Integrated Switching Power Research Articles

An Overview of Fully Integrated Switching Power Converters Based on Switched-Capacitor versus Inductive Approach and Their Advanced Control Aspects

This paper reviews and discusses the state of the art of integrated switched-capacitor and integrated inductive power converters and provides a perspective on progress towards the realization of efficient and fully integrated DC–DC power conversion. A comparative assessment has been presented to review the salient features in the utilization of transistor technology between the switched-capacitor and switched inductor converter-based approaches. First, applications that drive the need for integrated switching power converters are introduced, and further implementation issues to be addressed also are discussed. Second, different control and modulation strategies applied to integrated switched-capacitor (voltage conversion ratio control, duty cycle control, switching frequency modulation, Ron modulation, and series low drop out) and inductive converters (pulse width modulation and pulse frequency modulation) are then discussed. Finally, a complete set of integrated power converters are related in terms of their conditions and operation metrics, thereby allowing a categorization to provide the suitability of converter technologies.

A 2-MHz Wide-Input Hybrid Resonant Converter With Ultracompact Planar Coupled Inductor for Low-Power Integrated On-Chip Applications

A trend for low-power conversion system is to integrate every component to a single chip. Magnetic component has been the key to determine the power density of the integrated switching power converter. In this paper, a hybrid resonant buck-type converter with an ultracompact custom-designed coupled inductor is presented for low-power integrated on-chip applications. This converter achieves zero-voltage switching for the high-side switch and near zero-voltage zero-current switching for low-side and auxiliary switches. The soft-switching condition allows the circuit operating at high switching frequencies. An ultracompact planar coupled inductor with a dimension of 5.25 mm × 1.95 mm × 3.86 mm is designed and customized for future integrated on-chip applications. The high-power density of this magnetics component is achieved by high switching frequency and optimized printed circuit board (PCB) windings design. A hardware prototype with 24 to 60-V input and 3.3 to 5-V, 3-A output operating at 2–3 MHz is presented to verify the circuit operation. The prototype achieves a peak efficiency of 90.7% using silicon devices at 2-MHz switching frequency.

Passing the Plateau of Productivity: Development of RFSOI Technologies on HR Silicon Substrates for Reconfigurable Wireless Solutions

Products designed with RFSOI on HR silicon for the cellular handset industry are being deployed in large volumes by the leading RF FE providers. These consist of highly integrated RF power switches, RF tuners, and other types of RF circuit blocks. The technologies are available in several different foundries, and the volumes are running in the tens of thousands of wafers per month. The drive for improved linearity needed for LTE 4G systems, in particular CA, will continue to push these technologies to improve their respective figures of merit for continuous leadership in the RF FE. RFSOI on HR silicon is the leading switching technology in handsets today and is poised to continue its dominance for the next decade.

Survey and Benchmark of Fully Integrated Switching Power Converters: Switched-Capacitor Versus Inductive Approach

This paper surveys and discusses the state-of-the-art of integrated switched-capacitor and inductive power converters. After introducing applications that drive the need for integrated switching power converters, implementation issues to be addressed for integrated switched-capacitor and inductive converters are given, as well as design examples. At the end of this paper, a comprehensive set of integrated power converters are compared in terms of the main specifications and performance metrics, thereby allowing a categorization and providing application-oriented design guidelines.

Higher PV Module Efficiency by a Novel CBS Bypass

There is an increasing focus on reducing costs and improving efficiency for photovoltaic (PV) cells and modules as well as finding a more efficient approach to the product manufacturing. This letter introduces an innovative solution to bypass shaded PV cells instead of a traditional Schottky diode, in order to avoid overheating of cells in the case of partial shading. The goal is to reduce the power dissipation and improve the general efficiency of a PV generator. A novel device called cool bypass switch is then presented. It is made up of a Power MOS driven by a controller with the task to charge a storage capacitor. Tests and comparisons with standard Schottky diodes are then performed and experimental results are reported in terms of current intensity and operating temperature. The resulting circuit shows better diode performances and considerably lower dissipated power in shading condition. The little packing cases allow an easy integration inside the PV module. In comparison with traditional diodes, the integrated power switch provides a negligible leakage current during PV panel energy production.

