A switching regulator and lightning protector for a subscriber line interface circuit

Two monolithic ICs, a switching regulator and a crowbar protector circuit fabricated in a 90-V complementary bipolar technology are described. These devices enhance the performance of a basic subscriber-line interface circuit (SLIC) by extending the range to the customer so that 20-mA DC feed current can be supplied to a 2800-/spl Omega/ loop without the need for a -72-V office battery. The power dissipation of the entire SLIC subsystem is at most 1.5 W for any length of subscriber loop. All circuitry is robustly protected from foreign 60-Hz and lightning voltages.     

Subscriber line interface circuit LSI fabricated using high-voltage CMOS/SIMOX technology

High-voltage buried-channel CMOS/SIMOX technology which is characterised with the existence of an electric-field-shielding layer formed by oxygen implanatation was applied to fabricate a BSH-LSI for a subscriber line interface circuit, providing three functions of battery feed, supervision and hybrid. In this CMOS BSH-LSI, a high breakdown voltage of higher than 60 V and a low breakdown voltage of 15 V were fabricated by the same process. This BSH-LSI showed a high level of performance during operation. The chip size and dissipation power of the BSH-LSI were reduced to approximately one-third and one-half, respectively, compared with a conventional BSH-LSI fabricated with bipolar technology.     

A monolithic telephone subscriber loop interface circuit

An integrated circuit that interfaces a subscriber loop with the digital telephone exchange has been produced with conventional high-voltage IC technology. The monolithic SLIC controls DC loop current, converts signal transmission from two-wire to four-wire, and suppresses longitudinal induction. Bias control circuitry automatically reduces standby power when subscriber equipment is detected on-hook. High-voltage circuit techniques maintain performance when the supply voltage exceeds the n-p-n transistor BV/SUB CE0/, and circuit partitioning with two discrete transistors yields manageable junction temperature and an economical 102/spl times/112 mil die size.     

A High Voltage Line Driver for Subscriber Loop Interfaces in a Low Voltage Submicron BiCMOS Technology

This paper presents a 30 V line driver for short loop subscriber line interface circuit applications. The high voltage line drivers was implemented in a low-voltage 0.8 m BiCMOS process using 30 V extended-drain MOS transistors, fully compatible with the low voltage technology. Using a Quasi-Current Mirror architecture for the output stage, the line driver is capable of delivering more than 30 mA current into the lines with an idle current as low as 1 mA, satisfying the short loop requirements. With less than 0.24 mm² area, the circuit can be easily integrated with low-voltage circuitry on a single chip.     

A long reach digital subscriber loop transceiver

An echo-cancelling duplex transmission system is described for the digital subscriber loop which uses a 4-level zero redundancy line code (2B1Q) to give very long reach in the presence of crosstalk. Novel digital signal processing algorithms are used to simplify the analogue line interface circuitry. All the digital signal processing, along with sophisticated maintenance and interfacing circuitry, can be contained on a single LSI circuit. Measured performance results are presented.     

Monolithic 70 V bipolar line driver IC for PCM SLIC

Describes a monolithic 70 V IC which is an integral part of a PCM subscriber line interface circuit (SLIC). A special design allows the realization of a line driving operational amplifier with stringent requirements on power drive, consumption, output overload protection and breakdown voltage. Other special SLIC functions are also implemented. Experimental results demonstrate the performance of the chip.     

A three-terminal intelligent power MOSFET with built-in reversebattery protection for automotive applications

An intelligent power MOSFET with built-in reverse battery protection, which is important for automotive power switches, has been developed. The protection is accomplished by integrating an additional power MOSFET in series with a power MOSFET and the control circuit of the additional power MOSFET. The reverse battery protection is achieved without using external control signals. The positive drain breakdown voltage for the proposed MOSFET is 71 V and the negative drain current at a drain voltage of -16 V is only -750 μA. The on-state resistance is 170 mΩ. This new intelligent power MOSFET can replace the conventional three-terminal power MOSFET's used in automotive applications     

Line Circuit Interfaces for a Digital Switching System

Crucial to the design of digital switching systems for local switching applications is the line circuit interface. It forms the boundary between the analog, 2-wire, subscriber loop, with its attendant environment hostile to low-voltage electronics, and the digital logic environment. ITT North's DSS uses a Quad Line Circuit (QLC) that provides the line circuit interface between four subscriber loops and two PCM multiplexed highways. The QLC contains per-line elements consisting of an electronic 2W/4W hybrid, transmit and receive PCM filters, a codec, two card-mounted relays, and distributed logic for various gating and clocking functions. In addition, there is digital logic common to all four lines for interfacing with redundant microprocessors common to 320 lines. Design of the QLC in a dynamic technology evolution is discussed, and several evolutions of the initial design are presented.     

