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TPS2121 导通电阻特性

news 2026/8/14 13:19:56

简介：本文测试了多电源切换芯片TPS2121的导通特性，包括最低工作电压和导通电阻。测试结果表明，输入电压需超过2.6V才能正常输出，导通电阻约为0.1欧姆。通过单面PCB快速制板验证了其性能，适用于多电源自动切换场景。

关键词：TPS2121

TSP2121导通特性

电源多路复用起（Power MUX） TPS2121
TPS212X Datasheet

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01【导通电阻】

一、背景

昨天测试了多电源自动切换芯片 TPS2121的基本功能。今天测量一下这个芯片的其它特性。通过铺设单面测试电路板，测试一下电源切换芯片的最低输入电压。也就是输入电压需要超过多少伏之后，才能够从芯片的输出端口输出。另外测量一下芯片导通对应的串联电阻大约是多少。

二、测量电路

设计测试电路板，在昨天测试电路板的原理图基础上，增加了带个四芯单独输入端口。 TPS2121仍然配置成两路电压比较模式，也就是输出电压比较高的输入通道的电压。铺设单面PCB，适合一分钟制版。一分钟之后得到了测试电路板。

电路板制作的非常完美。下面焊接测试。

三、测试结果

焊接电路板，使用高压水蒸气清洗之后进行测试，通过四芯探针夹子将可调电源加入电路，在通道一输入正五伏电压，可以在 TPS2121输出端测量到5伏的输出电压，现在输出端是空载，接下来我们给输出端焊接一个510 欧姆的负载电阻，测量一下，输入输出电压关系，这样我们可以测量究竟该芯片最低工作电压可以低到多少。

绘制出输入与输出电压曲线，在输入电压超过 2.6V 之后，输出电压便与输入电压相同，同步上升了。输入电压从 3V 逐步变化到 12V，输出电压也从 3V 变化到12V。测量输入和输出之间的电压。可以看到也是线性上升，这是因为输出电压上升，在固定的负载上所产生的输出电压也是线性上升。由负载电阻以及对应的输出电压和输出压差，可以计算出TPS2121的导通电阻。这个到导通电阻基本上在 95毫欧姆左右，电阻大小基本上是恒定的。

※总结 ※

本文测试了多电源切换芯片 TPS2121 的导通特性。输入电压需要超过 2.6V之后，才能够输出相应的电压。通道电阻大约在 0.1 欧姆左右。

#!/usr/local/bin/python# -*- coding: gbk -*-#============================================================# TSET1.PY -- by Dr. ZhuoQing 2026-08-14## Note:#============================================================fromheadmimport*fromtsmodule.tsvisaimport*fromtsmodule.tsstm32import*dm3068open()vin=linspace(3,12,100)vout=[]vdiff=[]forvinvin:dh1766volt1(v)time.sleep(2)vv=meterval()vo=dm3068vdc()vout.append(vo)vdiff.append(vv[3])tspsave("meas",vin=vin,vout=vout,vdiff=vdiff)printff(v,vv,vo)plt.plot(vin,vout,lw=3)plt.xlabel("Vin(V)",color="steelblue",fontsize=24)plt.ylabel("Vout(V)",color="steelblue",fontsize=24)plt.grid(True,which='both',linestyle='--',alpha=0.7)plt.tight_layout()plt.show()#------------------------------------------------------------# END OF FILE : TSET1.PY#============================================================

