IC 723 as a Voltage Regulator

The IC 723 is primarily used as a voltage regulator. It is a versatile and reliable integrated circuit (IC) that is designed to provide stable and regulated voltage output. The IC 723 is widely used in various electronic applications due to its excellent performance characteristics and ease of use.

Additional Information
 Applications of IC 723

The IC 723 is used in a wide range of electronic applications where a stable and regulated voltage is required. Some common applications include:

• Power supply circuits: The IC 723 is used in power supply circuits to provide a stable and regulated voltage output for various electronic devices and systems.
• Battery chargers: The IC 723 is used in battery charger circuits to regulate the charging voltage and ensure safe and efficient charging of batteries.
• Voltage reference circuits: The IC 723 can be used as a voltage reference in precision measurement and instrumentation applications.
• Voltage regulators for microcontrollers: The IC 723 is used to provide a stable and regulated voltage supply for microcontrollers and other digital circuits.

Conclusion

In conclusion, the IC 723 is primarily used as a voltage regulator. Its versatility, stability, and ease of use make it an ideal choice for a wide range of electronic applications. The IC 723 provides a stable and regulated output voltage, making it suitable for power supply circuits, battery chargers, voltage reference circuits, and voltage regulators for microcontrollers.

Explanation:

To determine the correctness of the given statements about the IC 723 voltage regulator, we need to understand the specifications and characteristics of the IC 723.

IC 723 Overview:

The IC 723 is a versatile voltage regulator IC used for both positive and negative voltage regulation. It can operate over a wide range of input voltages and can be configured for different output voltage ranges and current outputs. The IC 723 is known for its reliability and flexibility in various power supply designs.

Specifications of IC 723:

• Output Voltage Range: The IC 723 can be configured to provide an output voltage range from 2 volts to 37 volts. This is achieved by adjusting the external components connected to the IC, such as resistors and capacitors.
• Output Current: The IC 723 can deliver an output current of up to 150 mA when used in its basic configuration. However, with the addition of an external pass transistor, the output current can be increased significantly, depending on the specifications of the external transistor.

Analysis of Statements:

• S1: The output voltage ranges from 2 to 37 volts.
• S2: The output current is up to 150 mA.

Based on the specifications of the IC 723, we can analyze the correctness of the statements:

• S1: This statement is correct because the IC 723 can indeed provide an output voltage range from 2 to 37 volts by adjusting the external components.
• S2: This statement is also correct because the IC 723 can deliver an output current of up to 150 mA in its basic configuration. The output current can be increased with the use of an external pass transistor, but the statement specifies the basic configuration.

Conclusion:

Since both statements S1 and S2 are correct, the correct answer is option 1, which states that neither S1 nor S2 is incorrect.

Important Information:

The IC 723 is highly versatile and can be used in various voltage regulation applications. Here are some additional points to consider:

• The IC 723 includes an internal reference voltage source, error amplifier, series pass transistor, and a current limiting circuit.
• It can be used to design both linear and switching regulators.
• The output voltage can be adjusted using external resistors connected to the voltage adjustment pins of the IC.
• The IC 723 can operate with input voltages up to 40 volts, making it suitable for a wide range of power supply designs.
• For higher current applications, an external pass transistor can be added to boost the output current capability of the IC.
• Thermal protection and current limiting features enhance the reliability and safety of the IC 723 in various applications.

In conclusion, the IC 723 is a reliable and flexible voltage regulator IC suitable for a wide range of applications, offering an output voltage range of 2 to 37 volts and an output current of up to 150 mA in its basic configuration. Both statements S1 and S2 are correct, making option 1 the correct choice.

The output voltage of an IC 7905 is −5 V.

Explanation:
The 79XX series (e.g., 7905, 7912, 7915) are negative voltage regulators.

7905 provides a regulated 5V output.

