This section provides an overview for constant current drivers as well as their applications and principles. Also, please take a look at the list of 10 constant current driver manufacturers and their company rankings.
Table of Contents
Constant current drivers are electronic circuits that can output a stable current regardless of variations in supply voltage, temperature, or load.
They control a constant current to flow to a load by utilizing the fact that the collector current of a transistor or the drain current of a MOSFET is controlled by the base current and gate voltage.
There are several circuit methods, such as those using Zener diodes or operational amplifiers, while others are controlled by switching methods such as PWM control.
The main application of constant current drivers is in LED driver circuits. In this case, they are sometimes called LED drivers.
Since the brightness of LEDs is determined by the current flowing through them, constant current drivers are used to control the current so that the brightness does not change due to fluctuations in power supply voltage or temperature. By controlling the current appropriately, it is possible to suppress variations in the characteristics of individual LEDs, to make them emit light efficiently, and to extend their lifespan.
Other applications include motor drive circuits. Constant current drivers are used when a constant current is required to turn a motor at a constant torque.
This section describes the circuit scheme using a Zener diode. A Zener diode is connected to the base of the transistor, an emitter resistor to the emitter, and a load to the collector. The Zener diode is also connected to the power supply via a resistor to provide the appropriate current for proper operation.
Since the Zener diode maintains a constant voltage regardless of supply voltage variations, a constant voltage is applied to the base of the transistor. The collector current is controlled by the base current, but if the collector current fluctuates in the upward direction, the voltage drop across the emitter resistor becomes larger, causing the base current to drop. Conversely, if the collector current fluctuates in the downward direction, the collector current is controlled in the upward direction. As a result, the collector current flowing to the load is controlled to be constant.
In the case of the operational amplifier method, the collector current is controlled to be constant by connecting a Zener diode to the non-inverting input, the emitter of a transistor to the inverting input, and the base to the output.
In the case of the switching method, the average collector current is controlled to be constant by PWM control of the transistor on/off.
*Including some distributors, etc.
Sort by Features
Sort by Area
Number of Employees
Newly Established Company
Company with a History
This is the version of our website addressed to speakers of English in the United States. If you are a resident of another country, please select the appropriate version of Metoree for your country in the drop-down menu.