This section explains how to decide whether to use a linear voltage regulator or a switching DC/DC converter.
First, let’s review the advantages and disadvantages of the linear voltage regulator.
Linear voltage regulator advantages
- The design is simple, operating by only connecting capacitors to both the input and output sides.
- Low noise
- Few components, saves space
- Low price
- There are many products, making it easy to select an optimal one.
Linear voltage regulator disadvantages
- The loss is large and the efficiency poor when there is a large difference between the input voltage and the output voltage.
- A large amount of heat is generated when the difference between the input voltage and the output voltage is large, so measures to dissipate the heat are required.
- Only step-down operations (lowering the voltage) are possible.
To determine whether to use a voltage regulator or a switching DC/DC converter, if the voltage regulator disadvantages can be tolerated, then selecting the linear voltage regulator is the optimum option.
The conditions for using a switching DC/DC converter are as follows.
In all other cases, using a linear voltage regulator is best.
Conditions when a DC/DC converter should be used
(a)Power supply configuration
- A power supply configuration other than step-down (step-up, step-up/down, polarity reverse) is required.
- A voltage regulator cannot be used due to the heat generated in the IC.
- Overall system heat generation must be kept down.
- It is desirable that heat countermeasure components, such as a heat sink, to lower the cost and save space used by the overall system.
(c)Loss and efficiency related
- Reducing the voltage regulator loss is desired to increase the battery operation life.
- Using a high efficiency DC/DC converter is required to reduce the overall power consumption of the device.
|Simple to design||Good||Normal|
|Number of parts/space saving||Good||Normal|
|Power supply configuration||Step-down||Step-down/Step-up etc|