Integrated high-inductance three-dimensional toroidal inductors

Fabrication, characterizations, and modeling of three-dimensional high-inductance value toroidal inductors are presented. The effect of substrate and number of turns on toroidal inductors with 16, 31, and 62 turn fabricated using prestressed metals are investigated. A 62-turn inductor on high-resistivity Si substrate has an inductance value of 81 nH, a self-resonance frequency of ∼2 GHz, and a peak quality factor (Q) of ∼10. It is found that the substrate loss is detrimental to the quality factor of toroidal inductors at high frequencies and should be suppressed by using high-resistivity substrate or SU-8 coated Si substrate in order to obtain high values of the quality factor. In addition, reducing turn-to-turn gap in toroidal inductors results in higher mutual couplings among the inductor turns and thus achieving high-inductance values. Integrated high-inductance value, high-Q inductors can be used in integrated switching power supplies, radio frequency (rf) and intermediate frequency filters, energy conversion circuits, and as on-chip rf chokes in rf integrated circuits.

Self-switching circuit based on IGBT suited for monolithic integration

A new self-controlled and self-protected integrated power switch dedicated to self-switching mode power converters is presented. To achieve this function, an original topology based on an IGBT is proposed and its operation is analysed by 2D physical simulation. The topology validates the functionality, the switching phases are instantaneous and the switch is compliant with technical specifications. These results motivate the realisation of this device, offering promising potential for a wide range of applications.

Virtual reliability assessment of integrated power switches based on multi-domain simulation approach

To develop reliable integrated power electronics, it is paramount to consider the coupling between electrical, thermal and mechanical effects. Though essential for final validation, experimental analysis is time-consuming, especially when trying out new designs. Simulative approaches at multi-domain physical analysis need to be improved. In this work, a platform is proposed, in which all physics are treated with dedicated simulation programmes, co-ordinated by a custom-developed core section. A case study, based on a novel integrated power switch developed for railway traction applications, demonstrates the validity of the envisaged solution for virtual reliability assessment.

An Accurate, Low-Voltage, CMOS Switching Power Supply With Adaptive On-Time Pulse-Frequency Modulation (PFM) Control

Integrated switching power supplies with multimode control are gaining popularity in state-of-the-art portable applications like cellular phones, personal digital assistants (PDAs), etc., because of their ability to adapt to various loading conditions and therefore achieve high efficiency over a wide load-current range, which is critical for extended battery life. Constant-frequency, pulsewidth modulated (PWM) switching converters, for instance, have poor light-load efficiencies because of higher switching losses while pulse-frequency modulation (PFM) control in discontinuous-conduction mode (DCM) is more efficient at light loads because the switching frequency and associated switching losses are scaled down with load current. This paper presents the design and integrated circuit prototype results of an 83% power efficient 0.5-V 50-mA CMOS PFM buck (step-down) dc-dc converter with a novel adaptive on-time scheme that generates a 27-mV output ripple voltage from a 1.4- to 4.2-V input supply (battery-compatible range). The output ripple voltage variation and steady-state accuracy of the proposed supply was 5 mV (22-27 mV) and 0.6% whereas its constant on-time counterpart was 45 mV (10-55 mV) and 3.6%, respectively. The proposed control scheme provides an accurate power supply while achieving 2%-10% higher power efficiency than conventional fixed on-time schemes with little circuit complexity added, which is critical during light-loading conditions, where quiescent current plays a pivotal role in determining efficiency and battery-life performance

The Integrated Power Switch

Utilizing a signal from transistor transistor logic (TTL) circuits, the integrated power switch (IPS) can control 40 kW. Protection against overload conditions enables the use of transistors which have ideal switching characteristics. Each half-section of the IPS is electrically isolated from the signal input using optical couplers. Discrete component assemblies, printed-circuit boards, thick-film or medium-scale integrated substrates each have been utilized. The forced-air-cooled heat sink was designed for maximum cooling. Two types of IPS's were initially constructed: 500 V/60 A, and 100 V/200 A, with additional availability of 500 V/100 A devices in small quantity. Its capability to work from continuous operation to 10 kHz makes the IPS universally applicable to most power-conversion applications with-in its current and voltage limitation.