IC基本电⽓特性-华为内部员⼯培训资料
IC基本电⽓特性
Quiescent current 静态电流
Standby current低功耗电流
Dropout voltage (LDO特性)压降的输⼊电压
Efficiency功率
Transient respon顺势特性
Line regulation线路调整器
Load regulation负载调整率
Power supply rejection电源排除/抑制
Noi
瓷器收藏
Accuracy精确性
IC量测
IC（LDO）结构框图
Capacitor电容reference参考（电压）error amplifier误差信号放⼤器
Pass element⽆源元件（⼆极管）dynamic load 动态负载
主要模块包括;
Voltage Reference参考（电压）Error Amplifier误差信号放⼤器
Feedback Network 反馈⽹络Series-pass Element⽆源元件（⼆极管）
优点：简单、输出纹波电压低、出⾊的line 和负载稳压、对负载和line 的变化响应迅速、电磁⼲扰(EMI) 低缺点：效率低、如果需要冷却设备，则要求较⼤的空间
IC基本电⽓特性－Quiescent Current & Standby Current
Quiescent Current(Ground current):
The difference between input and output。
Low quiescent current is necessary to
maximize the efficiency.低静态电流是最
⼤限度地提⾼效率必要条件。
Standby Current:
The input current drawn by a regulator when
the output voltage is disabled by a shutdown
signal.
Quiescent Current and Output Current
The value of quiescent current is mostly determined
by the ries pass element, topologies, ambient
temperature, etc.静态电流的值主要是⼀系列⽆源
元件，拓扑结构，环境温度等确定的
具体特性与IC结构、制程密切相关
IC基本电⽓特性－Dropout V oltage（特有规格）
◆Low-Dropout Linear Regulators
低压差线性稳压器
◆传统的三端稳压器如：LM78xx
Vdrop的典型值是2V，看到很多7805应⽤时
都会背着⼀个散热器。
LM317 2V
LM1117 1.2V。
◆调整管采⽤的结构LM317 输出
学雷锋标兵
Darlingtong Vdrop=Vsat+2Vbe 1.6~2.5V
NPN Vdrop=Vsat+Vbe >0.9V
PNP Vdrop=Vsat 0.15~0.4V
PMOS Vdrop=Io X Ron 35~350mv
NMOS Vdrop=Vsat+Vgs 1V
◆不同调整管结构的⽐较：
1． T he NMOS pass element is most advantageous due to its low on resistance. Unfortunately, the gate drive difficulties make it less than ideal in applicaitons and as a result there are few NMOS LDOs available. 传统上，PNP 双极型晶体管应⽤到低压线性稳压器，主要是因为它很容易实现了低压降电压。 2． T raditionally, the PNP bipolar transistor has been applied to low dropout applications,
primarily becau it easily enables a low drop out voltage. However, it has a high quiescent current and low efficiency, which are not ideal in applications where maximizing efficiency is a priority. 然⽽，
它的⾼静态电流和低效率，这是不理想的应⽤最⼤限度地提⾼了效率是⼀个优先事项。 3． P MOS devices have been highly developed and now have performance levels exceeding most bipolar devices. PMOS 上设备已经⾼度发达，现在的性能⽔平超过最双极器件。
Dropout voltage ：the input-to-output differential voltage at which the circuit ceas to regulate against further reductions in input voltage; this point occurs when the input voltage approaches the output voltage. 压降：对输⼊⾄输出差分电压在电
路不再规范对进⼀步削减输⼊电压；这⼀点时发⽣的输⼊电压接近输出电压。
Vds=Vo-Vin
IC 基本电⽓特性－Efficiency
◆ The efficiency of a LDO regulator is limited by the quiescent current and input/output voltage as follows: 效率是有限的LDO 稳压器的静态电流和输⼊/输出电压如下：输
⼊电压降低；这⼀点时发⽣的输⼊电压接近输出电压。
windows7怎么激活◆
To have a high efficiency LDO regulator, drop out voltage and quiescent current must be minimized. 具有⾼效率的LDO 稳压器，电压和辍学静态电流必须减少到最低限度
()100
o o
o q i
I V Efficiency I I V =
+_m in i o drop
V V V =
+
IC 基本电⽓特性－Load Regulation
Load Regulation:
A measure of the circuit’s ability to maintain the specified out put voltage under varying load conditions. 衡量电路的能⼒，保持指定的输出电压在不同负载条件下。
The load regulation is limited by the open loop current gain of the system. As noted from the above equation, increasing dc open-loop current gain improves load regulation. 负荷调节是有限
的开环电流增益的系统。正如上述⽅程，增加直流开环电流增益改善负载调节。
小写金额转换大写金额公式
()
/Vo Io ?
◆ Line Regulation:
a measure of the circuit’s ability to maintain the specified output voltage with varying input voltage. 衡量这条赛道的能⼒，保持指定的输出电voltage.open 环电流增益改善负载调节。
其中， Rds 为调整管Q1源漏等效电阻。
◆ Increasing dc open loop current gain improves the line regulation. 提⾼直流开环
电流增益提⾼了线路调整
Output Voltage With Respect to Input Voltage
Line Transient Respon
()
/Vo Vi ?
清除自由基
IC基本电⽓特性－Transient Respon
◆Transient Respon:
the maximum allowable output voltage variation for a load current (input voltage) step change.瞬态响应：允许的最⼤输出电压变化的负载电流（输⼊电压）⼀步变化。
◆The transient respon is a function of the output capacitor value (Co), the ESR of
the output capacitor, the buypass capacitor (Cb), and the maximum load-current
(Io,max). 瞬态响应是⼀个功能的输出电容值（公司）中，电⼦⾃旋共振的输出电容器，电容器的
buypass （炭⿊），最⼤负载电流（ Io ，最⼤值）。
Where △t1 corresponds to the clod loop
bandwidth. △ESR is the voltage variation
resulting from the prence of the ESR of
the output capacitor. △ESR is proportional
to ESR.
凡△ t1闭环带宽。△esr是电压变化造成在场的
情况下的ESR的输出电容器。△esr成正⽐esr。
话务员培训
Transient Respon of LDO Regulator瞬态响应LDO稳压器
◆输出电容的影响
ESL load-transient respon负载瞬态响应ESR load-transient respon
ESL 影响⽐较⼩，但不合适的PCB布线同样使得性能下降。
ESR是越⼩越好，但成本＋稳定性
IC基本电⽓特性－Power Supply Rejection
◆PSRR:
also known as ripple rejection, measures the LDO regulator’s ability to prevent the regulated output voltage fluctuating caud by input voltage variations.也被称为纹波抑制，措施的LDO稳压器的能⼒，以防⽌输出电压波动所造成的输⼊电压的变化
胎儿股骨长The same relation for line regulation applies to PSRR except that the whole frequency spectrum is considered.同样的关系线适⽤于的PSRR ，但整个频谱是考虑。
PSRR is bad on small signals, whereas line transients are large signals.PSRR是基于⼩信号，⽽电压瞬态⼤信号。
Very critical in many RF and wireless application⾮常关键的在许多射频和⽆线应⽤
supply rejection in the frequency band between
100 kHz and 1 MHz is especially important in
applications where the output of a dc/dc switch
mode power supply (SMPS) is ud to power the
linear regulator抑制频带在100 kHz和1 MHz的是特别重要的应⽤场合中的输出的DC / DC开关模式电源（ SMPS ）是⽤于功率的线性稳压器风的英语
But why battery-powered application??
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But why battery-powered application??
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The output voltage will show a large variation bad upon the current drawn from that battery.输出电压将出现⼤的变化根据⽬前从该电池。
