MOS Integrated silicon pressure sensor

An MOS integrated silicon-diaphragm pressure sensor has been developed. It contains two piezoresistors in a half-bridge circuit, and a new simple signal-conditioning circuit with a single NMOS operational amplifier. The negative temperature coefficient of the pressure sensitivity at the half-bridge is compensated for by a positive coefficient of the variable-gain amplifier with a temperature-sensitive integrated feedback resistor. The sensor was fabricated using the standard IC process, except for the thin diaphragm formation using the N2H4. H2O anisotropic etchant. Tile silicon wafer was electrostatically adhered to the glass plate to minimize induced stress. The -1750 ppm/°C temperature coefficient of sensitivity at the half-bridge was compensated for to less than +190 ppm/°C at the amplifier output in the 0- 70°C range. A less than 20-mV thermal-output offset shift was also Obtained after 26-dB amplification in the same temperature range.     

Design of adaptive dead-time control circuit for resonant half-bridge driver

To decrease the switching loss and the dead-time effect of resonant half-bridge inverter, a novel adaptive dead-time control circuit of resonant half-bridge driver Integrated Circuit (IC) is presented. Without increasing the pin number of IC, this circuit takes a novel strategy to adaptively regulate dead time to a temperate range between high and low thresholds. The high and low thresholds are adaptive to the fall time of output signal in a half-bridge clock cycle. The IC of the designed circuit is suitable for high-voltage applications. The dead-time regulation range of this circuit achieves 0–3.5?µs. The range of temperate dead-time state is 300?ns. The failure signal of this circuit can protect the IC and peripheral power devices by regulating operation in three clock cycles. Both simulation and measurement of the proposed circuit in a half-bridge driver IC with an operating frequency at 50?kHz are presented based on the 0.5?µm 700?V BCD process. The results of simulation and measurement show that the presented circuits’ performance is perfect.     

A Nonisolated Single-Phase UPS Topology With 110-V/220-V Input–Output Voltage Ratings

A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type of configuration size, cost and efficiency are improved due to the reduced number of switches and batteries, and also, no low-frequency isolation transformer is required to realize bypass operation because of the common neutral connection. Both stages of the proposed circuit operate at high frequency by using a passive nondissipative snubber circuit in the boost converter and insulated-gate bipolar-transistor switches in the double half-bridge inverter, with low conduction losses, low tail current, and low switching losses. Principle of operation and experimental results for a 2.6-kVA prototype are presented to demonstrate the UPS performance.      

Analysis, designing, and experimentation of a transformer-assistedPWM zero-voltage switching pole inverter

This paper proposes a transformer-assisted pulsewidth modulation (PWM) zero-voltage switching pole inverter. As the auxiliary-resonant-commutated pole inverter (ARCPI), the proposal guarantees zero-voltage switching of the main switch and zero-current switching of the auxiliary switch, with a small power auxiliary circuit and full PWM capability. In particular, problems outstanding with the ARCPI such as control complexity, auxiliary switch protection, and center-tap potential variation, etc., are solved in the proposal. The commutation process is discussed step by step in the paper. A detailed analysis for the auxiliary circuit with regard to commutation duration/duty-cycle limitation, auxiliary switch peak current/RMS current, resonant capacitor RMS current, as well as pole output voltage loss are presented afterwards. A design methodology for the auxiliary circuit is recommended based on the analysis. The proposal is experimentally verified with a 4.25 kW half-bridge inverter prototype     

基于SG3525A的半桥式开关电源

开关电源以其轻小高效的特点在很多方面得到了广泛应用,市场广阔。文中介绍了DC/DC变换器主电路的分类,分析了半桥型DC/DC变换器的构成,并深入分析了其工作原理、工作过程,分析总结了其相对于其他类型DC/DC变换器拓扑的优点。对开关电源的控制方式进行了比较,给出了集成控制器的优点,同时给出了电压型集成控制器SG3525A的内部结构、管脚功能,详细分析其工作原理、应用和优点。设计了一款基于SG3525A的半桥式开关电源,给出其工作原理、过程,尤其深入分析了由SG3525A构成的控制电路;实验结果表明,该电源具有效率高、电压调整率和负载调整率高、稳定可靠等优点。     

一种GaN半桥驱动器电平移位电路设计

GaN半桥输出点电压在死区时间为负值,给GaN功率器件栅极驱动电路信号通信带来了挑战.通过研究驱动器电平移位锁存电路工作状态与半桥功率级输出节点电压跳变、死区时间负压之间的相互影响,设计了一种新型的零静态功耗电平移位电路及其误触发消除电路.电路采用100 V BCD 0.18μm工艺设计,在输入电压100V、开关频率5...     

