The linear voltage regulator achieves the purpose of voltage regulation by controlling the voltage drop VDD (ie the voltage difference) of the regulator tube through a control circuit composed of output voltage feedback and an error amplifier. The principle block diagram is shown in Figure 1. The characteristic is that VIN must be greater than VOUT, and the adjustment tube works in the linear region (the linear regulator gets its name from this). When the change of input voltage or the change of load current causes the output voltage to change, the size of VDO is changed through the feedback and control circuit, so that the output voltage VOUT is basically unchanged.
The working principles of ordinary linear regulators and LD0 are the same, the difference is that the structure of the adjustment tube used by the two is different, so that the voltage difference of L D0 is smaller and the power consumption is lower than that of ordinary linear regulators.
The linear voltage stabilizer used in some liquid crystal displays has an output control terminal, that is, the output voltage of this type of voltage stabilizer is controlled by the control terminal. EN (sometimes represented by the symbol SHDN) is the output control terminal. Generally, the low level (or high level) is added by the microprocessor to turn off (or work) the LDO. When the power is turned off, the current is about 1μA.
