Switching power supply control system of multiple voltage levels

Abstract

The invention discloses a switching power supply control system of multiple voltage levels, and relates to electronic technology. The system comprises a first level voltage adjusting module, a second level voltage adjusting module, a low-voltage control module and a high-voltage control module, wherein the first level voltage adjusting module comprises a feedback circuit consisting of a depletion metal oxide semiconductor field effect transistor (MOSFET) device and an operational amplifier, and the source of the depletion MOSFET device is the output end of the first level voltage adjusting module; and a level conversion circuit is connected in series between the low-voltage control module and the high-voltage control module, and the level conversion circuit is also connected with the output end of the first level voltage adjusting module and the output end of the second level voltage adjusting module. The system can provide higher driving voltage at the same time of ensuring the control precision and broaden the model selection range of an external power device.

Description

technical field [0001] The present invention relates to electronic technology, in particular to integrated circuit technology. Background technique [0002] AC / DC switching power supply (SMPS) is widely used. AC / DC directly rectifies, filters and adjusts the grid voltage, and then stabilizes the voltage by the switching regulator, without the need for a power transformer; the switching frequency is tens of kilohertz, and the filter capacitor, The inductor value is small. Therefore, the AC / DC switching power supply has the characteristics of light weight and small size. When the grid voltage varies from 110V to 260V, a stable output voltage can be obtained. The working voltage of the SMPS control circuit part is low voltage (generally about 5V), so a step-down process is required between the grid voltage (220V) and the control voltage (5V). At present, more processing methods are to use resistors to step down to obtain a single-voltage power supply system, such as figure ...

AI Technical Summary

Problems solved by technology

However, the voltage driving the external power transistors 8 and 9 is also low voltage, so when selecting an external power transistor, it is required not to select a device with a high threshold

Because low voltage cannot fully drive power transistors with higher thresholds, in other words, the selection range of power devices is limited

Images