Auto-charge pump for half-bridge inverters

The auto-charge pump is a self-starting and self-sustaining circuit used to generate a floating voltage supply for the high side circuitry of half-bridge inverters. The switching output of the half-bridge replaces the dedicated pump oscillator thus simplifying the circuit. A model is derived which is then verified experimentally     

A novel single-stage half-bridge AC-DC converter with high powerfactor

A new single-stage AC-DC power converter based on a half-bridge converter suitable for low-power applications is proposed. The proposed converter offers high power factor and direct conversion from the line voltage to an isolated DC output voltage. High power factor is achieved by adding a resonant circuit between the rectifying diodes and half-bridge leg. For soft switching, a half-bridge series-loaded resonant converter is adopted as a DC-DC converter part. A prototype is built and tested to show the validity of the proposed converter     

开关电源全波整流输出结果的对比研究

采用脉宽调制方波作为输入信号,对全桥和半桥驱动型开关电源的输出电压、效率和纹波系数都做了对比分析和研究。并研究了不同频率、占空比以及不同范围的负载电阻对两种工作电路的影响,分析了两种电路各自的优缺点。实验结果表明,半桥驱动型开关电源,在一定程度上限制了驱动电路的最大输出功率,因此在要求大功率输出时还要采用全桥驱动电路。而且全桥工作的效果也要比半桥好,稳定性更强,可为电路的设计提供一个参考。     

Nonlinear-control strategy for the half-bridge series-resonant inverter

This paper concerns the analysis and design of the half-bridge series-resonant inverter with nonlinear-control strategy. A zero-current-switching (ZCS) half-bridge series-resonant inverter with nonlinear control is built. The presented circuit topology is simply configured by two power switches and one output filter. Only one conduction loss of the power switch is present in the power flow path during the inversion period. A turn-on ZCS for the power switch is achieved by an auxiliary resonant cell built before the output choke. The nonlinear-control strategy is designed against the input DC perturbation and achieves good dynamic regulation for the sinusoidal pulsewidth-modulation control. A state-space averaging approach is employed to analyze the system. A design example of a 500-W inverter is examined to assess the inverter performance and it provides high power efficiency above 91% under the rated power.     

Novel ZVS DC-DC converter with low current ripple for light rail transit

This paper develops and studies a three-level zero-voltage turn-on converter for providing auxiliary power system in a DC light rail vehicle. The proposed converter includes a three-level circuit and a half-bridge circuit sharing the same power switches on the high voltage side in order to reduce switch counts and distribute total power into two circuits. The Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with a low voltage rating and a turn-on resistance are adopted in the developed converter in order to decrease conduction losses on power switches. On the secondary side, two inductors and four rectifier diodes are employed to reduce output ripple current and transformer secondary winding turns. A duty cycle control based on the phase-shift pulse-width modulation is used to regulate the output voltage and achieve the wide range of zero-voltage turn-on. Experimental results with a prototype with a 760 V input and a 48V/30A output are provided to verify the feasibility and effectiveness of the developed converter.     

基于UC3825的半桥变换器分析

利用UC3825芯片构成了PWM控制的半桥变换器，给出了电压补偿网络和电流保护等重要的外围电路的工程设计方法，通过实验验证了电路的有效性。结果表明，该变换器功率可达81%，输出电压纹波在2%以内，电流保护可靠，电路工作稳定。     

Bidirectional DC resonant converter with magnetic-coupling current balance

This paper studied a bidirectional frequency-control dc converter with magnetic-coupling to achieve 1) current balance on low voltage side, 2) low switching losses on power devices, and 3) bidirectional power transfer capability. The developed circuit is basically constructed by half-bridge circuits on input and output sides. LLC resonant tank with frequency-control is used to obtain low switching losses on power devices. Magnetic-coupling element is used to achieve current balance on low voltage side. Synchronous rectifiers are employed on low voltage and high current side to decrease power losses and increase circuit efficiency. The effectiveness of the studied circuit is verified from a 720 W laboratory prototype.     

