**对比文件名称：** 2004-06-22_发明授权_US06753732B1 Accurate, wide-band, low-noise variable-gain amplifier structures and gain control methods
**目标专利名称：** 用于校准差分电路中跨导或增益随工艺或条件变化的方法和设备 CN107210716B
**本次调用的模型名称：** DeepSeek最新版本模型
### 特征比对表格
| 技术特征描述及公开性判断结果 | 对比文件原文引用 | 公开性论述 |
| **技术特征A《直接公开》** | “The variable-gain amplifier (VGA) 20 of FIG. 1 ... comprises a signal amplifier 24 and a bias amplifier 26 that includes a gain current source 27, a gain resistor 28, a control current source 29 and an **error amplifier 30**.” (说明书第3页第1段) <br> “The bias amplifier 26 is formed with a **bias differential amplifier 42**.” (说明书第3页第2段) <br> “The error amplifier 30 has a differential input coupled to receive a difference signal from the first and second bias loads 47 and 48 and an output coupled to provide the **error signal S_err** to the control terminals of the signal and bias current sources 39 and 49.” (说明书第3页第2段) | 目标专利特征A要求校准电路包括运算跨导放大器（OTA）和运算放大器（op-amp），并产生参考信号（VREF）。对比文件中，`bias amplifier 26`包含`bias differential amplifier 42`（相当于OTA，用于将差分输入电压转换为输出电流差）和`error amplifier 30`（相当于运算放大器），两者共同作用产生一个`error signal S_err`。该`S_err`信号用于控制放大器的跨导，其作用与目标专利中由OTA和运算放大器产生的参考信号`VREF`完全相同，即作为偏置电压控制尾电流以设定跨导。因此，本领域技术人员可以毫无疑义地确定对比文件公开了由OTA（偏置差分放大器42）和运算放大器（误差放大器30）组成的、用于产生参考信号（S_err）的校准电路（偏置放大器26）。 |
| **技术特征B《直接公开》** | “The signal amplifier 24 ... includes a signal differential pair 34 of signal transistors 35 and 36 that is coupled between first and second signal loads 37 and 38 and a **signal current source 39**. ... the signal current source is a transistor whose control terminal (i.e., a base) is available to receive an **error signal S_err**.” (说明书第3页第1段) <br> “The error signal S_err of the error amplifier is coupled as a feedback signal to the control terminal of the **signal ... current sources 39** ... Because the error amplifier has a substantial gain, the feedback operates to reduce the difference signal substantially to zero so that **g_m = I_c / (I_g R_g)** ... The error amplifier 30, however, also provides its error signal S_err to the control terminal of the signal current source 39 so that the **transconductance of the signal differential amplifier 32 will also be controlled** in accordance with the relationship of equation (1). ... In another important feature of the present invention, therefore, the signal amplifier 24 has the bandwidth advantages of an open-loop structure but the **gain-immunity of a feedback-controlled amplifier to temperature and process variations**.” (说明书第3页第2段，第4页第1段) | 目标专利特征B要求至少一个差分电路基于参考信号以相对于工艺或条件变化的经校准的跨导操作。对比文件中，`signal amplifier 24`包含由晶体管35、36构成的差分对34，这是一个差分电路。其`signal current source 39`的控制端接收来自校准电路（偏置放大器26）的误差信号`S_err`。通过反馈环路，`S_err`被调节使得偏置放大器的跨导满足`g_m = I_c/(I_g R_g)`，同时该相同的`S_err`也被提供给信号放大器24的信号电流源39，从而控制信号放大器24的跨导。说明书明确指出了这种结构使得信号放大器24的增益对温度和工艺变化具有免疫力（gain-immunity ... to temperature and process variations），即实现了经校准的跨导。因此，对比文件直接公开了基于参考信号（S_err）以相对于工艺/条件变化经校准的跨导操作的差分电路（信号放大器24）。 |
