Differential current-sensing for on-chip interconnects

This paper presents a differential current-sensing technique as an alternative to existing circuit techniques for on-chip interconnects. Using a novel receiver circuit, it is shown that, delay-optimal current-sensing is a faster (20% on an average) option as compared to the delay-optimal repeater insertion technique for single-cycle wires. Delay benefit for current-sensing increases with an increase in wire width. Unlike repeaters, current-sensing does not require placement of buffers along the wire, and hence, eliminates any placement constraints. Inductive effects are negligible in differential current-sensing. Current-sensing also provides a tighter bound on delay with respect to process variations. However, current-sensing has some drawbacks. It is power inefficient due to the presence of static-power dissipation. Current-sensing is essentially a low-swing signaling technique, and hence, it is sensitive to full swing aggressor noise.     

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。     

A 400-mA current-mode buck converter with a self-trimming current sensing scheme

A current-programmed mode (CPM) controller is designed for improved DC–DC converter control. The key building block of the CPM controller is an accurate current-sensing circuit. This paper proposes a lossless current-sensing technique to measure the inductor current by measuring the current through the power transistor. A self-trimming circuit is used to compensate for any inaccuracies caused by voltage and temperature variations. The measurement results validate the operation of the fabricated chip.     

电流模降压变换器抗干扰电流采样电路设计

A novel anti-jamming integrated CMOS current-sensing circuit for current-mode buck regulators is presented. Based on the widely-used traditional current-sensing structure, anti-jamming performance is improved significantly by adding on-chip capacitors and one-shot circuit. Also the transient response is faster through the introduction of current offset. The circuit is concise, simple to implement and suits for SoC applications with single power supply. A dualoutput current-mode DC-DC buck converter with proposed structure has been fabricated with a 0.5 μm CMOS process for validation. In the 2.5–5.5 V input range, the two channels work steadily in the load current range of 0–600 mA. And the measured maximum efficiency is up to 96%.     

A new fault current-sensing scheme for fast fault protection of the insulated gate bipolar transistor

A new fault current-sensing scheme employing the floating p-well for fast protection of the insulated gate bipolar transistor (IGBT) from the short-circuit faults is proposed and verified by employing 2D mixed mode simulation, based on the previous experimental results. The proposed floating p-well current-sensing scheme detects not the normal operating current but the fault current of the main IGBT by using the diode connected MOSFET and a resistor, when the short-circuit fault occurs. The diode-connected MOSFET eliminates the degradation of the forward voltage drop, because the floating p-well current does not flow under the normal operating condition due to the threshold voltage of the diode connected MOSFET. The proposed current sensor increases the protection speed without any additional delay time by the external blanking filter.     

Dynamically biased current sensor for current-sensing completiondetection

A dynamically biased current sensor for the current-sensing completion detection method, which cuts off the power consumption when the logic blocks do not operate is presented. The proposed method is an essential improvement to all completion detection methods that use static biasing in their current sensing circuits, and where the power consumption is an important issue     

Design of anti-jamming current-sensing circuit for current-mode buck regulator

A novel anti-jamming integrated CMOS current-sensing circuit for current-mode buck regulators is presented.Based on the widely-used traditional current-sensing structure,anti-jamming performance is improved significantly by adding on-chip capacitors and one-shot circuit.Also the transient response is faster through the introduction of current offset.The circuit iS concise,simple to implement and suits for SoC applications with single power supply.A dual-output current-mode DC-DC buck converter with proposed structure has been fabricated with a 0.5μm CMOS process for validation.In the 2.5-5.5 V input range,the two channels work steadily in the load current range of 0-600 mA.And the measured maximum efficiency is up to 96%.     

一种新的应用于降压式DC-DC变换器电流采样电路的设计

在分析了传统的应用于大负载电流降压式DC-DC变换器电流采样电路主要缺点的基础上,提出一种新的应用于降压式DC-DC变换器的电流采样电路。该方法通过一个电阻电容网络来消除电感寄生电阻的影响,并利用开关电容积分器来实现降压式DC-DC变换器的电流采样,在Chartered 0.35μm CMOS工艺下实现该电路并流片验证。最终的测试结果显示,提出的电流采样电路实现了对降压式DC-DC变换器精确的电流采样。     

Integrated current-mode DC–DC boost converter with high-performance control circuit

