Circuits & Schematics Supply

Adding four components to a negative linear regulator (U1 in the Figure 1) increases the load current by 60%. The additional pass transistor and associated resistors cost less than $0.17 in 1000-unit quantities. Figure 1. A pass transistor and ...

Electric vehicles, large-scale battery storage stacks, home automation, industrial, and telecom power all require converting high voltages to 12 V, where dual polarity rails are required for powering amplifiers, sensors, data converters, and ...

Rechargeable nickel-cadmium (NiCd) batteries are widely used in consumer electronics because of their high energy density, long life, and low self-discharge rate. Standard NiCd cells can be charged at different rates: a fast charge with high ...

Testing power supplies and batteries requires current loads capable of sinking large current and dissipating substantial amounts of power. A simple but accurate current load can be built using just a single op amp and a power MOSFET, as shown in ...

Figure 1 shows a flyback power supply that has low noise and uses a simple CMOS CD4093 IC for its control. The electrical noise of a converter arises mainly when current switches on. Diode recovery and charging parasitic capacitances create high ...

White LEDs find wide use in backlighting color-LCD screens in most portable devices, such as cellular phones, PDAs, and MP3 players. Multiple LEDs often connect in series to ensure that the same current flows through every LED. To forward-bias ...

LED-driver circuits can be dimmed by applying a variable duty cycle (pulse-width modulation, or PWM) to the LED. PWM exploits LED behavior: At higher current levels, the LED’s light output is higher for a given level of power dissipation ...

Portable battery-powered devices often spend most of their life in standby mode, in which the quiescent current of an internal boost converter continuously bleeds the battery. The quiescent current during standby can be larger than the actual load ...

Supervisory circuits normally monitor a microprocessor's supply voltage, asserting reset to the IC during power-up, power-down, and brownout. In this way, the circuit ensures that the supply voltage is stable before the microprocessor boots, ...

Fan noise is becoming a significant issue as electronic equipment increasingly enters the office and the home. Noise is proportional to fan speed, and the airflow hence, fan speed necessary for cooling is less at low ambient temperatures. Because ...