开关电容电压反转芯片

• ICL7660/MAX1044

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01 ICL7660电压反转

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一、前言

??基于开关电容电压反转芯片 ICL7660， 会在需要负电压的场景提供负电压。 ?手边有两片这个芯片。 ?下面对其基本特性进行测试。 ?为之后的应用奠定基础。

二、设计电路

??为了便于测试， 通过一个 5PIN的接插件将 ICL7660引出到面包板上。 ?利用快速制版方法， 一分钟之后得到两块测试电路板。 ?通过焊接电路， ?测试电压反转芯片的基本性能。

▲ 图1.2.1 测试原理图

▲ 图1.2.2 电路PCB版图

三、测试结果

??焊接电路板。?对电路板进行清洗。 ?在面包板上进行测试。 ?工作电压为 5V。 输出电压为-4.98V。 ?测试芯片中 管脚2 上的电压波形， ?可以看到芯片振荡频率为 4.3kHz。

▲ 图1.2.3 开关电容上的波形

??利用电子负载测试 ICL7660 输出不同电流情况下对应的输出电压。 ?可以看到在 小于9mA的时候， 输出电压基本上稳压在 -5V。 之后电压变发生了突变。 ?重新测试， 这次输出电流范围达到了 15mA， 结果是一样的。 并且在 9mA 之后， 随着电流增加， 电压基本上呈现线性下降。 ?利用 DM3068的交流电压档 测试输出电压中的交流信号。 当电流超过9mA 之后， 电流中的交流噪声突然增加了。 这说明在9mA 之后， 芯片处在不同的工作模式了。

▲ 图1.3.2 不同输出电流下对应的输出电压

idim=[0.0000,0.0001,0.0002,0.0003,0.0004,0.0005,0.0006,0.0007,0.0008,0.0009,0.0010,0.0011,0.0012,0.0013,0.0014,0.0015,0.0016,0.0017,0.0018,0.0019,0.0020,0.0021,0.0022,0.0023,0.0024,0.0025,0.0026,0.0027,0.0028,0.0029,0.0030,0.0031,0.0032,0.0033,0.0034,0.0035,0.0036,0.0037,0.0038,0.0039,0.0040,0.0041,0.0042,0.0043,0.0044,0.0045,0.0046,0.0047,0.0048,0.0049,0.0051,0.0052,0.0053,0.0054,0.0055,0.0056,0.0057,0.0058,0.0059,0.0060,0.0061,0.0062,0.0063,0.0064,0.0065,0.0066,0.0067,0.0068,0.0069,0.0070,0.0071,0.0072,0.0073,0.0074,0.0075,0.0076,0.0077,0.0078,0.0079,0.0080,0.0081,0.0082,0.0083,0.0084,0.0085,0.0086,0.0087,0.0088,0.0089,0.0090,0.0091,0.0092,0.0093,0.0094,0.0095,0.0096,0.0097,0.0098,0.0099,0.0100]
vdim=[-4.9836,-4.9837,-4.9834,-4.9835,-4.9833,-4.9835,-4.9835,-4.9836,-4.9836,-4.9838,-4.9837,-4.9836,-4.9836,-4.9836,-4.9834,-4.9836,-4.9837,-4.9835,-4.9834,-4.9835,-4.9835,-4.9837,-4.9837,-4.9837,-4.9836,-4.9837,-4.9836,-4.9834,-4.9835,-4.9835,-4.9835,-4.9837,-4.9837,-4.9836,-4.9837,-4.9836,-4.9835,-4.9835,-4.9835,-4.9835,-4.9835,-4.9838,-4.9835,-4.9837,-4.9837,-4.9836,-4.9836,-4.9835,-4.9834,-4.9835,-4.9836,-4.9835,-4.9834,-4.9835,-4.9835,-4.9835,-4.9834,-4.9835,-4.9835,-4.9836,-4.9836,-4.9832,-4.9836,-4.9835,-4.9833,-4.9837,-4.9832,-4.9835,-4.9835,-4.9839,-4.9836,-4.9835,-4.9835,-4.9834,-4.9834,-4.9834,-4.9836,-4.9837,-4.9836,-4.9836,-4.9835,-4.9837,-4.9836,-4.9834,-4.9836,-4.9835,-4.9837,-4.9836,-4.9834,-4.2901,-4.2939,-4.2996,-4.2942,-4.3042,-4.3024,-4.2975,-4.3076,-4.3143,-4.2290,-4.2316]