In this paper, integrated BiCMOS amplifier and current-sensing circuits are introduced for high-performance DC–DC boost converter. By exploiting the advantage of BiCMOS technology, the high gain amplifier and accurately sensed inductor current are obtained in the feedback control circuit. The proposed current-sensing circuit adopts a current-mirror instead of op-amplifier as a voltage follower so that it would reduce power consumption with a smaller chip-size. Bipolar transistor is also applied in the differential pair and current sources of the error amplifier to obtain a fast transient response. Frequency response shows the amplifier gain with the compensator affects significantly on the stability of the converter. The chip is fabricated in 0.35 µm 2-poly 4-metal BiCMOS process. The measurement shows that the current-sensing circuit can operate with accuracy of higher than 90 % at the frequency from 10 to 200 kHz and the transient time of the error amplifier is controlled within 10 µs. The converter with chip-size of 1 mm² operates at the output voltage of 4.5–9 V with the frequency of 0.01–1 MHz.     

Online calibration of MOSFET on-state resistance for precise current sensing

An approach for online current sensing calibration is presented where an auxiliary switch and a precision sense resistor are connected in parallel with a main power switch to achieve accuracy comparable to the sense resistor method, together with the advantage of essentially no additional power loss. The proposed current-sensing circuit and the calibration methods are particularly well suited for digital controller implementations where the required control and calibration functions can be easily accomplished. Experimental results with a digitally controlled 1.5-V 15-A synchronous buck converter demonstrate functionality of the online calibration approach, showing a significant improvement in accuracy over voltage sensing across the power MOSFET on-resistance.     

An integrated CMOS current-sensing circuit for low-Voltage current-mode buck regulator

An integrated current-sensing circuit for low-voltage buck regulator is presented. The minimum achievable supply voltage of the proposed current-sensing circuit is 1.2 V implemented in a CMOS technology with V/sub TH/=0.85 V, and the current-sensing accuracy is higher than 94%. With the developed current-sensing circuit, a buck regulator, which is able to operate at a 1.2-V supply, is implemented. A maximum output current of 120 mA and power-conversion efficiency higher than 89% are achieved.     

A novel current-sharing control technique for low-voltagehigh-current voltage regulator module applications

Future generations of microprocessors are expected to exhibit much heavier loads and much faster transient slew rates. Today's voltage regulator module (VRM) will need a large amount of extra decoupling and output filter capacitors to meet future requirements, which will basically make the existing VRM topologies impractical. As a candidate topology, the interleaved quasisquare-wave (QSW) VRM exhibits very good performance, such as a fast transient response and a very high power density. The difficulty with the application of the interleaved parallel technology is the current-sharing control. In this paper, a novel current-sensing and current-sharing technique is proposed. With this technique, current sharing can be controlled simply in parallel converters without a current transformer and current-sensing resistors. In addition, this technique can be easily integrated with an IC chip. The four-module paralleled QSW VRM is used to evaluate this technique. Experimental results verify that with this technique, the VRM has a high power density, high efficiency and a fast transient response. The concept of the current sharing technique is also generalized and extended     

On-chip CMOS current-sensing circuit for DC-DC buck converter

An on-chip CMOS current-sensing circuit for a DC-DC buck converter is presented. The circuit can measure the inductor current through sensing the voltage of the switch node during the converter on-state. By matching the MOSFETs, the achieved sense ratio is almost independent of temperature, model and supply voltage. The proposed circuit is suitable for low power DC-DC applications with high load current.     

A New Monolithic Fast-Response Buck Converter Using Spike-Reduction Current-Sensing Circuits

A new monolithic fast-response buck converter using spike-reduction current-sensing circuits is proposed in this paper. The proposed converters are designed and implemented with TSMC 0.35-mum DPQM CMOS processes. The operation frequency can be up to 1.887 MHz. The response time is only 2 mus and compared with other references. The maximum output current is 750 mA, and the maximum power efficiency can be up to 89.1% at 2.442-W output power. The chip area is only 2.157 mm².     

