The SM72441 is a programmable MPPT controller capable of controlling four PWM gate drive signals for a 4-switch buck-boost converter. Along with SM72295 (Photovoltaic Full Bridge Driver) it creates a solution for an MPPT configured DC-DC converter with efficiencies up to 98.5%. Integrated into the chip is an 8-channel, 12 bit A/D converter used to sense input and output voltage and current, as well as board configuration. Externally programmable values include maximum output voltage and current as well as different settings on slew rate, and soft-start.
Programmable Maximum Power Point Tracking Controller for Photovoltaic Solar Panels - [Link]
Giorgos Lazaridis writes:
I decided to write this quick tutorial for two reasons: First because there are many people who would like to know more about driving and controlling LED lights, and second because i was provided an excellent LED driver chip from Farnell for test, and i wanted to put it under the microscope. So i will place this chip against some other LED drivers to see how good it is.
The chip that I’m talking about is the A6210 from Allegro Microsystems. It is a Buck-Regulating LED Driver able to drive up to 3A load with constant current, with switching frequencies up to 2 MHz and supply voltage from 9 to 46 volts. It has an optional PWM input to control the brightness of the LED. The sense voltage is down to 0.18 volts for higher efficiency.
LED driving and controlling methods - [Link]
PowerXR Programmable Power Solutions
A range of serial (I2C) programmable step-down regulators for complex systems with multiple supply voltages.
- 3 or 4 completely independent PWM channels.
- One 3.3/5 V selectable linear LDO regulator.
- Programmable output voltage from 0.9 to 5.1 V.
- Programmable switch frequencies from 0.3 to 1.5 MHz.
- Up to 6 configurable GPIO pins.
- PowerArchitect™ » Free development software.
PowerXR – Programmable switching regulator - [Link]
This application note describes the operation of 12 volt DC cooling fans typically used to supply cooling air to electronic equipment: These fans are typically based on two-phase Brushless DC (BLDC) motors drawing between 1 and 50 watts of power. Single-phase brushless DC motors are also used in fans, but this is outside the scope of this application note.
Further discussion describes the addition of an Atmel ATtiny13 microcontroller and the benefits this offers, such as variable speed by external thermistor input. An additional input is a PWM pulse width-varying signal, which also controls fan speed.
App note: PC fan control using an ATtiny13 - [Link]
Here is a part from National Semiconductor designed for controlling high-power DC/DC boost regulators. What makes it interesting is that its PWM frequency can be pushed to 2Mhz. This allows for smaller and cheaper discrete components, like inductors and capacitors. The datasheet on this device also provides some nice PCB guidelines to maximize its efficiency and minimize noise.
App note: LM5022 DC/DC boost controller - [Link]
A very popular type of LED that has finally come about is the tri-color, RGB LED. The RGB stands for: red, green and blue since the LED is capable of displaying all three colors, independently. This means that an RGB LED can display any color of the rainbow. This is a powerful capability, but it also requires more control.
In this article, we shall look at how to build an RGB LED controller so that we have accurate and independant control over all three colors at any instant. The method of Fading LEDs via PWM will be leveraged for this design, since our goal here is quite similar, but with more control paths.
RGB LED Controller - [Link]
The up-side to this design is that all of the drivers are on-board, and only control signals are needed to manipulate the matrix. The down side is that his design requires 4 layers to route, and 4 layer boards are quite expensive to make.
I2C controlled 4X4 RGB LED matrix - [Link]
A new internet controlled lighting project called SplashLight is being developed. It has 4 relays to turn lights on and off, and 3 PWM outputs to drive RGB LEDs. The core of the project is a Cortex M3 uC with an Ethernet PHY/MAC from Texas Instruments.
The project includes iPhone, Android, and web applications to control the board over the web. It looks like the PCB and schematic files will be made available in the future, but the license is still unannounced. Might be ripe for a remake.
Network controlled relays & 3 channel PWM - [Link]
Geoff designed this USB PC case fan controller. It is used to control the speed of your fans depending on the temperatures in your case. Software that was developed for this project allows you to customize the temperature profiles for your computer.
The project is based on the PIC18F2550 that is connected to the computer via the USB and uses the standard Molex 4pin connector to access computer’s power supply. It has 4 analog inputs for temp sensors, and can control up to 8 fans.
One thing to note is that all the fan outputs work with 3 pin fans, while two are universal and work even with 4 pin PWM versions. The 3 pin fans are driven with a buck convertor. The UDN2981 provides the high side switch and diode that are driven from PIC’s PWM signals. A 100uH inductor and a 479uF capacitor complete the buck topology, thus providing variable analog output for the 3 pin fans.
Intelligent Fan Controller - [Link]
rsdio writes: This thing puts out so much torque that it has to be run at 3/4 power to avoid slipping the clutch! – [via]
Features: Programmable current limit 100-1200 motor amps, automatic over-temperature current limit cut-back, water-cooled copper heat sink, low-loss IGBT modules, and motor overspeed limit.
Processor: Microchip PIC 16F877 This small yet powerful microcontroller runs at 5 MIPS and 20MHz with 8kb of onboard program FLASH memory. It also has two onboard 10-bit PWM generators, eight 10-bit ADC channels, and a UART interface.
1.2 kA motor driver circuit based on the PIC16F877 - [Link]