#!/usr/local/bin/python# -*- coding: gbk -*-#============================================================# TEST2.PY -- by Dr. ZhuoQing 2026-08-14## Note:#============================================================fromheadmimport*vin,vout,vdiff=tspload('meas','vin','vout','vdiff')Rload=510Ron=[v1/v2*Rloadforv1,v2inzip(vdiff,vout)]plt.plot(vin,Ron,lw=3)plt.xlabel("Vin(V)",color="steelblue",fontsize=24)plt.ylabel("Ron(Ohm)",color="steelblue",fontsize=24)plt.grid(True,which='both',linestyle='--',alpha=0.7)plt.tight_layout()plt.show()#------------------------------------------------------------# END OF FILE : TEST2.PY#============================================================

vin=[3.0000,3.0909,3.1818,3.2727,3.3636,3.4545,3.5455,3.6364,3.7273,3.8182,3.9091,4.0000,4.0909,4.1818,4.2727,4.3636,4.4545,4.5455,4.6364,4.7273,4.8182,4.9091,5.0000,5.0909,5.1818,5.2727,5.3636,5.4545,5.5455,5.6364,5.7273,5.8182,5.9091,6.0000,6.0909,6.1818,6.2727,6.3636,6.4545,6.5455,6.6364,6.7273,6.8182,6.9091,7.0000,7.0909,7.1818,7.2727,7.3636,7.4545,7.5455,7.6364,7.7273,7.8182,7.9091,8.0000,8.0909,8.1818,8.2727,8.3636,8.4545,8.5455,8.6364,8.7273,8.8182,8.9091,9.0000,9.0909,9.1818,9.2727,9.3636,9.4545,9.5455,9.6364,9.7273,9.8182,9.9091,10.0000,10.0909,10.1818,10.2727,10.3636,10.4545,10.5455,10.6364,10.7273,10.8182,10.9091,11.0000,11.0909,11.1818,11.2727,11.3636,11.4545,11.5455,11.6364,11.7273,11.8182,11.9091,12.0000]vout=[2.9744,3.0639,3.1544,3.2451,3.3346,3.4251,3.5157,3.6053,3.6957,3.7852,3.8758,3.9663,4.0558,4.1463,4.2369,4.3264,4.4169,4.5074,4.5970,4.6875,4.7771,4.8676,4.9581,5.0476,5.1382,5.2288,5.3184,5.4089,5.4994,5.5889,5.6792,5.7688,5.8594,5.9499,6.0394,6.1300,6.2206,6.3101,6.4006,6.4911,6.5807,6.6713,6.7617,6.8513,6.9418,7.0314,7.1220,7.2125,7.3021,7.3926,7.4832,7.5727,7.6632,7.7536,7.8432,7.9337,8.0232,8.1137,8.2042,8.2938,8.3844,8.4748,8.5644,8.6549,8.7452,8.8348,8.9253,9.0148,9.1054,9.1959,9.2856,9.3760,9.4664,9.5560,9.6464,9.7368,9.8263,9.9168,10.0073,10.0968,10.1873,10.2769,10.3673,10.4578,10.5473,10.6378,10.7283,10.8179,10.9084,10.9988,11.0883,11.1788,11.2683,11.3588,11.4492,11.5387,11.6291,11.7195,11.8090,11.8995]vdiff=[0.0006,0.0006,0.0006,0.0006,0.0006,0.0006,0.0006,0.0007,0.0007,0.0007,0.0007,0.0007,0.0007,0.0008,0.0008,0.0008,0.0008,0.0008,0.0008,0.0009,0.0009,0.0009,0.0009,0.0009,0.0009,0.0010,0.0010,0.0010,0.0010,0.0010,0.0010,0.0010,0.0011,0.0011,0.0011,0.0011,0.0011,0.0011,0.0012,0.0012,0.0012,0.0012,0.0012,0.0012,0.0013,0.0013,0.0013,0.0013,0.0013,0.0013,0.0014,0.0014,0.0014,0.0014,0.0014,0.0014,0.0015,0.0015,0.0015,0.0015,0.0015,0.0015,0.0016,0.0016,0.0016,0.0016,0.0016,0.0016,0.0017,0.0017,0.0017,0.0017,0.0017,0.0017,0.0018,0.0018,0.0018,0.0018,0.0018,0.0018,0.0019,0.0019,0.0019,0.0019,0.0019,0.0019,0.0020,0.0020,0.0020,0.0020,0.0020,0.0020,0.0021,0.0021,0.0021,0.0021,0.0021,0.0021,0.0022,0.0022]