| **技术特征C《隐含公开》** | “The bias amplifier 26 is formed with a bias differential amplifier 42. Although this differential amplifier is substantially identical to the signal differential amplifier 32, it is generally identified for descriptive purposes by replacement of the adjective ‘signal’ with the adjective ‘bias’.” (说明书第3页第2段) <br> “The bias amplifier 26 is formed with a bias differential amplifier 42. ... the bias differential amplifier 42 includes a bias differential pair 44 of bias transistors 45 and 46 that is coupled between first and second bias loads 47 and 48 and a bias current source 49. ... the bias current source is a transistor whose control terminal is available to receive the error signal S_err.” (说明书第3页第2段) | 目标专利特征C要求校准电路独立于所述至少一个差分电路产生参考信号。对比文件中，产生参考信号`S_err`的电路是`bias amplifier 26`（即校准电路），它包含一个`bias differential amplifier 42`。说明书明确指出，这个`bias differential amplifier 42`与信号放大器24中的`signal differential amplifier 32`“基本相同”（substantially identical），但为了描述目的而称为“偏置”。这意味着校准电路（偏置放大器26）与待校准的差分电路（信号放大器24）在电路结构上是相似但物理上分离的两个实体。`bias amplifier 26`接收的是其自身路径上的增益电流`I_g`和控制电流`I_c`，并基于这些独立输入和其自身的反馈环路产生`S_err`。`S_err`的产生过程不依赖于信号放大器24的输出信号或其工作状态。因此，本领域技术人员通过阅读对比文件可以合理推断，校准电路（偏置放大器26）是独立于待校准的差分电路（信号放大器24）运作并产生参考信号（S_err）的。 |
| **技术特征D《直接公开》** | “Finally, it is noted that the **error amplifier 30 has a differential input coupled to receive a difference signal from the first and second bias loads 47 and 48** and an output coupled to provide the error signal S_err ...” (说明书第3页第2段) <br> “However, the bias load 48 also receives the **control current I_c of the control current source 29** which attempts to establish a voltage I_c R_c across the bias load 48. A difference signal is thus established across the input of the error amplifier 30” (说明书第3页第2段) <br> “the differential output current ΔI_out of the bias differential pair 44 will be given by the transconductance plot 56 ... The bias differential pair 44 will thus attempt to establish a **differential voltage across the differential input of the differential amplifier 30 equal to g_m ΔV_g R_c** wherein R_c is the resistance of each of the collector bias loads 47 and 48.” (说明书第3页第2段) | 目标专利特征D要求运算放大器将基于OTA输出的电压与独立于OTA的第二参考电压进行比较。对比文件中，`error amplifier 30`（运算放大器）的一个输入接收来自偏置负载47、48两端的电压差，该电压差由偏置差分放大器44（OTA）的输出电流（`ΔI_out`）流经负载电阻`R_c`产生，即`g_m ΔV_g R_c`。`error amplifier 30`的另一个输入则接收由独立的`control current source 29`提供的控制电流`I_c`流经同一负载电阻`R_c`（此处为负载48）所产生的电压`I_c R_c`。控制电流源29及其产生的电压`I_c R_c`是独立于偏置差分放大器44（OTA）的。因此，运算放大器（30）确实在比较一个基于OTA（44）输出的电压（`g_m ΔV_g R_c`）和一个独立于OTA的第二参考电压（`I_c R_c`）。该技术特征被直接公开。 |
| **技术特征E《直接公开》** | “A difference signal is thus established across the input of the error amplifier 30 and the **error signal S_err of the error amplifier is coupled as a feedback signal** to the control terminal of the bias current source 49. Because the error amplifier has a substantial gain, the feedback operates to reduce the difference signal substantially to zero so that g_m ΔV_g R_c = I_c R_c” (说明书第3页第2段) | 目标专利特征E要求参考信号基于所述比较。对比文件中明确记载，误差放大器30基于其两个输入端的电压差（即比较的结果）产生误差信号`S_err`。该`S_err`作为反馈信号输出。说明书中的等式`g_m ΔV_g R_c = I_c R_c`正是在反馈环路稳定（即误差放大器输入差值为零）时得出的，直接证明了`S_err`是基于比较产生的。因此，该特征被直接公开。 |
| **技术特征F《直接公开》** | “The signal amplifier 24 is formed with a signal differential amplifier 32 that is coupled between the differential input port 21 and the differential output port 22. The signal differential amplifier 32 includes a **signal differential pair 34 of signal transistors 35 and 36** that is coupled between first and second signal loads 37 and 38 and a **signal current source 39**. ... the signal current source is a transistor whose control terminal (i.e., a base) is available to receive an error signal S_err.” (说明书第3页第1段) | 目标专利特征F要求差分电路包括晶体管的差分配对，并基于参考信号产生尾电流。对比文件中，信号放大器24包含信号晶体管35和36构成的差分配对34。其尾电流由信号电流源39提供，而信号电流源39是一个晶体管，其控制端（基极）接收误差信号`S_err`（即参考信号）。因此，该差分电路基于参考信号`S_err`为其差分配对产生尾电流。该特征被直接公开。 |
