电流模式控制DC/DC转换器中的电流检测电路设计

应用于手机等通信电子产品电源系统的电流模式控制DC/DC转换器芯片,要求具有高性能电流检测电路.设计了一个高精度的电流检测电路,基于华润上华CSMC 0.5μmBiCMOS工艺库,利用Cadence Spectre软件进行电路仿真,经仿真得知所设计的电路电流取样精度达到1 000:1,具有很高的采样精度.该电流检测电路...     

一种DC/DC斜坡补偿电路的设计

本文提出了一种峰值电流模式控制的DC/DC转换器中斜率补偿电路.电路采用上斜坡补偿（补偿信号与采样信号叠加）方式.电路由采样电路、斜坡信号产生电路、叠加电路共同组成.采样电路采样电感电流信号,并生成一个带有采样信号信息的电流信号,输入到叠加电路,与斜坡信号产生电路生成的一个斜坡电流信号进行叠加,然后共同作于一个电阻之上,输出一个带有采样信号信息与斜坡补偿信息的电压信号,实现斜坡补偿.该信号与误差放大器的输出信号共同输入到PWM（脉冲宽度调制）比较器,两信号经比较后输出驱动信号,控制功率管的关断.     

DC/DC转换器中电流采样电路的设计

设计了一种用于DC/DC开关电源转换器的新型电流采样电路.常见的电流采样电路是通过检测采样管串联电阻上压降来得到采样电流,而该采样电路是通过检测开关管串联电感上压降来得到采样电流的.由于后者所需电阻更少,从而降低了采样电路的功耗,提高了效率;并且由于电感上压降对采样电流变化的灵敏度更高,有效地提高了采样的精度.     

一款电流型控制的DC／DC降压转换器

本文提出一种新型电感电流检测电路,该检测电路不需要一个放大器作为电压镜像,从而使用的器件更少,功耗更低。该电感电流检测电路应用于DC／DC降压转换器,采用CSM 0．18μm CMOS工艺进行设计和仿真,仿真结果显示该电感电流检测电路的精度可达到96％,输出电压的纹波仅为1mV。     

升压型DC—DC变换器电流环路补偿设计

针对固定频率峰值电流模式PWM升压型DC—DC变换器,给出了一种结构简单、易于集成的电流环路补偿电路的设计方法。该电路的斜坡产生电路可对片内振荡器充放电电容上的电压作V/I转换。其所得到的斜坡电流具有稳定、斜率易于调节等特点;而电流采样电路主体采用SENSEFET结合优化的缓冲级和V／I转换电路,从而在提高采样精度的同时。还减小了损耗。整个电路可采用0．6μm 15V BCD工艺实现。通过Cadence Spectre进行的仿真结果表明,该电路可有效地抑制亚谐波振荡,采样精度达到77．9％,补偿斜率精度达到81．5％。     

一种DC/DC转换器的短路保护电路设计

针对负载短路会对DC/DC造成性能不稳定或损坏的情况,提出一种新型短路保护电路,有效地避免了传统电路在短路时大电流输出造成的能量浪费。该保护电路采用在负载短接时,通过改变电流限比较器输入端基准电压达到降低电路最大输出电流的措施。采用0.35 μm BCD工艺将该电路应用于一款高压同步BUCK型DC/DC转换器中,specter仿真结果表明,当负载短路时,该芯片的短路电流只有30 mA,与传统保护电路相比,降低了短路时的输出电流,达到节约能量的目的。     

一种面向单片DC/DC的低压高效片上电流检测技术

本文提出并实现了一种面向电流模式单片开关DC/DC转换器的低压高效片上电流采样电路.该电路利用功率管等效电阻电流检测技术和无需OP放大器的源极输入差分电压放大技术,使电路的应用范围可低达2.3V;-3dB带宽12MHz;在最大负载电流情况下的静态电流峰值仅19μA,比常规采用功率管镜像电流检测技术的静态电流峰值低1.5个量级左右.转换器基于0.5μm 2P3M Mixed Signal CMOS工艺设计制作.测试结果表明,电流检测电路的最大检测电流1.1A,转换器的输入最低电压2.3V,重负载转换效率高于93%.     

一种基于DC/DC变换器的LED驱动电路的设计

提出一种基于电流模式DC/DC变换器的驱动控制电路。该电路可以与恒流电路结合在一起,用作LED驱动。电路由误差放大器、斜坡信号产生电路、电流采样与叠加电路以及PWM比较器四部分构成。采用华虹BCD350工艺进行仿真验证,结果显示,电路成功实现了电流采样信号与斜坡补偿信号的叠加,在Vea信号的控制下,输出了控制功率管关断的PWM脉冲信号。     

