A differential automatic gain control （AGC） circuit is presented. The AGC architecture contains twostage variable gain amplifiers （VGAs） which are implemented with a Gilbert cell, a peak detector （PD）, a low pas...A differential automatic gain control （AGC） circuit is presented. The AGC architecture contains twostage variable gain amplifiers （VGAs） which are implemented with a Gilbert cell, a peak detector （PD）, a low pass filter, an operational amplifier, and two voltage to current （V-I） convertors. One stage VGA achieves 30 dB gain due to the use of active load. The AGC circuit is implemented in UMC 0.18-um single-poly six-metal CMOS process technology. Measurement results show that the final differential output swing of the 2nd stage VGA is about 0.9-Vpp; the total gain of the two VGAs can be varied linearly from -10 to 50 dB when the control voltage varies from 0.3 to 0.9 V. The final circuit （containing output buffers and a band-gap reference） consumes 37 mA from single 1.8 V voltage supply. For a 50 mV amplitude 60% modulation depth input AM signal it needs 100 us to stabilize the output. The frequency response of the circuit has almost a constant -3 dB bandwidth of 2.2 MHz. Its OIP3 result is at 19 dBm.展开更多
以工作于混合导电模式(hybrid conduction mode,HCM)的单电感双输出(single-inductor dual-output,SIDO)Buck变换器为研究对象,文中提出一种动态续流控制技术。首先,分析HCM SIDO Buck变换器的工作原理;基于5个工作状态的电感电流、电...以工作于混合导电模式(hybrid conduction mode,HCM)的单电感双输出(single-inductor dual-output,SIDO)Buck变换器为研究对象,文中提出一种动态续流控制技术。首先,分析HCM SIDO Buck变换器的工作原理;基于5个工作状态的电感电流、电容电流有效值,计算主功率电路的功率损耗,得到不同负载条件下变换器的工作效率。其次,对比分析恒定续流控制伪连续导电模式(pseudo-continuous conduction mode,PCCM)SIDO Buck变换器、恒定续流控制HCM SIDO Buck变换器以及动态续流控制HCM SIDO Buck变换器的损耗与效率;推导动态续流控制与恒定续流控制HCM SIDO Buck变换器的负载与占空比的关系,并对两者的工作范围进行比较。研究结果表明:相比于恒定续流控制PCCM SIDO Buck变换器和恒定续流控制HCM SIDO Buck变换器,动态续流控制HCM SIDO Buck变换器具有低交叉影响、高工作效率和宽负载范围的特性。最后,通过仿真与实验验证理论分析的正确性。展开更多
基金Project supported by the National High Technology Research and Development Program of China(No.2008AA04A 102)
文摘A differential automatic gain control （AGC） circuit is presented. The AGC architecture contains twostage variable gain amplifiers （VGAs） which are implemented with a Gilbert cell, a peak detector （PD）, a low pass filter, an operational amplifier, and two voltage to current （V-I） convertors. One stage VGA achieves 30 dB gain due to the use of active load. The AGC circuit is implemented in UMC 0.18-um single-poly six-metal CMOS process technology. Measurement results show that the final differential output swing of the 2nd stage VGA is about 0.9-Vpp; the total gain of the two VGAs can be varied linearly from -10 to 50 dB when the control voltage varies from 0.3 to 0.9 V. The final circuit （containing output buffers and a band-gap reference） consumes 37 mA from single 1.8 V voltage supply. For a 50 mV amplitude 60% modulation depth input AM signal it needs 100 us to stabilize the output. The frequency response of the circuit has almost a constant -3 dB bandwidth of 2.2 MHz. Its OIP3 result is at 19 dBm.
文摘以工作于混合导电模式(hybrid conduction mode,HCM)的单电感双输出(single-inductor dual-output,SIDO)Buck变换器为研究对象,文中提出一种动态续流控制技术。首先,分析HCM SIDO Buck变换器的工作原理;基于5个工作状态的电感电流、电容电流有效值,计算主功率电路的功率损耗,得到不同负载条件下变换器的工作效率。其次,对比分析恒定续流控制伪连续导电模式(pseudo-continuous conduction mode,PCCM)SIDO Buck变换器、恒定续流控制HCM SIDO Buck变换器以及动态续流控制HCM SIDO Buck变换器的损耗与效率;推导动态续流控制与恒定续流控制HCM SIDO Buck变换器的负载与占空比的关系,并对两者的工作范围进行比较。研究结果表明:相比于恒定续流控制PCCM SIDO Buck变换器和恒定续流控制HCM SIDO Buck变换器,动态续流控制HCM SIDO Buck变换器具有低交叉影响、高工作效率和宽负载范围的特性。最后,通过仿真与实验验证理论分析的正确性。
