Circuits & Schematics Supply - 3

To control their brightness, LEDs need a constant current; this can be done with a resistor placed in series with the LED string. Both the LED-string voltage and the supply voltage can vary, so a dedicated LED driver is a must to guarantee the ...

While choosing an op-amp buffer, some sources of negative supply were considered, because the buffer op-amp had to provide true zero voltage on its output. In reality, a typical rail-to-rail output op-amp isn’t capable of this, it can ...

This Design Idea significantly improves conversion efficiency of externally driven flyback converter-based capacitor charging units intended for flash-lamp-pumped, pulsed solid-state laser sources. In a flash-pumped pulsed solid state laser source, ...

Many rechargeable battery types can be damaged by deep discharge. This Design Idea circuit performs under-voltage protection (UVP) to prevent this, as well as acting as a load switch (Figure 1). With little or no modification, it can work for ...

Sometimes you may need a group of switches where, if any switch is activated, it deactivates the previously active switch. This Design Idea implements such a function with relays. This “one and only one” function is often implemented as ...

With just one leftover op amp or comparator, you can add a battery-condition indicator to your portable circuit design. To indicate the life in an aging battery visually, the circuit in Figure 1 varies the duty cycle and flash rate of an LED when ...

Powering LEDs from a wide dc range say, 30 to 380 V without wasting a lot of power in the regulating block, is a difficult task when the LED current needs to be constant. Dedicated LED drivers are available, but they usually implement boost ...

Surprising facts, like “old fangled” 3-leg linear regulators ( LM317 , LM337 , LM350, et al.) can be used in shunt regulator topologies ( Reference 1 ) can sometimes inspire “new fangled” circuit designs. Figure 1 shows a ...

The purpose of this Design Idea was to improve reliability, add new features, and replace a latching power switch with a momentary one. The features are: The switch has foolproof protection against too frequent switching, which can be harmful for ...

The voltage-doubler circuit in Figure 1 can convert 2.5 V dc to 5 V dc or 1.8 V to 3.3 V. Most voltage doublers use an inductor, but this circuit doesn’t need one. The circuit uses a capacitor, C, by charging it through serially connected ...