One of the factors that must be considered for quiescent current low-power products of power chips
Friends who have just started their electronic design career have noticed that you have to jump out of the ideal world of physical laws into the real world. Before reading this article, let's figure out the fact that the power chip on your board also has power loss.
Each circuit board has a power chip, whether it is a linear power chip or a switching power chip, which is lossy. In general, the loss of the switching power supply chip is much smaller than that of the linear power supply chip. However, the switching power supply chip has a larger noise than the linear power supply chip. Therefore, when designing products, you need to consider specific projects.
The static current that this article says, in a nutshell, is the current that the power chip outputs directly to ground, not the current that supplies the load, which is the current it consumes.
Because the power chip is in the circuit, it only plays the role of voltage regulation and does not participate in the realization of the function of the circuit board. Therefore, we ideally hope that the power chip itself does not have loss, but in fact, it is definitely lossy, we generally Use the "quiescent current" indicator to determine the loss of the power chip itself.
The quiescent current of the most commonly used regulator chip 7805 is shown in the figure below. The 8mA quiescent current has been abandoned by low-power products.
Below is the quiescent current of the AMS1117, 10mA quiescent current, and the 7805 is a level.
Seeing no, these conventional power chips, in addition to their large size, have large quiescent currents and are not suitable for low-power applications.
Let's look at the quiescent current of a power chip TLV70033, as shown below:
The quiescent current of 31 microamps is really low compared to the previous two chips.
Here we have to pay attention, in some chip manuals, it is not necessary to use quiescent current to indicate quiescent current, and also use Ground current to indicate. For example, in this TLV70033 manual, Iq is used to indicate the quiescent current. As shown in the above figure, Ignd is used later. As shown in the figure below, it is not necessary to investigate the difference between their two names.
Finally, we recommend an ultra low power LDO chip: XC6206, quiescent current 1 microamp.
Low Power ConsumpTIon means low power consumption.
Here you also see that the continuous current is used to indicate the quiescent current.
Note: quiescent current is not the only factor for low power considerations, but also factors such as "conversion efficiency."
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