Rise time

About: Rise time is a research topic. Over the lifetime, 4748 publications have been published within this topic receiving 47512 citations.

Improved wafer-level VFTLP system and investigation of device turn-on effects

Abstract: We present an improved wafer-level VFTLP measurement system. This system produces pulses with sub-150 ps rise time and few distortions at the rising edge. By introducing a broadband power divider, the oscilloscope no longer limits the pulse amplitude, and arbitrarily high pulse voltages can be measured. Turn-on effects in diodes and NMOSFETs are investigated using this system.

Method to increase head voltage swing and to reduce the rise time of write driver

Abstract: A voltage-mode boosting write driver circuit ( 40 ) having a pair of voltage boosting PMOS transistor sets ( 44, 46 ) coupled to a high current H-switch ( 42 ). One set ( 44 ) of the boosting PMOS transistors correspondingly pulls output pin HY high, while the other transistor set ( 46 ) correspondingly pulls output pin HX high and the other output pin HY low thereby significantly improving the head voltage swing, and also achieving a faster slew rate. Moreover, resistors (R 3 , R 4 ) of the H-switch are both matched to each other and impedance matched to a flex cable (T 0 ) interconnection impedance, which interconnection is coupled to the thin film head, to thereby eliminate signal reflection such that the write current (Iw) settles quickly with minimum ringing to achieve a high data rate. Moreover, less power dissipation and smaller number of devices used are achieved by making use of existing transient currents of the pre-driver emitter follower stage.

Design and Development of a Compact All-Solid-State High-Frequency Picosecond-Pulse Generator

Abstract: The Marx circuit structure based on fast high-power semiconductor devices is the classical way of generating picosecond pulses. However, most reported studies suggest that as the number of stages in the Marx circuit increases, the output pulse amplitude tends to saturate. This has of late made high-voltage picosecond-pulse generation a challenge. In this paper, as the number of stages increases, the internal resistance of the avalanche transistor tends to decrease with increasing current flowing through the avalanche transistor. A step-by-step wiring and debugging of the avalanche transistor-based Marx circuit demonstrates this experimentally. That is, for a certain range in the number of stages, saturation of the output pulse amplitude for the Marx circuit of avalanche transistors is not apparent. Introducing a parallel structure for the transistors not only increases the current level of the entire circuit but also further reduces the equivalent resistance of the avalanche transistors, thereby improving the output efficiency. Drawing on microstrip transmission theory, and combining the Marx circuit and avalanche transistor parallel structure, component parameters and circuit topology of the picosecond-pulse generator were redesigned, and a 30-level Marx circuit with a parallel structure of two avalanche transistors was developed. The picosecond-pulse generator outputs a pulse with adjustable voltage amplitude of 0.9–3.1 kV, a 350-ps full-width at half-maximum, a 150-ps rise time, and an adjustable high-stability repetition rate of up to 10 kHz. The number of pulses is precisely controlled. The generator is an all-solid-state compact device with high frequency suitable for research needs.

Design considerations and loss analysis of zero-voltage switching boost converter

Abstract: A novel zero-voltage switching (ZVS) boost converter for medium- and high-power applications is proposed. Compared to conventional hard switching boost converters, the switching losses are decreased by a factor of 3 to 4. A design procedure is proposed, based on the minimisation of the total losses in the switch. It is shown that variations of operating frequency, turn-off current and voltage rise time do not affect the control algorithm or the design procedure, even for a wide range of loading conditions and input voltage. A 3 kW prototype using IGBTs is simulated (PSPICE) and developed. The efficiency obtained is more than 90% for load values higher than 20% of full load, and attains 95% for full load. Advantages of the circuit include zero-voltage-zero-current turn-on and zero-voltage turn-off for a wide range of line voltage and load; switching conditions do not depend on the load. The reliable control strategy makes the proposed ZVS boost converter attractive for medium-power applications where IGBTs are used predominantly.

Fast front-end electronics for experiments using silicon calorimeters at ssc /lhc colliders

Abstract: A fast VLSI preamplifier using HF2CMOS technology was designed and built. The preamplifier meets the requirements for silicon calorimetry application in experiments at hadron colliders SSC/LHC. The overall power consumption is less than 45 mW for a maximum output voltage swing of 5 V (≈ 7 ns rise time). The slew rate is about 700 V/μs for an input capacitance of 150 pF. The measured value of ENC (equivalent noise charge), for an RC-CR shaping time of 20 ns and an input capacitance of 150 pF, is 17 ke RMS .