Last revised: November 25, 2024

Reviewed by: Scott Orlosky, consulting engineer

Integrated circuit (IC) power supplies receive an unregulated input and provide a regulated output voltage.  They take unregulated input, change and/or regulate it to another voltage level, and output the adjusted power. Using a regulated IC power supply ensures the safety and efficient use of circuitry that requires a narrow voltage range for proper operation.

Product Specifications

Important specifications when selecting IC power supplies include:

• Input voltage (V_IN) ranges (e.g., 0.95 to 14 volts).
• Output voltage (V_olt) can be fixed (e.g., 4 or 12 VDC) or adjustable, regulated or unregulated, and of the same or opposite polarity. The output has a tolerance - a guarantee that it will remain within a certain range.
• Output current (I_out) range (e.g., 0.017 to 5 amps).
• Quiescent (operating or ground) current (I_Q) powers the regulator itself without any devices attached. Ranges are specified (e.g., 0.00014 to 0.85 amps).
• Power supplies are designed to operate in a certain ambient temperature range (e.g., -40 to 85 C).

For switching types of power supplies:

Switching frequency (f_sw) ranges (e.g., 112 kHz to 96 mHz)

Efficiency (including the duty cycle) can be a certain percentage (e.g., 74%,or 87%).

Features

IC power supplies are available with a variety of features as listed below.

• Shutdown (inhibit) pins disable the output.
• Protective measures guard against reverse voltage, input overcurrent, or thermal shutdown for protection against over heating
• An error flag alert when output has dropped (generally 5%) below its nominal value.
• Multiple outputs, sometimes with provisions for different connectors
• Synchronous rectification uses MOSFETS to improve performance and reduce heat generation.

Applications

IC power supplies are found in computing, medical, military, telecommunications, and industrial equipment; indeed, anywhere a circuit board is used.

IC Power Supplies FAQs

How do different types of IC power supplies impact the efficiency of electronic devices?

Switch Mode Power Supplies (SMPS)

SMPS are generally more efficient than linear power supplies. This is because they use switching elements (like transistors) that operate in either cut-off or saturation mode, minimizing power dissipation. When the switch is OFF, the current is almost zero, and when it is ON, the voltage is very small, leading to minimal power consumption in both states.

SMPS designs result in smaller power supplies due to the high switching frequency, which allows for smaller inductors and capacitors.

Linear Regulators

Linear regulators, such as Low Dropout Regulators (LDOs), are often used for localized regulation at lower current levels. However, they are less efficient compared to SMPS since they dissipate excess power as heat.

Reducing the power dissipation in modern LDOs by localizing their use can lower the thermal budget. This helps the overall thermal management of the device.

Combination of Both

Some ICs combine both switching regulators and linear regulators to leverage the benefits of each. For example, a switcher can handle the bulk power conversion efficiently, while a linear regulator can provide clean, low-noise power to sensitive analog circuits.

Load Conditions

Light loads: Power supply control ICs are designed to offer better light-load energy efficiency, which is crucial for devices that spend a significant amount of time in low-power states.

Duty Cycle: The efficiency of power supplies can also depend on the load's duty cycle. For instance, the efficiency of most switchers drops rapidly when used at less than about 60-80% of their rated load.

Environmental and Regulatory Impact

Efficiency regulations, such as those from the U.S. Environmental Protection Agency (EPA), have driven the development of more efficient power supplies, reducing overall energy consumption and carbon emissions.

In summary, the choice of IC power supply—whether it is a switch mode power supply, a linear regulator, or a combination of both—can have a significant impact on the efficiency of electronic devices. The specific application and load conditions will often dictate the most suitable type of power supply to use.

What are the challenges associated with using IC power supplies?

One common challenge is ensuring that the power supply provides the exact voltage required by the IC, as deviations can affect performance. Additionally, managing the transition between different load conditions (e.g., light-load to full-load) can be tricky.

What are some common issues with IC power supplies and how can they be addressed?

Issues such as surge current, leakage current, and grounding problems are common. Proper design and testing can mitigate these issues.

Can IC power supplies handle no-load or light-load conditions?

Yes, some power supplies are designed to handle no-load or light-load conditions efficiently. For example, certain DC/DC converters are capable of operating under these conditions.

What are the common voltage requirements for ICs?

Most ICs today require 5V, 3.3V, or even 1.5V DC, which is significantly lower than the 120V AC commonly available from wall sockets.

What is leakage current and how does it affect power supplies?

Leakage current is the small amount of current that flows through the insulation or dielectric materials in a power supply. It is important to minimize leakage current to ensure safety and efficiency.

What is the role of mixed-signal microcontrollers in IC power supplies?

Mixed-signal microcontrollers are designed to deliver exceptional processing performance at the lowest supply currents, making them desirable for portable device designs that require high performance and reliability within strict power and cost budgets.

IC Power Supplies Media Gallery

References

GlobalSpec—Circuit Design Know it All

GlobalSpec—Computer Power Supplies

Image credit:

Fuji Electric Corp. of America