on 1, A/D, serial port communication, etc. should be initialized 2 to prepare for the test.

(2)监听是否有中断3，如果有，则进入中断服务程序9；如果没有，则进入主程序。(2) Monitor whether there is an interrupt 3, if there is, then enter the interrupt service routine 9; if not, then enter the main program.

(3)进入主程序时，设置一个有8个元素的数组DAdata[8]，用于保存8个通道的D/A输入值，设置参数CHn＝0。(3) When entering the main program, set an array DAdata[8] with 8 elements, which is used to save the D/A input values of 8 channels, and set the parameter CHn=0.

(4)启动D/A转换，刷新通道CHn的D/A输出值，参数CHn的值为0~7，代表1~8个通道。(4) Start the D/A conversion and refresh the D/A output value of the channel CHn. The value of the parameter CHn is 0~7, representing 1~8 channels.

(5)参数CHn自增1，检测CHn是否大于7，如果没有，循环执行(4)步骤，如果CHn大于7，则循环执行(3)、(4)步骤。(5) The parameter CHn is incremented by 1, and it is detected whether CHn is greater than 7. If not, step (4) is executed cyclically. If CHn is greater than 7, steps (3) and (4) are executed cyclically.

(6)如果有串口中断，检测串口接收的是数据采集命令11，还是控制命令19；如果是数据采集命令11，则进入数据采集程序；如果是控制命令19，则刷新相应通道的工作状态。(6) If there is a serial port interruption, detect whether the serial port receives the data acquisition command 11 or the control command 19; if it is the data acquisition command 11, then enter the data acquisition program; if it is the control command 19, then refresh the working status of the corresponding channel.

(7)如果是数据采集命令11，设置参数CHi为0，选择采样通道CHi，参数Chi的值为0~15，代表A/D转换芯片U61的CH0~CH15。(7) If it is the data acquisition command 11, set the parameter CHi to 0, select the sampling channel CHi, and the value of the parameter Chi is 0~15, representing CH0~CH15 of the A/D conversion chip U61.

(8)CHi自增1，检测CHi是否大于15，如果没有，则循环执行(7)步骤；如果大于15，则发送16个采样数据至上位机，并返回主程序(3)。(8) CHi increments by 1, checks whether CHi is greater than 15, if not, executes step (7) in a loop; if greater than 15, then sends 16 sampling data to the host computer, and returns to the main program (3).

(9)如果是控制命令19，刷新对应通道CHn的工作状态，则设置通道CHn的反馈状态，写入移位存储总线寄存器U55的控制字；设置D/A的输入值，改变数组DAdata[CHn]的值；设置通道CHn的充放电状态，写入移位存储总线寄存器U53的控制字；设置结束后，返回主程序。(9) If it is the control command 19, refresh the working state of the corresponding channel CHn, then set the feedback state of the channel CHn, write the control word of the shift storage bus register U55; set the input value of D/A, change the array DAdata[CHn ] value; set the charging and discharging state of the channel CHn, and write the control word of the shift storage bus register U53; after the setting is completed, return to the main program.