Image Credit: Newark / element14
Current limiting diodes (CLD) regulate current over a wide voltage range.
CLDs are used in many applications. Some examples include waveform generator circuits, battery charger, and timing circuits. CLDs are also used as a constant current source for driving LEDs and can also be used to replace holding coils in telephone connection devices. CLDs follow the life cycle stages defined by Electronic Industries Alliance (EIA) in EIA-724.
Types of Current Limiting Diodes
There are several types of CLDs. Examples include a current regulator diode, constant current diode, and current limit diodes.
- Current regulating diodes regulate the current flowing through them to a maximum level and if current exceeds its current regulation point, it drops its voltage.
- A constant current diode is similar to a junction field effect transistor (JFET) whose gate terminal is shorted to source. A constant current diode can automatically limit a current through a laser driver current limit diode over a wide range of power supply voltages.
- A laser driver current limit diode is the CLD that works on the principle of a quantum process whereby light is emitted due to transition of electrons from high-level to low-level energy states. Current limit diodes are employed for coupling and biasing the circuits. Other CLDs are also commonly available.
There are several ways in which CLDs function. A CLD is available in wide range of current and voltage ratings to control a current. Some examples of current limiting diodes specifications include a current rating of 35A to 15mA, peak voltage ratings of 50V to 100V, and impedance ranges from 20M ohm to several kilo ohms.
A current regulator diode can maintain a constant current for a voltage range of 1V to 100V if the current is in the range of 5mA to 60mA. Current regulating diodes also increase the frequency response, voltage gain, rejection ratio, and reduce gain losses and noise density.
A constant current diode has currents from 0.192mA to 5.6mA and operates in a voltage range of 1V to 50V. A constant current diode provides good temperature stability and does not require any biasing.
Some specifications of a laser driver current limit diode include current ranges of 0 to ± 20mA, ± 100mA, ± 200mA, ±5 00mA, ± 1A, ± 2 A, and 3dB analog modulation bandwidth. A laser driver current limit diode also supports both constant current and constant power modes of operation.
CLDs are designed and manufactured to meet most industry specifications.
Related Products & Services
Diode arrays are composed of multiple discrete (usually unconnected) diodes on a single silicon chip. Diode arrays are important semiconductor products because they save assembly time and improve reliability over individually packaged diodes. In general, diode arrays use four or more diodes in a single package.
Diodes are electronic components that conduct electric current in only one direction, functioning as a one-way valve. Diodes are manufactured using semiconductor materials such as silicon, germanium or selenium and are used as voltage regulators, signal rectifiers, oscillators and signal modulators / demodulators.
PIN diodes are three-layer semiconductor diodes consisting of an intrinsic layer separating heavily doped P and N layers. The charge stored in the intrinsic layer in conjunction with other diode parameters determines the resistance of the diode at RF and microwave frequencies.
RF diodes are designed to handle high-power radio frequency (RF) signals in stereo amplifiers, radio transmitters, television monitors, and other RF or microwave devices.
Transient Voltage Suppressor Diodes (TVS)
Transient voltage suppressor (TVS) diodes are designed to limit over-voltages. They can dissipate high amounts of transient power in a short period of time.
Tunnel diodes are heavily doped P-N diodes in which electron tunneling from the conduction band in the N-type material to the valence band in the P-type region produces a region of negative resistance. This negative-resistance region is the most important area of operation. As the voltage is increased, the current decreases. This feature makes tunneling diodes especially useful in oscillators and radio frequency (RF) applications.
Varactor diodes are p-n junction diodes that are designed to act as a voltage controlled capacitance when operated under reverse bias.