| **技术特征G《直接公开》** | “the error signal S_err of the error amplifier is coupled as a **feedback signal** to the control terminal of the bias current source 49. Because the error amplifier has a substantial gain, the **feedback operates to reduce the difference signal substantially to zero** so that g_m ΔV_g R_c = I_c R_c” (说明书第3页第2段) | 目标专利特征G要求校准电路反馈参考信号并基于反馈调节参考信号。对比文件中，误差放大器30输出的误差信号`S_err`被反馈至偏置电流源49的控制端。该反馈环路通过调节`S_err`，迫使误差放大器30的输入差值趋近于零，从而精确设定跨导`g_m`。这是一个典型的基于反馈调节参考信号（`S_err`）的过程。因此，该特征被直接公开。 |
| **技术特征H《直接公开》** | “The bias amplifier 26 ... includes a **gain current source 27**, a gain resistor 28, a **control current source 29** and an error amplifier 30.” (说明书第3页第1段) <br> “In an important feature of the present invention, equation (2) also shows that the voltage gain can be varied by varying one or both of the **control and gain currents I_c and I_g**.” (说明书第4页第1段) | 目标专利特征H要求校准电路基于第一参考电流和第二参考电流产生参考信号。对比文件中，校准电路（偏置放大器26）明确包含增益电流源27（产生`I_g`）和控制电流源29（产生`I_c`）这两个参考电流源。误差信号`S_err`（即参考信号）的产生过程依赖于这两个电流（`I_g`和`I_c`），如公式`g_m = I_c / (I_g R_g)`所示。`I_g`和`I_c`分别对应于第一和第二参考电流。因此，该特征被直接公开。 |
| **技术特征I《直接公开》** | “the bias differential amplifier 42 includes a bias differential pair 44 of bias transistors 45 and 46 ... and a **bias current source 49**. ... the bias current source is a transistor whose control terminal is available to receive the **error signal S_err**.” (说明书第3页第2段) | 目标专利特征I要求运算跨导放大器（OTA）基于反馈产生尾电流。对比文件中，偏置差分放大器42（相当于OTA）包含一个偏置电流源49，该电流源是一个晶体管，其控制端接收来自误差放大器30的误差信号`S_err`（即反馈信号）。因此，OTA（42）基于反馈信号（`S_err`）产生其自身的尾电流。该特征被直接公开。 |
| **技术特征J《直接公开》** | “The gain resistor 28 of the bias amplifier 26 has a gain resistance R_g and is coupled across the differential input of the bias differential pair 44 and receives the **gain current I_g of the gain current source 27** to thereby generate a **differential gain signal ΔS_g (in particular, a differential gain voltage ΔV_g)**.” (说明书第3页第1段) <br> “In response to the **differential gain voltage ΔV_g**, the differential output current ΔI_out of the bias differential pair 44 will be given by the transconductance plot 56” (说明书第3页第2段) | 目标专利特征J要求校准电路包括将参考电流转换为参考电压的电路，且OTA基于该参考电压产生输出。对比文件中，增益电阻28接收增益电流`I_g`（参考电流）并产生差分增益电压`ΔV_g`（参考电压）。该电压`ΔV_g`被施加到偏置差分放大器44（OTA）的差分输入端。OTA（44）响应该输入电压`ΔV_g`，产生差分输出电流`ΔI_out`。因此，包含电阻28的电路实现了将参考电流（`I_g`）转换为参考电压（`ΔV_g`）的功能，且OTA（44）基于该参考电压产生输出。该特征被直接公开。 |
| **技术特征K《未公开》** | 未发现相关内容。 | 目标专利特征K要求校准电路被配置为相对于工艺或条件变化保持所述参考电压恒定。其说明书详细描述了通过使用带隙基准电压源和特定的电阻比例关系（`VIN = Kb × Vbg`），使得参考电压`VIN`在PVT变化下保持恒定。对比文件中虽然产生了参考电压`ΔV_g`（`= I_g × R_g`），但说明书并未描述任何旨在使`ΔV_g`相对于工艺、电压、温度变化保持恒定的机制或配置。相反，`I_g`和`R_g`都可以是变量（例如，`I_g`可通过DAC 60改变以调节增益）。对比文件关注的是通过电流和电阻的**比例**（`I_c/(I_g R_g)`）来使跨导稳定，而非保持`ΔV_g`本身恒定。因此，对比文件既未直接公开也未隐含公开“保持参考电压恒定”这一技术特征。 |
| **技术特征L《未公开》** | “However, the bias load 48 also receives the control current I_c of the control current source 29 which attempts to establish a voltage I_c R_c across the bias load 48.” (说明书第3页第2段) | 目标专利特征L要求第二参考电压基于第二参考电流，且该第二参考电流相对于工艺或条件变化恒定。对比文件中，第二参考电压是`I_c R_c`，基于第二参考电流`I_c`。然而，说明书并未声明或暗示控制电流`I_c`被设计为在工艺或条件变化下保持恒定。事实上，`I_c`是用于与`I_g`共同设置跨导比例（`g_m = I_c/(I_g R_g)`）的一个参数，其值可以是固定的，也可以是可变的（例如，在图3A的DAC 80中，控制晶体管89提供`I_c`，但其值取决于偏置电压V_bias，而V_bias会随工艺变化）。目标专利说明书则明确描述了通过使用片外电阻和带隙基准来产生恒定电流`I0`（对应于`I_c`）的机制。对比文件缺少对`I_c`恒定性的任何教导。因此，该特征未被对比文件公开。 |
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