Similarly:

• 7905 → −5V
• 7912 → −12V
• 7915 → −15V

Concept:

Series Voltage Regulator:

A series voltage regulator passes altering current through a series element to manage voltage drop.
The series transistor in these regulators is driven by the error amplifier which continuously adjusts its resistance in order to maintain a constant output voltage even if the input voltage or load current varies.
Shunt Voltage Regulator:

A shunt regulator works by providing a path from the supply voltage to the ground through a variable resistance.
The shunt regulator maintains the voltage across its output terminal at a fixed value by varying its resistance in response to input or output voltage changes.
The term shunt is used because the regulation element is placed parallel (electrically shunted) with the load.
Adjustable Voltage Regulator:

Adjustable voltage regulators have an extra input called an "adjust pin" through which the output voltage can be adjusted by placing a desired value of resistor between this pin and ground.
An adjustable voltage regulator is a kind of regulator that can be manually set to produce the desired DC output.
Switching Regulator:

Unlike linear regulators, a switching regulator adjusts the conversion ratio by modulating the energy input to the system, that is, it's continuously turns the input current on and off, and utilizes an inductor, capacitor, and diode to store and transfer energy to the output.
Switching regulators are noted for their high efficiency as compared to linear regulators.
However, they can generate more noise due to their switching operation and require more components, making them more complex.

• We need a full wave rectifier to convert AC to DC.
• The output of the rectifier will be positive cycles of the applied input AC voltage.
• A RC filter will be required to convert the positive cycles to ripples.
• The output of the combination of the two circuits will be ripples.
• Finally, to get a steady value of DC, we need a voltage regulator (that can be built with the help of a Zener diode) so that the output remains constant.

The device used for the voltage regulator is a Zener diode

Voltage regulator:

It is used to regulate the voltage level. It generates a fixed output voltage that remains constant for any changes in load conditions or input voltage.

Zener diode:

• It is PN junction (silicon PN junction) diode and has a low specified reverse voltage which takes advantage of any reverse voltage applied to it.
• Unlike a normal diode (Schottky diode, varactor diode, tunnel diode) that blocks any flow of current through itself when reverse biased.
• From the I-V characteristics curve above voltage across the diode in the breakdown, the region is almost constant.
• In the breakdown region, it can be used as a voltage regulator applications.

Schottky Diode:

• The Schottky diode is a semiconductor formed by the junction of a semiconductor with metal. It has a low forward voltage drop and near-zero reverse recovery time hence used in very fast switching circuits.
• Schottky barrier diode can be used as a low noise amplifier due to metal-semiconductor junction.

Tunnel diode:

• A tunnel diode is a highly doped semiconductor diode.
• The tunnel diode shows negative resistance when the voltage value increases by decreasing the flow of current. Tunnel diode works based on the tunnel Effect.

Tunnel diode is represented by the symbol

Varactor Diode:

• Varactor diode refers to the variable Capacitor diode, which means the capacitance of the diode varies linearly with the applied voltage when it is reversed biased.
• Varactor diode is commonly used for Electronic tuning.

It is represented by a symbol of diode terminated in the variable capacitor as shown below:

A transistor is connected as a power switch and is operated in the saturated mode.

Thus, the pulse generator output alternatively turns the switch ON and OFF in the switching regulators.

Differences between Transistor and Relay are as follows:

Concept: 

Efficiency is given by:

\(\rm η=\dfrac{output\ power}{input\ power}× 100\%\)

Calculation:

If we the circuit

total current supplied by source (I) = I_zmin + I₂ = 2.3 + 2 = 4.5 A

input power = V_IN × I = 29 × 4.5 = 130.5 W

output power at load = V_L × I_L = 16 × 2 = 32 W

efficiency (η) = \(\dfrac{32}{130.5}\times100=24.52\%\)

IC 723 is used as an op-amp voltage regulator.

Specifications of 723 IC:

• Output voltage range: 2 V to 37 V
• Output current: up to 150 mA
• Max supply voltage: 40 V
• Line regulation: 0.01%

Voltage regulator: 

It is used to regulate the voltage level. It generates a fixed output voltage that remains constant for any changes in load conditions or input voltage, i.e. it regulates or maintains a constant dc output voltage in spite of the fluctuations in ac input voltage or load current.

Voltage regulation is a measure commonly used to describe the percentage voltage difference between no-load and full load voltages to the full load voltage for electrical machines.

