The circuit that's shown in Figure 1 implements a programmable 0- to 20-mA precision current source. The REF192 low-headroom 2.5-V voltage reference (U1) can source up to 30 mA. An AD5280 digital potentiometer (U2) controls the voltage-divider ...
David Conrad Electronic Design In this Idea for Design, placing this circuit setup between the battery V DD bus and the PIC microcontroller allows you to execute in-circuit programming while protecting the application circuit. Many PIC processors ...
Batteries are the typical power sources for portable-system applications, and it is not unusual these days to find microcontroller-based portable systems. A variety of microcontrollers operates at low power-supply voltages, such as 1.8 V. Thus you ...
The enduring simplicity of PWM DACs will always earn them a place in the designer’s cookbook, but slow response time and the problem of PWM ripple tend to limit their appeal and utility. The usual way of attenuating PWM ripple, an RC low pass ...
Tom Gay EDN Most current microcontrollers offer I/O ports that can change their functions during program execution. As outputs, the circuits can sink and source reasonably large amounts of current. This Design Idea shows three alternative methods ...
It’s almost a corollary to Moore’s Law: Next year, microcomputers will have more features, and the software team will have bigger ideas. Unfortunately, though, the number of output pins will stay the same. Finding even one spare output ...
Dan Meeks EDN Most current microprocessors, DSPs, and field-programmable gate arrays integrate hardware and software resources that support either or both of two common interface standards SPI (serial-peripheral interface) and I 2 C ...
Jim Brannan EDN Combining PWM with a small R-2R ladder improves both. It reduces PWM ripple significantly and increases the DAC’s resolution. In this Design Idea, an eight-resistor array and three output pins construct a modified R-2R ladder ...
Most of us know about PWM DACs. They are easy to implement, cheap, and acceptable for low performance applications. The approach is to filter the HF components of the PWM signal and be left with only the LF or DC component that is proportional to ...
By using this simple capacitor-network circuit and software, designs using the Arduino Uno need only two I/O pins to read a hex-switch decoder, leaving the remaining pins for other functions. A pulse-width-modulated (PWM) signal and the RC-charging ...