Circuits & Schematics - Supply

It’s remarkable how many switching regulator chips use the same basic two-resistor network for output voltage programming. Figure 1 illustrates this feature in a typical (buck type) regulator. See R 1 and R 2 where: Quantitatively, the V ...

This design idea reprises another “1 A, 20 V, PWM controlled current source” ( Ref. 1 ). Like the earlier circuit, this design integrates an LM3x7 adjustable regulator with a PWM DAC to make a programmable 20 V, 1 A current source. It ...

Rheostats Rheostats are simple and ubiquitous circuit elements, usually comprising a potentiometer connected as an adjustable two terminal resistor. The availability of manual pots with resistances spanning ohms to megohms makes the optimum choice ...

This design idea revisits another: “PWM power DAC incorporates an LM317” ( Ref. 1 ). Like the earlier circuit, this one implements a power DAC by integrating an LM317 positive regulator into a mostly passive PWM topology. It exploits ...

This design idea (DI) takes an unusual path to a power-handling DAC by merging an upside-down LM337 regulator with a simple (just one generic chip) PWM circuit to make a 20-V, 1-A current source. It’s suitable for magnet driving, battery ...

Short-circuit protection is an obvious requirement for a power supply, especially when its load connects to a cable that's subject to damage. Many modern power-converter ICs include some means of protection, such as thermal shutdown, against ...

Figure 1 shows an example of on/off circuitry commonly used in battery-operated devices. The p-channel MOSFET, Q 1 , serves as a power switch. When you push the On button, S 1 , Q 1 ’s gate goes low. Q 1 turns on and supplies battery voltage ...

For the heating and cooling elements common in industrial systems, resistance is not a fixed quantity. These elements include such devices as positive-temperature-coefficient heaters and thermoelectric coolers. Their resistance can change more than ...

A free energy collector circuit helps to convert surrounding radio frequency waves to electric power and can provide 40 watts to 10 watts indefinitely. The circuit concept An option to increase the output power is achievable through proper set-up ...

Instead of the conventional approach of backing up a DAC with an amplifier to boost output, this design idea charts a less traveled by path to power. It integrates an LM317 positive regulator with a simple 8-bit PWM DAC topology to obtain a robust ...