Spacewrench over at Dorkbotpdx published a new build, a Power Playground project:
It’s a PMOS/NMOS H-Bridge with FETs that can handle 3 amps or so, plus a SPI current sensor, some switches & a rotary encoder (not stuffed yet), and a 7-segment display, all controlled by a Teensy-3.1 running FreeRTOS.
I made this because I’m always running into battery, power, inductor and transformer issues I don’t have any experience with. The idea is to use the H-bridge configuration and current sensors to experiment with moderate-current PWM, motor control, power-line synchronization, battery charging and discharging, etc.
Power playground project - [Link]
This evaluation board has been developed for ROHM’s H-Bridge driver customers evaluating the BD62x2FP series. The BD62x2FP series can operate across a wide range of power supply voltages (from 3V to 32V max), supporting output currents of up to 2A. PWM signal control (20 kHz-100 kHz) or VREF control modes are used to vary motor rotation speeds. ROHM’s ICs are complete with over current protection (OCP), over voltage protection (OVP), thermal shutdown (TSD) and under voltage lock-out (UVLO) protection circuits while also facilitating a low-power consumption design (10μA max).
Rohm H-Bridge Evaluation Board - [Link]
by deba168 @ instructables.com:
Welcome to my solar charge controller tutorials series.I have posted two version of my PWM charge controller.If you are new to this please refer my earlier tutorial for understanding the basics of charge controller.
This instructable will cover a project build for a Arduino based Solar MPPT charge controller.
Now a days the most advance solar charge controller available in the market is Maximum Power Point Tracking (MPPT).The MPPT controller is more sophisticated and more expensive.It has several advantages over the earlier charge controller.It is 30 to 40 % more efficient at low temperature.
But making a MPPT charge controller is little bit complex in compare to PWM charge controller.It require some basic knowledge of power electronics. I put a lot of effort to make it simple, so that any one can understand it easily.If you are aware about the basics of MPPT charge controller then skip the first few steps.
Arduino MPPT Solar Charge Controller v3 - [Link]
Davide Gironi writes:
The PWM frequency have to be selected in the way that the switch frequency is much higher than the dynamics of the motor.
To avoid noise from the motor, the choosen PWM frequency is 20Khz. Which is a know to know frequency.
So, with this one, you can drive up to 4 motors independently controlling:
*slow start / stop
Setup parameters are contained in dcmotorpwm.h
This library was developed on Eclipse, built with avr-gcc on Atmega8 @ 8MHz.
Driving a DC motor using PWM with AVR ATmega - [Link]
The LMR16006 is a PWM DC/DC buck (step-down) regulator. With a wide input range of 4 V to 60 V, it is suitable for a wide range of application from industrial to automotive for power conditioning from an unregulated source. The regulator’s standby current is 28 µA in ECO mode, which is suitable for battery operating systems. An ultra low 1 µA shutdown current can further prolong battery life. Operating frequency is fixed at 0.7 MHz (X version) and 2.1 MHz (Y version) allowing the use of small external components while still being able to have low output ripple voltage. Soft-start and compensation circuits are implemented internally, which allows the device to be used with minimized external components. The LMR16006 is optimized for up to 600 mA load currents.
LMR16006 SIMPLE SWITCHER 60V Buck Regulators with High Efficiency ECO Mode - [Link]
LT3795 – 110V LED Controller with Spread Spectrum Frequency Modulation. by elektor.com:
It’s standard practice to use Pulse Width Modulated (PWM) signals to control electrical energy delivered to a load. Special precautions are however necessary to mitigate the effects of electromagnetic interference (EMI) generated when high-energy loads are regulated in this way. Spectral analyses of the interference generated show strong peaks at the fundamental and harmonics of the PWM frequency. For high-power switch-mode drivers used to control LED car headlights it is important to ensure the interference cannot disrupt radio or GPS reception. EMI filters and gate resistors can be used to slow down switching edges but have the effect of increasing energy losses.