\(V.R. = \frac{{{V_{nl}} - {V_{fl}}}}{{{V_{fl}}}} \times 100\)

• The ideal voltage regulation for any machine should be zero.
• Zero voltage regulation indicates that there is no difference between its no-load voltage and its full-load voltage.
• This is not practically possible and is only valid theoretically for ideal machines.
• Therefore, for the practical application, it should be as low as possible for the proper operation of the electrical devices.

Fixed-Positive Voltage Regulator:

The series 78XX regulators are the three-terminal devices that provide a fixed positive output voltage.

IC 7805:

7805 is a voltage regulator IC which is used to provide a constant output voltage of 5V.

The last two terms (78  05) denote the output voltage of the Regulator.

Specifications of 7805 IC:

• Drop out voltage = 2 V
• Input voltage range = 7V- 35V
• Current rating Ic = 1A
• Output voltage range V_MAX = 5.2V, V_MIN = 4.8V

Fixed-Negative Voltage Regulator:

• The series 79XX regulators are the three-terminal IC regulators that provide a fixed negative output voltage.
• This series has the same features and characteristics as the series 78XX regulators except for the pin numbers which are different.

​Negative-Voltage regulators in the 79XX series are as shown:

V_P = -18V

V_N = 0

V_P – V_N = -18 V so zenor diode will work in Breakdown Region It will act as a constant voltage source.

V_B = 24.2 V

V_E = V_B – 0.7 = 24.2 – 0.7

= 23.5 V

\(I = {I_C} = {I_E} \simeq \frac{{23.5 - 18}}{{1.8}}\)

≃ 3.05 mA

Voltage regulator: It is used to regulate the voltage level. It generates a fixed output voltage that remains constant for any changes in load conditions or input voltage, i.e. it regulates or maintains a constant dc output voltage in spite of the fluctuations in ac input voltage or load current.

Zener diode: Zener diode is a device widely used in voltage regulator circuits.

• It is PN junction (silicon PN junction) diode and has a low specified reverse voltage which takes advantage of any reverse voltage applied to it.
• Unlike a normal diode (Schottky diode, varactor diode, tunnel diode) that blocks any flow of current through itself when reverse biased.
• From the I-V characteristics curve above voltage across the diode in the breakdown, the region is almost constant.
• In the breakdown region, it can be used as a voltage regulator applications.

Voltage Regulator:

It is an electronic circuit that gives a smooth output voltage. Smooth voltages are most important for the working of digital circuits.

An IC-based voltage regulator can be classified in different ways.

The 3 terminal IC voltage regulator block diagram is shown below:

• IC linear voltage regulators use an active pass element to reduce the input voltage to a regulated output voltage.
• IC switching voltage regulators store energy in an inductor, transformer, or capacitor and then use this storage device to transfer energy from the input to the output in discrete packets over a low-resistance switch.
• DC/DC converter chips, the third type of IC voltage regulators, also provide a regulated DC voltage output from a different, unregulated input voltage.

Conclusion: In a linear IC voltage regulator, the series pass transistor always operates in the active region.

Explanation:

Voltage Regulator:

1. It is an electronic circuit that gives a smooth output voltage. Smooth voltages are most important for the working of digital circuits.

2. An IC-based voltage regulator can be classified in different ways.

3. The 3 terminal IC voltage regulator block diagram is shown below:

Switching regulator:

• It is a voltage regulator that uses a switching element to transform the incoming power supply into a pulsed voltage, which is then smoothed using capacitors, inductors, and other elements.
• Power is supplied from the input to the output by turning ON a switch (MOSFET) until the desired voltage is reached.
• Once the output voltage reaches the predetermined value the switch element is turned OFF and no input power is consumed.
• Repeating this operation at high speeds makes it possible to supply voltage efficiently and with less heat generation. Hence series regulator has reduced power dissipation and increased efficiency.
• There are three types of Switching voltage regulators: Step up, Step down and Inverter voltage regulators.

So option (3) is the correct answer.

Important Points

There are three type of voltage regulators:

• IC linear voltage regulators use an active pass element to reduce the input voltage to a regulated output voltage.
• IC switching voltage regulators store energy in an inductor, transformer, or capacitor and then use this storage device to transfer energy from the input to the output in discrete packets over a low-resistance switch.
• DC/DC converter chips, the third type of IC voltage regulators, also provide a regulated DC voltage output from a different, unregulated input voltage.