高压大电流单片DC/DC的抗总剂量加固技术

采用电流模、电压模双环控制结构,结合峰值电流采样等关键技术,实现了一款功率集成的单片DC/DC变换器。设计的峰值电流采样、斜率补偿大大提高了系统的稳定性,提高了系统的快速瞬态响应能力;针对高压低压差线性稳压器(LDO)、电流采样等高压模块电路,通过采样齐纳二极管、高压NJFET代替高压厚栅MOSFET等的设计方法,从总体上降低高压器件的数量,在基于30 V BCD(Bipolar-CMOS-DMOS)工艺上,结合特殊器件的版图设计方法,制作出一款输入电压5.5~17 V,电压调整率小于10 mV,电流调整率小于25 mV,输出电流大于5 A,系统静态电流小于25 mA,最高工作效率为93%的高效单片DC/DC,其抗总剂量能力大于100 krad(Si)。     

同步整流BOOST型DC/DC软启动电路

针对开关电源启动中出现浪涌电流的问题,设计了一种通过控制电流的方式来实现升压电路中的软启动电路,避免了在切入正常调制时出现较大过冲的现象。通过仿真,所设计的5 V BOOST同步整流DC/DC电路输出电压曲线平滑稳定,未在启动阶段出现浪涌电流和结束后的较大过冲电压。通过对0.5μm 5 V CMOS工艺流片后的电路测试,结果证明利用该设计,5 V升压电路实现了预期的软启动作用,并可灵活应用在其他DC/DC同类开关电源管理芯片中。     

降压型PWM DC/DC中的峰值电流环电路的设计

设计了一种用于PWM降压型DC/DC的峰值电流环电路,详细地阐述了电路工作原理以及相关计算公式,设计了与之配套的功率管MOSFET的版图布局布线。该电流检测与信号放大电路结构简单,比传统的设计更精确地反映了峰值电流的大小。仿真结果表明,电路的电源调整率达到0.1%;在较大的电源范围内(4.75V~15V)增益保持不变。     

A novel PWM control for a bi-directional full-bridge DC–DC converter with smooth conversion mode transitions

A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC–DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC–DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC–DC converters operating at high switching frequencies (i.e. up to 10?MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18?µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC–DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.     

半导体激光管驱动电源设计与实现

为提高半导体激光器光功率输出稳定性,并保证激光器安全、可靠工作,设计了半导体激光器的驱动电源。驱动电源主电路采用同步DC／DC方式,输出效率高;驱动电路可以产生200kHz触发脉冲,降低了输出电流的纹波,保证激光器输出功率稳．定;驱动电路带有过压比较器及过流比较器,保证激光器安全工作。经过仿真和实验表明：该驱动电源在20A工作时效率达到85％以上．纹波小于5％。     

Lossless average inductor current sensor for CMOS integrated DC–DC converters operating at high frequencies

A novel average inductor current sensing circuit integrable in CMOS technologies is presented. It is designed for DC–DC converters using buck, boost, or buck-boost topologies and operating in continuous conduction mode at high switching frequencies. The average inductor current value is used by the DC–DC controllers to increase the light load power conversion efficiency (e.g., selection of the modulation mode, selection of the dynamic width of the transistors). It can also be used to perform the constant current charging phase when charging lithium-ion batteries, or to simply detect overcurrent faults. The proposed average inductor current sensing method is based on the lossless sensing MOSFET principle widely used in monolithic CMOS integrated DC–DC converters for measuring the current flowing through the power switches. It consists of taking a sample of the current flowing through the power switches at a specific point in time during each energizing and de-energizing cycle of the inductor. By controlling precisely the point in time at which this sample is taken, the average inductor current value can be sensed directly. The circuit simulations were done with the Cadence Spectre simulator. The improvements compared to the basic sensing MOSFET principle are a lower power consumption because no high bandwidth amplifier is required, and less noise emission because the sensing MOSFET is no more switched. Additionally, the novel average inductor current sensing circuit overcomes the low bandwidth limitation previously associated with the sensing MOSFET principle, thus enabling it to be used in DC–DC converters operating at switching frequencies up to 10 MHz and above.     

应用于DC/DC稳压器的误差放大与逻辑控制电路

设计了一种应用于DC/DC集成稳压器的误差放大与逻辑控制电路。误差放大器的核心部分采用电流镜、折叠式共源共栅等结构,显著提高了增益、电源抑制比和共模抑制比;逻辑控制部分实现了对芯片工作模式的选择控制,并具有钳位功能。采用Sanyo Hspice模型进行仿真后表明,在很宽的频带范围内,误差放大器的差模增益大于80dB;逻辑控制电路工作时序正确可靠;各项性能指标满足设计要求。     

Zero-voltage DC/DC converter with asymmetric pulse-width modulation for DC micro-grid system

This paper presents a zero-voltage switching DC/DC converter for DC micro-grid system applications. The proposed circuit includes three half-bridge circuit cells connected in primary-series and secondary-parallel in order to lessen the voltage rating of power switches and current rating of rectifier diodes. Thus, low voltage stress of power MOSFETs can be adopted for high-voltage input applications with high switching frequency operation. In order to achieve low switching losses and high circuit efficiency, asymmetric pulse-width modulation is used to turn on power switches at zero voltage. Flying capacitors are used between each circuit cell to automatically balance input split voltages. Therefore, the voltage stress of each power switch is limited at V_in/3. Finally, a prototype is constructed and experiments are provided to demonstrate the circuit performance.