Current Sensing for Automotive Electronics—A Survey

Current sensing is widely used in power electronic applications such as dc-dc power converters and adjustable-speed motor drives. Such power converters are the basic building blocks of drivetrains in electric, hybrid, and plug-in hybrid electric vehicles. The performance and control of such vehicles depend on the accuracy, bandwidth, and efficiency of its sensors. Various current-sensing techniques based on different physical effects such as Faraday's induction law, Ohm's law, Lorentz force law, the magnetoresistance effect, and the magnetic saturation effect are described in this paper. Each technique is reviewed and examined. The current measurement methods are compared and analyzed based on their losslessness, simplicity, and ease of implementation.     

A 4-W Master–Slave Switching Amplitude Modulator for Class-E1 EDGE Polar Transmitters

For Class-E1 EDGE polar transmitters, we proposed a 4-W master-slave switching amplitude modulator (MS-SAM) for both high efficiency and wide bandwidth. It consists of a combination of two step-down modules with different switching frequencies and different switch sizes. The master module was designed for wide bandwidth and the slave module for high efficiency. The paper also presents a new current-sensing circuit based on a sample-and-hold circuit operable under a high switching frequency (40 MHz). We showed the topologies and operating principles. The chip was fabricated in a standard 0.35-m CMOS process with an area of 6.45 mm . The MS-SAM could drive the amplifiers of up to 4-W RF power in the experiment. We obtained an efficiency of 89%, and the converter's bandwidth was wide enough to meet the EDGE spectral requirements.     

A multiple-output switched-capacitor DC–DC converter for individual brightness control of RGB LEDs with time-interleaved control and output current regulation

In this paper, an integrated multiple-output switched-capacitor (SC) converter with time-interleaved control and output current regulation is presented. The SC converter can reduce the number of passive components and die areas by using only one flying capacitor and by sharing active devices. The proposed converter has three outputs for individual brightness control of red–green–blue (RGB) LEDs. Each output directly regulates the current due to the V–I characteristics of LEDs, which are sensitive to PVT variations. In the proposed converter, the current-sensing technique is used to control the output current, instead of current-regulation elements (resistors or linear regulators). Additionally, in order to reduce the active area, three outputs share one current-sensing circuit. In order to improve the sensing accuracy, bias current compensation is applied to a current-sensing circuit. The proposed converter has been fabricated with a CMOS 0.13-μm 1P6M CMOS process. The input voltage range of the converter is 2.5–3.3 V, and the switching frequency is 200 kHz. The peak power efficiency reaches 71.8 % at V _IN =2.5 V, I _LED1 = 10 mA, I _LED2 = 18 mA, and I _LED3 = 20 mA. The current variations of individual outputs at different supply voltages are less than 0.89, 0.72, and 0.63 %, respectively.     

Lossless current sensing in low-voltage high-current DC/DC modular supplies

New data processing ICs require low-voltage high-current supplies together with high reliability and efficiency. The use of a modular power supply would be the ideal solution, but it requires detecting the current in each module, and resistive shunts are usually used. In this paper, a new lossless current-sensing circuit is presented. This lossless current transducer is obtained by applying the technique used to compensate the parasitic inductance in resistive shunts to the filter inductor of the DC/DC power supply. The causes that can influence transducer response are investigated. The current sensing was implemented in a modular DC/DC power supply and experimental results are reported.     

Transmission of microwave signals through an e.h.v. insulator for application to e.h.v. electronic current-sensing systems

It is shown how a conventional solid-core e.h.v. post insulator can be adapted for use as a fairly low-loss, physically robust, microwave transmission link for use in unconventional e.h.v. electronic current-sensing systems. Coupling into and out of the insulator is by way of an interesting adaptation of the short backfire antenna.     

Low-power repeaters driving RC and RLC interconnects with delay and bandwidth constraints

Interconnect plays an increasingly important role in deep-submicrometer very large scale integrated technologies. Multiple design criteria are considered in interconnect design, such as delay, power, and bandwidth. In this paper, a repeater insertion methodology is presented for achieving the minimum power in an RC interconnect while satisfying delay and bandwidth constraints. These constraints determine a design space for the number and size of the repeaters. The minimum power is shown to occur at the edge of the design space. With delay constraints, closed form solutions for the minimum power are developed, where the average error is 7% as compared with SPICE. With bandwidth constraints, the minimum power can be achieved with minimum-sized repeaters. The effects of inductance on the delay, bandwidth, and power of an RLC interconnect with repeaters are also analyzed. By including inductance, the minimum interconnect power under a delay or bandwidth constraint decreases as compared with an RC interconnect.