What is active load in differential amplifier?
• Active loads are essentially transistor. current sources used in place of the. resistive loads in the diff-amp circuits to increase differential-mode gain. • BJTs {MOSFETs} in the active load circuit are biased at Q-point in forward-active {saturation} mode.
What is the purpose of using a differential amplifier with active load?
The purpose of a differential amplifier with active load is to provide an increase in the voltage gain. The total gain of a differential amplifier with active load is the product of the voltage gains of the discrete stages.
What is CMOS differential amplifier?
A differential amplifier is a circuit whose output voltage is directly proportional to the difference between voltages applied at it’s to inputs. A typical CMOS differential amplifier circuit is shown below. Fig.1 — CMOS Differential Amplifier Circuit. All MOSFETs are in saturation.
How do we calculate output voltage of differential amplifier with active load?
I want to compute the value of VO. I would have guessed that VO = VCC – VEB. Asuming VCC = 5V and VEB = 0.6 V, that would render VO = 4.4 V, as in the left branch of the circuit.
What is the difference between active and passive loads?
If it is a active device like mos/bjt then its a active load. if its non active like resistor, capacitor then its passive load. Passive load naturally comprises resistance, capacitance and inductance elements. They need external source and do not alter nature of supply.
Why do we use active load?
In the area of electronic test equipment, an active load is used for automatic testing of power supplies and other sources of electrical power to ensure that their output voltage and current are within their specifications over a range of load conditions, from no load to maximum load.
Why active load is preferred in IC manufacturing?
Active loads are used because transistors are cheaper and easier to make on a silicon die than resistors are. Therefore, you find active loads more in integrated circuits while discrete circuits tend to use resistors more for simplicity (and less availability of matched transistors).
How does a CMOS differential amplifier work?
It may operate in two modes: common mode and differential mode. The common method produces a zero voltage output result while the differential mode produces a high voltage output result. When the two input voltages are unequal, the amplifier produces a high voltage output.
What is active load?
In circuit design, an active load is a circuit component made up of active devices, such as transistors, intended to present a high small-signal impedance yet not requiring a large DC voltage drop, as would occur if a large resistor were used instead.
Which circuit is used as active load for an amplifier?
current mirror circuit
Usually, this “active load” takes the form of a current mirror circuit, behaving as a current regulator rather than as a true current source. Explain why the presence of an active load results in significantly more voltage gain than a plain (passive) resistor.