High-voltage CMOS SIMOX technology and its application to a BSH-LSI

This paper describes high-voltage CMOS separation by implanted oxygen (SIMOX) technology and its application to a BSH-LSI that provides the basic functions of battery feed, supervision, and hybrid for subscriber line interface cuircuits. This technology is characterized by the existence of an electric-field-shielding (EFS) layer formed between the buried SiO2and the surface Si layer by oxygen implantation. The density of localized states at the Fermi level of the EFS layer has been estimated to be about 1 × 10¹⁹cm^-3. eV^-1using the Cohen-Fritzsche-Ovshinsky model. The EFS layer reduces substrate voltage dependence of the threshold voltage and increases the drain-to-source breakdown voltage for MOSFET's. Specifically, the drain-to-source breakdown voltage has been raised to 180 V. The BSH-LSI, which is composed of high-voltage CMOS of more than 60 V and low-voltage CMOS of 15 V, has been successfully fabricated containing resistors and capacitors. Compared with a conventional bipolar BSH-LSI, the chip size and the dissipation power of the LSI have been reduced to approximately one-third and one-half, respectively.     

A dielectrically isolated complementary bipolar technique for analog/Digital compatible LSI's

A dielectrically isolated complementary bipolar technique has been developed for use in analog LSI's or analog/digital compatible LSI's. This process makes it possible to form vertical double-diffused transistors in complementary islands and to obtain a high breakdown voltage of more than 350 V in spite of using shallow junctions with a depth of less than 2 µm. The gain bandwidth product fTis 450 and 200 MHz for n-p-n and p-n-p transitors, respectively. With this process, a subscriber line interface LSI that includes three functions (battery feed, supervision, and hybrid) has been successfully achieved within a 12.6 mm²die area.     

A CMOS SLIC with an automatic balancing hybrid

A CMOS subscriber line interface circuit (SLIC) that has an automatic balancing hybrid facility is presented. Some of the key system aspects of line interface circuits, such as the relation between zero-loss switching and an automatic balancing hybrid circuit, power dissipation in the line circuit, and foreign voltage protection are described first. Next, details of the SLIC LSI, which comprises a dial pulse detecting circuit and and automatic balancing hybrid circuit, are described. The LSI is implemented with CMOS switched capacitor technology and is mounted on a 20-in DIL.     

Fully analogue LMS adaptive notch filter in BICMOS technology

A fully analogue adaptive notch filter for meter pulse applications in analogue subscriber line systems is presented. The filter is part of an integrated circuit which includes both low voltage subscriber line interface circuit- (SLIC)- and CODEC-filter functions. The effects of offset, noise, and transient behavior are investigated, and a linear model for stability analysis is derived. Fabricated in a 1 μm BiCMOS technology this circuit uses the benefits of accurate SC-filters, low offset comparators, and linear multipliers. Due to the adaptive approach the performance of the filter is independent of process deviations and temperature effects. The filter has been designed for an attenuation of 50 dB @ 12 or 16 kHz, a dynamic range of 103 dB and a settling time of less than 5 ms     

A broadband high-voltage SLIC for a splitter- and transformerlesscombined ADSL-Lite/POTS linecard

A monolithic broadband subscriber line interface circuit (B-SLIC) has been integrated in the smart power technology SPT170B, combining the functionality of an analog 150-V ringing SLIC with that of a line driver for ADSL-Lite data signals. Thus the B-SLIC is the key circuit for the realization of a very compact integrated voice data (IVD) central office linecard that neither needs analog filters (“POTS-splitter”) nor transformers or relays. In spite of the fundamental voltage/frequency tradeoff, the B-SLIC is able to feed high dc or ring voltages to the line, while simultaneously acting as voice and data transceiver. Total harmonic distortion values are below -60 dB even for a high 25-V_pp/550-kHz sine wave signal into a 200 Ω load; ADSL-signal-based multitone power ratio (MTPR) measurements also yield results better than 60 dB. Power dissipation in simultaneous voice and data operation is about 2.2 W     

A monolithic subscriber line interface circuit [in bipolar technology]

A monolithic SLIC fabricated with high-voltage dielectric isolation (DI) technology has been proven to have excellent performance and requires a minimum of external circuitry. The SLIC provides battery feed, overvoltage protection (with some external devices), ringing control, supervision, and hybrid functions.     

