herpderp shares his waveform generator:
Here is my last project, a tiny waveform generator based on my previous project and some components:
- An AD9834 (DDS chip with sinus/triangle output)
- 2 x AD5310 (10bit DAC: one for the Vpp control, another one the offset control)
- 3 x LM7171 (Fast OPA)
- 3 x LT1616 (switching regulator: +5V, +7V, -7V)
This waveform generator is directly powered by a standard 12V jack and is capable of outputting a 10Vpp signal at 1MHz (between -5V and +5V, sinus waveform, no load). Above 1MHz, the output starts fading, reaching only 9Vpp at 4MHz (maximal frequency). Frequency, amplitude and offset are digitally controlled through the smart TFT.
Three “basic” waveforms are provided: sinus and triangle, coming from the DDS chip (0.1Hz to 4MHz, 0.1Hz step), and PWM coming from the microcontroller (0.1Hz to 1MHz, variable steps).
Tiny waveform generator - [Link]
An application note from Texas Instruments, white LED driver with digital and PWM brightness control (PDF!):
With a 40-V rated integrated switch FET, the TPS61160/1 is a boost converter that drives LEDs in series. The boost converter runs at 600kHz fixed switching frequency to reduce output ripple, improve conversion efficiency, and allows for the use of small external components.
The default white LED current is set with the external sensor resistor Rset, and the feedback voltage is regulated to 200mV, as shown in the typical application. During the operation, the LED current can be controlled using the 1-wire digital interface ( Easyscale™ protocol) through the CTRL pin.
App note: White LED driver with digital and PWM brightness control - [Link]
Ondrej Karas of DoItWireless writes:
This is simple illustration how to build easy PWM LED control with IQRF TR module and a few other components.
This device is powered from 12V/6A DC power supply and can power up to 5m of LED strip. This device can be controlled via RF, buttons or potentiometer. RF controlling is compatible with remote control device RC-04 with low battery signalizing – fast 3 time LED blinking.
RF PWM LED control - [Link]
An SMPS application using PIC16F785 from Microchip. [via]
In this application note, we will examine a typical buck topology intelligent SMPS design using the PIC16F785.
The design presented here shows an alternative single-chip approach to adding intelligence to SMPS designs. The basic design is really unchanged. There are current and voltage feedback loops, a counter-based PWM is used to generate the reference voltage to the voltage loop, and the microcontroller uses the reference voltage to modify the operation of the system in response to conditions sensed through the ADC.
App note: Switching power supply design with the PIC16F785 - [Link]
praveen @ circuitstoday.com writes:
PWM or pulse width modulation is a very common method used for controlling the power across devices like motor, light etc. In PWM method the power across the load is controlled by varying the duty cycle of the drive signal. More the duty cycle more power is delivered across the load and less the duty cycle, less power is delivered across the load. A hex keypad is used for controlling the speed. The speed can be varied in seven steps using the hex keypad. Arduino UNO is the type os arduino development board used in this circuit. The circuit diagram of the PWM motor speed control using arduino is shown in the figure below.
PWM motor speed control using Arduino - [Link]
Nich Fugalfrom @ Makeatronics is working on a BLDC motor controller.
Icall it a smart BLDC commutator. In a nutshell it’s a dedicated atmega328 that monitors the hall effect sensors on a brushless DC motor and takes care of the commutating and driver circuitry.
It’s smart because it has the ability to extract and keep track of motor position while monitoring the hall sensors. There’s also an option to plug in a quadrature encoder for higher resolution. The position can be sampled via a sample and hold input and communicated to a host controller via SPI.
I designed it to be an easy to use black box for interfacing with BLDC motors. All the host controller has to do is feed it direction (high/low) and PWM and the rest is done for you.
BLDC motor control using Atmega328 - [Link]
by Kalle Hyvönen:
I bought a small aquarium (54l) as an impulse buy and I needed some lights for it, so naturally I wanted to use LEDs. I also needed a timer for the lights. I also wanted the lights to fade in and out when they were going on or off as a cool effect.
I ordered four Cree XP-G R5 LEDs (cool white, apparently too warm of a light will cause algae growth) and a one amp (switching) constant current supply (with PWM support) from LED-tech.de. I had some Maxim DS3234 real-time clocks with a serial bus (SPI) which looked easy to implement so I decided to use one. I also had one spare Arduino board so that was going to be my microcontroller of choice. I used a laptop power supply as the power source.
LED aquarium lighting with an Arduino based PWM timer - [Link]
praveen @ circuitstoday.com writes:
In this article we explain how to do PWM (Pulse Width Modulation) control using arduino. If you are new to electronics, we have a detailed article explaining pulse width modulation. We have explained PWM in this tutorial using 2 examples which will help you learn how to control LED brightness using PWM and how to control DC motor speed using PWM.
PWM Control using Arduino – Learn to Control DC Motor Speed and LED Brightness - [Link]
by Susan Nordyk:
The LT8471, a dual PWM DC/DC converter from Linear Technology, employs two internal 2-A, 50-V switches and an additional 500-mA switch to facilitate step-down, step-up, and inverting conversions. Each 2-A channel can be independently configured as a buck, boost, SEPIC, flyback, Zeta, or inverting converter.
This broad range of topologies and output configurations makes the LT8471 useful for a wide range of industrial and automotive applications. The converter operates from an input voltage of 2.6 V to 50 V, allowing it to be used with input sources ranging from single-cell lithium-ion to automotive batteries.
The LT8471 is capable of generating both positive and negative outputs. Its switching frequency is programmable and synchronizable from 100 kHz to 2 MHz. The device’s 50-V switches achieve overall efficiencies of up to 85% for buck and inverting applications. Operating from a 6-V to 32-V input, the LT8471 delivers up to 1.5 A at 5 V and 650 mA at –5 V.
Housed in a 20-lead, thermally enhanced TSSOP, the LT8471 costs $3.75 each in lots of 1000 units. An industrial-temperature version is priced at $4.13 in like quantities. Both versions are available from stock.
Multiple-topology DC/DC converter integrates dual 2-A switches - [Link]