Дискретные компоненты, силовые модули - Решения

This circuit uses a parallel-to-series topology that dynamically adjusts LED load voltage as the instantaneous bridge output voltage varies. While a switch-mode power supply such as a buck converter reconfigures the input voltage to match the load, this circuit reconfigures the load to match the input voltage. When the instantaneous input voltage is relatively low, the LEDs are configured in parallel. When the instantaneously input voltage is relatively high, the LEDs are configured in series.

The circuit is designed for input voltages between 100 VAC and 140 VAC . ON Semiconductor CCRs are used to provide constant LED current and to protect LEDs from over-voltage conditions. The circuit employs an additional CCR (shown as CCR2) to increase LED current at high voltages for improved efficiency, PF, and THD performance.

• 120 and 230 VAC Off-line Regulation
• Typical Output Current of 10 mA
• Maximum Output Current Thermally Limited
• Transient Survivability of 2.5kV
• Overtemperature Protection
• Output Voltage Range of 3V to 5V
• Three Selectable LDOs:
  • MCP1754 (3.3V)
  • MCP1755 (5.0V)
  • MCP1790 (3.0V)

The Dual Stepper Motor Driver Shield Evaluation Board evaluates the AMIS30543, a microstepping stepper motor driver for bipolar stepper motors. It has an on chip voltage regulator, reset output and watchdog reset able to supply peripheral devices. The chip is connected through IO pins and a SPI interface with an external microcontroller that is regulated through the PCA9655E's 16 bits of General Purpose parallel Input and Output (GPIO) expansion.

The AMIS-30543 is a micro-stepping stepper motor driver for bipolar stepper motors. The chip is connected through I/O pins and an SPI interface with an external microcontroller. It has an on chip voltage regulator, reset?output and watchdog reset, able to supply peripheral devices. AMIS-30543 contains a current?translation table and takes the next micro?step depending on the clock signal on the "NXT" input pin and the status of the "DIR" (=direction) register or input pin.

The chip provides a so-called "speed and load angle" output. This allows the creation of stall detection algorithms and control loops based on load-angle to adjust torque and speed. It is using a proprietary PWM algorithm for reliable current control. The chip is fully compatible with the automotive voltage requirements. The AMIS-30543 is ideally suited for general-purpose stepper motor applications in the automotive, industrial, medical, and marine environment. With the on-chip voltage regulator it further reduces the BOM for mechatronic stepper applications.

The STEVAL-IHT003V2 evaluation board represents an innovative solution patented by STMicroelectronics to reduce the power losses caused by positive temperature coefficient (PTC) resistors in compressor starter circuits.

The solution features an ACST6 AC switch device to turn off the PTC current after motor start-up; note that the traditional PTC is still used in the electronic starter circuit as it increases circuit safety for AC switch short-circuits or diode mode failure (ref. EN60335-1).

The design reduces starter standby losses from (typ.) 2.5 W to 380 mW for 230 V applications, or 2.5 W to 40 mW for 100 V applications.

Before using the board with a compressor, the PTC behavior must be checked (especially VPTC1 and VPTC2 levels) and different R4 resistor values may be required.

This application note is a Ringing Choke Converter (RCC)-based, step-by-step cell phone battery charger design procedure.

The RCC is essential to the self-oscillating fly-back converter, and operates within the Discontinuous Conduction Mode (DCM) and Continuous Conduction Mode (CCM) boundaries without noticeable reverse recovery of the output rectifying diodes. RCC control is achieved by using discrete components to control the peak current mode, so the overall RCC cost is relatively low compared to the conventional Pulse Width Modulation (PWM) IC fly-back converter. As a result, RCC is widely used for low power applications in industry and home appliances as a simple and cost-effective solution.

В базовом проекте производится преобразование сопротивления терморезисторов (RTD) в напряжение с уровнем, удобным для использования в качестве входа АЦП. Прецизионный источник опорного тока производит возбуждение, а инструментальный усилитель масштабирует сигнал. В данном проекте также используется конфигурация с трёхпроводным RTD для минимизации ошибок, связанных с сопротивлением проводников.

Данный базовый проект имеет характер аппаратного решения.

This circuit uses active switching to change how the load is being driven. The LED load will either be driven from the capacitor, C1, discharging, or directly from the AC source. The CCR ensures a constant current through the LED throughout all modes of operation. The switching point of the circuit may be changed by varying the resistor, R1. Changing this switching point will change the amount of time the capacitor is charging. If a higher power output is desired a higher current CCR can be used and the switching point will need to be changed. A metal oxide varistor and fuse are designed into the circuit for surge protection purposes.