开关电源全波整流输出电压公式的实验验证

采用半桥式变换电路进行功率输出。对半桥驱动型开关电源的输出电压估算公式Uout=1n1/2n1 ton/ton toff Uin进行验证。得到实际结果值与公式值有差别．均比公式值大1．86～7．27倍。输出电压Uout除与公式中的几项因素有关外，还与负载电阻和滤波电容有关．当负载电阻较小时比较接近公式值。     

Single-stage electronic ballast with high-power factor

This article proposes a single-stage electronic ballast circuit with high-power factor. The proposed circuit was derived by sharing the switches of the power factor correction (PFC) and the half-bridge LCC resonant inverter. This integration of switches forms the proposed single-stage electronic ballast, which provides an almost unity power factor and a ripple-free input current by using a coupled inductor without increasing the voltage stress. In addition, it realises zero-voltage-switching (ZVS) by employing the self-oscillation technique. The saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Therefore, the proposed single-stage ballast has the advantage of high-power factor, high efficiency, low cost and high reliability. Steady-state analysis of the PFC and the half-bridge LCC resonant inverter are described. The results of experiments performed using a 30 W fluorescent lamp are also presented to confirm the performance of the proposed ballast.     

A 700-V interface IC for power bridge circuits

A 700-V integrated interface circuit is presented. It provides the gate drive for the high-side and the ground-side power MOS transistor in an offline half-bridge circuit. Ground separation for good intersystem electromagnetic compatibility (EMC) and a number of new provisions to alleviate control requirements on the low-power system control section are included. An electronic ballast for gas discharge lamps is considered as an application example. Experimental results are presented     

基于UC3863控制的LLC谐振变换器的设计及仿真

设计了一种以UC3863芯片为核心控制芯片的开关电源,其电路采用半桥结构的LLC谐振电路,带有PFC电路,且整个电路设计有自限流功能。分析了LLC谐振变换器整个电路的工作原理及自限流功能的实现。结合交流220 V输入1KW输出电路,分别对PFC电路和主电路进行仿真,仿真结果验证了该设计的可行性。     

数字控制感应加热电磁炉的设计

设计了基于DSP的大功率数字控制感应加热电磁炉,该系统采用DSP作为控制核心,主电路采用半桥谐振逆变电路,外围电路包括过流、过压、欠压、过功率和故障报警等保护电路。详细分析了半桥谐振逆变电路的工作原理,给出了其负载工作在感性、容性和电阻状态下的电路工作条件,并选择电路工作在感性状态才能确保主电路安全可靠的工作。最后制作了样机并给出了实验结果,实验结果验证了理论分析的正确性。     

A high-frequency electronic ballast for HID lamps based on aλ/4-long distributed constant line

A novel type of solid-state ballast, which operates in the megahertz-range frequency, is presented in this paper. A circuit composed of a voltage-source half-bridge inverter, a distributed constant line and a parallel LC resonant circuit has been developed for this purpose. The high-intensity discharge (HID) lamp is connected to the output terminal of the inverter through the distributed constant line. Here, since the length of the line is adjusted to 1/4 of the propagation wavelength λ (λ/4 condition), the output voltage of the voltage-source inverter can be converted to a current source on the load side. Therefore, the ballast can supply not only high voltage to the HID lamp for initiating discharge, but also stable current to it during discharge condition. The modification of the proposed circuit is also proposed in order to expand the operating frequency without increasing the undesirable harmonic current. The experimental results from a prototype system verify the theoretical procedure     

高压谐振控制器L6599在LLC半桥谐振变换器中的应用

介绍了高压谐振控制器1．6599的基本原理及内部组成,简要叙述了LLC半桥谐振变换电路的工作原理及数学模型,详细说明了L6599在LLC半桥谐振变换器中的典型应用,并给出了相关实验波形图。