Circuits & Schematics Supply - 3

The control circuit in Figure 1 senses a given load and automatically soft-starts the load by synchronously adjusting the power to that load. You can also manually adjust the power delivered to the load by controlling the phase angle of the line ...

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 ...