Cocoleia said:
A current mirror is a type of electronic circuit that is used to replicate or mirror the current flowing in one branch of the circuit in another branch. Its purpose is to provide a stable and accurate current source for various applications in electronics, such as biasing transistors, amplifiers, and voltage regulators.
A current mirror typically consists of two or more transistors connected in a specific configuration. The transistor in the first branch, called the reference transistor, sets the current based on its biasing. The transistors in the other branches, called the mirror transistors, replicate the current based on the reference transistor's current. This allows for a consistent and stable current to flow through the circuit.
There are three main types of current mirrors: the basic current mirror, the Wilson current mirror, and the Widlar current mirror. The basic current mirror uses two transistors and a resistor in a simple configuration. The Wilson current mirror uses four transistors and provides better output impedance. The Widlar current mirror uses two transistors and a diode to improve the accuracy of the mirrored current.
The use of a current mirror provides several advantages, including stable and accurate current replication, low output impedance, and improved circuit performance. It also reduces the need for external components, simplifying the circuit design and reducing costs.
Current mirrors are commonly used in various electronic devices, such as operational amplifiers, analog-to-digital converters, and voltage regulators. They are also used in high-frequency circuits, communication systems, and power management circuits.