Darlington pair basics
Darlington pair advantages and disadvantages summary
Darlington pair applications
- Audio power output stages: Sometimes audio amplifier power output stages may require significant levels of current gain to enable them to drive low impedance speakers. The limited bandwidth and is unlikely to affect the frequency response over the frequency ranges being used.
- Linear power regulators: The Darlington circuit configuration is ideal for use in linear power regulators. There is a requirement for the circuit to be able to drive high current levels and in this respect high levels of current gain are required. It is necessary to consider the slow response on the suppression of spikes in the design.
- Photo-Darlington: Phototransistors are widely used in sensors. To improve the sensitivity of these devices, photodarlingtons are available. These offer considerably higher levels of sensitivity and as a result they are widely used.
- General high power applications: The high current gain capability of the Darlington transistor makes it ideal for controlling high current levels. As a result special Darlington transistor modules are available that are able to carry current levels of 100 amps and more. These Darlington transistor modules are often relatively large and employ screw terminals and are designed for mounting on large heat-sinks. Possible end applications for these devices may include inverter circuits, AC motor control, DC motor control circuits and emergency power supplies, etc..
- LED and Display drivers: Darlington transistor arrays contained within IC packages are widely used for driving loads from standard logic families. Here high levels of current gain are required, making the Darlington an ideal choice. Typical arrays are suitable for driving LEDs, displays, solenoids or other loads. Often these arrays have built in suppression diodes to prevent any reverse voltages (back EMFs) from any inductive loads from destroying them when the current is switched off.