Popular Science | Power Management Knowledge
Power management integrated circuits (PMICs) are particularly important in battery-powered electronic devices, including smartphones and wearable devices, due to their small size, high efficiency and design flexibility.
Figure 1 : Batteries can be connected in different ways to provide different current and voltage outputs.
The type of power source that an electronic device uses depends on the type of power management subsystem. These sources include AC, DC, or ultra-low power DC sources, such as solar. Many devices have DC power from a single battery or a battery pack containing multiple cells. These batteries can be connected in different ways to provide different current and voltage outputs. In the example in Figure 1 :
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Using series connected batteries can increase the peak voltage and capacity of the battery pack.
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Using parallel cells does not increase the voltage of the battery pack, but it can increase its overall current capability and capacity.
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Using both series and parallel connections can increase voltage, current, and capacity.
In some battery-powered applications, system components may not be able to use battery power directly, and DC-DC converters are needed to monitor and stabilize the voltage supplied to the system. These converters, also known as voltage regulators, stabilize the supplied voltage. Voltage regulators can be divided into two types based on the voltage conversion method.
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Linear regulators use linear (resistive) components to stabilize V out , converting an input voltage (V in ) to a different output voltage (V out ). They are typically used in low power output applications. Linear regulators achieve low noise outputs, which are suitable for sensitive analog components such as sensors. However, the disadvantage is that they are not very efficient.
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In contrast, switching regulators are efficient, flexible, and small, but they emit high-frequency noise. Switching regulators use field-effect transistors (FETs) to convert a DC input voltage into an AC waveform, which is then converted to a different DC output voltage using capacitors and inductors.
Switching regulators are classified according to the relationship between their input and output voltages.
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Step-down switching regulator : V out is lower than V in .
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Boost switching regulator : V out is higher than V in .
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Buck - boost switching regulator: V out is variable: it may be lower, higher, or equal to Vin .
Figure 2 below compares four commonly used regulator topologies: low dropout linear regulator (LDO) and three switching regulators (buck, boost, and buck-boost).
Figure 2 : Comparison of four common regulator technologies.
Today's PMICs can handle many or even all of the voltage regulation functions required in electronic devices.
A PMIC is a small, multifunction integrated circuit that implements voltage conversion, voltage regulation, and battery management ( Figure 3 ). Today’s PMICs can handle many or even all of the voltage regulation functions required in electronic devices. They can be used in different applications with simple changes to firmware or register settings, without costly hardware changes. This helps develop new applications faster and at a lower cost.
Figure 3 : A PMIC is a small, multifunction integrated circuit that implements voltage conversion, voltage regulation, and battery management.
PMICs are used in many different industries and product types. They can provide a variety of functions, including charging, power loss protection, and DC-DC voltage conversion and regulation. PMICs are small in size and low in power, and can be used in many small devices such as wearables; hearables (such as earbuds), mobile devices, sensors; and Internet of Things (IoT) devices. They can significantly improve the performance and efficiency of products, increase their design flexibility, and reduce bill of materials costs, helping manufacturers reduce total costs and accelerate time to market.
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