Contents
How do you increase the current in a mirror circuit?
There are several options to improve the output of Current Mirror Circuit. In one of the solution one or two transistors are added over the traditional two transistors design. Construction of those circuits uses emitter follower configuration to overcome the base current mismatch of the transistors.
Why we get constant current in current mirror circuit?
An important feature of the current mirror is a relatively high output resistance which helps to keep the output current constant regardless of load conditions. Another feature of the current mirror is a relatively low input resistance which helps to keep the input current constant regardless of drive conditions.
How do you reduce mismatch?
The only way to reduce the effect of this source of mismatch is to use large devices such that the effect of variation which often occurs at the edges of the device can be neglected.
What is the advantage of current mirror circuit?
Answer: The advantage of using current mirror circuit is that it requires less number of components than the constant current bias circuit. It is simple and easy to fabricate. Therefore the current mirror circuit is widely used in the integrated amplifiers.
Is the output current accurate in a mirror circuit?
In case of basic current mirror circuit, the base current mismatch is a common problem. However, this Wilson current mirror circuit virtually eliminates the base current balance error. Due to this, the output current is near to accurate as of the input current.
How is the Wilson current mirror circuit improved?
Wilson current mirror circuit can be further improved to get perfect accuracy by adding another transistor. The above circuit is the improved version of the Wilson current mirror circuit. The fourth transistor T4 is added in the circuit. The additional transistor T4 balances the collector voltage of T1 and T2.
Where does the name current mirror circuit come from?
From the name of George R. Wilson, the improved current mirror circuit designed by him is called Wilson Current Mirror Circuit. Wilson current mirror circuit uses three active devices that accept the current across its input and provide the exact copy or mirrored copy of the current to its output. Wilson Current Mirror Circuit
How are transistors used in current mirror circuit?
So to get a stable output, additional techniques are used in current mirror circuits. There are several options to improve the output of Current Mirror Circuit. In one of the solution one or two transistors are added over the traditional two transistors design.