An Efficient Piezoelectric Energy Harvesting Interface Circuit Using a Bias-Flip Rectifier and Shared Inductor

Harvesting ambient vibration energy through piezoelectric means is a popular energy harvesting technique which can potentially supply 10-100's of ?W of available power. One of the main limitations of existing piezoelectric harvesters is in their interface circuitry. In this paper, a bias-flip rectifier circuit that can improve the power extraction capability from piezoelectric harvesters over conventional full-bridge rectifiers and voltage doublers by greater than 4X is implemented in a 0.35 ?m CMOS process. An efficient control circuit to regulate the output voltage of the rectifier and recharge a storage capacitor is presented. The inductor used within the bias-flip rectifier is shared efficiently with a multitude of switching DC-DC converters within the system reducing the overall component count.     

A high-voltage IC for a transformerless trunk and subscriber line interface

A new high-voltage, junction-isolated, complementary bipolar technology has been used to fabricate an IC for a transformerless trunk and subscriber line interface. The new technology provides both vertical p-n-p and n-p-n transistors with BV/SUB CE0/ greater than 60 V, betas of 100, and f/SUB T/'s of 200 MHz. It permits the straightforward op amp realization of a new op amp circuit configuration in transformerless line circuits. The new configuration uses the high-voltage IC plus some low voltage control circuitry to provide limited current battery-feed, loop-closure detection, reverse-battery signaling, two-wire to four-wire conversion, lightning protection, power-down capability, and longitudinal performance which is independent of the battery-feed current magnitude.     

采用高压模拟／I^2L兼容工艺的用户线接口电路设计

本文分析了高压模拟/I~2L兼容工艺的特点,着重介绍了一种采用介质隔离高压模拟/I~2L兼容工艺的用户线接口电路的特点、工作原理、版图设计与工艺特点,电路内部含有二-四线转换,检测用户摘挂机功能以及过压、过流保护功能,电路可承受70V以上的高压。采用薄膜电阻,使得匹配电阻精度大大提高,改善了电路的性能。     

A surge-free intelligent power device specific to automotive highside switches

A novel type of intelligent power device (IPD), which is suitable for automotive monolithic high side switch with high current capability, is presented. An integration of a vertical-power DMOSFET and planar MOS IC devices is performed by the newly developed junction-isolation technique using only one epitaxial growth. The isolation voltage of 80 V has been obtained, which is large enough for automotive IPDs if they are protected against high voltage transients on the battery line. A rugged vertical DMOSFET (VDMOS) has also been developed for this IPD. It has a cellular Zener diode between its source and drain, which prevents the secondary breakdown of parasitic bipolar transistor, and the resulting avalanche capability enhancement is more than an order of magnitude. This VDMOS is used for both output power device and protection device for low-voltage MOS circuitry, which makes the IPD free from any transients in the automobile without the need for external protection     

Rural Subscriber Physical Loops

This paper briefly traces the development of physical subscriber loop design in the Rural Electrification Administration (REA) Program from 1949 to the present. Development of equipment for overcoming in the most economical manner the signaling and transmission problems encountered with long subscriber loops is also discussed. This includes loading systems for wider bandwidth, better structural return loss, less bridging effects with multiparty lines; loop extenders in place of costly long-line adapters (LLA's); lower cost voice-frequency repeaters (VFR's) and switching methods such as Common-Mode Operation (CMO) where less equipment is required. Discussion of the problems still encountered with transmission and signaling on rural subscriber loop is presented with ideas for solution. Development of VFR equipment with automatic gain control for use in CMO or Common-Control Central offices would permit designing to common circuit net loss and minimize contrast between circuits. Extension of signaling limits of central office equipment (COE) now being developed could eliminate the need for external loop extension equipment on better than 90 percent of rural subscriber loops. Development of a telephone instrument requiring less dc line current would eliminate the need for elevated line voltages.     

DC voltage sensorless single-phase PFC converter

We propose a simple DC voltage sensorless single phase PFC converter by detecting an AC line voltage waveform. Both DC voltage and AC current sensors used in the conventional PFC converter are not required to construct the control system. The conventional converter circuit with a boost chopper circuit in the DC side from a rectifier circuit is used as the main PFC converter circuit. In the control system, the circuit parameters such as a series inductance L and equivalent load resistance value R/sub d/ are used to generate the sinusoidal current waveform. The DC voltage is directly controlled by the command input signal k/sub d/(=E/sub d//E/sub a/) for the boost chopper circuit. The DC voltage regulation is small because of the feed forward control for the AC line voltage E/sub a/ and no dependence of the circuit parameters. The sinusoidal current waveform in phase with the AC line voltage can be obtained. The feasibility of the proposed control system is verified by some simulation and experimental results.