#!/usr/local/bin/python
# -*- coding: gbk -*-
#============================================================
# TEST1.PY                     -- by Dr. ZhuoQing 2023-12-25
#
# Note:
#============================================================

from headm import *
from tsmodule.tsvisa        import *

dl3021open(109)
dm3068open()

dl3021setcurrent(0)
dl3021on()

idim = linspace(0, 0.01, 100)
vdim = []

for i in idim:
    dl3021setcurrent(i)
    time.sleep(1)
    v = dm3068vdc()
    printff(i, v)
    vdim.append(v)
    tspsave('test', idim=idim, vdim=vdim)

dl3021setcurrent(0)

plt.plot(idim, vdim, lw=3)

plt.xlabel("Current(A)")
plt.ylabel("Voltage(V)")
plt.grid(True)
plt.tight_layout()
plt.show()






#------------------------------------------------------------
#        END OF FILE : TEST1.PY
#============================================================

▲ 图1.3.3 15mA的输出电流

▲ 图1.3.4 不同负载下输出电压噪声

??在电子负载吸收10mA 的情况下， 测量ICL7660输出电压。 ?可以看到出现了很大的无规律的波动。 ?在5mA时， 输出电压非常干净。 ?由此， 可以看到 ICL7660在输出电流超过 9mA之后， 发生了突变。 工作模式发生了较大的区别。

▲ 图1.3.5 在10mA的时候输出的电压信号

??这是测试工作电压与输出电压之间的关系。 ?可以看到在1V 到 6V之间， 输出电压与工作电压为反向的关系。 ?超过6V之后， 输出便停留在6V了。 实际上这与 ICL7660数据手册中给定的参数不太一致。 ?除此之外， ? ICL7660数据手册给定的它的工作电流也都会超过 10mA。 ?这是否说明， 我测试的这篇芯片存在着故障呢？

▲ 图1.3.6 不同工作电压下输出电压

??经过检查是因为直流电源5V档位最大只能输出6V， 所以修改为另外一个通道， 这样便可以输出10V电压了。 ?这次是在没有负载电流下进行测量。 在工作电压超过 3V之后， 输出电压便开始反向输出了。 这验证了 ICL7660 工作电压范围可以达到 10V。

▲ 图1.3.7 不同工作电压下对应的输出电压
??在工作电压小于3V的时候， 输出电压不对。 ?ICL7660数据手册 要求将其LV 管脚接地， 能够适合电压小于3V的工作模式。 ?不知道为什么， 将LV接地之后， 测量的电压更加不对了。 也许是测试的过程中芯片损坏了。 具体原因现在不得而知。

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※ 总??结 ※

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??本文对电压反转芯片 ICL7660 进行了测量。 ?在输出电流小于 9mA的时候， 芯片工作非常好。 ?但输出电流超过9mA之后， 输出电压出现了非常大的波动。 也许是芯片是旧的， 内部存在着损伤。

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■ 相关文献链接:

• ICL7660/MAX1044

● 相关图表链接:

• 图1.2.1 测试原理图
• 图1.2.2 电路PCB版图
• 图1.2.3 开关电容上的波形
• 图1.3.2 不同输出电流下对应的输出电压
• 图1.3.3 15mA的输出电流
• 图1.3.4 不同负载下输出电压噪声
• 图1.3.5 在10mA的时候输出的电压信号
• 图1.3.6 不同工作电压下输出电压
• 图1.3.7 不同工作电压下对应的输出电压