Circuits & Schematics Power

When driving an H-bridge or a similar circuit, you usually must ensure that two or more transistors are not on at the same time. Eliminating multiple transistors from turning on reduces power consumption and lowers EMI (electromagnetic ...

The circuit in Figure 1 allows standard TTL logic levels to safely drive a high-power dc load. The circuit provides for both signal and ground isolation as well as a solid-state circuit breaker. Figure 1. An overcurrent condition in this isolated ...

The MOSFET power switch is commonly the most vulnerable part of a new switched-mode high-power circuit. One threat for this device is exceeding the value of the maximum allowed pulse current. You cannot exceed this limit, even for pulse durations ...

Ideally (in that magical land where theory and practice are the same thing), the speed of a permanent magnet DC motor is exactly proportional to the input voltage: Speed = K S V, where constant K S is specific to the motor in question. But since ...

You can use the circuit in Figure 1 to monitor the rotating speed of a dc fan motor and sound an alarm if the motor stalls. One potential application of the circuit is monitoring the CPU-fan speed in a PC in which overheating the CPU can ruin the ...

Thanks to a combination of low initial cost and low on-resistance, a conventional electromechanical relay often makes sense for switching large amounts of load current on and off and when proportional control of the load's current or voltage is ...

Three-phase controlled rectifiers and inverters, matrix cycloconverters, and cascaded power stages typically comprise large numbers of power transistors, each with its own driver circuit. The circuit in Figure 1 drives a capacitive-input power ...

With their excellent isolation and reliability, gate-drive transformers (GDTs) are commonly used for driving half-bridge power circuits. However, they pose challenges when you want to have both switches off for an extended period. This application ...

High efficiency and, hence, low loss is a usual design goal for a PWM circuit. Figure 1 shows one of several channels of low-loss PWM control for hydraulic valves used in heavy industrial machinery. These valves usually have dc resistance of ...

In the circuit of Figure 1, assume that a brush-type dc motor must drive a load back and forth between two endpoints on a lead screw. Optical sensors determine end of travel, and an SPDT switch selects to which end to send the load. The sensors ...