Spread Spectrum LED driver - [Link]
Minimum noise, easy speed control and a high power, those are another reasons why to decide for GreenTech EC fans from EBM-Papst.
A term „EC fan“ (electronic commutation) is generally used to mark energy-saving AC fans. In fact, these are DC (brushless) fans with AC/DC module and other electronics. EC fans reach up to 90% efficiency and they consume 50% less energy than traditional AC fans.
At the same time, a typical „50Hz“ motor noise is eliminated at EC fans and practically the only noise source is aerodynamic noise depending on overall fan design.
A good example of a modern fan is for example the type G1G140-AW31-42 i.e. radial (centrifugal) fan with 140mm diameter. Efficient motor with a „Soft start“ function enables to control fan speed through a DC input (0-10V) or PWM. To check a proper function, the fan also features „Tach“ output (2 pulses / revolution) as well as locked motor protection.
Thanks to the built-in electronics, at cyclic use it´s recommended to switch-off the motor through a control signal, not by switching-off main power supply.
G1G140-AW31-42 is suitable for a continuous operation (S1) and can be mounted in any position. It´s used for example for building ventilation.
Detailed information will provide you the G1G140-AW31-42 datasheet.
Modern EC fans are able to save up to 50% of energy - [Link]
MCP19118/9 Provide Simple Analog PWM Control and Configurable MCU in Compact Circuit Solution; Industry’s First PMBus Compatible Controller With Up to 40V Operation.
Microchip Technology Inc. announced its latest Digitally Enhanced Power Analog (DEPA) controllers—the MCP19118 and MCP19119 (MCP19118/9). They provide simple yet effective analog PWM control for DC-DC synchronous buck converters up to 40V, with the configurability of a digital MCU. And they are the industry’s first devices to combine 40V operation and PMBus communication interfaces. These features enable quick power-conversion circuit development with an analog control loop that is programmable in the integrated 8-bit PIC MCU core’s firmware. This integration and flexibility is ideal for power-conversion applications, such as battery-charging, LED-driving, USB Power Delivery, point-of-load and automotive power supplies.
New Digitally Enhanced Power Analog Controllers From Microchip - [Link]
If anybody is interesed, I have posed a follow up to this original post with a simple PWM LED driver, adding an ATtiny85 mCU. The post includes schematic, board layout and code for the ATtiny85. I hav tested the circuit up to 22 volts without a current limiting resistor. The FET only needs a small heat sink. Efficiency can be further improved by replacing the LM358 with an RC/LM741. The LM741 has a much sharper rise and fall time than the LM358 when run at 2KHz, resulting in the FET spending less time as a resistor. (during the slow ramp/fall the FET acts as a resistor, generating heat)
PWM Based LED Driver - [Link]
by Mark (Moonyoung) Lee & Kevin J. Wang:
What is seeing without feeling? The field of Virtual Reality has recently been gaining much attention, with the Oculus Rift and Google Cardboard paving the path of visualizing a world that is not physically there. But what if the virtual reality experience could be enhanced by incorporating tactile sensing? The Haptic Glove we developed accomplishes just that – without seeing the physical structure of the object, you will still be able to feel the presence of virtual objects.
The goal of the project is to create an exoskeleton on the forearm arm that provides tactile perception for the user. The volume of the virtual object will be emulated based on the intensity of a light source that is placed inside a black box. Depending on the relative brightness of the source to the phototransistors that are mounted onto the exoskeleton, a distance between the user’s hand and the light source can be determined. By varying the brightness of the LED light source, the size of the virtual object will vary. To provide the tactile perception, servos mounted on the exoskeleton provides a pulling force, preventing the user’s fingers from reaching closer to the light source. In addition to the resistive force that act against the fingers’ movement, there are also flat surfaces at the tips of the exoskeleton that will flip up to make contact with the user’s fingers, which actually provides the sense of touching a real object.
Feeling the light in a whole new way - [Link]